[BlueCamaro6]

LT4 conversion on mine and I know what you're talking about. When i did the install I didn't notice anything, then I backed the screw out a little bit for the bypass blade and it did it after that. It would slam closed I assume. So, I put the screw back in a little bit and it doesn't do it at all. Is there a stop screw you can move to make it not close completely? Mine stays open a tiny bit when its on the stop screw.

[Jhunsberger]

Originally Posted by BlueCamaro6

LT4 conversion on mine and I know what you're talking about. When i did the install I didn't notice anything, then I backed the screw out a little bit for the bypass blade and it did it after that. It would slam closed I assume. So, I put the screw back in a little bit and it doesn't do it at all. Is there a stop screw you can move to make it not close completely? Mine stays open a tiny bit when its on the stop screw.

Good Suggestion, there is a screw to adjust the bypass valve. I will give that a slight adjustment. Thanks for the input!

[Jhunsberger]

Originally Posted by KingLT1

We had decent weather today so I got my car out and cycled between 25-3000rpm several times and did not notice any rough spot. I'm wondering if it has to do with how my driver demand table is tuned or is it just a Manual trans issue?

Thanks for the reply, I am determined to try and sort this out. I will not accept that it cant be smoothed out.

[SpaceCadet]

I recommend NOT to 'adjust' the screw for bypass arm stop. The 'adjustment' screw is there to allow valve to fully close and not bind in bore when completely shut and needs to open. If the valve does not properly open it can damage supercharger rotors.

[JANNETTYRACING]

Originally Posted by SpaceCadet

I recommend NOT to 'adjust' the screw for bypass arm stop. The 'adjustment' screw is there to allow valve to fully close and not bind in bore when completely shut and needs to open. If the valve does not properly open it can damage supercharger rotors.

I believe they are referring to setting the min opening to a larger area to soften the boost hit when the valve closes.

The tighter the valve closes the harder the hit.

Ted.

[Jhunsberger]

Originally Posted by JANNETTYRACING

I believe they are referring to setting the min opening to a larger area to soften the boost hit when the valve closes.

The tighter the valve closes the harder the hit.

Ted.

Ted,

Do you have any additional input on this topic from my original post? have you experienced this "rough" spot around 2500-3000 when it seems like the bypass valve is closing? Is this something you generally address in the tune?

[JANNETTYRACING]

Originally Posted by Jhunsberger

Ted,

Do you have any additional input on this topic from my original post? have you experienced this "rough" spot around 2500-3000 when it seems like the bypass valve is closing? Is this something you generally address in the tune?

One thing you can count on you can not tune out mechanical issues.

I spelled it out pretty well, something I seen that works pretty well also is adding a spring to the bypass valve to soften the hit Edelbrock has this on they're Chrysler superchargers because they have an even bigger problem with this due to the throttle control, Chryslers can be very light switch like from cruise to holy shit with little to no pedal movement.

[Jhunsberger]

Originally Posted by JANNETTYRACING

One thing you can count on you can not tune out mechanical issues.

I spelled it out pretty well, something I seen that works pretty well also is adding a spring to the bypass valve to soften the hit Edelbrock has this on they're Chrysler superchargers because they have an even bigger problem with this due to the throttle control, Chryslers can be very light switch like from cruise to holy shit with little to no pedal movement.

Thank you for your insight Ted. Whipple also suggested making the bypass valve actuate from vacuum instead of boost. Good to know its a mechanical issue instead of a tune issue.

I guess the LT4 does not have this issue since it is an electronically controlled bypass?

[JANNETTYRACING]

Originally Posted by Jhunsberger

Thank you for your insight Ted. Whipple also suggested making the bypass valve actuate from vacuum instead of boost. Good to know its a mechanical issue instead of a tune issue.

I guess the LT4 does not have this issue since it is an electronically controlled bypass?

If originally an LT4 car Yes.

As does the LSA and LS9

Ted.

[teesee150]

Has anyone sorted this out. I have a manual trans with a Whipple at 700hp and it makes the car almost undrivable. I'm actually considering selling the car bc I can't stand it.

[Joshinator99]

Originally Posted by teesee150

Has anyone sorted this out. I have a manual trans with a Whipple at 700hp and it makes the car almost undrivable. I'm actually considering selling the car bc I can't stand it.

If you have a big cam, my advice is to immediately install the electronic Smoothboost bypass valve. Solves all these silly vacuum bypass-related idle and driveability issues. It’s available for the 2.9 Whipple and pretty easy to adapt to the new 3.0 too.

Full thread about it here:
https://www.camaro6.com/forums/showt...ht=Smoothboost

[JANNETTYRACING]

Originally Posted by teesee150

Has anyone sorted this out. I have a manual trans with a Whipple at 700hp and it makes the car almost undrivable. I'm actually considering selling the car bc I can't stand it.

If the car is undriveable I suspect there is something wrong with the calibration.

Feel free to call me to discuss. 203-753-7223

[toohighpsi]

Originally Posted by Jhunsberger

I guess the LT4 does not have this issue since it is an electronically controlled bypass?

The LT4 is not electronically controlled, its exactly the same as the maggie, edelbrock and whipple. It has a solenoid valve attached to the bypass that is used to turn off boost under certain conditions (such as limp mode).

Torque management within the E92 is most likely causing drivability issues on LT1 applications as the torque model was not created around a supercharged application.

[Jhunsberger]

In my case I got this sorted several years ago. The rough spot at 2500-3000 rpm was caused by the original tune switching between MAF and speed density, this is where the transition was. After I had someone else re-tune it the issue completely went away and drivability was way better.