Hi John,
I have had a number of turbo combinations on my GT4. There are a number of things you have to decide on as there is no 'right' answer to your question. The 2 main decisions are boost response and whether you want to keep the stock manifold. I assume your RWD setup already has some form of custom manifold? but that it takes a CT26 turbine.
A good easy upgrade is to keep the CT26 turbine side and go with a TO4E 40 trim compressor wheel in a machined front cover. This will give you an easy 350hp potential without having to screw the boost up too high....you can get maybe 380 out of this setup before you start overspeeding the thing.
You can go with bigger comp wheels but no point in my book and the turbine setup become your restriction.
The most common proven performer is the Trust T67...big hp potential but pretty big dollars as well.
Same for the HKS gear. Definitely works well but big dollars.
I have ended up with a Garrett S004 which is basically the equivalent of a HKS 2540. Much cheaper than a HKS unit with 95% the hp potential. It keeps the internal gate but still gives you 400hp potential. Should be enough for a Sprinter
If you go any bigger then you must have decided to use an external wastegate. More expense and complexity but a must for big hp applications. I have gone with an external gate even with my GT25 as the hp gains are there to be had.
As for grunt. At a lazy 13-14psi i had a rough tuned 190rwkw on a dyno dynamics AWD dyno. With the 17-18psi i want to run and optimised tuning i'm hoping for 220rwkw which will do me fine for this car.
If you have any questions drop me a line 0408481207
Fri, 19 March 2004 04:31
