Hi guys, been reading lots of older posts on all the debates on these turbos. As mentioned I’ve got an FD, full Bridgeport and studded, I’ve recently killed the factory twins but always planned on going bigger.

Which turbo will be best suited to run 550hp?
Street and track used.

 

Crank or wheel?

These are very different goals

 

*wheel hp

 

I did try the similar variants (8374 and 9280) and the 9280 gets my vote.
i loved the 8374 but it felt it was choking up on top on high boost.
the 9280 is laggier in comparison but I wouldn’t exactly call it a lazy turbo.

theres also room for more if you decide to turn up the boost to 600 or even 650whp with the 9280 whereas you will be pushing the 8374 to go to 550whp.

but in reality It really comes down to how you want the car to behave.
while i did like the immediate response of the 8374 it did actually hurt me on track because the power delivery was immediate and i had to be fighting the steering in certain tight turns

 

full BP, studded w the factory twins?

that's like sitting on a hand grenade after pulling the pin.

there are of course many options that would work for your needs...

one that would interest me would be a BW SX-E 64... or more accurately 64.47 or BW SX-E 8780.

it has a 9180 comp wheel cut down on the inducer side so it is a spool friendly 54 Trim. wide efficiency islands due to the later engineering in the compressor housing.

first class engineering and you can retreive a bit of change back from your $1000 bill if you shop around i have extensively tested the SX-E series and they are rotary friendly. the 64 comes w the larger 80 mm inconel hotside wheel so you won't have to worry about melting it on a road course and it will be quite linear. the primary consideration will be whether to go w a 91 or 1.0 housing. less EGT and backpressure w the larger housing, perhaps less spool. generally on a road course you keep the rpms up and the 54 Trim is a BIG deal as to enhancing spool.
since the BW hotside housings are inexpensive, you could always do a swap if you wished w minor $ damage.

here's the compressor map.... 550 rw rotary hp is 73 pounds.

 

being that you’re in NZ; if it will be on either a DynoDynamics or Main dyno, then you’ll need something larger than an 8374 to ever see 550 whp on either of them.

edit: looks like I’ll have to eat those words, it can just get there according to this thread:

https://www.rx7club.com/single-turbo...hread-1138737/

I would have expected it to be less though
.

 

I have 4 cars that have made between 580 and 590 rwhp on an 8374 on pump e85

takes around 30psi to make it happen.

all had 1.05 ewg rear housing, all were Bridgeports. OEM FD intake manifold.

550rwhp is achievable on an 8374 on a Bridgeport at around 25-26psi (beyond this boost level you can make a little more but the gains are small, presumably since emap is so high as seen above)

 

I had already assumed the 8374 would be too small, and thought about the 8474 to try keep the lag minimal, without losing any top end.

Was also told by a turbo supplier I should go with the 8474 with the 1.45 housing, but haven’t seen anyone else do the same?

I much prefer the price of the SXE series but thought the EFR series had a big advantage?

 

yeah, I saw your results in a past thread after my post and then updated it with the link to it. Looks like you posted while I was making the edit.

I’m still a bit surprised by that given the compressor map is indicating max flow at 77 - 78 lbs/min. So it’s definitely maxed out running there.
.

 

The posts above pretty much answer your question, but FWIW.

Built 13B, large-ish extend port.
EFR8374 EWG 1.05.
E85 @ 22psi (MAP on dyno is wrong)

It makes a very potent street and occasional track car. As others have said, there's still a little more in the 8374 (shaft speed at 104,000), but we also suspect the EMAP is getting up there. 1.45 housing may help, but I'd be inclined to just step up the turbine size altogether, especially on a bridge.

The 9180 is the sweetspot IMO. I'll probably go that way once I sort out my Tremec TKX conversion. Be prepared to run a wide semi slick if you want to use it. I would have thought the 9280 would be going a bit too far for a 13B, but sounds like it's working for others so that's another option.

If you're up this way (the Mt) and want to see how it performs, let me know.

 

the 1.45 housing will cost you more low end than it will give you top end. it was very disappointing when we did a back to back test on it. Safe to say the turbine wheel is the limiting factor

At that sort of boost your emap will be around 28-30psi based on all the data I have collected with that style of porting and turbo.

 

Interestingly, Matchbot's estimate for EMAP is +/- 29psi on this set up, FWIW. Thanks for sharing your real world data - pretty rare these days!

 

What's the max hp you can make with a bridgeport + 8374 on 98 octane pump fuel?
Asking because there's no e85 where I am...

 

Just go 8474 instead of 8374 if you want to run a large port.

8474 vs 9180 is the real question