If I remember correctly, MazdaManiac said that he could have gone with a different turbo on his setup...if so what would the ideal be? Based on the current understanding of a reliable setup and the results seen on the Greddy kits vs. MM vs. Others...

Just thinking of going FI and doing some...pondering...what are some fundamental guidlines, recommended variables, etc, when it comes to our beast...

Curiosity and cats with the murdering and all...

 

Depends on what your goals are. Dyno queen, 1/4 mile, street... once you narrow the performance requirements you can read the flow maps. It takes a fair investment of time with the maps and demand lines for your engine to choose a turbo. That's why the commercial guys don't give that info out too readily. G35R is a popular choice. Its modern, highly efficient, and rumored to spool quite quickly. But, much of the capabilities of this turbo will never be used on a Renesis. The Ren just can't use that much air. You'll be paying for capability that you'll never use. I think I remember someone suggesting a GT30 once. I seem to remember a quick glance at the maps seemed to indicate that it should flow enough to sustain a pressure ratio near 2 until redline. I thought it looked like a good choice for street use at that time.

 

I like the GT2871R. It is small like the GReddy and matches most of the flange profile (you will have to fab the intake pipe), but it is ball bearing, water cooled and will flow enough air to stay at max eff in the 2x PR range:
https://www.rx8club.com/showpost.php...6&postcount=11

 

Thanks fellas! I am intending a street application. Saw a few videos of turboed rx's which during dyno pulls it appeared that the turbo simply couldnt flow enough air and so there was a dead spot...I kinda was looking to avoid that.

 

So your saying that this could be used on the Greddy kit in place of the one they ship?

Getting the plumbing from a kit would be nifty...plumbing is always a problem...alas MM lacks a decent "kit" haa haa...

 

Yep. The GT2871R should flow enough. Its only slightly less efficient than the GT3071R.

Has anyone actually fit a GT28 on the GReddy manifold yet? Do we know it will fit - or do you have to break-out the BFH?

 

The BFH probably wont be needed, but the angle grinder will.
The 3071 needs more fabricating because the compressor scroll is bigger and doesn't come with flanges like the GReddy turbo has. It can run more boost, but I think we are pretty much knock limited to 35 lbs of flow at 10:1 and a PR of 2.
I'm going to pull the trigger on a 28 soon (need to clear the bench and sell some stuff first).
BTW MadDog - hows your project going?

 

I have been thinking GT30, but am not sure it can feed my ported Renesis. It looks like it's flowing quite a bit more than stock. Maybe that's not too important for a street app.

 

You can port it all you want, once you start stuffing the motor with FI, the displacement is all that matters.
Nothing raises effective VE like FI.

 

MM- my project is back on track after the emissions debacle. The fabrication should be done in 2 weeks or so. Then dyno tuning.

 

Emissions is always a debacle.
Maryland is still after me, but I don't think I'm going to make a 6000 mile round-trip spectacle out of it just to save myself a few hundred dollars in taxes.
I'll just have to register in Arizona in March when my emissions deferral runs out.

Now that I'm back on the EMU, passing won't be an issue.

 

can you reuse the greddy wastegate on the gt2871r?

how sure are you that its compatable? i think i found a pretty good deal and i might take a stab at it...

this is the correct part number right? GT2871R-472560-15

thanks in advance!

 

The wastegate will fit, but there will be one bolt left out.
The compressor-side will require that you cut the pipes and use silicone adapters instead of bolt-on fittings, though I would suggest you have someone weld flanges instead. It has a 3" inlet and a 2" outlet.
The hot side will bolt on.
You will need to clock the compressor housing and plumb the coolant lines.
The oil source and drain will probably be the same (threaded in, flanged out) also, but I didn't check that the measurements are the same.

Garrett lists the P/N as 743347-2.

If you can wait a few weeks, I'll be doing the real in-depth research on this since I want to upgrade myself.

 

Uses a GT 35r .82 ar. Good for 450 WhHP

 

mm are you gonna fab some parts to sell to us greddy owners =D

 

Perhaps.

Yeah, its a good turbo and a good choice.
It just isn't a "drop-in" replacement.
Not even close.
the 28 and even the 30 are a better choice for the street without a ton of fabrication.
The 28, as noted earlier, is exactly the same size as the GReddy unit.
The 23 is available with an .86 A/R.
Really, I'd like to see a .96 A/R on the turbine side, but a 15° clip on the wheel would probably acheive the same result.

 

I've been debating what to do so perhaps this is the best place to ask since we are talking fundamentally about the Greddy Kit and updates to it. I was pondering if going with one of the other kits that sell for much more online because I just didnt think the Greddy kit was worth anything. Now if MM is thinking of updating that kit...I may just buy one and follow MM's wacky scheme...maybe...

So any input on the Greddy Kit?

 

The search button is your best friend on that one.
TONS of stuff about that and some of it is even concise!

 

awwww...no newb pic for me??

your getting soft man...your getting soft...

 

True. Here ya go:

 

Lmao

 

I love that banner?
K&N 9.5 HP Increase...
Ha ha.

 

Hate to beat a dead horse but...With all the "improvments" which *could* be done to the kit, has anyone from Greddy even thought of perhaps re-releasing the kit with all the "updates" which the community has found?

 

My impression from limited discussions with GReddy is that the RX-8 kit was expected to be a low-volume seller in the first place. Probably due in part to the problems with the early versions they sold even less than they expected. I doubt there is much impetus at the company do make any changes at this point. Although they've damaged their reputation on this forum, we really don't amount to a hill of beans to them. Include all the RX-8 owners outside of the forum (and there are a lot), and we still are a very small hill of beans compared to some other target groups.

 

GReddy/Trust is a huge company. They are second only to HKS in sales in Japan.
The RX-8 kit was just a "place-holder" for them in the market.

You can bitch and moan all you want about them, but for the longest time they were the ONLY game in town. Even now, they are the only game in town that can deliver without a B/O to some degree. Only GReddy and MazSport can sell you a system RIGHT NOW, even though the market has been open for almost 4 years.

The engineering on the kit - pipe placement, manifold casting and turbo choice - is sound. Go try to beat it in a similar packaging.
The problem was the EMS - they didn't have it down and they rushed to market hoping they could catch up on that point.
They didn't.

When it comes down to it, even if you just used the kit as a parts bin for a better custom project ($3k for a turbo, intercooler, EMS, a cast manifold and all-aluminum cold-side plumbing is a steal), there is nothing that can touch it.