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?

No no no and no

Would need to be rebalanced. Fail

Also i thought you wanted gt30. Why build motor.

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.

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?

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.

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?

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

Just buy a 2560 and be happy with it. It will be easier and cheaper then any other route.

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.

God damn it when did i start sounding so retarded?

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.

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

"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

Go for 3076. I wish I did.

No rods min? Just supertechs? Lol.

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.

RODZ

rodz

rodz

AND

PISTONS

and OPG


and lots of spare 5 speed transmishons then.

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?

Then you sold the car, and the next dude broke it in like a week :D

lol.

:brain:

You'll get more than 15whp (where did you come up with that number), and it's a significant upgrade:

https://www.miataturbo.net/attachmen...ine=1335546841


swapping to a t3 wheel (45,50,60, super 60 trim) would make your turbo a t28.

t25 + t3 = t28




but.


I'd for the prices you listed, I'd rather just buy a godspeed t28. not a 3076, or 3071, or 2871. I'm talking 2860 or 2560 sized turbo.

DEFINITELY
a month iirc, but yeah. I never denied the fact that I babied the heck out of it when I had it. super smooth shifts, almost never any launching, just going WOT from time to time. (which is what Todd would probably be doing too).

had I money shifted it like him, I probably woulda popped it in a month too.

So how much realistic power gains should he expect from something like this, and how much lower boost would he be able to run yet achieve same peak power?
From everything I've seen on other cars, huge wheels in small housings usually require a TON of pressure to really shine.

well here's my old garrett super 60 t3 on my stock 1.6L vs a sr20 t25 on a stock 1.8L

https://www.miataturbo.net/attachmen...ine=1335547348

it can push a lot more air.



consider the last dyno I've seen of Todd's:

http://www.boostedmiata.com/gallery2/d/4675-2/todd.jpg

That dyno was when I was ms1 parallel with rx7 460's. I think I was on just under 12psi.
What boost were you running Scott? I can tell cfm's were higher cause you made a lot more torque than me.

he made less torque.

223 is less than 208?

my car was running about 13psi, and it's puny 1.6L that makes no torque. it made 201rwtq on that plot.


green is the 1.6L t3, blue was Lars's sr20. his plot looks just like yours we all dynoed on the same day.

Oh wait, I was looking at Lars, the blue line.

read the fine print: he is the green lines, and the blue ones are a different car.

you will lose a bit of low end torque but make power to redline.

I think just upgrading to a 2560 equvianalt bolt in chinacharger might just be the best thing for considering your stock rough and tumble motor.

Rough and tumble...That's an understatement.
160,000 miles, and 1 quart every 500 miles. That's how I roll.

:bowrofl:

i chuckled at that too.