Sorry I could not remember the size. Its a compturbo unit. A CT2-5862 with a tial 1.06 rear housing. All of the comp turbo units feature the billet compressor wheel. Turbine dimensions are the same as a gt35r, and compressor the same size as gtx3076r.

Nice ! That should be a pretty good comparison with my setup . Very interested to see how you get on !

I'm looking forward to it as well. My goal was different than your own.

My fitment is tight~! I have got fairly good and clearancing the firewall for turbos as this point.


https://cimg4.ibsrv.net/gimg/www.rx8...b80797fa70.jpg

All you're doing is moving the power up the rpm range. How much power do you need; 550+ at the rw isn't enough? I would rather have the response and don't agree, but that's just my opinion.



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that's a good choice IMO

if we extrapolate some data for an approximation

that assumes the GTX3076 compressor sizing, might be a bit less and closer to 100 ...

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You couldn't run the smaller AR twin scroll because it's IWG . Unless of course you split the siamese flow to seperate the two rotors. So the 1.05 becomes the next best thing.
The spoolup on these EFRs is so spectacular ......... it's a moot point anyway.

And no , I'm aiming for 400 - 450 reliably . with the emphasis on that last word .Something that has not been achieved to date .

But if I can achieve that , someone else may want to take the next step perhaps ...?

you can handle it several different ways, but if that's all you want then the 1.06 is too much and only adds more cons than pros again IMO

All hypothetical because I'm not ever planning to do that . But IMO , if you are going top mount , the ONLY reason to do so (apart from the bling factor) is to give you the ability to choose any turbo you want and make BIG power.

That 7670 is too small for that aim . As a side note ..... I see the first guy to fit one recently blew his engine AND turbo . ...... Maybe..................... because it's overspooling ??????

8374 makes that easily without the laggy 1.06 AR, again no need to go there

your facts are off, he broke the front plate where the turbo oil feed line was, turbo seems to be fine, but clearly it wasn't a turbo failure issue that took out the motor

EFR + 1.05 twin scroll + good runner design = Not laggy




I didn't state it as fact :p:

Still , cracked front plate from what ? Only a major detonation would cause that.

not compared to old technology, but the main basis to my opinion is there's no need to go there, larger A/R on an otherwise all-else-being-equal turbo is always slower to respond, always ...




So you just say anything to get other people to believe what you want??? (just joking back atchya :lol:)

Detonation is always a possibility an any turbo system. The reasons why are endless ... got anything to offer other than speculation?

True ... we seem to be going around in circles on this one so I'll stop .

Nope ... just speculation . Time will tell whether these guys running the 7670 well into the choke zone is a really bad idea .........................or not .
I suspect that people will realise in time that the 8374 spoolup is so good that there is no reason to overspin a smaller turbo anyway and people will just stop using it .

Hoss's pic is a little more clear of the clearance issue at the lower subframe. Right where the turbo clamps onto the manifold.

I'll be back mid spetember with a turbo rebuild also and I'm running.

The dyno graphs for both the 0.92 and 1.06 ARs on a 13B are out there, i just didn't want to belabor the point either. The 1.06 is more like an on/off switch below 4000 with a very steep curve and almost nothing at 3000 compared to the .92 making 15 psi there

Can't find one ..... got a link ? Would be interesting to see what the manifold differences are too .

BTW it's 1.05 AR not 1.06 .

yes, I knew that but it doesn't add any relevance

try looking in your own backyard by searching Ric Shaw :p:



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meh ... (note that it says flywheel TQ)



https://cimg5.ibsrv.net/gimg/www.rx8...6c9d314970.jpg




Ric Shaw's World Time Attack and Endurance racer FD RX7 -- 480hp @22psi boost

vs 0.92

10 psi @ 2500
15 psi @ 2800
20 psi @ 3000
28 psi @ 3400

hit 22 psig @3050 rpm and 220 lb-ft output, compare to 3050 rpm for the 1.05 above that was shooting for 22 psi boost

frankly the 0.83 IWG non-divided would make more sense than the 1.05 IMO, especially on a street car shooting for 400 rwhp ...





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That is a significant difference . I suspect there are more differences than just the AR though.



Yes it would in that scenario .... But we were talking about how to (hypothetically) make BIG hp on a Renesis . Which in my mind would be 500-600

first time you ever mentioned it like that, still laggy just the same

I wasn't clear enough ... My apologies for that.
Yes it is laggy ... If mine ends up as bad as that I'll be very disappointed !

well apparently the people with the most experience on these don't agree as they're tweaking on the EFR 9180 instead

still looks better than the 1.05AR 8374 on low boost, that's a big mofo though :Eyecrazy:

Doesn't make a lot of sense ......... my guess is that the manifold used was longer and larger on the 8374 1.05 AR

I feel like you still don't fully get the AR vs turbine design vs engine requirement relationship

it's not just a 1.05, it's a T4 1.05, which is not the same as a T3 1.05. I can't see a 500+hp 2-rotor engine having sufficient wastegate control through the restricted siamese center port, but maybe I'm wrong.

Turblown had a good post in Hoss-05's thread about why a larger than normal (normal = piston engine) turbine wheel is a better fit on the rotary. Since you had participated in the discussion, you may have forgotten about it from several years ago ...

as for an EFR 7670, more than a few highly experienced turbo gurus think it's perfectly acceptable for up to 400 rwhp 2-rotor application. Their reasoning is that for a street/autox application the low rpm boost response is superior to the 8374 and they aren't running continuous WOT for long periods of time. As always, the right configuration and tune matters.

As you eluded to earlier, a T3 1.06 with a GT3582R is a known quantity. You won't have any real issues and should hit your goal fine *assuming* the 3rd-port wastegate deal works. That doesn't mean it couldn't have been improved on with a different compressor wheel and turbine housing. You are already risking on the manifold setup so it was reasonable to play it safe otherwise.