Lol, the CHRA is not titanium aluminide, the turbine wheel is.

 

I would take anything FullRace says with a grain of salt. They are only "allowed" to say certain things until given the ok from BW. I recently asked Full Race about the VTV housings and they claimed they didn't know anything about them. Then I linked them this thread http://zilvia.net/f/showthread.php?t=460807&page=8 where Geoff talks extensively about them lol

 

I believe that the 9174 has an aluminum chra (and TiAl mft turbine wheel), so i expect there should be a similar 8370 coming along soon.

 

I would take an 8370 over the 9174. The 9174 might spool where a 9174 does but a 8370 would just be silly and have significantly better spool than a GTX3582 but the same flow characteristics.

 

I'm a little bit of a weight weenie so naturally I had to look. That is quite a bit. Naturally then I had to put an HTA3582 on the scale for comparison, ordinary cast iron single scroll turbine housing ... came in at 13.6 pounds.

 

I think is fair to point out that the IWG EFR does eliminate the need for 2 EWG's and dump tubes so that should be considered if there's a weight comparison.
The 9174 does not have a aluminum CHRA, at least mine doesn't.

 

It doesn't? I still haven't picked up mine. I probably will pass on it and stick to the 8374 if it doesn't since I'd rather have the spool on my application than the topend.

 

You may want to reconsider that. The 9174 is less then 100rpm behind the 8374 spool wise. I'll post some logs later tonight if I have time but I had started a review thread somewhere else but it got lost.
But having had all 3 large frame EFR's, the 8374, 9180 and now the 9174 I can say confidently the 9174 is the better turbo. The 8374 is really a 700whp turbo and has great durability (for the turbine wheel material), the 9180 is a 900whp turbo but the 80mm turbine is VERY delicate and doesn't take any incident of overspeed well.
The 9174 really is a good combination of the 2, having the more durable 74 turbine wheel and the bigger 91 compressor and from what I've seen so far it may make 900whp within its speed limits.

 

Will be interesting to see what BW shows at SEMA this year.

 

Ok so here's 2 logs overlaid, one is the 8374 and the other the 9174. Same engine setup, same turbo kit, same mods etc. Not the same day but in S.FL the weather doesn't really change that much lol.

 

Would you say that the lower rpm cruising is better or worse with the 9174 even though the delta in spool is 100rpm?

My application is as follows: 2.2L 11:1 f22c1 honda engine w/ custom 321 sch 10 manifold, sound performance quick spool valve, the 1.05AR housing either turbo I go with, and a 4" titanium exhaust. I am super tempted to get the 9174 simply because cruising at a "low" boost (19psi) will still net great power and when cranked up can make some silly numbers, whereas the 8374 will have to be pushed to make 650-700.

 

1 thing i think is important to note, the A/R and twin or open scrol configs. You mention the 8374 is a 700 whp turbo, but in a twin scroll config. Would it be a reasonable assumption that a single scroll 8374 is a high 700 hp turbo?


What is the A/R of the 9174??

 

I'm running the .92ar IWG twin scroll housing.
Yes, I agree that with a larger turbine housing a turbo should make more top end power but we all need to be clear with the fact that these turbos are RPM limited and in my experience the bigger the turbine wheel the weaker it is. A 8374 will take slight overspeed for a short period of time but it is a ticking time bomb at that point and that turbine wheel will disintegrate in a very short period of time if the overspeed continues, a 9180 will eat itself very easily with any overspeed event.
So no matter what housing you put on the turbo your still limited by how fast you can spin it. A larger housing will drop turbo RPM but not really enough to make another 80whp.
And as English Racing showed, even with a 1.45 EWG the 8374 makes ~750whp before turbo speed becomes a issue....and even then the 8374 they had on that car eat itself in a relatively short period of time. So I'll stand by my assessment that the 8374 is a 700awhp turbo, that is if you wanted to last at all.

 

Honestly on the street you can't tell the difference between the two while driving around.
I got your PM and I'll touch base later.

 

I am noticing an oddity on the compressor maps shown by Full-Race for these turbos.

It looks like the highest speed line is always at 560 meters/second tip speed, for all these turbos. Then when you look at the “English” chart where there is shaft rpm shown instead of tip speed, I see that the shaft rpm is calculated based on the OD of the compressor wheel, not the turbine wheel. What the heck? If it is the turbine wheels that are sensitive to overspeed, why isn’t the max rpm determined from the turbine OD rather than the compressor OD?

Can you tell me what shaft rpm you have been told is the speed limit (overspeed threshold) for these 3 turbos? (9180, 9174, 8374). Maybe the turbo “threshold rpm” is not as shown by the highest speed line on the comp map?

Since the compressor map is only for the compressor, it is not odd to have the max compressor speed based on compressor OD. But when we are talking about the whole turbo - there should be a max shaft speed that considers the whole turbo - compressor, turbine wheel, bearings, everything. So I am wondering what speed limits they give you for that.