blinx9900

the turbo in question is: http://www.turbobygarrett.com/...1.htm

and my exact question is how much power is it really capable of?
ATP claims they made 319whp at 10psi with that turbo on a b17:
http://www.atpturbo.com/root/t...r.htm

so it must be capable of more than 360 if they made 319 on a scant 10psi.

i have access to one of these that has an ATP T3 flanged .82hotside on it. my current turbo is bad (turbonetics t3t04e ball bearing) so i was thinking of picking this thing up. im running 14psi right now and made 317whp on 91octane so if the GT28rs really is maxed out at 360whp that dosent give me too much room to make more power

so whats the truth? will that thing make more than 360? will it run out of steam at high rpm?

here is my setup:

-b16b head on a b16a block with pr4 pistons.
- ~8.3:1 compression. i rev to about 8500.
-turbonetics t3t04e ball bearing .63 hotside stage III turbine wheel run at 14psi
-meutek mani
-tial wg
-3"exhuast and DP.

rmcdaniels

I made 385 at 23 PSI with that exact same turbo/housing on a B16A2 -w- 8.4:1 pistons and stock cams, probably would have made over 400 with some good cams. It does get inefficient when making that much power, but I drove it like that for a year or so, beating on it every day, and never had any problems with the turbo. It was in great shape when I sold it. Be sure to use the ATP oil restrictor if you use that turbo though, I blew out the seals on one just using a -3AN oil feed in just a few days.

The Meutek manifold may be a power limiter with that turbo though, I picked up a lot of top-end power when I switched from an Inline Pro cast manifold to a LoveFab SST, although I also switched from a 2.5" DP/exhaust to a 3" at the same time, which probably accounted for some of my gains.

JaredKaragen

how much would you want for that blown turbo >=D

rmcdaniels

It's long gone.

Pompiuses

The GT28RS is only efficient to about 13-14psi. Above that it'll choke because of it's small size, and you won't see very big gains. It usually makes about 300-330whp at 10-12psi on a B18C.

The turbo is designed for response and midrange, not topend. As said by rmcdaniels 360whp is possible if you boost the crap out of it, but I wouldn't do it.

Lots of GT28RS dynos:
http://forums.evans-tuning.com...=2434
http://forums.evans-tuning.com...=2494
http://forums.evans-tuning.com...=2711
http://forums.evans-tuning.com...=3473
http://forums.evans-tuning.com...=3615



Modified by Pompiuses at 5:31 PM 12/12/2007

0morgan@synapse motorsport

319whp on 375cc injectors?

rmcdaniels

I have to disagree about the 13-14 PSI limit though, the compressor map shows it being efficient at 18+, which matches with my experience having it tuned and running it on my car. I'd put its sweet spot at 15 PSI, but you really have to plot your application on the map to see where you stand.

Above 15 PSI the efficiency does start to drop off, but even pushing 35 lbs/min at 18 PSI (which should put you about where you want to be), the efficiency is still decent.

Again, plot your application against the map for the turbo and you will see where you stand.

blinx9900

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rmcdaniels &raquo;</TD></TR><TR><TD CLASS="quote">I made 385 at 23 PSI with that exact same turbo/housing on a B16A2 -w- 8.4:1 pistons and stock cams, probably would have made over 400 with some good cams. It does get inefficient when making that much power, but I drove it like that for a year or so, beating on it every day, and never had any problems with the turbo. It was in great shape when I sold it. Be sure to use the ATP oil restrictor if you use that turbo though, I blew out the seals on one just using a -3AN oil feed in just a few days.

The Meutek manifold may be a power limiter with that turbo though, I picked up a lot of top-end power when I switched from an Inline Pro cast manifold to a LoveFab SST, although I also switched from a 2.5" DP/exhaust to a 3" at the same time, which probably accounted for some of my gains.</TD></TR></TABLE>

wow great numbers, what type of gas were you using? by saying the meutek would be limiting do you mean compared to a manifold with a merge collector? thanks for the info

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Pompiuses &raquo;</TD></TR><TR><TD CLASS="quote">The GT28RS is only efficient to about 13-14psi. Above that it'll choke because of it's small size, and you won't see very big gains. It usually makes about 300-330whp at 10-12psi on a B18C.

