When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Car is a street driven M6. Currently have twin s256's. The response is great, just looking to simplify the turbo system so I want to go single. Runs 20psi as I am limited to 2.5bar. leaning towards an s476 of some varienty but just looking for any other suggestions people make have.
Motor setup -
332ci cathedral port engine.
.578 / .587, 226 / 232, 108
Yes I am sick of having to spend hours to change plugs when it should take 10 minutes. Its a C6 street car,AC, Power steering, etc . I just do some spirited Mexico runs every once and awhile. Its a built motor so why not turn it up. 256's are making about ~110 lb/min at 20psi.. so I would like something comparable that will still spool quick. Thats about it.
Last edited by Driftin_240sx; 05-30-2018 at 04:19 PM.
Those headers look like a disaster to do plugs on, but why are you changing plugs so often on a street car? I would keep the twins and rework the hot side you're good at fabbing like you said. Twins are sweet and fitting a large single in there just creates other problems elsewhere instead of plug change problems.
When I put the motor back in I put in some stock zr1 plugs because I was like, ok I’m done breaking **** on this car.. I’ll put my 7psi springs in, drive it like a normal person. That lasted all of 20 miles. So I started to develop a miss. I need to pull the plugs and see what they look like. As far as other problems, I’m not quite sure what other problems it would make except having to make another turbo setup. Maybe I will remake headers... maybe I’ll go single.... the point of this thread.
Cool...has tune issue or some other unrelated problem...decides to yank a good custom fabbed TT kit for a big single knowing the lousy space they have under the hood....good call. Good luck with build.
With a Vette I hate to say it, but I'd consider a rear mount.
If you want to keep it up front a S400 is a huge compressor to fit, I think a GT4780 with a "GT42" cover would be perfect and have similar airflow characteristics. I went from twin 67s to a Single 4780 and the single spolled a har faster made the same power.
Cool...has tune issue or some other unrelated problem...decides to yank a good custom fabbed TT kit for a big single knowing the lousy space they have under the hood....good call. Good luck with build.
Does nobody make a simple set of log manifolds for them ?
Huron Speed list a kit for a C5....no idea what the differences are though. Plug access still a little tricky looking, but nowhere near as bad as what you have now.
Run iridium 8-9 heat range plugs and leave them in forever! I'd work on the MAP limitations before playing with a bigger turbo. Know what kind of power it makes now?
Lots of space in the nose of those though. Flipped factory manifolds for easy plug access and a low mount with scavenge pump would be my pick. Size of turbo would depend on the power you're after and what kind of budget.
05-30-2018, 10:53 AM
Switching turbos - twin s256 to something single 
I'd work on the MAP limitations before playing with a bigger turbo. Know what kind of power it makes now?