Ok, so that AFR kooks kinda leanish what do you guys consider the safe limits of AFR? I was alwasy told between 10:1 and 11:1 to stay on the safe side. But then my knowledge on tuning and AFR is little to none

 

You can run the ragged edge up to about 12.0:1, but anything leaner than that is asking for trouble.
If this is a street daily driver, keep it under 11.5:1; there's no reason to risk killing your engine for that last 10hp or so.
As a rule of thumb, normally aspirated "best power" (on a piston engine) is 12.5:1 to 12.8:1.


-Ted

 

Glad to know she's still running strong.

 

I realize this thread was started a coupla months ago.

Having said that, go and drag race it at 10 psi. If you are not trapping around 125 mph, something is not right with the dyno sheet. Trap speeds don't lie.

 

still bickering about this oh well. hell i'd drag race it for him but even at 10psi he will blow the rear end and trans. ask me how i know

 

Ito said your today setup would pin him in the seat......and he drags everything. I was asking if I should sell My GT40 before I mount it!

 

yeah the *thrust* i guess ??? was ridiculous in my car.... nose would pick up. rear would squat. it was so much fun to drive. GT40 is a big turbo it should make alot of power

 

gt40 56 trim is big, rest arent

 

SAE'd dyno numbers in New Mexico .... what were uncorrected numbers?

example: Santa Fe is at 7000 ft. The SAE corrected hp and torque will be about 10% overstated there for turbo at 10 psi.

---------------------

At sea level and 75F for an FD at 10 psi and 7200 rpm with:

100% true VE, 80% compr and IC efficiencies
.5 bsfc, and a/f=12
no IC or intake pressure drop

engine hp is 397 for these ideal conditions.

this number will be lower with usual higher bsfc (.6), and more realistic VE. You would need an indy turbo, race port, and tuned headers to get back pressure low enough to be assured that a full clean 10 +14.7 psi was filling the chambers, for 100% VE.

 

Fact of the matter is, he isn't making that kind of power on a streetport at a measly 10 psi. In my opinion, it's just not possible.

Rich

 

thats what im sayin

 

i drove in that car and it felt every bit of 410+rwhp, believe it or not. i've only driven like 12 FD's in my life from stock to 450+rhwp. wait maybe more than 12 haha

 

Whether these numbers are b.s. or not doesn't matter. As soon as he goes to the track, his mph will tell his real power. This dyno was either not callibarated right or the graph was fudged or the boost level was twice that. Its simple math people. All you have to do is look at the compressor map of the T78 and you can see it will not push enough air at that boost to make that power.

 

i cant find a compressor map for t78 or t88 do you have one?

 

what about my car???

415rwhp 10psi.....call the dyno place

 

Anytime you see torque climb with rpm is a clear indication boost is also climbing !!!!

The problem/issue is not believing the hp #'s *but* the boost amount.
Torque #'s also give an idea of boost amount....few of us know that.

JD

 

Sorry Vosko, but your car never seemed to trap as high as the dyno numbers indicated.

 

never had the same tune and i still trapped 118mph....

 

118 is about 375-385 rwhp.....congrats.......

 

118 is about 375-385 rwhp.....congrats.......

Rich is it even that much power? I trapped almost 117mph on my stock non-seq twins 2yrs ago. My car mayble felt like....330ish rwhp. Just my .02, CJ

 

if FD driveline parts weren't complete crap i probably would have done better. atleast i tried drag racing unlike everyone else who has never been on the drag strip

 

Hey CJ,

Actually, 117 is right around 350 or so. I was drunk as hell when I posted that(4am), so I was a bit off

btw, that is a great trap speed for stock twins, non-seq or not.

 

Someone is defensive.

(a) your excuses are getting old, i wouldnt sweat it one way or the other

(b) your entire post is ridiculous........fd driveline parts are fairly stout, and i am sure many of us have more passes down the quarter than you

(c) it is impossible to make a true 415 rwhp at only 10 psi on a streetported 13b

(d) Happy Thanksgiving

 

 

Ive trapped 118 mph on a hurt motor with 13.8 psi on a GT3540. With air fuels in the 10's. My Motor was a total piece of **** and I dynoed at this boost and put down 369 rwhp. Oh and the motor was Ported.