BacktheBlu

Just finished off the Stage II Procharger install on a 98 Vert. Running 7-8 lbs boost with a 3.85 pulley, LS6 intake/80 mm BBK TB, LG street Series/no cats and AIS meth system. The car is running great but is outflowing the stock LS1 MAF which will be slated for replacement in the spring along with a FAST intake and 90 mm TB.

The meth is set to come on around 3 lbs. Final numbers are 479 RWHP and 448 RWTQ. Timing at WOT is around 18 deg. The motor is a stock LS1 otherwise. AFR is almost dead on 12.

I feel these numbers may be on the low side for the combo. Thinking they should be in the low 500's for RWHP and around 480 + for RWTQ. Is the stock heads/cam combo the culprit?

Any input from the FI experts would be greatly appreciated.

BUBBAS 01Z06

I just had the Vortech S trim installed on my 01 Z...

The numbers were 600/512 with a custom grind cam, fast 90/90, ARH's, stock heads and no meth....

I'm a FI noob so I'm not really qualified to make comments on your installation and set up....but the #'s do seem a bit low...

I'll sit back and on this one.....

What kind of dyno was it ??

Bubba.

SpeedyD

Is this on an auto?
What type of Dyno?
If an auto, it seems a bit low. If stick, I think it's low.
When you said the AFR is dead at 12, 12:1 right? Is that on the Meth? To me that is lean while on Meth. Most will say the basic rule is a point lower while on meth, so if you were to run 11:1 on gas, add meth, you should be 10:1.
Just my opinion though.
Dan

rplaster

Mn6 in your profile. Those are low numbers for a 6-speed. I was running 10#'s on my 98 with a D1sc. Dynojet or Mustang dyno?

95BlueBomber

I just finished a 99 Auto and it made 501 on a stock motor. Stock ls1 intake, heads, and all... Its a vortech v3 with the 3.8 pulley

BLOWNBLUEZ06

A good blower cam will make more difference than a set of ported heads. ECS cam is very popular. I have the A&A cam and love it. Arun at CDNperformance has good cam grinds as well. There are many vendors to choose from. EPP, Dallas Performance, Canadian Performance, A&A, and ECS. Give one of them a call and they will determine the best cam for your driving style and performance desires.

BacktheBlu

Thanks for all the info guys. Sorry, I did forget to include that it is a Mn6 with stock sizing wheels and that the car was tuned for meth with the AFR being 11.8 - 12.0:1.

The car previously made 337 RWHP and 351 RWTQ with LG headers, X-pipe, no cats, LS6 intake, 80 mm BBK TB and a VR2 Vararam.

Both the runs prior to and after the supercharger install were made on the same Dynojet for comparison.

Is it possible that out flowing the stock LS1 MAF is killing the top end HP?

I will post a dyno graph of the run as soon as I figure out how to copy it.

JustinStrife

Seems a bit low to me. I'm making the same and my only mod is headers and the D1SC @ 7-8psi(still rocking the LS1 intake manifold and no meth on 91' Octane).

SpeedyD

The MAF shouldn't have anything to d with it, I'm running 700 WHP on a LS1 MAF, stock LS6 intake and stock LS6 heads.
Dan

willig72

I am no tuner or F/I expert, but I have read where a lot of high HP cars still have the MAP sensor.
They say the MAP does max out, how they tune for that I don’t have a clue.

madmatt9471

Darren,

Got your PM too!

The numbers seem a little low for your set-up! so here goes:

1. The stock MAF - If you have not changed to the 2 BAR MAP sensor you need to - our MAF's do not have enough table for the SuperChargers amount of flow.
AC DELCO Part# 213-1631 or GM Part#12580698

2.A4 ? Torque Converter - Stock or Stall?

3. Which rear gears? MN6 3.42's or A4 with 3.15's or 2.73's

It should be over 500 RWHP at least! We did one on my buddies 2004 STOCK LS1 Vette and he put down 525 RWHP and 490 RWTQ and it was completely stock MN6 with full Kooks exhaust system and Meth.

Do not use the stock MAF but go to the 2 BAR MAP sensor set-up and you'll get the desired results - It will need to be re-tuned but it'll be worth it.

Let me know when the graph is up too!

Thanks,Matt

NemesisC5

In my beginning with only catback & cats deleted, CAI, Hypertech "canned" tune I made 337rwhp on my 99 MN6. With AFR 205's, Kooks LT's and the baby blower cam in my sig power moved up to 397rwhp. Then a couple months later the LS6 intake & A&A Vortech S-Trim system with 7-8psi was installed and the power jumped to 606rwhp

FWIW for everyone that may not know, the camshaft specs on a 98 are .479/.472-207*/198*-117lsa.

Good Luck with Your Car

madmatt9471

The 98's MAF's suck in comparison to the later model MAF's on the Vette's!

Plus the 98's operating system is limited, so a 2 BAR MAP sensor would do well in his case as it did for me, being I also have a '98.

It takes it past the stock MAF table so there is "NO" guessing at what the VE tables etc should be at, as opposed to using the 2 BAR MAP
and being able to tune for the best HP and TQ under BOOST.

Thanks,Matt

SpeedyD

I don't disagree that it's better but he should still be pulling a decent amount more power even using the stock MAF. SD tuning is the best way to go with forced induction but regardless the reults are low. Thee might be other issues at hand.
Dan

BacktheBlu

Thanks for all the info fellas! I will make the upgrades and retune the car in the spring as winter is now upon us here.