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-   -   $300 ebay GT28RS (https://www.miataturbo.net/diy-turbo-discussion-14/%24300-ebay-gt28rs-5894/)

lukydvll 11-30-2006 04:44 PM

$300 ebay GT28RS
 
After reading about MarkP's positive experience with his Chinese turbo, I'm beginning to wonder if this turbo might be worth messing around with...
Those specs don't seem to make any sense though (.60 AR turbine).
That compressor's inducer seems to be a little small to move 57lbs of air as well.
$300 ain't to bad. If I could make 300whp at 15psi on a 1.8, this might be a better option than a T3/T4 (faster spool and lower boost threshold).
I've currently got a GT256 and I think this would bolt right up.
What y'all think?

http://cgi.ebay.com/ebaymotors/GT28R...spagenameZWDVW

Markp 11-30-2006 08:24 PM


Originally Posted by lukydvll (Post 60741)
After reading about MarkP's positive experience with his Chinese turbo, I'm beginning to wonder if this turbo might be worth messing around with...
Those specs don't seem to make any sense though (.60 AR turbine).
That compressor's inducer seems to be a little small to move 57lbs of air as well.
$300 ain't to bad. If I could make 300whp at 15psi on a 1.8, this might be a better option than a T3/T4 (faster spool and lower boost threshold).
I've currently got a GT256 and I think this would bolt right up.
What y'all think?

http://cgi.ebay.com/ebaymotors/GT28R...spagenameZWDVW

Actually they do make sense, the GT28 has a smaller turbine wheel than the T3 turbo and thus needs a larger A/R to move the air. There is no way that this turbo will move that amount of air (57 lbs/min) and it's too small to efficiently make 300 RWHP. If you want to make 300 RWHP on a cheap turbo, it's either a Ghettocharger (T3S60) or a Chinacharger (T3/T4 Knock-off)

Now you might find this interesting, I finally did some highway testing today, and the Chinacharger was actually at 10 PSI in top gear before 4000 RPM. Something that really surprised me and was making 18+ PSI by 4500. Turbo's are sensitive to load, so the fact that it won't spool until 4,500 in second gear isn't too surprising. I was making > 5 PSI at 3500 RPM in top gear.

Mark

PS - The specs on my turbo were all wrong in reality it was much different than advertised but I knew what it looked like in person already, it's likely the case here too.

lukydvll 11-30-2006 11:49 PM

Thanks Mark,

Guess I'll be moving back to a T3 footprint.

Now I need to decide if I should get a T3/T4 or a GT3271.

Any idea which will spool faster and which has more hp potential?

I'd probably get a 50 trim .48 ar with a "stage 3 wheel" if I went T3T4.

I'd like to make an honest 300whp and still have decent response from the turbo.

When will these turbos spool on a 1.8 with 3-inch exhaust?

Kelly 12-01-2006 12:04 AM

The T3/T04E 50 trim with a .48 hotside will spool great on a 1.8...especially utilizing a 3" exhaust and downpipe.

Braineack 12-01-2006 02:06 AM

WOT get flipside to start producing us some nice cheap 3" exhausts, or buy me a cheap flux-core welder and i'll build on myself...(christmas is soon)

Markp 12-01-2006 06:33 AM


Originally Posted by lukydvll (Post 60855)
Thanks Mark,

Guess I'll be moving back to a T3 footprint.

Now I need to decide if I should get a T3/T4 or a GT3271.

Any idea which will spool faster and which has more hp potential?

I'd probably get a 50 trim .48 ar with a "stage 3 wheel" if I went T3T4.

I'd like to make an honest 300whp and still have decent response from the turbo.

When will these turbos spool on a 1.8 with 3-inch exhaust?

I think that the T3/T04E has the higher HP potential (only slightly) but that the GT3271 is the better responding turbo. Although this can depend greatly on the actual configuration of the T3/T04E. You don't have to move back to the T3 footprint, the GT3071R is a T25 footprint and will make an honest 300+ RWHP.

