97superchgedz28

not sure if i shld post this here..forced induction..or drag section.
i have 97 camaro z28.. procharger 8lbs boost..52mm tb..lt headers..flowmaster exhaust.. moser 12bolt ..4.10 gears.. short shifter.. bigger injectors..bigger fuel pump..shorter lower control arms ..spohn torque arm.. 6spd.. spec stage 3+ clutch.. running slicks.. dyno tuned for 530hp

heres my drag times.. hitting 13.6 1/4 mile ..1.8 60ft time..104mph.. without nitrous. 13.1 with similar 60ft times and mph with 75shot nitrous.

what is going on???.. i shld be running faster times right? lol
im getting decent 60ft times right?
my friends dont notice wheel hop down the strip.. unless there is and its not visible.
what else cld it be? this consistent today.. and last summer after dyno tune the 2nd time. dyno tune after 1st time at a different shop still disappointing times

Injuneer

530HP at the flywheel, or at the rear wheels? With or without the 75-shot of nitrous?

97superchgedz28

without the nitrous... on a mustang dynamoter.. i assume flywheel.. alao tuned for 100 octane fuel and used.

Injuneer

What else has been done to the engine (heads? cam?). Adding 8# of boost would increase the stock HP by about 50%. To get to 530 flywheel HP on a stock engine it would seem you need more boost. I know the inter-cooler and the meth allow you to be a lot more aggressive on the timing, but something still doesn't seem right.

Ask the guy who tuned it if it's flywheel HP or rear wheel HP.... makes a huge difference in what the car should do in the 1/4-mile. What does the car weigh with you in it? MPH is a good measure of the car's HP, without regard to issues like traction, and 104 MPH in a 3500# car takes maybe 325-350HP at the flywheel.

What's the MPH with the 75-shot of nitrous? Should pick up about 8MPH.

Injuneer

Let's move this to "Forced Induction".... they know what they are talking about.

97superchgedz28

I think around 3600-3700 with me in it.. no head no cam work, LT headers, 52mmTB, gutted out cats, and flowmaster exhaust.. Even if the HP was less of the two and it was at flywheel, I should still be running in low 12s shouldn't I? I am thinking about increasing boost. The timing is the same, should that be adjusted?
Car is being looked at by my guy..He's going to check and see if the belt is slipping.. and check the procharger valve. something is going on.. its been like this since the procharger install... even after 2 tunes and upgrading injectors and fuel pump.

Zfbod94

Just as a reference point. The car in my sig had a best run of 13.31 at 105 w/1.97 60ft. On bald street tires.

With your setup I would expect high 11's

97superchgedz28

I definitely appreciate that.. thanks!

97superchgedz28

so i was runnin with a bad sparkplug.. 2nd time this happened.. 1st with acdelcos..then the tuning guys suggested ngks and swapped them in..my mechanic doesnt like ngks so hes searchin for recommended plugs right now... he says car runs like a champ now..but only getting 4lbs of boost. shldnt i get 8 with the procharger psc1?.. or 7lbs?.. mechanic says i lose a lb of boost havin long tune headers.. but ive got 4lbs..hes gonna check and make sure wastegate is workin.. no belt slippage.. procharger on a separate belt with 8 rib. hes lookin to put a smaller supercharger pulley to get more boost. any thoughts why i may ne only seeing 4lbs of boost?

97superchgedz28

Sparkplugs being changed out per procharger recommendation...So procharger says I should be running like 6lbs of boost with my set up, i'm getting 4.5. Belt setup is separate on the procharger, seems no slipping, and all connections tight. What do you guys think? I think i'm going to change out the prochrger bypass valve and put in a vortech mondo bypass valve. also going with 3.7" pulley recommended by the tech guy at procharger. What you think? stock internals.. probably going with a bigger cam next year.
(fyi update: car seems to sit up high in the back, going with a set of lowering springs in the back to help with traction and launching with the increased power)

97WS6SCharged

Anything you do to increase the efficiency of the engine should reduce the amount of boost you see on the gauge. That being said, a centrifugal blower will only produce max boost at engine redline (or shift point) so if the mechanic wasn't taching it out then he wouldn't see the full 7-8 psi. What altitude are you at and what type of dyno was the car tuned on?

97superchgedz28

424 altitude here... 650 at the track. first time dyno tuned was at kennedys.. 4 wheel drive chassis dyno. the 2nd time was with a mustangdynometer.

97WS6SCharged

If you have any scans of the car while it's running down the track that would help. Also a full time slip with numbers for the 300 and 1000 ft mark. FWIW with similar mods I was trapping 124.

CALL911

Sometimes something as small as the air filter can cause a loss of boost. Try changing to a larger air filter as well. I swapped to a larger filter, and went with a metal inlet tube vs the factory one ATI provided me and I gained 5#'s of boost and 100 RWHP. I would not expect you to see similar results as mine was a fully built motor and a maxed out D1SC, but you get my point. A quick way to see if that is your restriction would be to remove the air filter, just while on the dyno and see how much boost increase you get. If its significant, you need a bigger filter.

A vacuum leak can also cause a loss of boost. Besides that, it sounds like you are making logical decisions. Belt slip for example.

Be care full running the boost on a stock motor. Even low levels of boost on stock LT1's (and LS1's for that matter) will cause the motor to wear prematurely, and eventually you'll be looking at a rebuild. It may last 20,000 miles, or it may be 2,000 miles, but eventually the high CR non forged internals your factory came with will not agree with the boost.

97superchgedz28

great thanks I went with a bigger air filter. I'm going to go with a 3.7 pulley, just to get a little more boost since i'm only getting 4.5psi of boost now.