I thought this was a descent article.

http://www.gmhightechperformance.com...ing/index.html

I got a TON out of my car with a tune. We are still tweaking it, too.

 

Cool, but I think I'd be too nervous to dig into a cars tune that much while it was still under warranty.

 

I would too, but with what Jason has planned...keeping the warranty probably never crossed his mind.

 

WOW! The gains down low for both hp and tq are awesome! Over 50 more hp and 80 more lbs at some points!!

 

Those are some great gains in power.

What I still don't understand is why the car is tuned the way it is from GM. What are they trying to protect....A6, IRS?? Like was shown here in some places they were on the lean side and in others too rich. I just don't remember the LS1's being tuned this poorly from the factory even when torque management was ramped up. Even now the LS3 isn't having this issue.

Because 317hp/310tq from a 400hp L99 is almost worthy of a GM "fix" like Ford did with the 1999 Cobra.

 

It's what I've been saying right along.
People are talking about putting cams and headers on without thinking that the car just needs a good tune.

 

It seems most of the power difference in the illustrated passes is made below 4k rpm, and that it is torque management that is the single biggest culprit. While you will feel that on the street for sure, it won't make a big difference in ET/MPH at the track.

Above 4k, where the runs are more comparable, the power gains were good, and likely showed real HP increases from the motor vice being electronically limited by the computer. These gains were more in line with what you would see when tuning other performance cars, and is power that will show up in timeslips.

Yes I know, I'm drag strip centric. Forgive me.

Also, while the power gains that are made with tuning are solid, make no mistake....to get seriously bigger power....cams, headers, etc will be required. The LS3 is an excellent platform from which to achieve awesome power in N/A form with those kinds of mods, and I assume the L99 is also.

BTW, there are those of us who will ditch the warranty rather quickly to do these kinds of things.

I don't know if it is that bad, but it does seem low for a 400 HP rating.

 

Incredible gains! 51 rwhp at the top end... but I'm more impressed by the gains from below 3000rpm.

It took a very good tune to get 50 rwhp from an LS1. It was generally attainable with headers and cat-back exhaust and PULP.

But the L99/LS3 is in another league altogether.

 

The only explanation I can offer is that GM had basically run out of money and decided to cut some development time out of the engine and transmission tuning. The powertrain tunes ex factory leave a lot to be desired.

Good fun for a self tuner, though.

 

I would think it is detuned more to protect themselves against warranty claims.

 

Bob, the reason for the low dyno numbers is due to the ambient conditions, auto trans, 20" wheels, tyres, IRS...

See quote below.

 

What i don't understand is GM keeps making these engines more and more powerful and then they basically detune them and put in so much torque reduction BS that you basically have 400+ hp that when it's hot outside and you hammer it you only get 300hp. Give us what you advertise and quite cutting the power back in the computer. If 350hp is all it can take then give us 350 hp all the time, not 400 one minute and then 300 after 5 minutes of getting on it.

 

13hp and 20 something torque is pretty impressive. thats just the stock car right? nothing is different about it? thats not bad. i need to go get my car tuned with this exhaust and see what it gets me.

 

Where do you see 51 RWHP "at the top end"? I see ~15. A solid gain from just a tune to be sure - but hardly the amount you quoted.

Note that I've already addressed the low rpm power - whether folks agree with my analyis or not is a different story.

I read the article, and looked at the data.

- Ambient conditions were accounted for via the SAE correction factors. Not an issue.

- No clue why 20" tires would make a difference on the dyno. Weight matters not on the rollers, and higher gearing (lower numerically) that would result from those tall tires would typically show MORE power than lower gearing. Not an issue, in fact, could even skew numbers up a bit.

- Why on earth would you mention tyres? Were they spinning on the rollers? Not an issue.

- How much power does the IRS chew up? I would suggest very little - as in less than 5 RWHP. I did back-to-back testing on my 99 Cobra with its stock "band-aid" IRS vs a live axle, and the average result was <5 RWHP. Minor issue, at best.

- Auto trans will obviously not show as much power, on average, as a manual. I got that. I think most people get it too.

350 HP LS1s (we all know that's what they made) with A4s typically produced in the neighborhood of 300 RWHP. I will stick with my opinion that 317 SAE Corrected RWHP through an A6 with a rated engine HP of 400 seems low. Perhaps I'm wrong - but that is my opinion/perception.

If your opinion differs, ok.

Bob

 

Nah, yer right...

That's low.

Mustang dyno or a dynojet?