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View Full Version : Head debate please, I got some flow numbers



V8Supercoupe
10-13-2005, 11:10 AM
Well, I picked up some heads that were said to have been worked, but there is a slight bit of confusion on my end. I have brought them to a reputable gentleman who flowed them and he has given me some options, but I could really use some advice from you guys. Especially Dave, Dave, Damon, the usual argumentitive controversial bunch! :D

To start:

Lift/intake/exh.
200- 74 - 86
300- 96 - 123
400- 112- 158
500- 124 - 183
600- 146 - 198

Now the confusion. Based on Coy's site my intake side is flowing less than stock? How the hell can that be? I guess it could be a botched port job. :rolleyes:
Onto the advice needed. I talked to this gentleman about what he could do.

Our conversation went from big this and big that to actually talking more about what the air was going to do while entering and exiting. He went on to talk about the exhaust end and how bad it is. He leaned heavily away from welding it and reshaping, although he didn't deny it could be a decent idea, I guess he was just thinking that unless your going for every drop of HP, it's not worth it. The valves he was saying were not too good due to their shape and could be improved upon using Chevy style valves.(I guess they are close to our application) Anyhow, Makes sense to me.
I guess I am trying to get a feel for what I should do. Some of you guys are turning 220-ish intake and 220-ish exhaust and the way he is talking I am not thinking I will get close to that if he does the work. I suppose I am naive, although I do trust the guy, he gives me absolutley no reason to doubt him. The work he has done for others is top knotch, so my gut says to go for the work he wants to do.
Do you guys have any recommendations on what to ask for? What to look for, or how I should have something done?

Skip

sizemoremk
10-13-2005, 01:41 PM
When I did the work to my heads, I was contemplating having the heads flowed; but I found by reading here, that most shops don't have the proper bore size to correctly flow a set of our heads. They can "rig something up" but its only good for future reference on the same bench, with identical
"rigging" i.e. you would have to have flowed them im stock form prior to the porting to know what the relative improvemnets were...

Somewhere I read Coy Miller was the only shop that had the proper setup, but I'd think someone else has our 3.8 setup somewhere...


So if there was supposedly "port work" done to them you might want to consider getting another set of stockers to compare, contrast, and possibly flow again...

I didn't flow mine becasue I would have had to pay for them to be flowed twice, and the numbers wouldn;t mean that much anyways...

The real numbers are on those little little slips they hand out at the end of the 1/4 :D

V8Supercoupe
10-13-2005, 02:07 PM
Well I suppose. The numbers seem real whacky to me. I know this particular person probably isn't setup exactly the way he should be for our heads, but I suppose it's a starting point anyway.
Even if he isn't setup for our heads, it's still is odd that the exhaust is so much higher than the intake. He wants(I want) him to report/polish and drop all new, larger valves. He is obviously concerned more about airflow pattern then he is size of the portwork. I suppose that's good, and I know he is going to hog them out a bit more, I just don't know how much more of a dramtic effect it will make.

sizemoremk
10-13-2005, 02:29 PM
Well I've been suggested to maintain the stock intake valve, and only enarge the exhasut valve. So this is the route I went. I got 1.625 SBC exhaust valves in the heads at the shop now..

The intake is already gonna be compressed, and even (effectively) more so in my case as I'm gonna be hitting the bottle. I'm not sure what a rule of thumb I:E ratio is for an N/A heads is gonna be, but the ratio has got to be differnet in a FI application, particularly at higher boost levels and N2O...

V8Supercoupe
10-13-2005, 03:14 PM
Well, that's brings up a good point considering I am wanting(wanting) to run a higher than normal boost level and run a small shot to cool the intake charge.

92strokedbird
10-13-2005, 03:19 PM
I believe that the best you can do with our heads is a I/E ratio of 93%.These #'s are from Coy Miller Stage II heads with a 1.62" valve.Even if the shop did not have the proper diameter pipe to flow thru,you should have seen better than stock #'s.That is why it's important to see flow #'s when you get a set of heads ported,so you can be there to see the #'s not just be quoted them(and take their word for it).

Conan56
10-13-2005, 03:19 PM
Those exhaust flow numbers are very good for No welding (Prob about as good as you can get )

I couldnt even guess why the flow numbers are so low for Intake side
The intake Just requires some reshaping to acheive decent numbers


Those numbers do Indeed seem a lil wacky to me also

lube70
10-13-2005, 03:21 PM
Very easy to screw up porting....I will say though that those intake numbers are VERY LOW>>>>>

I feel that the flow bench they were using was not set up properly.

The exhaust numbers are impressive for not doing any other work besides porting and blending.

