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View Full Version : Good tune but bad numbers...



r33pwrd
04-05-2009, 06:28 AM
So long story short my car dynoed 290/311 stock (assuming 87 octane or what ever the dealer put in her) After bolting on headers, X-pipe and Vararam, and 92 octane she did 307/322 ?? not much gain for a Intake and headers? All nomber are corrected and on the same dyno....

After a tune I did 337/346 so I did pick up nice numbers from my tune but stock to headers / Vararam where quite depressing for tha amount of money spent.

G8GT721
04-05-2009, 06:39 AM
well from what i understand you don't really use anything to its full potenial until tuned so thats why you would se a small gain with no tune, and i believe OTR intakes perform better on the street than on the dyno

-Ray-
04-05-2009, 06:44 AM
What gas did you have in your G8 at the time of the dyno?
Where are the dyno sheets and the afr?

jbradsh1
04-05-2009, 06:46 AM
So long story short my car dynoed 290/311 stock (assuming 87 octane or what ever the dealer put in her) After bolting on headers, X-pipe and Vararam, and 92 octane she did 307/322 ?? not much gain for a Intake and headers? All nomber are corrected and on the same dyno....

After a tune I did 337/346 so I did pick up nice numbers from my tune but stock to headers / Vararam where quite depressing for tha amount of money spent.

I remember when I was up at VMS, we installed the Kooks shorties + high flow cats without anything else done, no tune, no cai, but I did have premium gas in it. Picked up exactly 15 rwhp from just shorties, then with the RF and tune it picked up a total of about 40 rwhp. Just for comparison, hope this helps you in your deliberations.

GRRRR8
04-05-2009, 07:24 AM
Get a tank or 2 of 92/93 run through it and a HSRK and get back on the dyno. It should be closer to 355-365. Minimum. Vector got 346/358. I know dynos, air temps etc can cause a difference. Did they have a big fan in front of the car and close to the grille?

r33pwrd
04-05-2009, 08:18 AM
Get a tank or 2 of 92/93 run through it and a HSRK and get back on the dyno. It should be closer to 355-365. Minimum. Vector got 346/358. I know dynos, air temps etc can cause a difference. Did they have a big fan in front of the car and close to the grille?

Yes BIG fan... had 92 in it for 2 plus tanks (for yesterdays dynos but base line runs had 87 I believe) car feels pretty good but still no chirp into second? Like I said the # we gained from the tune apear to be on par with other but my car with headers and intake has less HP than a lot of peoples stock cars...

I will get dyno sheets up once I can get to my wrk e-mail (where he sent the files)

I am hoping to get to the track next weekend to run her..

r33pwrd
04-05-2009, 08:19 AM
Get a tank or 2 of 92/93 run through it and a HSRK and get back on the dyno. It should be closer to 355-365. Minimum. Vector got 346/358. I know dynos, air temps etc can cause a difference. Did they have a big fan in front of the car and close to the grille?

anyone running a HSRK with the vararam? Are they worth the money? where do I get one?

GRRRR8
04-05-2009, 08:21 AM
Yes. Vector Motorsports. They work!

modern-muscle
04-05-2009, 10:44 AM
It's not uncommon for us to see exactly what you saw on the dyno after bolt on s without a tune. In fact, many times on C5 corvettes, we see a drop in peak torque after bolting on long tube headers. After a tune, that all changes.

One of the great things that headers allows you to do is to run more timing advance than stock manifolds. These Gen3/4 GM powerplants respond very well to increases in timing advance. Increases in the motors efficiency is good for a few HP, but it's really all about maximizing the use of timing advance.

That being said, the HSRK kit is another method to keep timing advance in the motor. The stock GM timing retard vs. IAT table is overly conservative. Timing begins to be pulled pretty quickly and ramps up quite a bit. One way to combat this trend is to keep the actual IATs recorded instead of heat generated by a heat soaked sensor. The other way is to make the IAT vs timing retard table much less conservative while making it more useful and still very safe.

r33pwrd
04-05-2009, 12:46 PM
thanks for the great input guys! I will try the HSRK and report findings! Just had the car out and man it is a blast to drive now :)

2ltrgsr
04-05-2009, 03:28 PM
mine put down the same exact number but with jba longtubes and a custom x-pipe, with roto fab intake

r33pwrd
04-06-2009, 07:00 AM
HSRK ordered from Vector! (Thanks for the fast shipping)

Here is the dyno chart... one is car with stock tune with headers and vararam other is tuned. Let me know what you think. Thanks

r33pwrd
04-07-2009, 07:04 AM
TTT feedback on the dyno chart above?

ddcook08
04-07-2009, 07:22 AM
I wouldn't be too concerned with dyno numbers IMO. Take it to the track, that'll tell all...just make sure you're consistent with your runs

r33pwrd
04-07-2009, 08:11 AM
I wouldn't be too concerned with dyno numbers IMO. Take it to the track, that'll tell all...just make sure you're consistent with your runs

Im very happy with the gain from Vince just a little supprised at how little I gained with the headers and Vararam (pre tune)! The car drives amazing! Vince did a nice job on the tune!

modern-muscle
04-08-2009, 05:12 AM
Fueling needs a little work, but it's pretty close. Too fat at peak torque and HP. There's a few more ponies in her.