DYNO RESULTS from my 331 swap

[Andres2882]

Ok, took my car to the dyno today over at Lamotta in the Central Florida area. I just recently swapped a stock block stroked to 331 with forged internals, an FTI custom ground cam, AFR 185s and a performer RPM intake.

Base dyno pull put me at 277.5 max hp/ 315 tq, definately not the number I was looking for. A/F ratio was never above 11 though, and generally hovered around 10ish.

With decreased fuel pressure and a little timing adjustment, car made 314 hp/ 345 tq by the fourth pull with A/F hovering closer to 12, though never going above, generally 11.8ish.

What could be messing my A/F and thus I'm assuming my results so much? Can the MAF calibration really be that far off? I have a C&L with the correct sampling tube. Any thoughts/input into what can be so wrong would be great. My guy at Lamotta expected 370ish hps with my setup.

 

[lxwants12's]

ur about in the right range 300 - 350 rwhp maybe...but 370 would be too much N/A unless you have really high comp..like 12:1 or something like that and the cam has to also be ridiculously large....IMO..im running 347 stroker all forged with a nitrous cam not the best for n/a and i got 340 rwhp untuned...so im expecting maybe another 15 to 20 when tuned on 91 octane..sodont b dissapointed ur numbers are nothing to laugh at

 

[Grn92LX]

What did you ask Ed for when he designed the camshaft? Are the valve springs changed to match the cam? Whats the rpm range on it?

Whats the timing at? That a/f is WAY too rich.

 

[2002BLGT]

air fuel needs to be dead on 12.9-13.0 and if you have a A9L computer set the base timing to 15 degrees initial should give a solid 36-37 degrees total , whats the compression ratio and post a graph of the dyno sheet , is the power falling off before 6200 rpms or is it still climbing ??

 

[jjd975]

The numbers are way low. I make that with a 302 and small parts. TFS 1 cam, ported eddy heads, and the RPM intake.

I agree the AF is way low but I dont see it getting you the HP your lacking.

Whats the rest of the set-up? Complete exhaust? More cam info.

 

[seanw]

Ok, the AFR is more than likely off, but I would look to other causes. Tuning a car starts with making the biggest changes first. Spark advance makes more of a difference on a normally aspirated car than does fuel pulse width. I would start with your base fuel around 12.5-12.8:1, but make sure that your spark advance is correct. I would start around 14 degrees initial advance, and verify with a timing light that the distributor is indeed advancing.

Unless your combination is severely mismatched, then your car should make in the 330-360 hp range.

Sean

 

[Andres2882]

EDIT: ADDED COPY OF ACTUAL DYNO SHEET

 

[Andres2882]

Car has full exhaust, bbk long tubes, h-pipe, no cats etc. I was curious as to what could make the AFR so poor? What factors would prompt the computer to run the car that rich?

As far as cam goes, .5728/.5632 and 224/228 at 110*. Cam specs were designed around a slightly milder idle and for use with nitrous, so I have no qualms with the cam. Moreso I'd like to get it running properly as it's obviously pig rich at the moment.

 

[mikemustang289]

your torque curve just seems to take a dive after 5k. Something doesn't seem right, you should make power all the way to 6k.

 

[Andres2882]

You think I'll be able to pick up another 35 rwhp when we get the A/F ratio to 13?

And yes, the valve springs were upgraded to match the cam according to Ed's recommendations.

 

[Numbles]

Im with mikemustang. Something is preventing that motor from breathing up top. You might be in need of a bigger intake. But work out the tune and timing first before you start changing parts.

 

[tmoss]

The RPM I lower is a choke point for the flow capability of those heads. This is an RPM I right?

 

[Modular2v]

with those heads u should be pulling more

 

[vikingpower]

iF thats a RPM I, you definitely need a bigger manifold with those heads

 

[tmoss]

Porting the RPM I would make it servicable on 185 heads.........but the engine needs more air.........

 

[Andres2882]

Tmoss, what would you recommend as far as a better intake then?

EDIT: To eliminate confusion and keep things up-to-date. This thread has been continued here http://forums.stangnet.com/showthread.php?t=634778&highlight=running+rich with updated information.

 

[neikoblu]

Something is deffinitly up...I put a set of AFR 185s on a stock 302, E cam, stock injectors, cobra intake, cold air, underdrives, mac shortys, 2 chamb flows w/ dumps, and 3.55 gears. Dyno pull was 301hp, 305 torque, and A/F ratio was about 12-1. Something is deffinitly not letting your motor breathe right.