fivelitrecobra

I currently have an STS rear mount twin turbo setup on my 02 C5 Z06. I've upgraded the turbo's to two GT35R's. Fantastic turbo's that make great power, only issue is they don't really wake up until about 5k rpms. I'm currently running the stock exhaust manifolds and stock H-pipe with gutted cats, would swapping those for a set of longtubes and an offroad X-pipe help with low end power? Would the turbo's spool sooner being that its moving a bigger volume of exhaust gasses? Beneficial mod, or just wasting my money?

StatmanRN

Similar setup. I have had the x pipe pre turbo so I cant say directly but it definitely helped the midrange when NA. I also wrapped the hot side.
Rearmounts just tend to be laggy by comparison. Stock STS turbos varied in size and make but were on the small side to help. A reverse split cam is said to help, I have one but have not installed yet. I think an electronic boost control would help and will try that ay some point.
I have an n2mb no lift box and can build 4# off the line. Also Power brake it for roll hits
Sqires himself told me long tubes were not a problem but wouldnt help either as the heat loss offsets the flow gain. As much as they cost for C5s I wouldn't try it. You can pick up short tubes for cheap and wrap them. I did and will install with the new forged motor

2000BC

2000 C5, original stock motor (except springs), original STS turbos (smaller) with 6lbs of boost. I have long tube headers, Random high flow cats, x-pipe, but 4:10 gears. Hit's all at once 4 to 5 thousand and up. Gears contribute to that but also help make up for the lag but not for everybody. I don't think you can get these to function like a roots or supercharger without getting extra creative. Hope this helps.

JoeyG

fivelitrecobra

Appreciate the info fellas. I did some research as well as talked to Squires at STS turbo. All pointed to the same outcome, not much to be gained with long tubes and X pipe on a rear mount system. The common consensus was between 5-10hp, with no improvement in spooling over the stock parts. Not worth it to me.

GTRSOLO

Just curious if your new turbos are ball bearing center section or standard journal. When I switched turbos on a conventional front mount set-up the difference between ball bearing and standard journal was significant. I even went with a larger more aggressive compressor side, which I thought may cause lag. But the bigger ball bearing turbo spooled instantly with no other mods. Good luck.

fivelitrecobra

They are ball bearing. Majority of the reason for the lag is probably the turbo size, pretty big for a stock block application. May swap in some smaller turbine housings in the future to help with spooling.