AFRs not all they're cracked up to be?

nmcgrawj · Sep 11, 2005

final5-0 said:
I see three things I wonder about with that combo list.

1) You gotta be very close to the limit of those 24's!

3) This one is the big one IMHO .............

I pegged the stock maf with my combo which in no way, shape, or form should be able to move as much air as yours.

I'd go for 30's with bigger maf & intake.

Grady

And those 2 should have been addressed by the tuner if they were a problem right? I mean...if they failed then that would mean they couldnt tune it correct? Or would the car just not perform like it should?

nmcgrawj · Sep 11, 2005

walker95svt said:
t I'm sure are just fine for low 300s. Maybe just as fine for 300 as 24lb injectors...Anyway, a 331 with heads and cam should outpower a stock cobra 302, at ANY gear ratio 1.31, or 4.10. Thank you everyone that gave me honest answers.

Low 300's can be done by 302's

And it "should" outpower the cobra....but it WONT beat the cobra with a tall(numerically low right?) gear. I cant imagine driving a car with a 1.31 gear. I wonder if you could beat a semi truck? lol But I understand you were probably just over exaggeratting(sp? thats gotta be wrong) a little.

WhiteDevil · Sep 11, 2005

nmcgrawj said:
Low 300's can be done by 302's

And it "should" outpower the cobra....but it WONT beat the cobra with a tall(numerically low right?) gear. I cant imagine driving a car with a 1.31 gear. I wonder if you could beat a semi truck? lol But I understand you were probably just over exaggeratting(sp? thats gotta be wrong) a little.

Exactly most of us put around 300hp to the wheels with stock blocked 302s which is like 350hp flywheel. You say you only want 270-300 flywheel???????? You should be way obove your goal.

walker95svt · Sep 11, 2005

correction

I did mean to say 300 rwhp, in my haste at work I made that post. and yes, I was exaggerating about the 1.31 or whatever it was I said about gears. My point was, 3.08s are 3.08s, and one "modified" motor should feel a whole lot faster than a stock one, given the similar gear ratio that's stayed with my car for both motors. The tuner never got my car on the dyno, and before everyone jumps my case, yes, it IS possible to put a DECENT tune on a car without it making it on a dyno. Note I said decent, not perfect. and before I get my case jumped about that, I'm referring to NA, non-exotic setups. The computer does a damn good job on its own, it just needs a lot of help to be maximized. There's probably no more than five horsepower and slight tweaking of timing to be had by me going back. The tuner refused to put my car on the dyno due to a fuel pressure leak down. oddly enough, he messed with it not on the dyno.......... but that's a different deal for a different time.

walker95svt · Sep 11, 2005

I do agree with the guys who think I need to get my car to the track and see what happens there, and not neccesarily how it feels on the street. Nor should one judge an engine by it's peak numbers on the dyno.....we all know powerband equals acceleration with an average street-going tranny.......

But I do wish I'd gone with CNC trick flows

walker95svt · Sep 11, 2005

low 300's?

low 300s at the wheels (mustang dyno, not dynojet) can be done by an average 302 with compression in the low 9's? show me please!!!

final5-0 · Sep 11, 2005

nmcgrawj said:
And those 2 should have been addressed by the tuner if they were a problem right? I mean...if they failed then that would mean they couldnt tune it correct? Or would the car just not perform like it should?

I guess I should remember that the 24's could be made to act bigger with elevated fuel pressures and I do forget about that since I tune at stock fuel pressure. It still it is my opinion that they are too small for that combo and with the issues that can happen with lean ratios .....................................

I just don't understand the reason or logic of taking a chance on bad things like that to happen with inj's that may be too small.

So, I will say that of the two things you ask about, the 24's are not as bad as the maf being too small.

I could be wrong about the maf but based on my findings with my combo and what I've seen happen over and over on the tuning forums .......................

I think the maf is too small for his air aiflow. Remember he said it is a stock oem Cobra maf. Heck fire, the maf transfer for that maf will only go as high as 875 kg/hr and I just don't see how it is able to support the air flow that his stroker combo is capable of producing. My little combo has pushed as high as 940 kg/hr so his has to flow more ............... don't ya think?