The turbo is designed for response and midrange, not topend. As said by rmcdaniels 360whp is possible if you boost the crap out of it, but I wouldn't do it.

Lots of GT28RS dynos:
http://forums.evans-tuning.com...=2434
http://forums.evans-tuning.com...=2494
http://forums.evans-tuning.com...=2711
http://forums.evans-tuning.com...=3473
http://forums.evans-tuning.com...=3615

Modified by Pompiuses at 5:31 PM 12/12/2007</TD></TR></TABLE>
thank you for the links and info

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mike@synapse motorsport &raquo;</TD></TR><TR><TD CLASS="quote">319whp on 375cc injectors?</TD></TR></TABLE>
i was wondering the same thing, but thy didnt rev it past 7500rpm.

rmcdaniels

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blinx9900 &raquo;</TD></TR><TR><TD CLASS="quote">wow great numbers, what type of gas were you using? by saying the meutek would be limiting do you mean compared to a manifold with a merge collector? thanks for the info
</TD></TR></TABLE>

93 octane pump gas, and yes, I meant any cast-type manifold vs. a merge collector manifold.

Here's a dyno of the first time we fired it up, the crappy part up top is where the clutch was letting go, later we tried it with a better clutch and made 385, but I never got that printout.



Before anyone says anything about Dyna-Pak vs. Dyno-Jet, this dyno actually read 20 WHP lower than a 24" Dyno-Jet and read the same as a 48" Dyno-Jet that we tried, so just take the dyno numbers at face value.

Here's the exact same setup with a GT3071R, same boost, only the turbo was replaced and the tune was updated:



It spooled slower, but made more power up top. My trap speeds went up, but I had better ET's and more fun on the street -w- the GT28RS. The 3071R was better for road courses though, it was easier to control the car when rolling on the throttle coming out of a turn with the slower spool.

For street use the GT28RS is still my favorite turbo, makes decent power, spools freakishly fast, and hits hard.

KevronsEG

I agress 100% with rmcdaniels. GT28rs is so damm hot for street car. I dont know if this is true or not but does the ATP T3 housing help with making more power over the t25 or is it the same just T3 flnaged. Also at 15psi what do you think your WHP was at?

Kevron

blinx9900

thank you rmcdaniels and everybody else, this information is exactly what i was looking for

Drummerboy

i'm running an ATPgt28rs with the .82ar t3 hot side, and COULD NOT make ANY MORE than 340whp, no matter what the tuner tried.
this was at 13psi, and raising boost would only fatten up the midrange, with it quickly tapering off just after 7000rpm.
no matter what boost we threw at it, the peak would always stay between 335-340whp, and 235-240wtq.
also, it doesn't seem to spool nearly as early as i hoped it would. full boost at around 5k for me...

b16a1
ITR cams
stock bore/sleeves
9.2:1 JE/Eagle
custom top mount
3" turbo-back, no cat
91 octane pump gas

it's still fun to drive, but i'd have an easier time dealing with the falling boost if it kicked me in the pants a little sooner. that's why i bought the thing...




Modified by Drummerboy at 11:55 PM 12/14/2007

rmcdaniels

Have JDogg tune it

Drummerboy

i'd try that, if i wasn't in eastern Canada!



seriously though, the tuner in question has a great reputation, and a fleet of very impressive cars.
he's known to be a little conservative with the timing, but that's also partly why he has a great reputation. the motors last a loong time.

i expected my topmount to delay my spool time slightly, but there's quite a lag compared to some of the setups in here...

cam timing maybe?

rmcdaniels

With a turbo I've never gotten significant improvement over OEM cam timing.

I originally had mine tuned by Turbo Tune, a local Hondata tuner who's done a lot of very impressive cars. His tune was conservative, and the power was disappointing. I took it to Jason (JDogg) the following day, and he made something like 60 more WHP on the same amount of boost. The car was very reliable and I drove it for years. The motor is still running today in another car. My 8.4:1 B16 liked a lot of timing though, Jason just kept adjusting the tune until it worked like it should. He also did some other timing stuff to make it spool faster, but I'm not a tuner, so I really can't tell you what it was.

