VVTI vs NON VVTI exh manifolds (1 Viewer)

[rckymtngx]

Hey guys,

I am curious if anyone has used non vvti manifolds or DT headers on a VVTI engine? The SAIS has already been bypassed, so theoretically they should work fine? Found a set of LT's non vvti and a Y pipe for sale brand new, so trying to determine if theyll work or not..

 

[Rednexus]

They will not work without modifications. The SAIS ports in the VVTI cylinder head would be open with the non-VVTI headers, so there would be huge exhaust leaks.

I have heard of folks drilling, tapping, and plugging the SAIS ports in the head to allow for non-VVTI headers, but that would be a difficult job with the engine in the vehicle as space is very limited. Others have welded tabs to the non-VVTI header flange to cover the ports in the head.

Given the backlog at DT, these might be viable options unless you want to wait 6+ months for VVTI headers.

 

[rckymtngx]

They will not work without modifications. The SAIS ports in the VVTI cylinder head would be open with the non-VVTI headers, so there would be huge exhaust leaks.

I have heard of folks drilling, tapping, and plugging the SAIS ports in the head to allow for non-VVTI headers, but that would be a difficult job with the engine in the vehicle as space is very limited. Others have welded tabs to the non-VVTI header flange to cover the ports in the head.

Given the backlog at DT, these might be viable options unless you want to wait 6+ months for VVTI headers.

Luckily I’m on the list for some LT’s that see due available at the end of the month. I was more so interested in getting the set so I can have the Y pipe. DT apparently did stop making the y-pipe so I’m unsure of any other options. Guess a custom one would work.

 

[Rednexus]

I think the OEM Y pipe is actually pretty good. Others have reported only nominal power gains with it, and you lose cats and will have a stinky exhaust. I'd spend your money on headers and a catback instead. Both gave me big seat-of-pants gains.

Fyi I had to wait 4 months for my LTs. You'll love them once the nightmare install is over

 

[white_lx]

I have heard of folks drilling, tapping, and plugging the SAIS ports in the head to allow for non-VVTI headers, but that would be a difficult job with the engine in the vehicle as space is very limited. Others have welded tabs to the non-VVTI header flange to cover the ports in the head.

For reference: 06/07 Air Induction Pump Failure & Bypass - https://forum.ih8mud.com/threads/06-07-air-induction-pump-failure-bypass.814912/post-14138738 I thought it was very ingenious.