This is important, once spooled, the T3/T4 Chinacharger is NOT laggy, it hits hard and fast. It does not lag between shifts or fall out of boost, even short shifting the damn thing and pedaling it out of the hole at the track resulted in a 2.23 60ft time and an 1/8 mile of 8.59@86 and a 1/4 mile of 12.93@115.77 and this was with shifting it at 7000 RPM! Compared with my best run that night of 2.16 60 ft and an 1/8 mile of 8.37@89 and a 1/4 mile of 12.76@115.21, it's obvious that the car is not falling too far off the mark even when short shifting. It most definately was in boost the whole time and never gave me the perception of lag...

Now down lower in the RPM range, yes, this turbo is not the happy camper that the T3S60 is. At 4250 RPM on a rather special motor I was making 270 ft/lbs of torque at 14 PSI and 295 RWHP at 10 PSI at 7000. That car was violent and fast too. I would call the motor in my car, built but nothing special, and certainly not the level of effort that was in the T3S60 car.

I think that the bottom line is that if you run the turbo where it's happy, you won't have issues with response. e.g. A T3S60 ghettocharger will be happy from 3000-7000 RPM in top gear, A GT2554R will be happy from damn near 2000-5500 RPM in top gear, and the T3/T4 Chinacharger will be pretty happy from 4500-8500 RPM in top gear assuming you want to make 10 PSI of boost. Like I stated earlier, the more load on the motor, the earlier it will spool. In lower gears I need more RPM to get the turbo to spool. The GT2554R will spool well below 3000 RPM in any gear, the T3S60 ghettocharger spools below 4000 in any gear and the T3/T4 chinacharger will spool by 5000 RPM in any gear.

Most of my time on the throttle is not in first gear, alot is in 2nd and 3rd gear, and by the time I am in 4th gear... well the car is really flying then. 4th gear is taking me past 100 MPH with relative ease. So in reality something that spooled a little earlier might be helpful in daily driving, but as it is the car is just blowing the tire off through 2nd and 3rd gear. Even Jesus couldn't find me enough traction to keep the rear end planted in those two gears. Where it would become painfully obvious that this was a bad pick for a turbo would be at an auto-x event. This is where a large turbo really has no place, it's simply too hard to get the most out of when running in this environment, as highlights why a smaller turbo is sometimes better on the street too. Put the larger turbo on a real track (even something as tight as the Streets of Willow) and it will hand the smaller turbo its ass. I could drive this car plenty fast on any real road course and much faster than I could with the T3S60 or GT2554R at the same boost level.

Mark

PS - I am running a 2.5" exhaust... LOL.

m2cupcar 12-01-2006 09:15 AM

IMO- The later spool on a larger turbo isn't bothersome. I'm only asking for reasonable amount of torque for street driving in the lower rpms. Just something to keep from down shifting all the time in traffic or passing.

F20turbo 12-01-2006 09:29 AM

If you want to see 300whp from a GT3271 just have a gander at my dyno thread. You can see that by 4000rpm that GT3271 is already making 190ft/lb and by 4500 its at 260ft/lbs. This is a turbo that spools in the 3500-4500rpm range. In 5th gear I can have 16psi @ 4000rpm.

Braineack 12-01-2006 09:51 AM

Damn I need to dyno at 12psi and see what I'm putting down now.

m2cupcar 12-01-2006 10:20 AM

I just noticed those dyno #s - on a mustang! Nice. Fuel?

y8s 12-01-2006 10:48 AM

hows comes you TO4E guys always talk about the -50? Wouldn't the 46 be better suited to the 1.8?

F20turbo 12-01-2006 11:22 AM


Originally Posted by m2cupcar (Post 60980)
I just noticed those dyno #s - on a mustang! Nice. Fuel?

never went more lean than 12.5 and that was a lean spike at full boost Z( 4200-4300 rpm ) other than that it was rich across the board.

m2cupcar 12-01-2006 11:40 AM

phenomenal- really curious to see the before/after once you get a standalone in

Braineack 12-01-2006 11:49 AM

11.3psi, 305c injectors, OEM AFM
http://www.rev2red.com/images/cars/11psi_305cc.jpg

I'd expect his plot to look very similar to this.


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