Erickeown3

I bought my car on 22's but I have since switched over to 17 inch rims, but now the speedometer is off by 5 to 10 mph depending how fast I'm going. I plan on putting 342 gears in the Car soon also, So how exactly do I adjust speedometer?

I also plan on running headers no cats in a cut out soon. Will attuned keep my check engine light from coming on when I take the cats off?

And if I do do a tune, what kind of power can I pick up from it?

Most likely it would just be a program to know what someone in town do, but maybe a Dino tune. Also should I get the cartoon to 93 octane?

codyvette

iTrader: (24)

Always run the car on 93. A tune is always a good idea and on stockist car is worth 20-30 whp. The seat of the pants feel will be great though. The speedometer is also fixed during the tune.

Erickeown3

A Dyno tune specifically or will a hand held tuner or computer tune work?

codyvette

iTrader: (24)

No hand held will do worth the cost. A good street tune or mail order tune will work well. A dyno tune will always have the best optimization though. There are several sponsors on here that do mail order tunes.

Erickeown3

How does mail order work? And what's the price vs dyno?

SouthernRex

You take your PCM out and mail it to them, they tune, and send it back. Everyone I have ever talked to about this swears by Frost of "Tuned By Frost." Nothing but good press about him.

RPM WS6

iTrader: (3)

I agree about tuning for 93 octane, as long as it's available locally. However I disagree about the power gains; I wouldn't ever expect to see 20-30rwhp from a dyno tune on an otherwise stock LS1. Having said that, as the OP did mention doing headers/ORY, with several bolt-ons in place one might see gains near the lower end of that range from a dyno tune.

Simple speedometer adjustments can certainly be accomplished with a hand held tuner, but you'd be better off getting at least a mail order tune as mentioned above.

Yes, a custom tune will take care of this issue.

Not very much if the car is otherwise completely stock, but it's definitely worth it after the headers. For now, the main benefit will be getting the speedometer corrected.

murphinator

iTrader: (2)

on a stock car you wont pick up a lot of power unless the tuner is using a wideband and gets fueling optimized and is able to add a fair amount of timing advance but it still wont be a huge amount as far as max #'s you would see on a dyno. Where the most gains will be is from removing torque management (which limits power at pre determined times like during shifts) , increasing rpm's a bit for WOT shifting , verifying throttle bodyis opening all the way and mechanically adjusting until the tps values show it is indeed fully opening , adjusting downshift and upshift data , shift pressures ,etc... to just feel tighter and more aggressive.

The speedometer/tire calibration stuff is simple , tuner will just go to the speedometer tab and enter new gear ratio in the gear ratio field and choose the tire size from a drop down and apply. tuning out the dummy light for no cats is just changing a check mark as to how it reports.

J1newso

I would look at tunning only for what octane gas is easily available in your area. Running different octanes on a tune will not be good since the timing will not be right for the different combustion rates.

I did a cam and long tubes (full exhaust) only on a stock ls1 and hit 368rw and 375tq. This was a 91 octane tune from a dyno.

My check engine light did not come on with no cats, but could happen.