Low Performance and No Idea Why. HELP!!!
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Teching In
Joined: Jan 2005
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Low Performance and No Idea Why. HELP!!! First off here are all my mods: Its a 98 T/A. Stock Crank, 6.0 Liter Truck Rods, Mahle Stock CR forged pistons,Stock 98 Heads, TSP 232/234 .595/.598 112 LSA Cam, Comp Lifters, TSP +.100" pushrods, Stock Rockers, PRC Gold Valve Springs (good to .650 lift), LS6 Intake, Ported TB, SLP Smooth Bellow, MTI Lid, Pacesetter 1 3/4" LT's, TSP 3" OFY, Magnaflow 3" Catback w/ cutout before muffler, Vigilante 3600 converter, FLT Stage IV 4L60e, 3.23 gears, and 15 x 4 Telstars up front w/ metric radials, and 15 x 8 Telstars in rear with 275-50r-15 MT ET Street Radials in the rear.
Ok, i went and had the car dyno tuned by Allan Futral and Futral Motorsports, and the car would just not make any power ( 342 rwhp unlock converter, and 357 locked). Everything I have seen says my car should make 360-365 unlocked, and around 390 locked. Allan said he has no idea why it wont make power. One thing is was kinda worried about was that he tuned my car to a 14.1-14.2 AFR, and he said that his Wideband meter reads .6-.7 higher than most so my AFR is really 13.4-13.5 and thats where he likes to set his. I was still leary so i pluged in a buddy's computer with HP Tuners to check for Knock Retard, and there was none. I still think it is lean because i took it to an 1/8 mile track and it only ran a 8.14 @ 86 w/ a 1.85 60'. It was just a dog off the line. What do you all think. Im dumbfounded. Could being just lean with no knock retard rob 20-30 hp. Any suggestions or comments are welcome. Thanks
Ok, i went and had the car dyno tuned by Allan Futral and Futral Motorsports, and the car would just not make any power ( 342 rwhp unlock converter, and 357 locked). Everything I have seen says my car should make 360-365 unlocked, and around 390 locked. Allan said he has no idea why it wont make power. One thing is was kinda worried about was that he tuned my car to a 14.1-14.2 AFR, and he said that his Wideband meter reads .6-.7 higher than most so my AFR is really 13.4-13.5 and thats where he likes to set his. I was still leary so i pluged in a buddy's computer with HP Tuners to check for Knock Retard, and there was none. I still think it is lean because i took it to an 1/8 mile track and it only ran a 8.14 @ 86 w/ a 1.85 60'. It was just a dog off the line. What do you all think. Im dumbfounded. Could being just lean with no knock retard rob 20-30 hp. Any suggestions or comments are welcome. Thanks
I was reading your post thinking that was a lot of cam for stock 98' heads. Have you checked simple things like fuel pressure? If you are able to, hook an FP guage to it and tape it to the windshield to see if the FP drops off any at higher RPMs. A safer way would be to throw it on a chassis dyno and watch the guage throughout the dyno run. Given you rear tires & stall... I'd think it would do better than a 1.85 sixty foot. 
My car w/ full bolt ons, SY3500 stall w/ a soft 1.63 STR, 3.42's, & M/T 255/50-16's mounted on stock 16" wheels was a tenth or so faster in the 60'. My friend's car w/ 17" M/T's and a fuddle 2.1 STR 3400 stall did a bunch of 1.62's last winter.
My car w/ full bolt ons, SY3500 stall w/ a soft 1.63 STR, 3.42's, & M/T 255/50-16's mounted on stock 16" wheels was a tenth or so faster in the 60'. My friend's car w/ 17" M/T's and a fuddle 2.1 STR 3400 stall did a bunch of 1.62's last winter.
hey dont feel bad man, my car has almost same exact mods with stock heads and TB and i made 350 rwhp and 353 rwtq after dyno tune... but she drives ubelievable and hard, DD it and runs so smooth, also 26 mpg on highway 
. so dont feel bad man, i am right there with ya, i bet with some new heads, PRC 2.5 on there for both of us we be pushin alot more. plus its what u get at the track that counts. i also have 2.73 gears though. also, dont forget its an automatic, tough to get them up there in high number with big stalls and such.
. so dont feel bad man, i am right there with ya, i bet with some new heads, PRC 2.5 on there for both of us we be pushin alot more. plus its what u get at the track that counts. i also have 2.73 gears though. also, dont forget its an automatic, tough to get them up there in high number with big stalls and such. Last edited by 1WICKDZ; Jun 29, 2006 at 06:26 PM.
TECH Apprentice
Joined: Sep 2005
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I hate to say it but 390 rwhp locked with your setup is wishful thinking. I'm sure there's M6's barely making 390 rwhp with those heads and your setup. I also doubt there's any questions in the tune since Alan tuned it. You really should invest in a set of budget heads, I think it will pickup quite a bit over the heads you're running.
Very few cam only 98's will break 360 unlocked, your numbers seem right to me for your car, 98 heads aren't too great. Trust me, I know. I dont think you'll sniff 390 cam only though, it took me some ported and polished heads to get there (but then again, my cam is a BABY, 224/224 dur and .563 lift, woot!) Don't sweat it though man, A4's and dynos don't go together!
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