V8Supercoupe
10-13-2005, 03:28 PM
Well, I have no doubt this guy can neaten things up, I just don't want to get talked into something less then what I could get for the money.
I always hear the stories about the guys who are real good with the V8 cars but seem to apply that same knowledge to a 6. I have heard a lot of people say that just doesn't work. When it comes to heads I don't know what the difference is, you'd think the basic concept is all the same.

XR7 Dave
10-13-2005, 03:36 PM
A lot of people post things of which they know very little. I'd take some of the things you read on this site with a grain of salt. There is a short list of people on here whose opinions I personally trust when it comes to headwork.

Regarding the heads in question, unless the heads received an absolute hack job, the intakes will flow better than the exhausts. Perhaps someone got the numbers mixed up?

Also, Coy is not the only one with the proper equipment to flow test our heads, but regardless flow numbers are just that. Numbers.

Good flowing heads can be generated at any shop with a decent porter who has flowed heads before and knows what a good port/chamber looks like. It is not necessary to try to achieve Bob Steigemeier flow numbers anyway. Marc Petillo proved that at the SC shootout this year with heads that I ported for him with no flow numbers or even any verifieable "experience".

His car made 290rwhp and ran 104mph in the 1/4 on an early style blower that I also ported for him in my garage. My only point in saying any of that is that "uber cool" heads are not going to make the difference between making power and not. I could go on and on but you'd get tired of hearing about it. :p

Regarding valve sizes, you are limited to the diameter of the stock seats which means that if your machinist is worth his metric weight he should be able to tell you what sizes to run just as quickly as he can pop a valve out and look at it.

Oh, and 1.625 E is way too big. ;)

V8Supercoupe
10-13-2005, 04:03 PM
I could go on and on but you'd get tired of hearing about it.
I doubt it, I am more likely to talk your ear off about it.....
er..but I guess that won't happen cause I can't get someone to call me! :p :D

This guy did rattle off this and that, I don't understand whats what, but he rolled off some chevy valves that he said would open things up. How much I don't know....This isi one of these deals where the guy has a good reputation, but I am trying to apply what I have heard and not what I know.

I'll at least be honest about that.

S_Mazza
10-13-2005, 04:36 PM
Why not grab a set of stock heads and ask him to flow-test them for reference?

007_SuperCoupe
10-13-2005, 04:37 PM
It is not necessary to try to achieve Bob Steigemeier flow numbers anyway. Marc Petillo proved that at the SC shootout this year with heads that I ported for him with no flow numbers or even any verifieable "experience".

His car made 290rwhp and ran 104mph in the 1/4 on an early style blower that I also ported for him in my garage. ;)

David,
Did you change the valves on those heads you ported? I'm not trying to get any trade secrets, but an trying to better uderstanding just like others. The machinist that I'm going to use for my head project is very familiar with Ford heads and has produced exhaust flow numbers close to Stieg heads without the welding. I just want to know if I can achieve good power numbers by re-working the stock valves, or if I should go a bit larger. I don't want to hijack the thread here, but I do think that this is relavant. Although my power level goals may be different, I think that we can all benefit from additional information.

Basically what I'm looking for is 1)what type of "generalized" power levels can we expect from porting/reworking the bowls, runners etc with a 3 and 5-7 angle vlave job on the stock valves?

2) What type of power levels can we expect by going to a larger set of valves?

Obviously, cam selection would play a very large role in determining power levels of different types of heads. I would request known combinations that you have tuned, worked on, etc so we have real world type information, not just numbers from a flow machine. I think that would give everyone looking at this some information as to guide them to making better decisions based upon power goals and current applications. Thanks.

V8Supercoupe
10-13-2005, 04:53 PM
Why not grab a set of stock heads and ask him to flow-test them for reference?

Well, I suppose I don't feel like spending the 50 bux to do it.

Skip

CMac89
10-13-2005, 05:19 PM
With the experience I had with porting my own heads, all the humps, rigidities, and all other casting marks being removed along with gasket matching helps alot more than you think.

A ported, stock valve, nonwelded head would be good enough for 12's. Port shape, cross sectional area, turn radius, and valve size are all relavent to eachother in terms of flow/velocity. In my experience in the porting of high performance heads, whether its pro stock, SuperStock, and even stock, flow numbers had their biggest jump in flow numbers with valve size.

The valve seat angles are very important also. In my superstocker I picked up 22cfm on stock sized valve going from 30 degrees to 58 (highest valve angle recommended to go to on any head) and unschrouding the valves.