The maf being too small doesn't mean the car won't run or make power. It is not gonna be able to report the amount of air flow in the upper rpm range like it should.

So, YES ...... if the maf is too small, your not gonna get the best performance from that condition.

Now that I think about it, maybe the Cobra intake would not flow enough air at the upper rpm range to peg that maf ...... but I kinda doubt it. We don't have any data to tell us what happened during the pull so I'm just thinking out loud I guess.

He did ask for our thoughts

Grady

Redsnk95 · Sep 11, 2005

walker95svt said:
low 300s at the wheels (mustang dyno, not dynojet) can be done by an average 302 with compression in the low 9's? show me please!!!

My buddies combo, pretty much "run-of-the-mill set-up".

http://forums.stangnet.com/showthread.php?t=572565&highlight=svegt

Troy

VibrantRedGT · Sep 11, 2005

I get the feeling you think we are bashing your car. We simply addressed a few areas that can help get a bit more out of your combo is all. It will probably knock down 300 Rear wheel HP as it sits if the tuner will allow it to. With that meter and injectors he may shut it down early. Bigger injectors, mass air meter and that blower your going over 400 easy so don't sweat it. Lose the highway gear and she will rip.

Welcome to the boards.

tmoss · Sep 12, 2005

The intake does need to be worked or replaced for best N/A power - especially if blown. I agree about the tune without a wide band. It needs to be done at some point.

Killercanary · Sep 12, 2005

I at or near the stock compression (9.2:1) and I made 304rwhp/331rwtq on a dynojet. My bottom end is COMPLETELY stock and my heads are 60cc combustion chambers as delivered from AFR. Stock are between 62-64cc's. So I guess I did it, and I know there are others hear that have done it as well.

95snoozer · Sep 12, 2005

VibrantRedGT said:
I get the feeling you think we are bashing your car. We simply addressed a few areas that can help get a bit more out of your combo is all. It will probably knock down 300 Rear wheel HP as it sits if the tuner will allow it to. With that meter and injectors he may shut it down early. Bigger injectors, mass air meter and that blower your going over 400 easy so don't sweat it. Lose the highway gear and she will rip.

Welcome to the boards.

i get the feeling this guy doesnt know what the hell he is talking about, yet thinks he does.

Killercanary · Sep 12, 2005

95snoozer said:
i get the feeling this guy doesnt know what the hell he is talking about, yet thinks he does.

95snoozer · Sep 12, 2005

i was referring to the thread starter

Killercanary · Sep 12, 2005

95snoozer said:
i was referring to the thread starter

I know and I agree with you.

Rootus · Sep 12, 2005

There have been many cars I've driven that did not have good SOTP feel, but were in fact quite fast. When it was stock, my Cobra felt slower than my '95... and in fact it was faster -- a good flat torque curve is great for going fast, but it's a peaky torque curve that gives you that feeling of power. I guess it depends on whether or want to think you're fast, or be fast

Dave

1EVIL88VERT · Sep 12, 2005

walker i know you car will hit 300hp right now on a mustang dyno, It does'nt feel that fast because #1 your gear ratio is far from optimal for your car right now # 2 you car is damn heavy.....but that HUGE blower you got will change everything, i promise you that your car will scare you after you put that thing on

walker95svt · Sep 12, 2005

replies

Anyway, I was referring to a mustang dyno, not a dynojet, about the 300 hp 302s. I hope those knocking me know the difference between the two. a 300 rwhp 302 makes about 270 on a mustang dyno. I never tried to act as if I knew more than anyone here, but if someone wants to tell me they have know idea what I'm talking about, they'd better spell it out to me exactly what I'm saying that's incorrect, and correct it. Slinging mud without reason is childish. Thanks to all those that gave ACTUAL thought to the issue.

walker95svt · Sep 12, 2005

perfection.....

perfection? a 1/4 mile at a time? reminds me of a quote from a certain movie...

am I slinging mud now? It's okay I don't know what I'm talking about.....

95COBRA241 · Sep 12, 2005

My engine builder recommended I use TFS T/W's for my 347 build when I suggested AFR's. He stated that AFR's might give better peak numbers, but he like the T/W's numbers across the board better. My car like yours will be mostly street driven.

AFRs not all they're cracked up to be?

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