I'm slow:( Do I have enough flow??

[LarsD]

I was looking at one of my time slips from my last run at the local track and wondering what my problem is. What I think my problem is, is that my heads don't flow enough to give me the air that the engine needs once it's above 4500 rpms. I'm running 9.8:1 with GT40P's, Explorer intake, 70mm EGR and TB, 1.7's, and a TF stage one cam. Everything is unported. My dyno sheets show my powerband dropping off and 4700 rpms (car runs real rich too, like 11.0:1), which with my 4.10's I'm at that rate or higher most of the time. The car also feels real strong in 1st, 2nd, and about halfway through third. So I did some figuring. My fastest run to date was:

2.15 60'
9.2 1/8
14.20 1/4
99.12 MPH

I was thinking that if the top end air flow really was my problem, then the 1/8 mile would translate into a faster 1/4 mile time. So I multiplied 9.2 X 1.5 and got a 1/4 et of 13.8 which seems to support my theory. Does this sound right? Or am I totally off base?

Thanks,
L.D.

 

[maverick0716]

I plugged the 1/8th mile time into a calculator I use all the time that's pretty damn accurate and I got a conversion of 14.35......so I think you're theory is off. About the flow not being there.....yes I can understand where you're coming from, but they're still a decent flowing head (way better than stock) The only thing I can think of is elevation and air quality.....how high is the track you're racing at? Did you run on a very dry hot day?

 

[bhuff30]

I have always seen 1.55 being the multiplier. that gives you a 14.26 with a 9.20 1/8, which is dead on.
lean it out a bit. 11:1 has to be hurting you. Lean is mean I would shoot for 13:1 on an NA motor, and 12:1 (max of 12.5:1) on a motor with a power adder.
Your trap speed shows easy 13's with some stickier tires.
To get big improvments, everything has to flow well. Do you have a descentexhaust system, because I didn't see anything listed in the sig.

 

[25thmustang]

Tune it on the dyno, theres a LOT left in there. The GT-40s are good heads and will sned you deep 12s!

 

[LarsD]

The car is N/A, I have the "P" headers that are made by FRP on it, plus an O/R H pipe and Flows. Like I said, the car feels real mean though the first 1/8 of the track, then gets kinda lazy. I still don't understand why I'm so rich, is it the 24lbs'er just flowing too much? I have a TwEECer on the car, but I'am teh suck at tuning.

EDIT: Oh yeah, this was at like 700 feet with high humidity, don't know how much though...

 

[25thmustang]

Gotta tune it, and the elevation didnt hurt you. I ran my best at 1500' the other day!

 

[Nottoofast50]

what did u dyno at

 

[LarsD]

Hmm... 222 HP I can't remember the TQ...

 

[maverick0716]

Yeah, you need that baby tuned. You can get another 40 rwhp out of it with untouched P heads.

 

[25thmustang]

I agree 222 sounds like a stock motor!