Anyway, back to the SC heads, the exhaust port talk is all wack, nonetheless, overrated. All thats really needed is to clean up the casting marks and polish it. The port has a really short turn and the length of valve to flange is very short. Just manipulate this with headers. If i'm not mistaken, I remember a while back reading Kevin L. has stock exhaust ports.

sizemoremk
10-13-2005, 06:14 PM
Oh, and 1.625 E is way too big. ;)

You mentioned this to me at some point before, and never did elaborate :mad:

I've been worrying about it now, but its too late, the new seats have already been installed....

Why do you say that the 1.625 is too big :confused: :confused: :confused:

XR7 Dave
10-13-2005, 06:28 PM
David,
Did you change the valves on those heads you ported? I'm not trying to get any trade secrets, but an trying to better uderstanding just like others. The machinist that I'm going to use for my head project is very familiar with Ford heads and has produced exhaust flow numbers close to Stieg heads without the welding. I just want to know if I can achieve good power numbers by re-working the stock valves, or if I should go a bit larger. I don't want to hijack the thread here, but I do think that this is relavant. Although my power level goals may be different, I think that we can all benefit from additional information.

Basically what I'm looking for is 1)what type of "generalized" power levels can we expect from porting/reworking the bowls, runners etc with a 3 and 5-7 angle vlave job on the stock valves?

2) What type of power levels can we expect by going to a larger set of valves?

Obviously, cam selection would play a very large role in determining power levels of different types of heads. I would request known combinations that you have tuned, worked on, etc so we have real world type information, not just numbers from a flow machine. I think that would give everyone looking at this some information as to guide them to making better decisions based upon power goals and current applications. Thanks.

Marc's heads have larger valves. There are no trade secrets here. We used 1.88 intakes and 1.50 exhausts and then the seats are formed with a custom selected 3 angle Serdi cutter. Then we add the appropriate hardware on top.

I am not a fan of stock valves at all. Not because they are so bad, but they prevent the use of good valve springs which I feel are necessary for proper operation under high boost conditions.

In our world power comes primarily from boost. The ability to use boost is the key to making power.

Ya, I'm rambling here.

Anyway, a qualified systems approach is the best way to achieve a goal. Select your parts based on solid theory and make sure that they all match up. The end result will make it difficult to say exactly where the power came from, it will just be there. All too often people hone in on one particular part of a successful combination without buying into the whole program.

Kevin's car is an excellent example of a successful combination. No one single part of his car is responsible for his success. It's his careful application of parts which work together that has gotten him where he is.

XR7 Dave
10-13-2005, 06:36 PM
You mentioned this to me at some point before, and never did elaborate :mad:

I've been worrying about it now, but its too late, the new seats have already been installed....

Why do you say that the 1.625 is too big :confused: :confused: :confused:

Because the port itself is the choke point, not the valve, and so a bigger valve is only going to create problems with shrouding.

The stock seats were quite adequate.

Blown 91 Bird
10-13-2005, 06:49 PM
not sure if this has been said... but flow benches will pretty much always give different #'s bench to bench. You will rarely (if ever) find 2 shops that will have benches that will get the same #'s as each other.

For example.. the heads on my company race car from TEA flow I398/E305, on another bench they were only I374/E288, and on another they were only I380/E295. Granted these are just peak numbers which hardly mean ~~~~, and across the board they were all relatively close..but they were still off by 10-15cfm on each bench at .800" lift.

i had a set of TFS-R heads done by TEA and the flow sheet that came back with them were I368/E277 @ .700", but on another bench they only made I345/250 @ .700".. and across the board every number was off by about 12-13cfm.

sizemoremk
10-13-2005, 06:50 PM
Because the port itself is the choke point, not the valve, and so a bigger valve is only going to create problems with shrouding.

The stock seats were quite adequate.


Damnit, you're gonna force me to flow these heads :p

David Neibert
10-13-2005, 08:15 PM
Damnit, you're gonna force me to flow these heads :p

Don't worry about it....I've got 1.625 EX valves and 1.94 IN valves. They probably aren't needed but they aren't flowing less than stock size valves.

I'm getting 232 CFM Intake and 218 CFM Exhaust @ .500

David

XxSlowpokexX
10-13-2005, 08:34 PM
I'd give him a stock head for flow comparisons.


Because the port itself is the choke point

The port is huge..And badly shaped thus why reshaping works so well. But thast much larger valve or a welded port.

Now why I would change the valve is because of shape and like Dave said...To use some decent springs.

A change of valves, a cleanup and a GOOD 5 angle valve job will do WONDERS for flow. An overbore will help with unshrouding but keep in mind when you bore a motor the CR goes up..

