Dyno sheets and cam ??? SC in stang

BKB

Registered User
Do you think i will gain anything with a cam with more duration??? What i have in it now is a Comp grind i came up with years ago when i wasent power hungry i now want 400 crank HP. My mods are huge front mount IC, 75mmTB, 89mm pro-M, Tuner, 3.27 gears, 5-speed, 3400 pounds, 1.73 RRs, 50lb injectors, 3'' IC pipe, raised roof on lower intake, ported blower, long tube headers, 2 1/2 duel exhaust.
My heads are ported stock valves
IN .50 229cfm
.60 241.67 cfm
.65 245.73 cfm
EX .50 149.71 cfm
.60 148.5 cfm
.65 161 cfm
.70 164.44 cfm
 

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I doubt it. That is enough cam for 400 crank HP. You need better heads and/or more boost likely. Definately need better exhaust flow. I suppose a little more exhaust duration wouldn't hurt but I wouldn't change the intake duration. How much boost do you run again?
 
I noticed your card says .333 lobe lift and .532 valve lift. It looks like those spec's are based off of a 1.60 rocker ratio. What size rockers are you using with that cam?
 
So how bad is my cam? Is .576 to much lift? Looks like i picked up a little flow from the exhaust going that high. Would i be better off going to something like a 210/215 duration .520 lift? I kind of like the power my cam puts out it builds a little slow but keeps pulling past 5K.
 
For some reason your motor seems to have a narrow power band. From that dyno chart it seems to have peaked by around 5000rpm but torque is only 275 at 2500 where as most of the high output SC's have surpassed 350ft lbs at 2500 and peak hp at least as high as you do. I'm not sure what the explanation is for that. If I were to guess it would be to say that maybe you have too much lift and not enough exhaust port flow. Or maybe your tune is off?

Hey I'm just guessing, I have no idea really.

BTW, what kind of dyno is that????
 
It was a mustang dyno. My tune gets a little lean around 3k going 12.74 A/F then it goes back to 12.5 and goes a little rich past 5 going to around 11.7. Since no one wants to help with my tune it has been one long learning curve. One thing im having problems is with timing, what im using now is 14' @2200 15' @2500 16'@2600 17'@3k 18'@3300 19'@3500 20'@3600 21'@3700 22'@3800 23'@3900 24' to redline. That spark adv. is actual read using a Ford Star Tester at WOT. I dont have the money to spend half the day on the dyno with a WB setting up my timing curve. Things that might change my power band is the lower intake i cut the top off and raised it 1''. Also i dont know if my 3'' IC pipe and HUGE front mount IC has any effect. I also feel this motor is not performing well and i think its partly the cams falt. Does anyone have a rough idea how much CFM i would pick up installing 1.60 exhaust valves???
 
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First of all a Mustang dyno reads about 10% lower than a Dynojet due to the loading of the rollers. That being said your numbers look much better than first thought.

Your timing curve looks REALLY conservative. You could pick up some power right there. You could add probably 4 degrees pretty much across the board to that tune. 12.0:1 AF would be safer and not cost any power as well. I think you have too many low rpm timing points specified. Timing needs to be a held off a little at your torque peak due to boost but then as torque falls off timing can be added back in at higher rpms due to reduced cylinder filling at high rpm.

Of course those are just my opinions. ;)
 
I thought it was the mustang dyno that read low. XR7 Dave the first few pulls i was running 2' more timing globally. Since my goal was to run as little timing as possible until power fell off i pulled 2' globally, but the dyno operator said the motor really liked what ever i did and torque increased everywhere. I didn't have time to play with the timing much after that, but my motor responded well to less timing. I used to run 28-30'' of total timing with no detonation (also watching knock sensor) but power didn't seem any better. But i will try what you suggested and adding a little timing from around 3300 down then keep it steady between 3400-4k and then up it a little from 4k to redline. Do you use the SC or EEC tuner? If so could i look at some of your timing tables?
I looked into getting 1.60 exhaust valves and was told they should add around 30cfm. So i would be up around 180cfm at .50 and could just go with a duel pattern cam to help the exhaust side. Does anyone know of a reputable company that could install the seats for the 1.60 valves???? Are 1.60 to large for stock bore (valve to shrouded)

Thanks
Brian
 
50lb injectors

over kill ....IMHO ... with the mods you have on the intake .. air intake is not a problem ...it should scream past 4,700 rpm ... a plug check after a dyno run is always a good idea ...and valuable information ....if it is tuned right or wrong ...then you know what the plugs should look like ...when it is tuned and what they look like when it's not ...if you didn't have timing issues ... I would say you are running way too rich on fuel ...based on the torque curve [or the lack of a curve] ....dave
 
Well fuel is not a problem, the WB said 12.5 A/F all the way. It only went a little lean 12.7 at 3k
 
Im using the Mustang computer so i have no Knock Sensor. At WOT im pulling 12.5 A/F all the way to about 5k then it goes to around 11.7 A/F
 
When I tried putting 1.56" ex valves on stock seats I was able to get 150cfm@.050". With new seats that had bigger ID, I got 165CFM and I really didn't port them all that much. So 20-30CFM from bigger valves and seats wouldn't be out of the question.

If you want 200CFM like Dave mentioned above, just have the guy flow testing them put a piece of 1 3/4" pipe on the exhaust port. That's how every head porter I've seen data from has gotten over 200 on the SC heads. With tube, they're like 220. Without, they're like 185. It's just a method to make the numbers look better. So if you get 'untubed' exhaust flow around 170-180, you're doing pretty good.

Personally, I think you have 2 options. 1.) Get a new cam with 10-15 degrees more exhaust duration than intake. 5 degrees more on a blown motor is a waste of your time. If you're going to do that, leave the cam in you have now. Keep intake duration around 210, exhaust at least 220 and it'll work quite well. 2.) Get a pair of killer $2000 heads or put 1.6" valves and seats in your heads and have the exhaust port floors welded up and ported to a D shape. That will match you In - Ex flow more to your cam.

I'd go for option 1. It's a lot less $$$ and easier too. I wouldn't go with more lift unless you know the valve guides were cut down for more clearnace. .525" lift is the general lift for stock hieght valve guides. More than that and the retainer will smash the valve seal, bend pushrods and other bad stuff will happen.

Regards,
Steve

P.S. I'd also degree the cam when you install it. That power curve looks like the cam was retarded to the middle of last week (or would it be middle of next week since retarded is later?). A 208 duration cam should have peak torque around 2800-3000. Get a Morana timing chain to have +/- 4 degrees and straight up options.
 
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I did degree the cam when i installed it. I did have make a offset key for it because it was way off.
 
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