Drummerboy

thanks for the input, man.

blinx9900

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rmcdaniels &raquo;</TD></TR><TR><TD CLASS="quote">My 8.4:1 B16 liked a lot of timing though</TD></TR></TABLE>

you can say that again! my 8.3:1 b16 loves timing too 22-20 degrees up top and were considering that conservative since im on 91oct.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Drummerboy &raquo;</TD></TR><TR><TD CLASS="quote"> full boost at around 5k for me...</TD></TR></TABLE>

wow! my t3tO4e bb gets full boost (15psi) at 4800 and i thought that was laggy. before it was hitting full boost at 5200 but like rmcdaniels said there are ways to tune to increase spool up, we leaned it out a lot and gave it a lot of timing during the spool up part and it spooled 400rpm earlier

KevronsEG

My b18c with ATP T3 Gt28rs with inlinepro manifold and full 3in all the way spooled 10psi by 3600-3800. And that was with me just street tuning it. I'm super happy with it.

Drummerboy

damn! that's the response i was looking for.
.82ar?
my manifold's runners are fairly long, i suppose, but that's still a huge difference in response.

HiProfile

If the turbo is spooling a little late and has no improvement in power higher up, its most likely a leak somewhere on the intake-side.

IMO the exhaust is good for a street car, but I'd expect a divided manifold using ATP's T3 divided housing to spool the turbo up faster while making more power everywhere. Nobody seems to have a dyno of them though, although at that point I'd rather get a GT30 with that exhaust setup anyways.

Drummerboy

i do have my wastegate's vacuum source plumbed off of my intake manifold, and that could potentially hide a boost leak from me, couldn't it?

my turbo's compressor housing isn't tapped for a vacuum fitting, and maybe i should look into that. i've triple checked my couplers and such, though, and that all seems fine.

i want the response you guys are getting. i'm feeling a little gipped here!

LeGeND4LiFe

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rmcdaniels &raquo;</TD></TR><TR><TD CLASS="quote">I made 385 at 23 PSI with that exact same turbo/housing on a B16A2 -w- 8.4:1 pistons and stock cams, probably would have made over 400 with some good cams.</TD></TR></TABLE>

Yours seems to be the only 28RS setup I've ever seen to make 385whp, the norm seems to be much more like the 300-330whp dynos linked earlier. Also the 3071R dyno seems to spool within 200 rpm of the 28RS. What was the hotside on the 3071R?

blinx9900

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LeGeND4LiFe &raquo;</TD></TR><TR><TD CLASS="quote">

Yours seems to be the only 28RS setup I've ever seen to make 385whp, the norm seems to be much more like the 300-330whp dynos linked earlier. Also the 3071R dyno seems to spool within 200 rpm of the 28RS. What was the hotside on the 3071R?</TD></TR></TABLE>

i have seen t3t04e's make 490whp! and most people struggle to get them to 450, everything is a factor, im sure not everyone can do it, and i know a lot is in the tune.

mrx

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rmcdaniels &raquo;</TD></TR><TR><TD CLASS="quote">It spooled slower, but made more power up top. My trap speeds went up, but I had better ET's and more fun on the street -w- the GT28RS. The 3071R was better for road courses though, it was easier to control the car when rolling on the throttle coming out of a turn with the slower spool.</TD></TR></TABLE>

Hallo rmcdaniels,

how did you come to the impression that the 28RS spools faster? not that i don't trust you, because it's the smaller turbo, so it should spool faster, but:

if you look at the torque curve of both turbos, the 3071 (lower graph) seems to have more torque at nearly any rpm. Or did you think more about throttle response situations?

how much more laggier is the 3071 (what ar?) in your eyes, compared to the 28RS .82ar T3 housing?

best regards

rmcdaniels

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mrx &raquo;</TD></TR><TR><TD CLASS="quote"> Or did you think more about throttle response situations?</TD></TR></TABLE>

I should have been clearer, but that's what I was referring to. On the street, anywhere I mashed the gas, the GT28RS responded almost instantly, where the GT3071R took a little longer to respond. I don't think that the 3071 was necessarily laggy, but it wasn't freak-show quick like the 28RS.