Anyways get a stock head...And go back to him and start there...Let us knwo what you get

XR7 Dave
10-13-2005, 09:24 PM
The port is huge..And badly shaped thus why reshaping works so well. But thast much larger valve or a welded port.



The port is shaped like a megaphone. It is large at the outlet but the diameter beneath the the valve (in the pocket) is the choke point. That doesn't mean that the port is literally choked because of the bowl, what it means is that the bowl area is the smallest diameter section of the port and you can't open it up enough to match a 1.625 valve. Anyway, you just plain can't support that big of a valve. The stock seats support all the flow that even a Steig port can generate.

In case anyone wasn't paying attention, Stieg heads use stock seats. :)

When it comes to cylinder head flow big enough is just that - big enough - and bigger than big enough is never better.

Of course that is just my opinion. :)

007_SuperCoupe
10-13-2005, 10:57 PM
Ya, I'm rambling here.


Okay, David. I really think the point of my question was for you to "ramble." Those of us who are not as knowledgeable about head porting (which I would estimate at greater than 85% of sccoa posters) can't really learn much if you guys don't talk about it because it is "rambling" in your minds. Sure you've been there, and done that, but there's a lot who haven't and can learn from it.

I think that you know enough about my SC and how I've modded it to know that I take a "systematic" approach to my SC as well. I don't just throw parts at it and hope it works. I've stayed back and read posts, talked to people smarter than me, etc to educate myself on how to get a very successful combination. I'm ready for the next step now, but I want to know more about that step before I blindly take it.

I know that it does take some time to post lengthy explanations about how to build the proper combination. I also know that you don't have all the time in the world to devote to answering questions regarding this mod or that mod. That said though, it would be nice to see something a little better than "a qualified systems approach," especially since I already subscribe to it.

I know that every SC is going to have it's own formula for success, simply because of the owner's way of wanting to modify it. I know that for me, in order to make the power that I'd like to, heads and cam will be my next serious performance modification. I know that Marc has a great combination. I don't know the specifics of his mods, but I know it works well. He's got roughly the power level that I'm after with my home ported M90. I think that it is attainable to reach that level as well, maybe just a touch more.

Maybe I should consult you off-line about it, but I figure that more people would benefit from it here. Especially since it looks at though V8Supercoupe is looking to get a little more work done to the heads that he has. Hopefully some of the information will help him out as far as what to get done.

V8Supercoupe
10-13-2005, 11:13 PM
I agree with Sam. Definitely helps to talk about this stuff so others can learn.

Anyhow, After talking to Dave a bit, it appears the numbers are actually reversed on this flow sheet which makes a little more sense now. I will also be selling thses heads and taking my spare heads to have them ported. Hopefully I can recoup a little money to pay for some of the new work. I think I will be happier this way, and hopefully someone can pick up a set of mild heads cheap.

CMac89
10-14-2005, 12:10 AM
When you guys talk about flow numbers on these heads are you stating the best flowing ports numbers? Cuz I know that the middle ports wont ever flow the same as the outsides. The ports are actually good size until you get into the valve bowl area.

I know what hurts these heads is there is hardly a cross sectional area and no turn. Theres basically a 90* turn from the port to the entrance of the combustion chamber. Of course i'm talkin about the intake side.

Bigger valves help, but it still generates a poor flow number. I know Niebert has more money in his heads than most of us (maybe all), and if 232 cfm is all that is gained then it is obvious our heads are choked down by the valve bowl design and a little bit of port shape.

The exhaust side is a good sized port, but the valve bowl area and valve size is tiny. I had a hard time gettin the 3/8 bit down in there.

XxSlowpokexX
10-14-2005, 12:12 AM
It's funny...Sometimes I look back at my post sand say..Hey what the hell did I just type...Anywayyyyyyyyyy

See what this guy can do for you. Like Dave said big isnt always better. Big and properly contoured isnt always better either. It all depends where you want to be with your setup. Also what Dave said about the big opening and the small throat of the exhaust port is true..That is one part of the equation of why the exhaust flows poorly..And why raising the floor works so well with these heads. Its more then just flow but velocity thats affected.

If your guy knows what hes doing he should get you pretty good numbers on stock heads using a good valves, some port work and a god valve job. I cant stress the valve job enough. But they will never flow as good as a welded up port.

