Hi this is my second post and is mostly directed for owners of the JMTC turbo. I have a 2013 mcs with a upgraded intercooler, downpipe, afe exhaust (2.5") and I just purchased a s42 JMTC turbo. JMTC recommends at least a 2.5" exhaust for reliability but I am curious if anybody runs it with a smaller exhaust or downpipe. I am curious if the entire exhaust has to be 2.5" and if I would be able to add a resonator without creating problems. Im writing this quick so if anything needs clarification let me know and thanks in advance.

 

I hope that turbo works out for you. I’ve heard many horror stories about those turbos…

You should be good with at least a catless downpipe. Any exhaust after that would be bonus. A good resonator should be straight through and provide minimal extra exhaust resistance. Anything from Magnaflow will work perfect.

If you don’t have a tune yet, talk to to @Lou@Prototype-R

 

im curious what have you heard about the turbo?

 

I've heard the wastegate not actually sealing unless the tension in the wastegate rod is adjusted way too tight. I've also heard the bearings give out in short order. Another one is that boost is inconsistent on a tuned vehicle.

I don't care for JMTC as a company either. They have had some poorly designed parts in the past.

But, I know they wouldn't be in business unless some of their stuff worked great.

 

ah dang, I just bought a rebuilt one from allmag, what turbo would you recommend? im looking for something that doesnt have a lot of turbo lag so something thats on par or a bit better than a jcw turbo

 

If you don't plan on running it that hard, such as on a track car, you might be OK with it.

Alternately, I would go with a JCW or BorgWarner AirWorks unit. Either of those will give good power gains on an otherwise stock Cooper S N18 engine, and still give good spool responsiveness. If you want BIG power, Owens Development sells a hybrid turbo that will still bolt on, but you'd have to add a meth injection kit to the budget.

 

All depends on your application.

Also - on what to look for in a rebuilt turbo. For the turbo you just bought - search for "JMTC" or "JMTC rebuilt"