I've decided that my 383 is slower than it should be. Last night I raced a LS1 w/ exhaust and maybe intake. He said he put down 330 rwhp and I barely barely beat him. I do have a problem with traction but I still should have pulled him more than I did. Here are my engine specs. I was hoping for close to 400rwhp but if I can barely beat a 330rwhp car then I've got problems.

383 Cu.
230/244 .544/.576 Cam (CC306)
Ported LT1 heads flow 272/192 @.500 & 283/203 @ .600
Hooker LTs and other bolt ons (TB, fuel pump, etc)
M6

Any ideas on where the rest of my horsepower is hiding? My car doesn't weigh too much, I just have the usual crap.

No knock either.

Thanks

 

Is it tuned? What kind of times you run in the 1/4mi?

 

Not dynotuned, but it has been programmed by PCMforless along with some small tweaks done by me. I know I need a dynotune but I can't afford it and it seems that I have other problems that need to be fixed first. *I think* it should be faster even with a crappy tune. Anyone disagree?

Sorry no times either, I was afraid to break something with 400 hp but now that I doubt I have that I might take it to the track.

 

I put down 378rwhp through a 700R4 and a 3200 stall.

I have a serious traction problem even on Nitto DRs and some stock LT1s will pull 2 cars on me while I spin through 1st gear.

I start to pull in 2nd and then murder them in 3rd.

Going to cure my traction problem right away with some ET streets and draglites.

 

Just go to the dyno and verify how much power you have. If you're only making 350 RWHP or so, check if anything is wrong..foul plugs, weak ign coil and/or Opti, dirty air filter, clogged cat, fouled O2 sensors. If not, then you have a mismatch of parts in your engine combo. Bear in mind LS1's are lighter than us due to their all aluminum engine.

 

If you can find someone w/ a laptop and cable to run some logs of your car while @ WOT and @ driving around, send them to Bryan at pcmforless and he will be able to look at hundreds of parameters that may show your problem. How do you know you're not getting knock? Bare in mind that you need to upgrade your ignition as well. Also, you may have deceived yourself. I've had lots of customers that go out and drive there LT1 after heads/cam/stroker and expect it to have the same power band. In reality, cams such as the CC306 make the power feel a lot smoother so that you don't realize the power about 5K rpms. My LT had heads that flowed 265/190 @.50" w/ an LT4 hotcam and I did horrible against LS cars until we really got rolling. What sort of stall/gears do you have? Also, who did your heads? Those flow numbers seem a little unrealistic unless you got a REALLY high dollar set of heads. What size throttle body are you using? What is your fuel pressure set at. Yes, you have more traction problems than you know. Once I got my car to hook I went from a 2.3 on DRs to a 1.7 on DRs w/ suspension tweaks. That's a HUGE difference that would be the difference between losing and annihilating the guy next to you

 

I have a 383 with a much smaller cam (actually smaller than a hot cam) that put down 407 rwhp through an SLP 2600 stall. You should be making alot more than 330 rwhp. I can think of only two things...either the LS1 car is making alot more than you think or you have a big problem with your combination.

LS1s with bolt on mods are no problem to beat, especially off the line. I only run street tires (firehawks) and murder everyone off the line. From a roll with an auto it's touchy depending upon where you are in the powerband when the race starts.

One last thing, no knock is not an indication of having a good tune. The KR tables may have been zeroed out. You did mention that PCMforless did the tune so based on what I've seen on this board it's probably not the source of your problem, but still worth checking into.

 

Thanks for the advice/incouragement guys. Maybe I am decieving myself.

LT1Brutus, its 52mm TB, running stock fuel pressure, the car is a 6 speed with 3.42 gears, and the heads were done buy Lloyd Elliott who seems to have a good rep.

I have datamaster as well as a scanmaster in the car so that is how I know if I have knock retard. I guess I could have seriously mismatched parts but I don't have the money to pay someone to design custom cams etc to make the most hp.

Thanks again

 

dude i had the same problem after i got my 383 going.. ill tell you what i had to do - 1)changed fuel pump (walbro) picked up ALOT! 2) 30lb injectors (my stockers were shot, 90k miles) after that my car felt like a viper! 1st dyno pull - 330wrhp. oh you need an adjustable fuel pressure regulator. btw my computer was tuned by pcm4less to as a base tune also. my guys LT1edit wasnt working the dyno day so he turned down the fuel pressure w/ the regulator i think it was set at 50psi first, he put it down to 40 then 30 and i made 380rwhp and like 411rwtq.

good luck dude! i know how pissed u are right now because i was on the same boat a couple weeks ago.

 

I won't deny Llyod's product reputation.....I'd look @ fuel delivery. ONe way or another you need to run some logs of your vehicle's realtime readings

 

What kind of compression do you have? Sounds like you need injectors, fuel pump, and a lil more compression. Big cam N/A needs compression. Gear ratio could be a big factor to, I woulda stayed in the 4's. What kind of clutch is in the tranny? If your clutch is slipping slightly you might not feel it but its hurting enuff for speed. It doesnt always mean its in the engine so dont get dissapointed yet.

Zach

 

Can the clutch really slip when accelerating? I know it can when launching and whatnot but can it slip enough to slow the car even though it is pulling good (confusing)? I have a stock clutch that slips bad on launches but seems to catch eventually. I can't afford a replacement right now. I really hope this could be the problem.

My fuel system should easily be able to keep up; 36# injectors and 255lph Walbro in-tank. Compression is about stock, I was aiming for 10.4:1 cause I can't get good 93 all the time.

 

Uh, yeah, that clutch has got to go. Yes it can slip far past when you're able to actually detect it slipping. SPEC clutches arent that bad these days. I could hook you up w/ a stage 3.

 

no dude something has gotta be wrong... i can race my buddy that has a ZO6 w/ the LS6, FROM A SECOND GEAR ROLL, and i pull away from him like no ones business... ALL MOTOR

check that tuning

 

i think you should definitely replace the clutch. my car is running great after cam install, but i can't even chirp second on street tires. also a bad clutch will greatly affect midrange/topend because the torque and horsepower peaks have been moved even higher up the rpm range with the big cam.