The smallest things can seem so big...

007_SuperCoupe

Registered User
My machinist finally has been able to start work on my heads this week. His first goal is to get one port completed from runner to valve, flow test it and then complete the rest of the heads. On this particular head, he had already ported it a couple years ago to demonstrate the difference between stock and ported. Yesterday he installed the new intake and exhaust seat. What a difference that makes! By the time I got there, the intake seat was pretty much complete, but he still had some cutting to do on the exhaust seat. Then, of course, he has to clean up the bowls on each. I'm very anxious to see what the new flow numbers will be.

Hopefully I'll have some preliminary flow numbers by next week and the heads completed by mid to late June. Then it's taking on the task of installing everything...
 
I received preliminary intake flow numbers today. I say preliminary because of two reasons, 1) a ton of work needs to be finished on the center port to bring those flow numbers close to what these are and 2) the machinist still has to back cut the valves and work a tad more magic on the runner. In truth, flow numbers will not likely get more than 3-4 cfm than what is listed here. That said, here are my numbers as of today: :cool:

INTAKE
.100 - 60 cfm
.200 - 117 cfm
.300 - 172 cfm
.400 - 215 cfm
.500 - 238 cfm
.600 - 251 cfm

Again, after a little more fine tuning, the overall flow numbers will not increase dramatically from these. I might see as much as 5 cfm in the mid lift range, but likely not more than that. Bottom line is that the intake runners just do not have enough volume to support any more flow. This is pretty much maxing out the flow. (P.S. I'm running 1.940" intake valves)

I do not yet have the exhaust numbers. I should have those tomorrow if things go well for my machinist tonight. I expect the exhaust flow to increase dramatically over stock. The intake averages 62 cfm greater than stock flow (on these heads) between .300 lift and .500 lift, which is really where it matters. I think the exhaust will be greater.

I guess this is pretty good timing since my engine took a crap on me. It's time to upgrade anyway... :rolleyes:
 
it took me arouind 2 and 1/2 years to put my mods in my sig together. doing it working at a fast food restaurant. :rolleyes: cost me around 6-7k :rolleyes: and im not done. tho now im working a better job now.:D
 
One thing to be wary of. You don't want to do changes to one cylinder that you can't do to the others as you could create a balance issue in your cylinders. Shoot for good balance, with good flow.
 
One thing to be wary of. You don't want to do changes to one cylinder that you can't do to the others as you could create a balance issue in your cylinders. Shoot for good balance, with good flow.

That's why I defer to an expert with 30 years of porting experience. He says it won't be too bad to make that center port flow the same. I know it's the hardest to get to flow, but it is still entirely possible. I completely defer to the experts, which is why I'm not attempting the porting with my dremmel! LOL!

He's ported our heads before. The big difference he's doing here is the valve size with new seats. Looking at the flow numbers from previous port jobs (progressively more performance) you can see how the larger valves and seats affect the flow. At .100 and .200 lift we actually lost a little flow because velocity fell off, but that is passed very quickly starting at .300 lift and higher. (I've got a spreadsheet comparing all flow numbers). The difference here is simply larger valves with new seats. He's actually going to reshape the center port to straighten the flow, but was successful in getting 200 cfm at .400 lift and higher with a peak of 230 cfm at .600 lift. He's installing new seats, cutting his "secret" valve job and reshaping the bowl (as he has already ported these heads).

The flow numbers I have are stock, ported with stock valves, ported with larger valves on stock seats and ported with larger valves and new seats. The stock seat larger valves are 1.840" and the larger seat valves are 1.940" (all intake, obviously)

Similarly on the exhaust I've got stock, stock ported, ported with 1.600" valves and ported large seat and 1.600" valves.

Again, I'm greatly looking forward to the exhaust numbers tomorrow. I think they will surprise a lot of people. Once I get the flow numbers someone will probably try to convince me that turbo is the way to go...but I don't have the money to put more into the heads to increase the rpm range of the motor... But it sure would be fun if I did...
 
