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Old 05-06-2008, 01:01 AM   #1
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Default Convince me to keep the gt2860rs

No, I'm not trying to be the next hustler...
I've bought a Begi S3 and it'll be using a 3" downpipe and exhaust, a #2 intercooler, and MSPnP. I got some wrong parts initially so some things are going to be exchanged anyway. I've been thinking (especially after seeing Paul's results) that the gt2560 might have been a better choice. Of course his success is partly due to the Begi intake manifold and a 99 head. I went with the potato because it should keep the intake temps a bit cooler and as I'm not planning to build the motor anytime soon I thought this would be the friendlier option for the stock block. That being said this is a DD and not a track car so I don't how much that actually matters. Furthermore, the more I think about the more I worry about it being a dog down low and not as fun, it has the .86 A/R. I'd ideally like to make somewhere around 250-280HP. So, keep it, or exchange it before I install it?

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Old 05-06-2008, 01:28 AM   #2
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Corky himself talked me out of doing exactly what you are thinking. He's a big believer in the better thermal efficiency of the 2860. My 94 is at BEGI right now getting an S4 system installed with MSPNP and the 2860rs. Hopefully they'll have it on the dyno for tuning late this week. Don't make any decisions until we see how that comes out!

I'm curious how much of a difference EBC will make in spool vs the MBC #'s we've all seen lately.
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Old 05-06-2008, 02:12 AM   #3
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I'd also be interested to see what EBC will do for spool on this turbo. So it sounds like your setup is pretty similar except you have the tubular manifold and an external gate. Are you running a stock motor as well? The .86 A/R or the .64?
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Old 05-06-2008, 03:04 AM   #4
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Won't someone please do a 2871 so we can see what the thing will do
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Old 05-06-2008, 03:10 AM   #5
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It would be interesting, but it seems kind of pointless on a stock motor.
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Old 05-06-2008, 09:46 AM   #6
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I'm still a big ***** about this, but I've never seen anyone complain about the gt2860rs on the internet. I've only seen a bunch of ------s who don't have it tell me not to get it. I've asked everyone under the sun about spool and "when the car starts moving" and everyone said from 3500-4000. There are people out there with 1.6 motors getting the gt2860rs to make 10psi at 3200rpm.

I have a 1.9l now with a 99 head, so I'm pretty confident that I'll make 9psi by 4000, and that's all I care about. If I wanted boost at 2500rpm, I would have bought a pea shooter turbo.
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Old 05-06-2008, 10:01 AM   #7
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Quote:
Originally Posted by Savington View Post
Won't someone please do a 2871 so we can see what the thing will do
Brad has.



keep in mind, it hit 13+psi then the clutch slipped and dropped to 10psi at redline....still spools very well on a 8.3:1 CR motor. This was also an open wastegate line, so we didn't even try to spool it faster. We should be getting it on a loaded dyno for tuning in a few weeks.

This is also the .63 A/R, while the .83 will spool slower by a few hundred RPM, it will make more power per psi. If you take the right steps to increase flow and efficiency you'll be fine.

Think about this, my 1.6L is spooling my journal bearing T3 as fast as a BB GT25 turbos on 1.8L motors. 59mm turbine (.48 T3) vs. 53.8mm
(.63 T25). The only thing I really did was some mild diy headwork and my 3" exhaust.

The power will be easier to make on the 2860 vs the 2560, you may consider a smaller turbine housing, but it's not like the 1.8L T3 guys with .63 housings (the equvialant) are complaining about the spool. It's ultimately what you want from your car. If you're tracking it, I say keep the larger turbo. Compared to the 2560 it's goign to have better heat management, since the power will be made well within the 60% mark, while the 2560 well outside. If serious autoxing, maybe consider the smaller guy
to get some of the low-end grunt back.
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Old 05-06-2008, 10:46 AM   #8
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It's really going to be neither of those for the time being. It's only going to be a DD until I have more time in my life and/or a second car. Still the reduced heat is appealing for keeping the block in one piece. I have to talk to Corky today anyway so I guess I'll let him tell me what he recommends. Thanks for putting up with my waffling.
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Old 05-06-2008, 10:51 AM   #9
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I'm at 180 WHP Dyno Dynamics numbers at 7-8 PSI at the manifold. from what folks have told me that is around 210 whp Dynojet numbers.

