I saw that as well, it was pretty interesting.

Here is another comparison
GTX3076R vs EFR 7670 vs GTX35R


From the looks of it, EFR spools a tad bit slower than the GTX30 but makes roughly the power of a GTX35.

 

Everyone that has compared them so far is saying response and re-spool time between shifts is much better in the efrs

 

ugh, they are the same ******* size. Seriously, the wheel specs are within 1mm. 76.2mm wheel on the GT3076, 76.6mm on the GTX3076.

It would be pretty awesome if every third word in this thread wasn't blatantly incorrect, guys. This could have been a pretty good comparison thread but instead it's full of total garbage.

 

So, 7670 spools faster than a GT3076R, a tad slower than a GTX3076R but makes the power of a GTX3586R sounds like good news to me. I would love to see how well the twin scroll performs next to the single scroll though, Sav do you have any input on the difference?

 

Full-Race has talked a lot of talk about the TS being a lot better than the SS, and I don't necessarily believe it all - I'll wait for someone to compare the .83 single-scroll to the .92 twinscroll before I say anything other than "it should be better". Having said that, it should be better (just based on the physics). You obviously need to change the manifold and make sure the timing map is set up to take advantage, so whether we'll ever see a TRUE single vs. twin experiment remains to be seen.

I'll play with a 7064 .92 TS on the black car later this summer, once our 6258 development is done. (oops, probably said too much there. )

I have two problems with the NASIOC/Perrin testing, BTW.

-Similar boost levels. The EFRs are designed to be highly efficient at high boost - the big, long technical brochure(that I actually read through cover to cover) talks about how they specifically gave up some low-boost efficiency to make the turbo work at 35-40psi. Comparing a GTX to an EFR at only ~21psi or whatever is a little harsh on the EFR - the GTX is a lot more efficient, the maps show that, but the EFR still maintains the same power.

-Similar timing map. Again, the EFR opens up the exhaust which should allow for a lot more timing than a comparable GT/GTX setup. Same reason why Hustler and I make so much more torque than .64 A/R cars - open up the turbine and you can run a lot more timing. Opening up the turbine and NOT running more timing will give you... the same power and less spool.

It's not practical for someone like Perrin, and I applaud the guy for giving us that data, but I would have liked to see him choose two of the turbos and spend 3-4 hours tuning each setup - dial in the fuel map, play with the spark, and experiment a bit, and see what he ended up with on each setup. Just slapping the turbos in is a cool "controlled experiment", but that's not going to give a full picture of the true performance.

 

Also if "opening up the turbine"=more timing (i assume via less backpressure?), then why not run a T4 flanged housing?

 

"T3" and "T4" are just flange sizes - the area ratio (A/R) takes the area of the turbine inlet into account already. The BW twinscroll units are all T4 flanged, though.

 

I talked with my buddy Reed at SuperNaturalTurbo (also a dealer for BW - and built my current setup) and for some reason he really wants to go with the T3 flanged 7064 with the smaller .83 A/R (compared to the other 2 T4 7064s) - he says it should be available in a couple weeks, FWIW.... we'll see. Input on why the T3 flange over the twin scroll T4s? In any case, he's researching some more and will trust his judgement... just a curious question. Mind you - this will be for an E85 application.

 

I was actually recommended the twin scroll by Full-Race what are your power goals? A lot of time attack cars run twin scrolls however.

 

So someone like me shouldn't look at getting the smallest EFR to run ~220-240 whp on a 1.6?

 

This thread sucks. None of us are even making that much power. Fail. I think zero miatas have ever had a twin scroll setup. Twin fail.

 

No, you absolutely should. The adjustment towards high boost mostly came in the bigger stuff (starting with 7064 or 7670, IIRC). The charts I've seen from 6258s are pretty wicked.

 

Realistically 350-400 with ease - but its a track car so spool time is important. On the smaller EFRs his thinking was the T25 .64 A/R where too small, but the T4 .92 A/R where too big - Maybe that's why he stuck with the T3 .83 A/R

 

According to Geoff from Full-Race on my car he said I should be able to hit full boost by 4,000 RPM with a Twin Scroll T4 .92 A/R 7064. Take it for what it's worth no one has done testing (twin scroll) on a Miata that I know of, I will be the first.

Fae, what are you talking about no one is making that much power? I will easily make over 500 whp and I am going to be running a twin scroll set-up.

 

nvr mind -

 

Power is relative and compared to other import motors the bp community is the unambitious hp lightweight. That said Hopefully you and I both will see over 500 hp this year.

 

I couldn't agree with you more, however, it seems like a lot more people are wanting over 400 whp now...maybe a step in the right direction?

 

I have a 1.6L as well, I would assume a BP with a 7064 TS would spool a few hundred RPM better which isn't bad at all. Similar to GT28R spool I would assume?

 

Word back from BW/Full Race.

The CHRA bolts are non-spiralocked A2-80 grade stainless.

Said there's no indication of them failing.

http://www.fullermetric.com/technica...less_steel.htm

Looked it up here, that should be about the same as an M20 graded bolt. Pretty impressive stuff.

 

I would defiantly make some sort of lock, or safety wire them. I cant afford to buy one of those turbos once much less twice.