Turbo Comparisons (GT25R, T3/T04, Big T28)

[drivewaysk8er]

Will somebody please compare these three turbos? If possible, I'd like the power, price, additional cost (cost of other things required to install the turbo and make it work), and whatever else.

[Beau]

There are several different configurations for the T3/T04 and 2 types of GT25R, so you need to specify exactly which turbos you want compared.

[Dugi]

for fast spool up GT28. big hp levels T3/T04. The GT28 rates at about 320hp. T3/T04 about 500hp (depends on configurations). GT25R 400hp or 450hp. GT28 and the GT25R are bolt on turbos. GT28 goes for about $850, GT25R $1100 and the T3/T04 $700. The GT25R does not come with wastegate. So depends on what hp level you want to reach and for what purpose. Do the math!!!

[MadSideways]

Heh, show me one person that makes 400+rwhp with a gt25r(hks gt2540)...

I think what you're talking about is 400-420 crank hp....Most all turbo factory ratings are crank hp...because they measure in cfm output initially, which doesn't account for drivetrain loss...

The gt2540 has been shown to max out at about 387rwhp with a .86 a/r housing, completely upgraded drivetrain and intake plenum.

Or if you want a little less lag at the cost of running a little hotter - about 380rwhp with an external waste-gate on the .64 housing...

Those ratings are at 19.5psi, which is the max this turbo can go on pump gas.

[drivewaysk8er]

The GT25R does not come with wastegate.

But you can use the stock SR wastegate, right? Also, you say that the GT25/40 (which is the one I meant) is a bolt on with the GT28. Does that mean that the GT25/40 works with say the Greddy IC hot pipe and the stock intake hose/pipe or do you have to get a new hot pipe and intake pipe?

[robbbby]

It is internally gated, you can use the actuator from the stock turbo.

[Dugi]

that's why I put HP and not RWHP. the GT25/40 has the option for internal gate. but if you want to use external you can just weld the flapper shut. If I'm not wrong the inlet is 3" or something. anyways it's bigger than the stock turbo, so you would have to get a bigger one. But one suggestion, If you have the money go with the HKS GTRS. it's bolt on, spools quicker than all and is rated at 400hp. Good for drifting, get my drift .

[VitaminT]

I think that the GTRS is a great turbo especially with the stock inlet/outlet flanges and it probably does spool better than the .64A/R GT2540R, BUT when the budget is tight the $600+ difference comes into play.

[drivewaysk8er]

I went to the HKS website and I looked for the GTRS under Garrett Ballbearing turbos but didn't see it. Is it actually called the GTRS or is that short for something like GT25/40?

[MadSideways]

If you're talking about the gt28rs, (disco potato), that turbo only pumps 270whp at 15psi, that turbo will never reach 400hp, flywheel or not...on pump gas...

[drivewaysk8er]

So for the GT25/40 is there some kind of adapter you can put on the inlet to adapt the 4 inch to the stock intake? Same thing with the hotpipe connection, can you adapt that in some way to make it work?

[Dori Dori]

I think the biggest problem is the 90 degree bend it has to make b/c of the p/s pump being in the way. AFAIK, there are no 'kits' made...you'll have to make your own. As for the GTRS, it's a 'new' HKS turbo, so you'll probably have to look at the japanese site. Here's a link to PDM's website w/ that turbo: http://www.store.yahoo.com/pha....html

Hey MadSideways, a GT25r (or GT25/40) is not the same turbo as an HKS gt2540. Please don't confuse Garrett's naming w/ HKS's...they are completely different. And if you want to see a 400whp sr w/ a GT25r, search around Freshally...there's a few of them.

[Dugi]

Yeah like dori dori said. Try searching under HKS GT-RS.

[drivewaysk8er]

I was looking at cheapturbos.com and saw that the T28 flows more air (albeit only 2 lb/min more) than the GT28. Now I know that the GT28 spools quicker because it's ballbearing but does it really spool that much quicker to persuade choosing it over the T28? Also, how does the T28 compare to the GT28 as far as power and stuff? Is it the same but with a slower spool time or does that extra 2 lb/min do something for it?

[MadSideways]

Quote »And if you want to see a 400whp sr w/ a GT25r, search around Freshally...there's a few of them.[/quote]I am a regular on freshalloy.com and I repeat my challenge, show me an sr that makes over 400whp, on pump gas, below redline, using a stock bottom end with the gt25r.

Feel free to use this thread as a reference:

http://forums.freshalloy.com/ubbthreads ... art=1&vc=1

[Dori Dori]

12.2 hp too low, so you're right. :rolleyes

[VitaminT]

I was looking at cheapturbos.com and saw that the T28 flows more air (albeit only 2 lb/min more) than the GT28. Now I know that the GT28 spools quicker because it's ballbearing but does it really spool that much quicker to persuade choosing it over the T28? Also, how does the T28 compare to the GT28 as far as power and stuff? Is it the same but with a slower spool time or does that extra 2 lb/min do something for it?

Keep in mind that both T28 and GT28 are both ball bearing turbos. Someone please correct me if I am wrong. See Garrett's website for the differences in T and GT series turbos.

[Dori Dori]

Not all T28's are ball bearing, consider the GTiR's T28...

[MadSideways]

Now this t67 Greddy turbo kit:

http://www.jspec.com/433rwhppackage.html

Makes over 400whp at 7500rpm's, (and more depending on when you stop revving).

This turbo, even though some may think it has lag, produces the same hp as the gt25r at the same rpm, (as viewed w/overlaying dyno charts).

It is a bit pricey, but IMHO is better than the t3/t4 setup.

[Dori Dori]

Now this t67 Greddy turbo kit:

http://www.jspec.com/433rwhppackage.html

Makes over 400whp at 7500rpm's, (and more depending on when you stop revving).

This turbo, even though some may think it has lag, produces the same hp as the gt25r at the same rpm, (as viewed w/overlaying dyno charts).

It is a bit pricey, but IMHO is better than the t3/t4 setup.

Dude, overlay them again because that t67 dyno doesn't catch up w/ the gt25r dyno until after 6.5-grand!

If you plot it correctly, the gt25r car makes:[email protected]@[email protected]@[email protected]@[email protected]

Again, correctly plotted t67 (peak hp):[email protected]@[email protected]@[email protected]@[email protected]

That Jspec car also has some crazy cams on it, increasing the top end even more (270degree intake and exhaust).

[MadSideways]

You're right, i was off by 500rpm when i looked at it...

272 cams aren't that agressive, they have been proven to work with a 1k idle and proper tuning...Although, its most likely contributing to the loss in low end power...

[Dori Dori]

270 degree cams not aggressive?!?! Maybe not on a race car. Consider that they are the most agressive cams you can get for an sr (minus a solid tappet version made by Tomei).

[drivewaysk8er]

Also, how does the T28 compare to the GT28 as far as power and stuff? Is it the same but with a slower spool time or does that extra 2 lb/min do something for it?

Yea I was wondering that too.

[MadSideways]

Quote »270 degree cams not aggressive?!?! Maybe not on a race car. Consider that they are the most agressive cams you can get for an sr (minus a solid tappet version made by Tomei).[/quote]I didn't say not aggressive, i said not that aggressive, which implies that they are, 'slightly'. To me an aggressive cam means won't idle below 1500rpm. 270's will idle at 1000rpm.

Also, the first company i checked, (Jim wolf techonologies), makes both a 275 w/12.75mm lift and a 285 w/13.35mm lift cam for the sr20det block.