Setup tips for 90mm TB needed!

[Redline Motorsports]

Still trying to better grasp the parameters that need to be tweaked to get the PCM to accept the increase from 75 to 90mm. The application is based upon an F-body (non ETC). B4349 is in the file but looks geared for the ETC cars. I read some old posts regarding this and there seems to be some conflicts as to which direction to adjust this and not sure if it even effects the non ETC cars.

Does 4350 have any impact?

I would think that manually getting the throttle blade where it gets enough air in the motor and still keep IAC counts between 60-80 would be ideal.

I guess while we are on the subject we mind as well discuss the ETC cars as well.

Howard

[Black02SS]

Honestly Howard, I don't do anything different and have never had an issue. I just adjust it so the steps are in that range and go on with the tune. I haven't had a problem on any Fbody.

[Bruce Melton]

I put a LS2/Fast on C5 and did not change anything from Shaner/LS6. I hated the FAST intake for fit issues but it idled and ran fine.

[Redline Motorsports]

I agree that the F-body should not be as much as an issue as the ETC C5. I have been having some issues with high and hanging idle with just the switch alone from stock to a 90mm. What about all the conversation about effective throttle area??

Seems to me with the larger opening and that the throttle blade has to replace the IAC function, that more would be needed to let the PCM know the size difference.

[Bruce Melton]

I agree that the F-body should not be as much as an issue as the ETC C5. I have been having some issues with high and hanging idle with just the switch alone from stock to a 90mm. What about all the conversation about effective throttle area??

Seems to me with the larger opening and that the throttle blade has to replace the IAC function, that more would be needed to let the PCM know the size difference.

Lean idle surge?
In the end if you are getting more air than before you will change your LTFTs a bit and lean your AFR. Which you fix with your choice of methods.

[ringram]

Bottom line as I understand is to reduce your desired airflow to reflect less iac counts due to extra flow around larger throttle blade.
Some move their iac effictive area, but that shouldnt be necessary. Just log the RAFPN and RAFN logging & adjusting etc.

[Redline Motorsports]

Can we talk a bit about the ETC cars?? I know it gets a bit more touchy with the ETC TB's. Do you have to play with the effective area? That parameter seems to be debated in many posts.

I have a 02 C5' to tune tomorrow and I would like to try some new tricks. Its a header, 90 mm setup, stock cam.

[BenKey]

I just put a FAST 90/GM 90 TB on a 410ci from a truck intake. I'd be interested in anything you guys can provide.

[Black02SS]

Can we talk a bit about the ETC cars?? I know it gets a bit more touchy with the ETC TB's. Do you have to play with the effective area? That parameter seems to be debated in many posts.

I have a 02 C5' to tune tomorrow and I would like to try some new tricks. Its a header, 90 mm setup, stock cam.

Shouldn't really need to do too much to it Howard. Just get the VE in line and the rest should be cake.

[TAQuickness]

Shouldn't need to change the IACEA unless you change the physical size of the IAC passage or IAC motor.