[pavetim]

I have a Katech 87mm throttle body sitting in the garage. If I throw that on my LT4 will it require tunining?

[JSH]

Originally Posted by pavetim

I have a Katech 87mm throttle body sitting in the garage. If I throw that on my LT4 will it require tunining?

I would call and ask them, but I wouldn't think it would.

[RobZL1]

you should be good. might need to do the throttle body relearn

[2023_ZL1-AUTO]

I put a 100mm on my new 2023 ZL1 and didn't require a tune. But, yes it require that I unhook the battery for a minute, reconnect and drive a bit to do a throttle "re-learn"

[KingLT1]

Originally Posted by 2023_ZL1-AUTO

I put a 100mm on my new 2023 ZL1 and didn't require a tune. But, yes it require that I unhook the battery for a minute, reconnect and drive a bit to do a throttle "re-learn"

what does the timing show at idle with the throttle body?

[Joshinator99]

Originally Posted by KingLT1

what does the timing show at idle with the throttle body?

That’s the question of the hour. I tried a “ported” TB by a vendor that was supposed to be better than a 103mm…absolute nightmare. Tons of negative timing at idle and the car acted possessed. I took it off and put the Katech 103 back on, problems are gone. I then upgraded to the Katech 112, also no problems.

[SJFGTO]

Originally Posted by RobZL1

you should be good. might need to do the throttle body relearn

^^^Agreed.^^^ Unhook the battery, install, hook it back up and go for a long drive. You should be good to go.

[Katech_Mike]

The CNC ported 87mm throttle body does not require a tune.

The CNC ported 95mm or billet 103mm throttle bodies both require tuning.

[RobbyBeefcake87]

I'm seeing negative timing at idle. I have a Nick William's 103, on a tuned car the TB relearn would not be a necessary thing to do correct? I suspect mine is coming from a probable MSD leak and I know the MM Wild is causing some vacuum leak because when I cap it off idle timing is much better. Just trying to make sure the TB relearn is not necessary on a tuned car.

[RobZL1]

Tuning should have fixed the negative timing by adjusting the torque and airflow modeling.

[2023_ZL1-AUTO]

Originally Posted by KingLT1

what does the timing show at idle with the throttle body?

I will have to get back with you on that one!! I just installed my long tube headers and getting ready to do the rest of the exhaust and the Corsa Axle back with NPP. Then on to the sweet looking Katech valve covers with coil relocation kit, new Granatelli new coils and 0ohm plugs wires, then reassemble the rest that I took off to do all this work! So at the moment, she isn't firing up! But once she ready, I'll check the timing before any tune is done.

[LiqTenExp]

Originally Posted by RobZL1

Tuning should have fixed the negative timing by adjusting the torque and airflow modeling.

Yep!

Anyone attempting TB should observe their Zero Pedal Engine Torque and compare it to Predicted and Immediate Tq and update their Torque Model values to get their timing back in the positive values, somewhere like 0 to +10 degrees (ish). Also want to tweak the throttle body area values and if you are feeling skilled go into driver demand tables to adjust curves for improved driveability.

Here is a video that touches on this topic, it is associated with changing the CAM but at the end of the day both TB and CAM are changing the airmass into the cylinder: