Basically, I'm trying to decide between two kits. One is a kit made by Rotary Performance and one made by TurboSource. The Rotary Performance kit uses the GTX turbo and the TurboSource kit, the BW.

The RP Kit includes...
-Garrett GTX3582R turbocharger
-TiAL 1.03 stainless V-band housing
-TiAL MV-R wastegate
-RP custom V-band manifold
-RP V-band downpipe with recirculation

Turbo Source includes...
-7670 or 8374 IWG turbocharger;
-Stainless hard line turbo cooling lines
-304SS TIG welded & back purged Mandrel Bent 3" V-Band downpipe with single o2 sensor bung
-304SS TIG welded & back purged schedule 10 1.5" pipe twin scroll turbo manifold
-Replacement WG actuator bracket for necessary placement
-Inconel T4 Turbo Gasket, and Inconel turbo manifold studs & nuts

The BW kit seems simpler; which I like. The rotary performance kit seems to be very well thought out though. All v-band clamps and the wastegate is recirculated into the DP so it's not open. After seeing a video of an FC running the BW7670 I was blow away by the spool characteristics but it had me thinking, how far behind (in terms of spool) is the 8374?

Looking to hear thoughts on both from everyone, good and bad. First hand experiences being a plus!

 

In theory the 8374 should be about 400rpms behind the 7670 because of the size difference. This is based off my experience in dyno tuning different turbos. Results coming in are showing this is about right.

I have attached the dyno chart below showing the response of our 8374 kit at higher boost pressures. Now keep in mind response SHOULD be even better with a proper waste gate actuator for high boost pressure. TurboSmart is building us a custom actuator right now so we can get more data on what is really going on.
Like the unit below.

Sensor Caps

Going from 3 to 5 turns of preload on the wastegate actuator netted us around 300rpms faster spool back to back on the iwg 8374. This is because the actuator was actually cracking early and slowing the turbo down. So running a turbosmart actuator with the correct spring for your target should give faster boost response.

Keep in mind if you are looking to run LOW boost( less than 12 psi) the IWG kit is NOT right for you. The 42mm wastegate is simply not big enough to run very low boost pressures in the FD orientation( super short runner at high velocity). Now on the FC cars its a different story( lower compression rotors, and longer runners even with the same runner diameter).

I have also attached a GTX35R kit( with Tial housing) we built showing it's boost response. Keep in mind that was a large side port vs the stock port on the 8374 shown( stock ports favor boost response, while ported engines favor peak power).

Also the GTX35R had a single 12 psi spring( which ended up over-boosting from a single wastegate, and needed duals to fix it). So for comparison sake just look below 3000rpms between the two to get a better idea of response between the two( below 3k rpms is when both wastegates are shut completely).

Here is the 8374 in a roll racing video showing response. Response is identical to the dyno on the street( via catalogs). Video was made at 27psi however, at only 415rwhtq IIRC. The attached dyno sheet was later with more boost.

http://www.youtube.com/results?searc...74+roll+racing




If you click on our blog in the link there is some more info you might want to read.

 

It sounds like the IWG turbos (from what you said) aren't good unless you're running high boost all the time. This seems like a flexibility compromise which I'm not sure is something I'd be prepared to deal with considering I wouldn't want to run high boost all the time. How do others deal with that scenario?

 

If your definiton of high boost is 12 plus psi, then you are correct that you are limited to high boost. If one needs to run less you have to restrict the exhaust system. Ie run 2.5 inch piping , a cat or restrictor plate.

Keep in mind that most single turbo manifolds with single wastegates do the exact same thing(boost creep). This is why our standard t4 fd3s manifold has dual wastegates tear dropped smack in the direction of main runner flow. Our standard fd manifold has been proven to hold as low as 6 psi.

 

Turblown are you saying that as long as you are at or above 12 psi the IWG will not creep on a 13b-rew? I really like the IWG turbos because of the simplicity and boost response and one day (when I pay off my student loans) I'd wanna go with the 8374 set-up. But I'm more interested in simplicity, reliability and would not want to run more than 1 bar/14.5psi...

 

That is correct. Jacob Cartmill on here told me last night that with the silencer in his 3inch ( not cat ) exhaust system he can hold 7 psi to redline on his 8374 iwg fd turbo system.

 

If it were me, I would go with the BorgWarner from Turblown. Actually either kit I would get from Turblown, As he has excellent communication which helps should any issues arise. Have you looked into the TDX61 kit from Turblown if you don't want the Internal wastegate setup?

 

Here is a little video I put together from the last time I was on the dyno with one.

https://www.youtube.com/watch?v=dfoh...ature=youtu.be

 

Awesome, just the information i've been looking for. If i'm going for around 400 hp with a EFR 8374, i should have no issues with boost creep correct? Assuming this is achieved at 16psi, would this be a semi reliable daily driver/AutoX/Road course set up?

 

Yes to all of the above.

 

Is there anyway to know how much lag I would expect from the setup as mentioned above? At what rpm should I expect to hit boost?

 

Just wondering, stock REW port is 52x47(??) from memory, nominal ID of the pipe is 43, is there a taper in the exhaust flange?

 

Any results yet with the 9180?

 

If one has a target of 15 psi it should be seen by 3000rpms.

Our manifolda taper through the flange.

9180 results are in our blog.

 

" That thing spools stupid fast. Its really hard keeping it out of boost before I can get it tuned."- Rx7club member JTurton RX&7

^^^ pictures are attached.


It also looks like we are going to be sending out an IWG 9180 soon. They are only available in T3 open volute so it will be interesting to see the results..

EWG 9180 results are on our blog as mentioned.

 

I'm researching single turbos, and am not technical in the sense that compressor maps mean nothing to me. In terms of relative sizes, I think of "smaller" turbos as roughly 35R or T04e sized (optimal around 13-20 psi), vs. "larger" turbos like a 40R, T04R, or T78 that get rolling over 20 psi (don't cringe, I realize this is a gross generalization and that there are smaller (RX6) and larger (42R) out there).

Would it be fair to say that the 7670 is more 35R (1.06) sized, with the 8374 being more T78 sized generally speaking?

 

yeah guys i can confirm i restricted the exhaust on my large streetport engine and the boost held 7psi to redline. it wont hold below about 14-15psi with open 3" exhaust with a large streetport. with stock ports it should hold boost as low as you want.

and ptrhahn, check out howard coleman's turbo size chart. the EFR 8374 is very similar to the GTX3582 (gtx compressor slightly larger, gtx turbine slightly smaller). EFR 8374 compared to the regular ol' gt35R: the 8374 has a couple MM larger compressor wheel and several MM larger turbine wheel.

the 8374 really is a great match for the 13b... it's very similar to the GTX3582 (great turbo) but the larger EFR turbine wheel is more rotary-friendly, and it's super lightweight and faster spooling (educated guess).


you also have to factor in the available turbine housing footprint (gt35R with t3 turbine housing is way too small) and A/R. the .92 divided EFR housing is a great match for a rotary.

 

In terms of relative sizes, I think of "smaller" turbos as roughly 35R or T04e sized (optimal around 13-20 psi), vs. "larger" turbos like a 40R, T04R, or T78 that get rolling over 20 psi (don't cringe, I realize this is a gross generalization and that there are smaller (RX6) and larger (42R) out there).

Kinda, but because (unlike the Garrett GT line) the EFR line has generous exhaust wheel and exhaust housing options even the smaller EFR 7670 can be run up to high boost with favorable results on a rotary.

They were able to increase the exhaust sizes due to the lighter exhaust wheel still providing acceptable (exceptional on rotary) spool.

This is a motorsports turbo and best results will be at high boost with race gas like the Garret GT line. The compressor delivers less flow at lower boost than the old school pre Garrett GT line turbos.

Check out the comparison of my EFR7670 @26psi where I ran out of injector and my T04B 60-1 hiFi @ 18psi where the compressor ran out of flow.

I literally gained 100ft/lb torque from 3,000rpm to 4,000rpm on the EFR and no where lost torque from chocking out on the exhaust side.

https://www.rx7club.com/single-turbo...sults-1070794/

Really the EFR 7670 is comparable to a GT3076R except it is actually worth putting on the rotary due to the larger exhaust side.

The EFR 8374 is comparable to the GT3582R except again, more hot side means it doesn't choke the rotary as much at high boost/rpm. Plus, it spools much faster due to the light exhaust wheel and the dynamics of rotary exhaust.

The downside to this high boost oriented compressor (like the GT line) is that my EFR 7670 made less peak power at the lower boost that my 60-1 ran at (peaked flow at).

So, on pump gas/low boost I do still make more torque/power under the curve from early spool on the 7670, but less peak power by about 25hp.

Works out fine for me as I'm not out there doing freeway pulls- I actually appreciate the power when/where I need it.

 

^ Great comparison? Very helpful information! Thanks guys!

 

This is definitely a shame—I'd love to run this turbo (8374) for a lot of reasons, but a 35R sized turbo running 12-13 psi on a ported motor/open exhaust would be a pretty standard configuration on a track car. I don't need 7 psi, but 12 yes. I assume the wastegate can't be ported like the factory twins?

I'd also prefer an all v-band.

 

One can get vband inlet turbine housings for the 7670/8374, but only in .83 a/r( external WG ONLY)

 

Again—a shame, that sort of defeats the purpose.

 

You thinking about ditching the twins ptrhahn?

 

I am. It's all about heat on track. As I keep going faster, it's incrementally more throttle time, and higher IATs. I can still do a V-mount, vented hood, and bigger oil coolers, but the handwriting is on the wall. I want to be able to go out and run at VIR in August and not worry too much about it or have to run 100 octane.

It's looking like it's going to be an all v-band 35R variant with a TiAL housing, single (HKS) wastegate and custom (more heat resistant) manifold.

 

while the GT35 and GTX35 are nice turbos you might do well to consider another option as they have small hotsides which is exactly what you don't want. turbo'd road racing is all about heat management and the GT35 has a 5.1 square inch turbo matched w a 6.3 inch compressor.

Borg Warner offers approx the same (size) compressor paired with a 6.31 hotside turbine. 24% more area means lower retained heat in your engine, lower EGTs. OE build quality.

the BW S300 62 is offered with a cast wheel or billet compressor wheel. neither feature V band options. i would trade away the Tial V band connection for a significantly better hotside.

just as in coil overs the spring rate is the thing... in turbos the wheels are most important, especially w a rotary.

either way your engine is going to be much happier w a single as properly fixtured the motor will retain less heat.

good luck,

Howard