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-   -   The Official Tuning Thread (http://legacygt.com/forums/showthread.php?t=80345)

Infamous1 01-30-2008 05:19 PM

The Official Tuning Thread
 
I figured we could try to keep this stuff in somewhat one location. So if you got anything tuning related post it up and hear different options.

Let me start with a topic that has came up alot recently. I know the answer but a lot of folks don't.
*How does one gain power from higher octane points safely?

Post away any of your tuning related questions!!!

rao 01-30-2008 05:24 PM

More timing and/or more boost :)

Boostjunkie 01-30-2008 06:58 PM

Leaner too, especially for those stuck with 91 octane at the pump.

MiniStiGuy 01-30-2008 10:59 PM

step 1. add boost
step 2. adjust timing
step 3. adjust fuel
step 4. log, log, log
step 5. adjust steps 1,2, and 3 accordingly after step 4 is peformed a lot.

Infamous1 01-30-2008 11:28 PM

Rob, Paul and Garrett all good points.

MiniStiGuy 01-30-2008 11:35 PM

don't forget about injector cycles. :D

Boostjunkie 01-31-2008 12:18 AM

Quote:

Originally Posted by MiniStiGuy (Post 1676185)
step 1. add boost
step 2. adjust timing
step 3. adjust fuel
step 4. log, log, log
step 5. adjust steps 1,2, and 3 accordingly after step 4 is peformed a lot.

Actually on a race gas tune, you would first lean out the AFR's. I'd then add boost, then tweak timing. Then maybe a little more boost. Hey, what can I say... I live up to my screen name!:lol: Just tuned an Evo 8 on 91 octane pump gas. Made 414whp, running 26 psi, without a hint of knock. I really prefer to make power with boost (rather than timing or lean AFR's) as long as the car has a turbo capable of running the PR's needed efficiently.

Boostjunkie 01-31-2008 12:26 AM

The same car made 500 whp on race gas. I targeted 12:1 AFR rather than the 11.5.1 I usually tune Evo's to. Ran 30 psi and quite a bit more timing. This particular car seemed to have a weak ignition system as it was incapable of firing the plugs cleanly at higher boost levels, so I didn't raise the boost as much as I might have liked and made the power with more timing. Since I couldn't cram any more air/fuel in to the cylinders, I just used more timing to get what was in there to burn. Of course, higher octane fuels inherently need more timing as they burn more slowly than pump gas.

MiniStiGuy 01-31-2008 12:33 AM

I didn't know we were talking race gas though....

Boostjunkie 01-31-2008 12:39 AM

Quote:

Originally Posted by MiniStiGuy (Post 1676349)
I didn't know we were talking race gas though....

Doesn't matter what the fuel is. You never add a bunch of boost without first dialing in your AFR's. I run wastegate boost while I first tune in fuel.

NSFW 01-31-2008 12:45 AM

Subscribed.

MiniStiGuy 01-31-2008 01:00 AM

well I didn't put a whole bunch of boost.

if I was tuning it I would start with 1lb at a time and go up from there while going through the steps as necessary.

Boostjunkie 01-31-2008 01:41 AM

Quote:

Originally Posted by MiniStiGuy (Post 1676365)
well I didn't put a whole bunch of boost.

if I was tuning it I would start with 1lb at a time and go up from there while going through the steps as necessary.

Never add boost before being sure that AFR's are dialed in and safe and timing is super conservative. No shortcuts. Boost is how we make power, but it is not the first thing to change. If it was, then we'd all be running MBC's and cranking it up. Rome was not built in a day. Get fuel dialed in first before you touch boost.

Boostjunkie 01-31-2008 01:47 AM

It's really pretty simple. Fueling is one factor that doesn't need to be changed much when dialed in. When you start with one factor being a known quantity that makes your life a lot easier. About the only time I touch AFR after getting them set to my satisfaction is if the car responds differently than it should when boost and timing are added. If the car seems incredibly knock prone then I might add fuel to the offending areas.

Paul@FWMotorsports 01-31-2008 10:10 AM

Yup.

I pull a little timing, dial in the A/F ratio, add boost, smooth out the boost, and then play with timing.

Sounds easy, but there are so many variables/parts combinations, that every car is slightly different.


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