how big a difference would a T28 make versus my T25 on my DET?? is it worth the money to upgrade from the T25 to the 28, or should I go T3/T04. i drive my 200 thirty miles to work and back every day so it has to be very streetable. what turbo out performs a T28 that will bolt up to the GTI-R manifold? I've searched the forum trying to make up my mind, but i can't decide. any opinions would be appreciated.

The T28 from an 'R is a pretty nice upgrade to a T25-based system. You'll make more power at the same levels of boost (compressor efficiency?) and suffer from a lot less backpressure (turbine sizing). You can even add more boost with less danger of detonation; up to about 16 PSI in bursts, assuming your fuel system is also up to task. An upgrade to the 'R's T28 would be the compressor housing and adapter ring from an S14 or S15 turbo, which is bigger still, making you more powerful still. T25s typically top out around (conservatively) 220 WHP, "plain" T28s are more like (generously) 280, I have no idea about the bigger housing.

Beyond that, the next step is the Disco Potato T28, but you can't buy one of those yet. It adds a ball bearing center section and even higher efficiency with even better-matched components than the 'R model. Mik Kojima says that it's like driving a car with a positive-displacement supercharger because the boost is so early and linear. Rob Cadle said that the 'R's T28 was about 85% as powerful as a D/P turbo, and I'd be willing to believe him. Especially with the S14 compressor housing, I can't see the D/P turbo being economical simply because 'R T28s are so cheap and effective. The D/P T28 should be capable of over 300 if not 320 WHP. Rob, would you mind correcting me?

Lots of things bolt up to an 'R manifold. When you convert for an external wastegate, the sky is kind of your limit. Well, the sky and the cylinder block, anyway. People have been known to fit GT3037s to modified 'R manifolds, but that's kind of pushing it, IMHO; you should really have a better manifold by the time you're adding that kind of turbo.

A T31/T04E may fit, but I think you have better options to consider. Keep component matching in mind as you do your selection...

If i went with the "R" setup now, and bought a DP turbo later, all i would have to do is swap the 28 for the DP. i assume it has an internal wastegate? how much will the DP go for and when could i get a hold of one

Yes, the D/P T28 will fit to the 'R's T28 manifold; they're both T28s. ;) The D/P turbo does have an internal wastegate. Due to my intermittent ability to even connect to this server, I can't search for you, but the price (ballpark) has been stated. Somewhere between $1100 and $1400. It's expensive, and may not be worth it if you're starting with an 'R turbo. If you can find the S14/S15 compressor housing and adapter ring, you'll have almost the same turbo except for the ball bearing center section and a slightly smaller turbine.

For now, I'd get about Two Grand scraped together. A little less than a grand for a GTi-R manifold/turbo setup from Andreas Miko or somebody like him, and a little more than a grand for the Hot Shot DET installation kit. The HS kit has cool stuff like a 3" downpipe, big pretty pipes for installing a big, pretty HKS intercooler core, and stuff like that. You'll be well on your way to maxing out the 370cc injectors and stock MAF sensor you probably still have installed. :D

Beyond that, get a Z32 MAF sensor, an adjustable FPR (up to 4 bar), and send your ECU back to JWT for appropriate reprogramming (about a hundred dolllll-ars ;)). You should be able to tickle 300 WHP on those injectors, and you'll be good for way more than that from the Z32 MAF. See if somebody on TwinTurbo.net will sell you their spare sensor for cheap!

what about the 'R' setup w/ the S15 housing and adapter(don't know where to get that), the HS install kit, and the JWT rail, 50 lb'ers cobra maf, FPR set a 4bar. could i expect 300hp? if something in this setup is out of place please let me know, thanx for the info:cool:

Delete the Cobra MAF sensor, add a Z32 "TTZ" MAF sensor in it's place, and put those 50-lb'ers at 3 bar instead of 4 (you don't need 4 bar of fuel pressure for this).

Why the TTZ maf, instead of the cobra, just curious? where could i look for the S14/15 housing?

Originally posted by ITR_KILLR
Why the TTZ maf, instead of the cobra, just curious?

First off, the TTZ MAF is a Nissan piece. And, you'll never reach it's limits for airflow. Your JWT ecu will need to be programmed for it, but that's easier than the other option...

The Cobra MAF is a fine piece, but requires a subtractor program to run it on your JWT ecu. No extra sweat on your part, just on JWT's.

I've also heard it's easier to find a free-flow filter for the TTZ MAF, but that's just people talking to me. I do not know this for certain.

In the end...it all comes down to what you can find, for what price, I guess.

Good luck!

Well, at HP levels like we're talking about, they're actually about in a dead heat. The TTZ MAF sensor is more expensive initially ($240 vs. $120), and for your situation, the Cobra MAF may actually be less expensive. After about 350 HP, though, JWT has to do Funky Stuff (tm) to make the Nissan ECU read data from the Cobra MAF in a usable way. This costs $150 ($50 more than usual), but is a one-time deal. You can go either way at "only" 300-ish.

It's also said that the JWT POP charger for the 300ZX MAF sensor is more expensive than other options for the Cobra sensor (by about 100-120%), so that is another point on the Cobra side. Honestly, though, I really really really like the idea of keeping it as many Nissan part numbers as possible under my own hood. We're talking about a non-trivial percentage difference, but in the lifetime of your car, it becomes a trivial dollar amount.

Your call. :)

Originally posted by CowboyDren
After about 350 HP, though, JWT has to do Funky Stuff (tm) to make the Nissan ECU read data from the Cobra MAF in a usable way.


dren never ceases to amaze me....

Hmmm... the best T28 series from Nissan factory comes from a Silvia S15. I believe it's a Garrett Ceramic twin-ballbearing.

The S15 T28 has a ball bearing center section, but it can't make as much horsepower as the T28 from a GTi-R; the turbine is too small. If you have a GTi-R turbo, though, the compressor housing from the S15's turbo is an excellent upgrade.