DIY Turbo Discussion greddy on a 1.8? homebrew kit?

Opinions on upgrading compressor side of turbo?

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Old 04-26-2012, 12:17 AM
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Default Opinions on upgrading compressor side of turbo?

My SR20 turbo has been on my car now for 4 years. I have never had any problems with this turbo, and if I would go to sell it, I'd get next to nothing for it. Therefore, I'd like to keep it, but make it better.
I contacted Gpop Shop and inquired about upgrading the compressor wheel. This would also obviously require machining to the CHRA and the compressor to get the new wheel to fit. The wheel gets upgraded from a 56mm diameter wheel to a 60mm diameter wheel, with a said gain of 15whp? Doesn't seem at all worth it to me to upgrade 4mm's for a mere 15whp, but what about upgrading the whole compressor with one from, say, a 2871?
What I am looking for is a swap of compressor and compressor wheel, and that's it. I want slower spool, and I want to move more cfm's than I do now. Instead of making 225whp on 12psi...I want to do it on, say, 8?
I have a spare complete CHRA and spare compressor, but would a compressor from a larger turbo such as a 2871 fit my CHRA? Would the compressor wheel fit my shaft?
Who has input or experience with this?
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Old 04-26-2012, 12:19 AM
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No no no and no

Would need to be rebalanced. Fail

Also i thought you wanted gt30. Why build motor.
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Old 04-26-2012, 12:25 AM
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I was thinking godspeed gt3076, but I am really attached to my turbo and would like to upgrade it. I guess I just like to do things in way that nobody else does. I'm sure you know what I'm talking about, Min. Besides, my power goal is under 300whp. The turbo I have now maxes out at like 240whp, and that's at mid teens boost at the top of it's efficiency range, and it spools way too damn fast.
I know I'd need a rebalance, that's no biggy.
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Old 04-26-2012, 12:30 AM
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Originally Posted by Faeflora
Why build motor.
If you meant that as a question, then my answer is simple.
Thirdgen rebuild:
Stock pistons, new bearings, M-tuned rods, new rings, cylinder hone, freshed up head w/ stock valves and cams and all new seals for entire motor...game over.
I want to use RX8 425cc PNP's with a whp goal of whatever gets close to max DC of those injectors. If it's 240whp...that's fine with me, but I don't want to spool at 2600RPM and then make 240whp with 15psi. I want to spool at 4500 RPM at the earliest and make 240 at like 10psi.
Ya dig?
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Old 04-26-2012, 01:08 AM
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You should really talk to Gpop shop about this, Thirdgen. They'd know within seconds, and as a bonus they'd actually know what they are talking about. In theory you might be able to get it to work, but you should really talk to them about it.
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Old 04-27-2012, 11:28 AM
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I talked to Gpop Shop and asked about swapping a compressor from a larger turbo onto my SR20 CHRA. This is what they said:
This is possible to do and has been done, but you would still need a slight amount of machining done to your bearing housing to fit the larger backside size of the compressor wheel. You would need the following:
GT2860RS Compressor housing $175
T25 to GT28 adapter ring $55
GT2860RS compressor wheel $115
Machining for the bearing housing $45

I'm wondering how much of an increase this will actually be. Let's say I make 240whp now with my SR20 turbo on 15psi. I hope to make around the same whp with like 10psi with that larger compressor upgrade. Think it'll happen? Gpop shop said that if I did the compressor upgrade and I felt it still spooled too fast, I could clip my turbine wheel and that would slow my spool down? I'm not looking to do that, because I assume that the larger compressor will cause it to spool slower than it does now, but I wonder how much slower it'll be?
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Old 04-27-2012, 11:38 AM
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Ill give you my honest opinion: I think this idea sucks and will be a total waste of time and money. No offense man, but any time I hear someone say "I just want to be different" its almost 100% guarrantee that its a terrible idea.

the 2860 aint much bigger than the t25. You're NOT going to retain same power while running 5 less psi. Its not going to happen. You will see minimal increases for a lot of time and money spent (money/hp ratio).

You want slow spool and make 240 or whatever at like 10psi, get a big ol 30 or something equally oversized for that power. I was a little over 200 at just 7psi iirc. If that's REALLY WHAT YOU WANT, then that would be the path to take. Just my .02
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Old 04-27-2012, 11:52 AM
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Just buy a 2560 and be happy with it. It will be easier and cheaper then any other route.
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Old 04-27-2012, 12:17 PM
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Todd this is a horroble idea. Please. No. Nobody "upgrades" supershiiitu tirbos. You are tryig wayyyy too hard. All this optomization studf is missig the point. All you have to donis boost the bitch.
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Old 04-27-2012, 12:18 PM
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God damn it when did i start sounding so retarded?
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Old 04-27-2012, 12:19 PM
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Vlad, I am still on the fence about either upgrading my "sentimental attached" sr20, or just going the Godspeed 3076 route...The 3076 is cheap, but it's more turbo than I need. The sr20 upgrade costs more than the 3076...fml, I should just do an ls swap and say F this car.
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Old 04-27-2012, 12:23 PM
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I think you should shell out the $300 and put in supertechs, get 1000cc injectors, 6spd, 3.6 or 3.9 reard, and run the gawdspeed <3
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Old 04-27-2012, 12:25 PM
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"more turbo than I need"

But you want slower spool and lower pressure producing similar power.
You want exactly the same thing you don't want?

WTF

Do you even know what you want?

LOL
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Old 04-27-2012, 12:25 PM
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Go for 3076. I wish I did.
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Old 04-27-2012, 12:25 PM
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No rods min? Just supertechs? Lol.
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Old 04-27-2012, 12:31 PM
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Fine...I'm sick of this. I get my bonus check at work in like 3 weeks. I always pay my taxes with it, but with what's left over...I'm buying the Godspeed. F*ck it. I'm sick of debating it.
Besides, then I can use the WGA you sold me, Vlad.
But F supertechs and gears, Min.
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Old 04-27-2012, 12:56 PM
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RODZ

rodz

rodz

AND

PISTONS

and OPG


and lots of spare 5 speed transmishons then.
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Old 04-27-2012, 12:59 PM
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My 5sp lasted a year maybe more on the godspeed. the torque comes on so smooth and progressive that the trans is actually somewhat able to handle it.
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Old 04-27-2012, 01:03 PM
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Originally Posted by 18psi
My 5sp lasted a year maybe more on the godspeed. the torque comes on so smooth and progressive that the trans is actually somewhat able to handle it.
OK so should I put a 5 speed in my car?
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Old 04-27-2012, 01:07 PM
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Originally Posted by 18psi
My 5sp lasted a year maybe more on the godspeed. the torque comes on so smooth and progressive that the trans is actually somewhat able to handle it.
Then you sold the car, and the next dude broke it in like a week
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