Another GOOD option is to get a set of later model non splitport 3.8 heads to port. They have thicker decks then standard earlier 3.8 heads and use a skinnier more common valve which coincidently allows better flow through the ports. I believe the heads to get are the 96 and up. It's been awhiel since I looke dinto this but I'm sure you can find mention of them on some of the 3.8 stang boards..Also Matt Maxwell at Comp cams will get you a custom ground cam for your application whatever it may be

Good luck

Damon

V8Supercoupe
10-14-2005, 07:42 AM
Thanks Damon,
I have a cam to go along with these. I have no information on that either. This is my reasoning for having the heads flowed and have the cam checked. I just really want to know where I stand with this stuff before I bolted it on.
I guess there is no reason why I couldn't bolt it on now, I guess I just figure that while they are off I want them to be as good as they could be. Most of my struggle is with my own mindset, if I don't have it in m head that they are as good as they could be, then I would never be happy with them only based upon the constant, "what if's" that run through my mind.....Hope that makes sense.
I'm going to stop back there today with my spare heads and have him port those and try to peddle these. We'll see what happens. Like I was saying to Dave off the boards, there is so much information to read, and it tends to get scrambled up in your mind and I wind up looking for something that's impossible for me to get.

Skip

XR7 Dave
10-14-2005, 09:35 AM
Okay, David. I really think the point of my question was for you to "ramble." Those of us who are not as knowledgeable about head porting (which I would estimate at greater than 85% of sccoa posters) can't really learn much if you guys don't talk about it because it is "rambling" in your minds. Sure you've been there, and done that, but there's a lot who haven't and can learn from it.

I think that you know enough about my SC and how I've modded it to know that I take a "systematic" approach to my SC as well. I don't just throw parts at it and hope it works. I've stayed back and read posts, talked to people smarter than me, etc to educate myself on how to get a very successful combination. I'm ready for the next step now, but I want to know more about that step before I blindly take it.

I know that it does take some time to post lengthy explanations about how to build the proper combination. I also know that you don't have all the time in the world to devote to answering questions regarding this mod or that mod. That said though, it would be nice to see something a little better than "a qualified systems approach," especially since I already subscribe to it.

I know that every SC is going to have it's own formula for success, simply because of the owner's way of wanting to modify it. I know that for me, in order to make the power that I'd like to, heads and cam will be my next serious performance modification. I know that Marc has a great combination. I don't know the specifics of his mods, but I know it works well. He's got roughly the power level that I'm after with my home ported M90. I think that it is attainable to reach that level as well, maybe just a touch more.

Maybe I should consult you off-line about it, but I figure that more people would benefit from it here. Especially since it looks at though V8Supercoupe is looking to get a little more work done to the heads that he has. Hopefully some of the information will help him out as far as what to get done.


Sam, part of the problem with this type of answer is that I am not the guru when it comes to head porting. I could go into detail on how I ported the heads on Marc's car but I'm quite sure I did some things that were not necessary or maybe even wrong so I can't claim to be a teacher for everyone else to follow. I'm a student of the art of porting and you just don't ask a student to teach others. I can help some but there is a limit.

It also remains that I spent a ton of time learning what I have figured out so far. In a perfect universe I could spend another ton of time spelling it out for people here, then spend another ton of time re-explaining it to people when they email me or call me (no offense Skip, :D) and so on. There's just a limit.

Honestly if you really want to learn something about head porting, there are tons of good books already out there. Invest in one of them! What some of the guys here keep alluding to is that 95% of what applies to a SBC is applicable to our application. You won't go wrong if you use those techniques and theories on your heads.

Then once you come armed with that knowledge base and have specific questions about SC heads, there are many people who will be happy to jump up and offer you assistance including myself.

See, now I'm rambling again.


:)

CMac89
10-14-2005, 09:59 AM
I could go into detail on how I ported the heads on Marc's car but I'm quite sure I did some things that were not necessary or maybe even wrong so I can't claim to be a teacher for everyone else to follow.
Did you just do a gasket match and some clean up, or did you change valves too?

XR7 Dave
10-14-2005, 10:22 AM
Did you just do a gasket match and some clean up, or did you change valves too?

I used larger valves, some forming work in the chambers, 3 angle valve job, extensive cleanup and shaping of the bowls, straightened the center port, and gasket matched the intakes. I think I spent about 8hrs on each head.

007_SuperCoupe
10-14-2005, 11:36 AM
Sam, part of the problem with this type of answer is that I am not the guru when it comes to head porting. I could go into detail on how I ported the heads on Marc's car but I'm quite sure I did some things that were not necessary or maybe even wrong so I can't claim to be a teacher for everyone else to follow. I'm a student of the art of porting and you just don't ask a student to teach others. I can help some but there is a limit.

It also remains that I spent a ton of time learning what I have figured out so far. In a perfect universe I could spend another ton of time spelling it out for people here, then spend another ton of time re-explaining it to people when they email me or call me (no offense Skip, :D) and so on. There's just a limit.

