Where does the Greddy turbo fit in?
 

What does the stock 15g turbo from the miata Greddy Kit compare too? 2554, 2560, 2860? Hopefully a simple question with a simple answer....

it doesn't fit in. it sucks compared to the gt-r garretts.

Back up this statement.

The 15g and the garrett 2554 are VERY close in design. The wheel design and exhaust housing of the greddy - looking at numbers only - would allow it to spool faster than the 2554 and still move as much air. However, the garrett is a BB and I honestly do not know what that does for spool. It very well may make up the difference. As for the 2560 and 2860, they are both larger and will obviously move more air but at the sacrifice of spool. It all depends on your goals and usage as to what turbo is better. The NA I just bought will be strictly an autocross car and the greddy kit that came on it will be a great turbo for that application. The 2860 would slow it way down.

I was busting mikes balls because he likes it but since you asked the greddy sucks when it comes to spool. Please don't try to compare it to a gt2554r or gt2560r. Where is it in this thread?

I disagree that the greddy is ideal for auto-x.

anywhere? https://www.miataturbo.net/forum/showthread.php?t=26641

15g vs my T3

Attachment 210413

Where is what in this thread? Did I miss something?

Why point me to a thread about spool that is a bunch of different cars with different electronics, different fueling, different heads, different exhaust. There is no evidence in that thread at all that tells me that a 15g spools or lights any slower than a gt2554. I'm not saying I'm right and you're wrong. I just want evidence. On paper, the 15g and 2554 would be very similar in performance. Support your statement and I'll believe it. Here is what I know by looking at the specs.

15g has a smaller exhaust AR = faster spool
2554 has a smaller turbine exducer = faster spool
15g has a smaller trim on the compressor side = typically faster spool
2554 is BB vs JB = faster spool

So I've made points for both. I'm not saying the 15g is better. I'm saying they are similar. Convince me otherwise. I can admit when I'm wrong.

Braineack

Are those cars 100% identical other than the turbos?

What are the specs on your T3?

how can they be identical setups? they would have to have different designs for the downpipe and the intercooler piping.

Who here has started with a Greddy kit, "downgraded" to a GT2554R, and wish they could go back because spool got worse?

Anyone?

There has to be someone.

How bout the opposite?

Damn I don't know shit about turbos but I know that a 2554 spools better than a greddy turbo. Like you say evidence is in the specs. BB vs journal bearings is the biggie that you're underestimating the significance of. Also, the garrett is more well designed turbo from a performance perspective. Again, no expert but it's gonna have "better" blade designs and what not. It's more turbo in a sense.

So your approach is to convince me with sarcasm rather than knowledge?
You still have not given me a single reason that the 2554 is better - other than "I said so."
I told you that I am open to convincing. Convince me - with knowledge this time.

Here's the deal. It's "known". There is no debating it. There are underlying facts behind it and there are real world results. No I'm not linking you to them. If you want them, search. They are out there. It's accepted knowledge here as it's been proven many times in the past. Some speak from experience. Find 10 greddy dyno plots and find 10 gt2554 plots and have a looksy.

I went from a greddy to a gt2554r. It's better with out question. Spool is super fast and the power delivery is linear. The td04 spooled slow(er) and the power delivery was somewhat extreme.

I found the greddy to the shits for autocross. Sure it pulled like a motherfucker (at 15psi) but it always seemed to be at the wrong time. You don't really want that big rush of midrange power 1/2 through a decreasing slalom or right at the apex of a 90* turn.

Paul gets to be a dick in this situation because he has experience with at least one of the turbos. What experience gives you the right? When you start driving a turbo car then maybe you can inject some personal experience. Until then, shut the fuck up supercharger boy.

Ok, this is ACTUAL evidence to me to prove that the 2554 spools faster than the 15g.

However, I think I'm going to stick with the 15g though for a couple reasons.
1. I have read and jayc72 in a pm to me that the 2554 is only going to support around 200hp.
2. I did autocross the car as is last weekend and with left foot breaking, I pretty much keep the car in boost anyway.

so the 2554 spools faster? so fucking what.

here's a Greddy (194rwhp) vs a 2554 (181rwhp):

Attachment 210398



if a 2554 cant support your 250rwhp goals, then it's obviously not a great turbo. I'm not saying the greddy is anything special, but spool isn't everything.



what about a 1.8 T25 vs a 1.6L greddy making about the same peak torque:

Attachment 210399


what happens when you care more about top end?



just sayin' yo.

I'm not sure the difference in spool can't be made up for with better boost control and a decent downpipe.

im sure a new manifold would do wonders as well.

I really doubt it. In my experience the power delivery is completely different. I had a good DP on both my setups and used the same MBC, so a pretty close comparison. My "data" is all subjective so take my OPINION for what it's worth. I'll stand by what I said, the gt2554r is a better turbo for the 1.6 if you are interested in spool with autocross in mind.

well have to see what a gt2554r can do in 3 weeks on my 268,000 mile original 94 motor.

i was considering swapping in my new motor with 99 head before the dyno day but i'm really curious what it can do on a straight up beat ass 94 motor at 15psi