L76 vs LS3 ETC Area Scalar

[VodeAn]

I noticed from the factory the L76 in the G8 GT has an area scalar of 4725 and ls3 vehicles (like the Corvette, G8 GXP, and Camaro) are set to 5636.

Is there a size difference between the two throttle body sizes to warrant the change, or did GM make the change in the cal for a different reason? (like the OS differences between the L76 G8 GT and LS3 vehicles)

I checked the repository and a 2009.5 G8 GT uses the larger number, 5636 like the LS3 vehicles. Is the 2009.5 G8 GT throttle body different from the 2008 and 2009 model years?

[johnbell2]

Yes, the 2009.5 uses an LS3 tb, the 2008 and 2009.1 use an LS2 tb.

[VodeAn]

Thank you for the quick response. I examined a LS3 throttle body after you confirmed a difference. Although similar in size, after a comparison I suspect the differences in the calibration are due to the increased flow and reversal of the throttle body's opening direction. The ls3 throttle body looks to be of higher quality and the intake manifold side seems to match the ls3 intake better.

[snowvette]

LS2 = silver blade.
LS3/LS7= gold blade, I believe.

[MikeOD]

The silver and gold blade TB's don't work the same (electrically) either. If you plug a silver blade TB into a gold blade vehicle, it will not open 100%, something closer to 85%. If you put a gold blade TB on a silver blade vehicle, I'm not sure if it opens too far, or trips REP.

You have to be careful of that as they share the same bolt pattern and electrical connector.

[johnbell2]

Thank you for the quick response. I examined a LS3 throttle body after you confirmed a difference. Although similar in size, after a comparison I suspect the differences in the calibration are due to the increased flow and reversal of the throttle body's opening direction. The ls3 throttle body looks to be of higher quality and the intake manifold side seems to match the ls3 intake better.

Fortunately GM made this easy to figure out on the G8... if your L76 G8 is a 9L1 or 9L2 VIN, it has the LS2 tb... if 9L3 (either L76 or LS3), it has the LS3 tb

[griffincox]

The silver and gold blade TB's don't work the same (electrically) either. If you plug a silver blade TB into a gold blade vehicle, it will not open 100%, something closer to 85%. If you put a gold blade TB on a silver blade vehicle, I'm not sure if it opens too far, or trips REP.

You have to be careful of that as they share the same bolt pattern and electrical connector.

I have never heard this. TBSS guys seem to swap between a myriad of throttles with no ill effects. Any calibration changes needed?

[johnbell2]

I have never heard this. TBSS guys seem to swap between a myriad of throttles with no ill effects. Any calibration changes needed?

pull up the diffs between a 2008 and 2009.5 G8 GT stock file and you'll see what we have to put up with

[ScarabEpic22]

I have never heard this. TBSS guys seem to swap between a myriad of throttles with no ill effects. Any calibration changes needed?

It's been an issue for a while, some trucks have issues and some dont. Most of the well-known TBSS tuners have got it squared away, not sure what was changed tune-wise.

[griffincox]

I made this to help clear up any confusion. Most vehicles that carried production across the 2008-2009 border will have different throttle bodies depending on year. LS2, LS3, LS7, etc.

Most notably... pretty much all cars use what is usually called a "car" throttle body, except the supercharged ones. All LSA, LS9 cars share a throttle body with the truck lineup.

Can anyone point me to some of the discussion on calibration changes depending on throttle body?

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[johnbell2]

http://youtu.be/Dms8_nBrIDE