Input on my boost control issue

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Sep 4, 2013 | 02:52 PM

357i

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From: Richmond, VA

Input on my boost control issue

To bring you up to speed, I'm running a mostly stock LS1 with a TC78. The entire setup was made by me to fit the tight constraints of a BMW engine bay.

Here are a few pics of the setups progression

Made a plan for the wastegate:

Wastegate is a PTE 46mm. I really thought this setup would work great. It does not. I have a 7lb spring in it with no boost controller. The wastegate is an open dump and the car has a full 3" exhaust. The gate opens right at 7.5-8psi. It will hold 8-9 psi in 1'st gear, about 11psi in 2nd gear and 16 in 3rd gear. I havent run it at all in forth gear, but I can imagine that it will continue to climb. I guess this winter I will pull it back apart and try something else. Tight spaces will not allow me to run a wastegate right out of the side of the collector. Any other ideas?

Sep 4, 2013 | 03:06 PM

Forcefed86

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Quote:

Originally Posted by 357i

To bring you up to speed, I'm running a mostly stock LS1 with a TC78. The entire setup was made by me to fit the tight constraints of a BMW engine bay.

Wastegate is a PTE 46mm. I really thought this setup would work great. It does not. I have a 7lb spring in it with no boost controller. The wastegate is an open dump and the car has a full 3" exhaust. The gate opens right at 7.5-8psi. It will hold 8-9 psi in 1'st gear, about 11psi in 2nd gear and 16 in 3rd gear. I havent run it at all in forth gear, but I can imagine that it will continue to climb. I guess this winter I will pull it back apart and try something else. Tight spaces will not allow me to run a wastegate right out of the side of the collector. Any other ideas?

How much room do you have on the pass side? Can you add another gate to that side? If you went to a larger turbine housing it would be easier to control the boost as well. What is on there now?

Sep 4, 2013 | 03:07 PM

turbocamaro125

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From: Warfordsburg PA

It looks like that setup should work good. what exhaust housing? .96 t4? I wouldn't think back pressure at that low boost would cause that...I had a single 44mm tial gate welded 90* off of the merge with a cammed ls1 and a t6 s480 and it would hold right a 9lbs with a 8lb spring.....idk try adding another 46mm gate.

Sep 4, 2013 | 03:16 PM

Camaro9969

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From: Granby, Mass

Can you post pictures with everything in?

Sep 4, 2013 | 03:25 PM

357i

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it is a .96 AR T4.

Adding a second gate will be tight. I feel like the single should be more than enough if set up correctly.

Here is the whole package

Sep 4, 2013 | 04:22 PM

357i

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was considering coming off the back of it like this:

or i may have room to do something like this:

Sep 4, 2013 | 05:25 PM

stevieturbo

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From: Norn Iron

Cant see in the picture, But how have you the w/g signal line plumbed ?

For low boost you should be blowing boost directly into the bottom port only.