Honestly if you really want to learn something about head porting, there are tons of good books already out there. Invest in one of them! What some of the guys here keep alluding to is that 95% of what applies to a SBC is applicable to our application. You won't go wrong if you use those techniques and theories on your heads.

Then once you come armed with that knowledge base and have specific questions about SC heads, there are many people who will be happy to jump up and offer you assistance including myself.

See, now I'm rambling again.


:)

Fair enough...however I guess that some of the specifics of porting aren't needed to get the point across though...I have all the confidence in my machinist that I will get all the performance that I want...however, there are a few variables that would need to be addressed for him to optimize the heads for ourt application. For instance, I'm looking for a durable engine making some somewhere in the ballpark of 300-325 rwhp with my supercharger. I know that I may be pushing it, but that is my goal. That said, a lot of the R & D has been done to what valves work, what springs work, etc. This is information that we are stuck looking for when it's already been done. Thus, re-inventing the wheel.

Now into some more specifics that I was hoping not to go into, but the answers will benefit all who see this thread. David, you've done a lot of tuning on a lot of different cars. You have seen many more different applications than many of us. You are also one of the most respected members of this organization. So there are a lot of people who listen very intently to your comments. That's not saying that others are not valued or don't know more than you. I'm just drawing on your experience of seeing so many different applications to get an idea of what works really well.

Cam and head go hand-in-hand. You recommend a much milder cam than Stieg does. And I've seen evidence for this. However, I haven't really seen any recommended cam specs for a durable cam that won't pull rocker arm bolts, bind springs, etc. There's also a general sweet spot for those cams where they make good power to a certain point. I personally would like a cam that is not too aggressive, but enough to get some really good numbers with the M90. But some of this information is what I would like to take to my machinist so he can optimize the heads for the application that I'm looking for. For instance, if the cam only has .590 lift or so, I need to let him know so he gets the proper springs...etc.

Bottom line is David, you've seen so many applications, you know what works really well for the street/strip SC that can hold its own on the track. I trust and value your opinion as do a multitude of others on this site. I'm ready to take that next step to the heads/cam combo as are others, like V8Supercoupe, who started this thread. Now it's obvious that he emailed you and received an answer to some of his questions...

Basically what I'm looking for is given "X, Y and Z supporting mods" the best power levels can be achieved by using this type of cam, with heads with intake of A", exhaust of B" with a peak rpm of N, and an overdrive of w% on supercharger K. And also to know if there is room to grow in the future. I don't think that is too specific, but can benefit a great number of people on this site. And unfortunately, there's no quick reference to answer those questions. Sure you can look at the dyno list...but only if that dyno info is accurate to the mods that they have. I sent in my dyno #s in April and am still not posted. So I have to assume that they are not all that accurate.

V8Supercoupe
10-14-2005, 01:14 PM
(no offense Skip, ) and so on. There's just a limit. :eek: :o :(

Geesh...didn't know I was being a pain! :(

XR7 Dave
10-14-2005, 02:46 PM
Fair enough...however I guess that some of the specifics of porting aren't needed to get the point across though...I have all the confidence in my machinist that I will get all the performance that I want

I think you pretty much answered your own questions there. You want my information so you can take it elsewhere.


...however, there are a few variables that would need to be addressed for him to optimize the heads for ourt application. For instance, I'm looking for a durable engine making some somewhere in the ballpark of 300-325 rwhp with my supercharger. I know that I may be pushing it, but that is my goal.

So you want my advice on how to get 325rwhp, but you are going to have someone else do it, and if it doesn't reach your goals, then I will be partially at fault.


That said, a lot of the R & D has been done to what valves work, what springs work, etc. This is information that we are stuck looking for when it's already been done. Thus, re-inventing the wheel.

Not hardly. Your machinist should be able to put together that information in a matter of minutes. That is what you pay him for. Make him earn his money rather than take my time (which I'm not getting paid for) and use it to save him time. Not fair in my book.


Now into some more specifics that I was hoping not to go into, but the answers will benefit all who see this thread. David, you've done a lot of tuning on a lot of different cars. You have seen many more different applications than many of us. You are also one of the most respected members of this organization. So there are a lot of people who listen very intently to your comments. That's not saying that others are not valued or don't know more than you. I'm just drawing on your experience of seeing so many different applications to get an idea of what works really well.

Nope. I'm still learning. I'll help who I can but I will not be put on some pedestal. We all need to learn. It is not healthy for one person to learn and everyone else follow along. That is what has happened to this community in the past and stunted it's growth. Everyone did this or that because so and so said it was the way to go. I don't want any part of that.