I received preliminary intake flow numbers today. I say preliminary because of two reasons, 1) a ton of work needs to be finished on the center port to bring those flow numbers close to what these are and 2) the machinist still has to back cut the valves and work a tad more magic on the runner. In truth, flow numbers will not likely get more than 3-4 cfm than what is listed here. That said, here are my numbers as of today: :cool:

INTAKE
.100 - 60 cfm
.200 - 117 cfm
.300 - 172 cfm
.400 - 215 cfm
.500 - 238 cfm
.600 - 251 cfm

Again, after a little more fine tuning, the overall flow numbers will not increase dramatically from these. I might see as much as 5 cfm in the mid lift range, but likely not more than that. Bottom line is that the intake runners just do not have enough volume to support any more flow. This is pretty much maxing out the flow. (P.S. I'm running 1.940" intake valves)

I do not yet have the exhaust numbers. I should have those tomorrow if things go well for my machinist tonight. I expect the exhaust flow to increase dramatically over stock. The intake averages 62 cfm greater than stock flow (on these heads) between .300 lift and .500 lift, which is really where it matters. I think the exhaust will be greater.

I guess this is pretty good timing since my engine took a crap on me. It's time to upgrade anyway... :rolleyes:

Sam,

Are these numbers with stock seats or oversized ?

David
 
I got my exhaust flow numbers today. The, too are a great increase over stock.

.100 - 55 cfm
.200 - 105 cfm
.300 - 146 cfm
.400 - 181 cfm
.500 - 197 cfm
.600 - 206 cfm

The average increase between .300 and .500 lift was exactly the same as the increase on the intake 62% (both were actually 61.6667%). These numbers are not going to increase. The port work on the exhaust is finished with no more minor work.

Now my machinist has to get to work on the second head while I have to get to work on a manifold that will support that much flow...
 
Yes, the heads were flow tested using the correct bore size, otherwise the exhaust numbers would have been much higher.

As for price, I know what I'm paying, but my machinist is cutting me a deal. :) I imagine the final cost would be around 1200-1500. But I'm also keeping the stock valve train set up too. I'd love to set the heads up for 7k rpm, but that's not financially feasible right now.

Just fyi these are the same heads I brought to the KC meet several years ago just with superflo valves and new seats installed.
 
I got my exhaust flow numbers today. The, too are a great increase over stock.

.100 - 55 cfm
.200 - 105 cfm
.300 - 146 cfm
.400 - 181 cfm
.500 - 197 cfm
.600 - 206 cfm

The average increase between .300 and .500 lift was exactly the same as the increase on the intake 62% (both were actually 61.6667%). These numbers are not going to increase. The port work on the exhaust is finished with no more minor work.

Now my machinist has to get to work on the second head while I have to get to work on a manifold that will support that much flow...

Sam,

Are these numbers using welded exhaust ports like Steigimier used to build ?

David
 
Sam,

Are these numbers using welded exhaust ports like Steigimier used to build ?

David

No the ports are not welded. My machinist said that would get better flow but has concerns about the welding process and possible issues later. Besides, I don't think there is anyone around here who would do that. These are with larger valve seats and 1.600 superflow valves.
 
don't forget that when looking at these head flow numbers, that the intake manifold itself presents a significant bottle neck. Stock exhaust as well.
From this thread XR7 Dave had mentioned loosing 25cfm of air flow bolting on a intake manifold with a port that flowed more air than the head, but the combination of the intake manifold and the head resulted in lower cfm than the head or intake manifold alone.
http://www.sccoa.com/forums/showthread.php?t=104246&highlight=intake+manifold+flow
 
I'm well aware of that fact. That's why I've been working on a different manifold for a while now. It will be a total custom, 1-off piece that will not be reproduced, so there will be no production thoughts. I just want to be able to make a manifold that is capable of supporting the flow of the heads. Yes, that means it will be flow tested. I've got a couple different options there and have not yet made my final decision on which style of manifold that I'm going to use. I've enlisted the help of a former Ford engineer who specialized in fluid dynamics.

Once I get the manifold worked out, then I've got to figure something for the IC tubes if I want to (also read as "have to") keep my 2x IC. I've got the feeling that this is going to morph into a much larger project.
 
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