Well the PT5858 CEA should be right on. I don't see a comparable T4 divided turbine housing for it though.
Or the PT5862 CEA - this one they list a T4 divided .84 a/r for it.
With a PTE you could get a plain bearing one. Who cares it it only lasts for 6 runs?

 

The GTX3576 is the closest match to the EFR7670. Also, based on my results you would not want to run the GTX3076r on a 2.2L and will likely give up ~40-50hp from the smaller turbine wheel. Because I want to see the comparative data send me a PM to chat about moving forward.

GTX3076r vs. GTX3576r on my 2L

 

Ah yes thanks for that info. And I quote from a year ago:

 

The GT30 hot side may restrict the GTX wheel but the GTX wheel is bigger and higher flowing than the EFR wheel. Given Buschurs comparison found a GT30HTA to make more power happily, and GTX3076R I have seen to go easily over 600hp on E85.... I think the GT30 probably is the fairest comparison.

Here is a 30psi GTX3076R result from a Nissan SR20 on E85

Works our as about 630-640whp

 

^ Good numbers. I think the HTA3076 or the GTX3076 would be a good comparison... and it shouldn't be that hard to compare the GTX3576 as well. I think starting with the 3076 will be a good start though. Thanks for the input!

 

Am I misreading the specs on these turbochargers?

EFR 7670 has a 70mm turbine wheel and compressor flows 64lbs/min
GTX3576r has a 68mm tubine wheel and compressor flows 64lbs/min

whereas the
GTX3076r has a 60mm turbine wheel and compressor flows 64lbs/min

Unless I am misreading the specs you would be handicapping the Garrett results by going with a turbine wheel that is 10mm smaller than the EFR unit.

 

That would make sense if all things were equal. For a start the turbine wheels are not of the same design between the two companies, do you really think Borg Warner put a 64lb capable compressor wheel on a turbine only slightly 'smaller' than the Garrett turbine wheel FP use on a 900+whp turbo? (72mm wheel on the 3794HTA) when response is their main target?

 

The height of the EFR wheel is MUCH taller and the OD is larger and that is POSSIBLE because it's a titanium turbine wheel.

So here's the rub... if you run the same size OD wheel as the BW Ti Wheel... the GTX wheel is REALLY heavy and the transient response suffers terribly, and the threshold boost just a little...

if you run the Garrett matched wheel GTX3076R against the EFR... now you have a turbine wheel will a similar MOI so it will be competitive on spool and transient response, but not have the top end potential because it's choking up top.

Both are compromises... where the EFR is going to out spool and have better transients than a smaller diameter steel alloy wheel... and flow just as much as a steel alloy wheel that is the same size, yet destroy it on transient response.

That's my hypothesis... If I test the 3076 and 3576 I can quantify these theories. maybe the 3576 will compete on the dyno graph, but I find it difficult to believe it's going to look comparable when it comes to transient response.

That being said... That's my theory. I want to TEST IT, WITH DATA, WITH DYNOCHARTS, and SEE the results.

You might be right that the 3576 is the turbo to test, but I know that someone else will post directly after I post that data and say... well of course it spools slower than the 7670... it's a 35R turbine!

 

Of course the wheels are not the same design and all things aren't equal, which is why you would perform the comparative test. The GT35r turbine wheel is still 2mm smaller in diameter vs the EFR7670, but is the closest in size. If you intentionally choose the 30r turbine wheel that is 10mm smaller in diameter then I would question what you hope to prove.

 

Can you share these inertia calculations?

If the MOI of the EFR7670 turbine wheel is indeed better vs. GTX3576r then let the tests show such results via transient response or spool.

 

People considering the GTX3076R versus the EFR7670...

I say test both and show how the EFR compares to the 2 Garrett offerings... with regards to a dyno plots and TRANSIENT data.

 

Model your 30R turbine wheel... I've already modelled and measured the 7670 wheel in catia.

 

That is great, but what I am hearing is that you have not modeled the 30r or 35r turbine wheel. If this is true then we don't know the differences between the wheels and can only postulate MOI similarities/differences. Just run the GTX3576r and compare so we can be done with these theoretical debates.

 

Man, you guys need to look at the actual flow data and conditions. I already posted this here once...

If you correct all to the same inlet conditions and go by the maximum airflow on the charts:
GTX3076R - 65 lb/min
EFR7670 - 62 lb/min
GTX3071R - 57 lb/min

If you correct to the same inlet conditions and look at max flow while maintaining 60% efficiency:
GTX3076R - 64 lb/min
EFR 7670 - 60 lb/min
GTX3071R - 57 lb/min

On the turbine side:
GT30 T3 0.82 A/R - 23 lb/min
EFR 7670 - 24 lb/min
GT35 T3 0.82 A/R - 27 lb/min


The EFR7670 is right in the middle between the GTX3076R and GTX3071R on the compressor side and is pretty comparable to the GT30 on the turbine side in a T3 single scroll housing.


If the EFR7670 can beat the GTX3071R on response AND beat the GTX3076R on power, it's a clear winner. But if the GTX3071R outspools it but makes less power or the GTX3076R makes more power but spools slower...well, it simply a matter of the turbos not being the same size.

 

How are you able to make such comparisons relating turbine flow and compressor flow when Garrett does not post shaft speeds for the turbine flow charts?