Cam and head go hand-in-hand. You recommend a much milder cam than Stieg does. And I've seen evidence for this. However, I haven't really seen any recommended cam specs for a durable cam that won't pull rocker arm bolts, bind springs, etc. There's also a general sweet spot for those cams where they make good power to a certain point. I personally would like a cam that is not too aggressive, but enough to get some really good numbers with the M90. But some of this information is what I would like to take to my machinist so he can optimize the heads for the application that I'm looking for. For instance, if the cam only has .590 lift or so, I need to let him know so he gets the proper springs...etc.

Choose your cam based on your driving style, rpm range, gear ratio's and your machinists recommendations. I have my own theory on how to select cams and I'm not going to get into it here. I will be happy to recommend and provide a cam for anyone in any application but I'm not going on trial as to why I chose one vrs. another.


Bottom line is David, you've seen so many applications, you know what works really well for the street/strip SC that can hold its own on the track.

I'm not the only one here who knows but in fact I've posted specs many times as have others. I don't have the fastest SC here and I haven't actually seen anything that isn't posted in the member's section. I see things, I use what I feel is good and I pass over what I feel is not impactful.


I trust and value your opinion as do a multitude of others on this site. I'm ready to take that next step to the heads/cam combo as are others, like V8Supercoupe, who started this thread. Now it's obvious that he emailed you and received an answer to some of his questions...

Nothing is very obvious. I called him to talk about the flow numbers on his heads. I talked at length with him about his new Whipple that he is going to put on his car. I did not talk specifics with him on much of anything. You make it sound like I'm holding out. I'm not.


Basically what I'm looking for is given "X, Y and Z supporting mods" the best power levels can be achieved by using this type of cam, with heads with intake of A", exhaust of B" with a peak rpm of N, and an overdrive of w% on supercharger K. And also to know if there is room to grow in the future. I don't think that is too specific, but can benefit a great number of people on this site.

Holy mother of pearl! I don't think there is one person on the face of this earth who could answer all those questions!


And unfortunately, there's no quick reference to answer those questions.

Yep, sure ain't.

:)

XR7 Dave
10-14-2005, 02:47 PM
:eek: :o :(

Geesh...didn't know I was being a pain! :(

Skip, you are not being a pain. I called you, remember? :p

V8Supercoupe
10-14-2005, 03:05 PM
Bust'in beans Dave, I've always appreciated your help, I just need information beat into me sometimes. :D

V8Supercoupe
10-14-2005, 03:59 PM
BTW, I just wanted to add to this thread. I did drop off my spare heads this morning.
I think it worked out good for both of us as he prefers an untampered set of heads. They will be done in a month. What I really need to do is decide on the cam so we can(ahem,,,he can) decide on what corresponding components to use.

I don't really know where to start with the cam. I guess I need to figure out how I want this thing to run.

Can anyone fill me in(us who don't know) what the effects of a big cam would have on emissions? If any at all. I don't want to get this together and not pass the tree hugger test.

sizemoremk
10-14-2005, 04:23 PM
I know its off topic, but your little HK makes me wanna share something :D

V8Supercoupe
10-14-2005, 05:20 PM
UH, that would be an interesting thing to own. They photshopped the hek out of that glock didn't they?

David Neibert
10-14-2005, 05:25 PM
BTW, I just wanted to add to this thread. I did drop off my spare heads this morning.
I think it worked out good for both of us as he prefers an untampered set of heads. They will be done in a month. What I really need to do is decide on the cam so we can(ahem,,,he can) decide on what corresponding components to use.

I don't really know where to start with the cam. I guess I need to figure out how I want this thing to run.

Can anyone fill me in(us who don't know) what the effects of a big cam would have on emissions? If any at all. I don't want to get this together and not pass the tree hugger test.

Skip,

Mine would not pass emissions with the last two cams I had. It seems there was enough overlap to blow a portion of the intake charge (includes fuel) into the exhaust.

The cam I've got now might pass, but since I removed the cats to avoid anymore nitrous backfires, I'm sure it would fail.

Order the cam from Dave...if you want a high lift cam like I'm using (.600), you may need longer valves and will need different springs. But keep in mind, that you don't need a big cam like mine to make good power. I think the stock springs and valve lengths are good up to about .540 lift which is more than I had with Steigs big cam.

Some people seem to forget that Dave has to support a family doing this stuff. This SC stuff is his full time job....so it's really unfair for people to expect to receive the info and his time free of charge.

David

V8Supercoupe
10-14-2005, 05:42 PM
Some people seem to forget that Dave has to support a family doing this stuff. This SC stuff is his full time job....so it's really unfair for people to expect to receive the info and his time free of charge.

