tbirdscwd

It kinda depends on how aggressive your timing curve is, but I've always been told that anything above 12.0 at WOT from 3K and above is pushing it on centri cars. Especially if your on the stock bottom end and in the 10-12 psi range.

paulstang

Do you have forged internals? if not 12 is starting to get dangerous.

2000GT4.6

+1, I have mine going from about 11.40s to 11.60s. I am a bit on the safe side, intentionally tuning it to keep the horsepower down around a non rod snaping level, but IMO 12.3 is to lean.

So far as the power dropping off, I would not expect it to start dropping that early, even on stock cams. Hell, even n/a you should be making power past 5200 on the stock cams. You need to be dynoing it all the way to 6000+ RPM, as that is where you should be shifting at regardless.

Do you trust your tuner? I would be looking into getting it tuned by someone else...

BTW, the pipe your talking about is generally refered to as a "power pipe". You can get them almost anywhere for aroud 200 bucks with the bungs already welded etc.

Mine pulled all the way to 6K and past, but I do have the stage 2 cams. However you should be puling much farther than that... you should not be peaking at 5000 RPM.

Where you present when the dyno was done? I know that on my dyno, the RPM was simply not reading correctly, so I shut the run down by watching the tach and having them set the dyno when the tach read 6000 RPM. Its possible that the RPM is simply not reading correctly, in which case your tuner is probably fine (other than that lean a/f ratio) and its just a error in how its displayed...

blstoff

11.8-12.0 is considered safe . I doubt you'll have any problems at 12.3 but if it were me I would prolly richen it up a little .

oxfordgt

+1 12.5 is good and still safe but 11.5 would probably be the safest.

PushinTheLimit

Honestly, for a blown car... I wouldn't want to see anything out of the 11's for an air/fuel ratio. 11.5-11.8 is about spot on and where it needs to be. 12.3 is too lean for my taste. I look at it as if your gonna pay money for it... get it exactly where it needs to be.

2000GT4.6

Did you just redyno or something? I just thought I remeberd that you have had the numbers in your sig for awhile.

Someone said something about 12.5... that is WAY to lean for a FI car. IMO 12.3 is playing with fire. Does your tuner have alot of timing pulled or something?

12.3 might be OK if everything else is, but IMO if you get a bad batch of gas or run it hard on a hot day, or any number of things, you have absolutly no saftey net... and thats not a good thing.

Get him to retune it down to around 11.80s or so. I dont want to see anything over 11.80s on a blower car thats a DD/frequent streetdriver.

The TQ also seems funny IMO.. I have never seen a centri car making more TQ than horsepower like that. I made 420/410 for refernece, the TQ being the 2nd (lower) number.

I still want to know if they acutally had it at 6K RPM but it only read 5xxx on the dyno. I dont see how your car at 10 PSI could possibly make 395 at 5000 RPM.. thats headed to440+ WHP at 6000 RPM IMO with the average setup.

Also, after thinking about it some more, even with the stock cams the car (with a centri) should be pulling fairly hard to 6000 RPM. Maybe not peaking at 6K, but it should at least have a nice flat curve after say 5500, with a peak around there.

MustangChris04

torque #'s looks usual to me.

Quicktime_GT

Not a retune.. I was jut looking back over the dyno sheets after reading an article about AFR's and kinda got to thinking maybe i'm pushing it on the lean side..

It wasn't on a dynojet, it was on a superflow dyno... He explained that this is why they it shows a higher torque reading, because he can apply a brake at rpm at any speed at any level...

I actually just asked him about the afr.. He said I could add 2% to4% on the xcal If I wanted it more in the high 11 range.. He seems to think that 12.3 is fine though..

The car has 21degrees of wot total timing..

2000GT4.6

What about the situation with the RPM? I still don't see how it could peak at 5000 RPM, espcially not do that AND make 395 WHP.

IMO you are on the dangerous side for a/f ratio, and more than likely its just an incorrect reading of RPM. Either that, or the dyno reads REALLY high and you have a problem somewhere in the tune. Like I said, there isn't any reason for a centi PI 2v to peak at 5000 RPM and start dropping off, even with stock cams.

Not for a centri car on a dynojet, but he later stated that its on a different dyno.