Try doing that on a GT2560.. ain't gunna happen.. i'm running a T3 Housing .63 A/R with an external gate so it's a bit different but shouldn't be THAT much different.

What are your plans for the car? are you planning on Autox or track time?

The only thing I might change is your exhaust housing.. switch to the smaller A/R.
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Old 05-06-2008, 11:19 AM   #10
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Jeremy @ FM had a potato on his car and hated it.
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Old 05-06-2008, 11:25 AM   #11
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Jeremy @ FM had a potato on his car and hated it.
I've been reading that and other anecdotes of people shitting on it. Why would corky offer it as a choice for his kits if it was garbage?
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Old 05-06-2008, 11:29 AM   #12
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Quote:
Originally Posted by johndoe View Post
I've been reading that and other anecdotes of people shitting on it. Why would corky offer it as a choice for his kits if it was garbage?
I'm guessing they got the wrong turbo for what they wanted to use the car for.

If you want serious boost at 2500 rpm it's not going to happen with a tater on a 1.8 or 1.6 liter engine.
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Old 05-06-2008, 11:46 AM   #13
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Just had a nice chat with corky, I'm sticking with what I got. Damn, he's a nice guy
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Old 05-06-2008, 11:48 AM   #14
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Quote:
Originally Posted by johndoe View Post
I've been reading that and other anecdotes of people shitting on it. Why would corky offer it as a choice for his kits if it was garbage?
Well... you said you were looking for 250-280hp. That sounds like the low end of a potato--especially with the .86 turbine housing. Maybe Corky is thinking "headroom" and that when people say they want 250-280 they mean "i want to sound conservative but really 280 is my minimum"?

if you keep the 2860RS, consider that IF it sucks on the low end you can still swap exhaust housings. I did that with my 2876R (to the .64) and I like it. It's a solid, efficient turbo that can do 250-280 without breaking a sweat and I have over 180ft-lbs from 3500 to redline at 9.5 psi.

Course if you plot my pressure ratio / airflow on my map, i'm right at the peak efficiency line. Not sure where you fall on the T3.
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Old 05-06-2008, 11:53 AM   #15
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well, I explained that I'm not building the motor and the realistic goals I had and he said he believes the gt28rs is the right turbo for those power levels over the gt28r, but like you said, if it turns out I'm not satisfied I can swap the hotside.
Edit: Also I have the T2 housing, not the T3
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Old 05-06-2008, 12:01 PM   #16
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tell you what... i'll trade you my 2560 for your 2860....
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Old 05-06-2008, 12:12 PM   #17
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I'll get back to you on that after I install it at the end of the month I'm going to take the big man's word for the time being.
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Old 05-06-2008, 12:34 PM   #18
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atpturbo.com is showing a T3 .48 A/R exhaust housing that will work with the tater.. That looks interesting for a quick spooler application. I wonder what the Garrett part number would be. I don't see it on the 2008 catalogue.
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Old 05-06-2008, 12:44 PM   #19
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Mine is getting the tubular mani but internal WG. It's a test mule for them so they are trying some different stuff on it to see what works. My motor is a stock 94.

Again, I'm hoping it hits the dyno this week. Not holding my breath though.
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Old 05-06-2008, 01:08 PM   #20
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Quote:
Originally Posted by johndoe View Post
well, I explained that I'm not building the motor and the realistic goals I had and he said he believes the gt28rs is the right turbo for those power levels over the gt28r, but like you said, if it turns out I'm not satisfied I can swap the hotside.
Edit: Also I have the T2 housing, not the T3

isn't the tater's compressor a T3?
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