Ummmm.

HUH?

I must be a friggin idiot, cause in all the time I have come around here, I never knew Dave did this full time. I just thought this was a side deal for the fun of it and to make some extra dough.

Geez. I feel like a goober. :mad:

XR7 Dave
10-14-2005, 05:50 PM
BTW, I just wanted to add to this thread. I did drop off my spare heads this morning.
I think it worked out good for both of us as he prefers an untampered set of heads. They will be done in a month. What I really need to do is decide on the cam so we can(ahem,,,he can) decide on what corresponding components to use.

I don't really know where to start with the cam. I guess I need to figure out how I want this thing to run.

Can anyone fill me in(us who don't know) what the effects of a big cam would have on emissions? If any at all. I don't want to get this together and not pass the tree hugger test.

I thought I posted above the specs for Marc's cam but I guess not. His cam has about .570" lift and about 220 dur. I do not spec cams based on any assurance that the car pass any emissions test and I don't know of any of my cams either passing or not passing emissions.

I do know that the cam I have in the XR7 passes emissions with no problem, makes over 400rwhp, and seems to rev 6000rpm with no real trouble. It is 210/220 dur and .513" lift but it isn't one of my current grinds.

There are a number of factors that play into whether or not the car passes emissions and the cam is only one of them. I would err on the conservative side if you are worried about it. If once you get flow numbers you want to talk to me about a cam that would be fine. Valve spring selection is integral with cam selection so be sure to line them up together.

sizemoremk
10-14-2005, 06:04 PM
I just thought this was a side deal for the fun of it and to make some extra dough.



I didn't know that either, I've actually kinda been wondering what he did for a livin :o

That must suck, working on SCs for alivin :p

I'll have to keep that in mind next time I'm axin for free advice!

He'll hopefully be commning to my area for tuning in the semi-near future, so I'll patronize his business then ;)

007_SuperCoupe
10-14-2005, 06:07 PM
David D, I apologize for pushing you. I didn't know that you had ventured beyond the AR and tuning on these cars. I was going from the point of view from one hobbiest to another who just happens to have a lot more knowledge than I. I guess I crossed that line.

V8Supercoupe
10-14-2005, 06:07 PM
Dave, I emailed you, but did it before I saw this post.

XR7 Dave
10-14-2005, 06:48 PM
David D, I apologize for pushing you. And after reading my response I feel I was being a little rough on you as well. I try very hard to remain "one of the guys" here with everyone and try not to seperate myself as a vendor as such. I haven't defined what I plan to do beyond what I'm currently doing. It started out as headgaskets for a few people and now I'm finding that I am investing a huge amount of time in R&D with little return. I don't mind because I really am a hard core enthusiast just like anyone else here. But it just doesn't make sense for me to divulge everything I've figured out over the time I've been working on this before I even have a chance to use the info myself. Marc's car is the first car I've done according to my plan(s). He gave me free reign to do whatever I felt was right. At the shootout we saw that the car works. I don't know if I'm going to do anymore cars like that or not, but it just doesn't make sense to toss out all the info before I have a chance to even offer a package from myself.

My committment to you and everyone else is just as it always has been. I will not mislead anyone with any info and I don't hold things back. If I don't answer a question, then probably there is some discussion on the correct answer and/or different ways to answer the question. Info I do give out is as accurate as possible and should provide direction to get you where you need to go. For example David Neibert has the cam card for the cam I spec'd for him and is free to post the info wherever and whenever he wants. However his cam may not be right for your application. I'm not going to just toss all the info out there for everyone that I have been working on for the past 6 months (or more) but I have nothing to hide either.

Some of the things I've been working on include improved camshaft service and pricing through Comp Cams, a stock replacement forged piston through Wiseco at reasonable prices, stainless steel exhaust systems, and possibly some head work but that is pretty iffy at the moment.

I'm not here to "make a buck". I really just want to make it so that SC's can kick butt in the real world (we are getting close :)). This does require that I devote my time and efforts to SC's alone, and as such it is necessary for this to create an income for me. The fact that many of you didn't seem to know that is a reflection of the fact that I'm not out here to make money off you guys first, I'm here to help first and if there is an opportunity for us to do business in there somewhere, then great. That's all.

:)

XxSlowpokexX
10-14-2005, 09:09 PM
Is that the .588 .600 lift cam or the .572 .580?

XR7 Dave
10-14-2005, 09:58 PM
Is that the .588 .600 lift cam or the .572 .580?

Actually neither exactly, although they are similar.

XxSlowpokexX
10-14-2005, 10:20 PM
Dave N posted those numbers in the past which is why I asked. The smaller of the two