I'm running a s14 t28 at the moment.(Installed on my Blacktop SR) I would like to upgrade to a turbo that I can just bolt into my car without having to modify anything besides maybe a tune. Anyway's, my question is. Is it worth going from a s14 t28 to a s15 Spec R turbo? If so, what kind of HP increase can one expect with the same supporting mods used with the s14 t28? (How much more boost.) or is it a waste of time and money just to go from the s14 t28 to the s15 Spec R turbo?
Thanks....

 

s14 to s15 turbo is a waste of time and money. disco potato is next up but even that turbo has pretty low limits.

 

same turbo, just one more ball bearing. might be another small difference, i forget, but thats it. waste of money. only a good upgrade if you have a T25 on an S13. a simple search would have answered your initial question. happy hunting.

 

Pretty sure there is no difference in the bearings, the only difference is the S15 spec-r one has the cast in divider wall for the wastegate outlet.

 

I did a search, but was getting mixed reviews/answers. Some say a good upgrade and some say same as you guys a waste. I was looking to get 300+ hp, but read that a s14 turbo was only good to about 290hp, while the s15 would get me to the 320+hp mark.

 

320 is reaching ALOT.. just bite the bullet and buy a bigger turbo and after market manifold and downpipe and hot pipe and etc etc. long story short putting the s15 OR any stock turbo as a replacement for what is stock on yours the fits your mani is going to be disappointing.

 

GT28RS will reach your goals and will bolt on to the stock manifold. All you'll need is injectors and a tune.

Though cams and valve train work would help out.

 

If spending that money, i'd just go for the 2871, the 52 trim is available with the same 28R stock style compressor housing.

 

+1 on the 2871

 

Just so Im looking at the correct turbo, is this the one you guys are talking about?
Garrett GT2871R turbo with GT28R style Compressor Housing W/ ACTUATOR : atpturbo.com