Took the car for a drive tonight and found a couple of folks to run against. An LT1 95'ish vette w/ exhaust (automatic) and a Supra turbo.

The auto vette took me off the line (which I expected) but I couldn't real him in and went all the way to 80. The supra was an embarassment. ran him 2 times first time wasn't too bad only 3 or 4 lengths in a very short run.. 2nd run he gave me 3 lengths and then he past me like I was standing still (plus he had a guy that must of weighed 300lbs in the passenger seat). The supra was certainly a single turbo with front mount/etc.

My peak boost was only .82, but my injector duty was 84.x%. My performance mods include, greddy smic, sr tuned pfc, cb, dp, hi flow, and efini y pipe.

I'm taking it to RP next week, to get tuned. But am I expecting too much out of this car???? Seems like I was doing better before I changed my wheels (from stock to 18" volk GTN's) but I can't imagine it being that significant.

Thoughts, insight, whatever???

 

Your car should be able to hang or beat a stock LT-1 auto Corvette. The Supra, it depends.

When you say your PFC is "tuned", what does that mean? Did you buy it "tuned" or have you already had it dyno-tuned using a wideband?

Also, why only run 11.6 psi? You should be able to run 12-13 psi on the stock fuel system.

And yes, going to the 18" GT-Ns definitely will give you measurably less performance. The GT-Ns are not Volk's lightest model and the 18" size has much more rotational inertia.

Are all of these races off the line or did you go from a roll too? Do you have another boost gauge besides the Commander? The Commander displays incorrect boost for most people.

 

I would say change your blinker fluids and let us know how your perfomance raises

Im just kidding,
What kind of numbers are you putting out, if you have had it dynoed.

 

Topped off my blinker fluid the other day..,.

to answer a few questions:

-- my PFC I bought used was tuned for someone elses car with my same modifications.

-- The races were a mix of roll and off the line.

-- I have a boost pod on my pillar and it looks like it hits 12psi give or take

-- I haven't dyno'd it yet but am taking it to RP next week.

Further, I know my car was fast (I've beaten a supercharged cobra and hung with a '02/03 Z06 to 65)

The things that have changed were apexi intake & wheels (+ y pipe but I'm leaving that out)

The only thing I can think of is a boost leak and damn if everything isn't tight...

 

When you say SR tuned PFC, do you mean how it came from him out of the box, of did he personally dyno tune your car? Most of what I've read states that most of the PFC's you get from tuners (mail order) will be pretty rich for safety sake. Spend some money on an intake system (didn't see that in your description) and get some dyno tune time in. Of course you can always port your wastegate and go with a mid pipe, underdrive pulleys, RRFPR or bigger pump, etc. The age old adage comes to mind: "How fast do you want to go?" "How much money you got?!"

Regards,
Frank

ps. I tried to send this last night so some of this may have been covered by now.

 

yeah - its definitly rich. failed inspection with hydrocarbons at 300 range. Everything else was perfect. Oh yeah have an apexi intake - always forget something.. At least it looks pretty http://photos.yahoo.com/bc/jbg28/vwp...iew=t&.hires=t

Anyone else with idears??

 

A little bump to get me through the day.

p.s. I'm now thinking I need to change the stock hose clamps from the t-bo's to the bov's as they were noticibly loose..

 

13psi was pushing the stock fuel system for me atleast. Thats with a 11.2 afr.

 

how long has it been since you changed your spark plugs? maybe its time for a tune up

 

That seems consistent with what I've seen from others. I wouldn't run daily at 13 psi on the stock fuel system (or an upgraded fuel system for that matter). Once the PFC comes in next month, I will be running 10 psi daily and reserving 12-13 psi for the weekends/fun driving. Once I upgrade the fuel pump and injectors, I'll still be running 10 psi daily and up to 14 psi for fun....

 

heh it should beat the hell outta that vette....

 

All my driving is "fun driving" got another car for transportation.

Changed spark plugs and wires 7 months ago or 900 miles.

Even if I am leaking boost somewhere with 84% injector duty. I should have 355 flywheel horsepower (minus some if I am running rich) right?? Here is the calculator
http://www.rx7.com/cgi-local/3rdgencalc.cgi

 

sorry but no brent... 355? off hand I had similar mods w/ about 290 to the wheels. have you felt the difference in the acceleration? what plugs did you put in...? hmm whatelse... its always the stupid crap that messes things up. Computer sounds like it to me... do you hear any air escaping?
-Ryker

 

I'm going to go with Ryker on this one brent. Get that computer looked at or take it off, see how it runs without it. Good luck man.

-Marshall

 

what kind of air temps are you seeing? maybe the highflow cat could have clogged up. Its been pretty hot and humid lately, I have noticed a pretty big drop in how my car is running with the weather.

 

355 flywheel - not rw. I'm pretty sure I'm loosing some HP through the 1" hoses that go to the BOV's.

Regardless, I don't like loosing to a freaking LT1..

 

brentis- someone mentioned an SR tuned PFC but i didn't see where you actually said that is what your ecu is.

if that is the case though i can tell you that I got my pfc from SR and my car was SLOWER with the pfc than stock ecu, turned 220rwhp with intake/dp/hiflo/exhaust/street port. Much timing and 15% fuel had to be taken out just to get an 11.5 afr even after i went to a bigger smic and 13lbs of boost. so if thats your situation then that could be it, then running that rich could f the cat up of course...

 

airborne - so what what your whp after tuning?

ps: I have a pfc and commander

 

when i first got the pfc i had the stock IC@10lbs and after just adjusting timing pulled 270rwhp. probably woulda been more but my clutch was slipping. backed up the # with that 13.2@106.

now w/ic and 13lbs i think i pulled like a 305 w/intake temps in the 60/70C range. gets hot after all that tuning, haven't had a dedicated "lets see how much power" dyno session yet... no 1/4 time yet. nuttin but rain out there these days...

 

Thanks - so you adjusted the timing yourself??

 

I wouldn't touch the timing unless you know what you're doing. Very dangerous. But your car should definitely be faster than that .... unless the LT1 Vette has more than you think. Before I added a midpipe and ran 13lbs of boost, I easily outran my buddies bone stock LT1 Vette .... my setup was almost identical to yours. I did have a lightened flywheel, but that shouldn't make that much difference in third and fourth gears.

Check for boost leaks. Change your spark plugs. When's the last time you changed your fuel filter? How's your clutch feel ... slipping or anything? The GT-N's are definitely more unsprung weight, but it shouldn't weigh you down THAT much. That said, how's the tread on your tires?

 

brand new tires, less that 800 miles on fuel filter & plugs. Tires have 200 miles max. Clutch feels solid.

 

Ok - I changed my 1" hose clamps from stock to the worm screw type. Took it for a drive and seems to make a difference in sound :? The turbos seem more pronounced which doesn't make sense to me if I had a boost leak. Maybe if it was on the exhaust side, but not on the compression side.

Anyway, it still feels laggish in the upper rpms and I wasn't hitting too high of boost. I am now thinking my 1500 mile new hiflow cat may be clogged?? wtf?

 

Hmmm ... perhaps some larger-than-normal drivetrain losses? When's the last time you flushed your tranny and differential fluids? Just throwing out some ideas. I doubt your hi-flo cat is clogged. If you're getting full boost at all, then it's unlikely that the cat is the problem. It could be that your fuel maps are super rich, but I ran my bud's LT1 with fairly rich maps and still walked him pretty good.

 

tranny fluids were changed at 14000 miles. Car has 21000 now.

Hmm it is weird though - It almost feels like the wastegate is fluttering or the cat is clogged as it has micro hesitations as it isn't pulling.