the gt4202r on the car, is a tial in/out turbine housing. why go t4 split pulse on a 3 rotor? with minor changes to the manifold, the tial 1.32 a/r 9174 will fit.
how will the odd number of exaust pulses affect the spool and so on, with an open t4 manifold matet to a t4 devided turbo?

The 9174 is a bad choice for a 20B. It’s not really even a great choice for a 13B. It really only exists to allow smaller engines to utilize the high flow/high PR area of the larger 9180 compressor without overspeeding the 80mm titanium aluminide turbine and causing failure. From an cross sectional area, the 9174 on a 20B is roughly equivalent to a EFR 6758 on a 13B (2/3 of the C/S area). You would not choose an EFR 6758 to make 466whp on a 13B (2/3 of a 700whp).
There isn’t really an EFR option for a 20B-sized engine.

An EFR 8374 sized turbo is a great choice for 450-500whp on a 13B. If you add roughly 50% to the compressor and turbine cross sectional areas, you’re looking at something similar to an S476 SX-E. Also, if you’re interested in the Tial housing, they make an investment cast stainless housing for the S476 87mm turbine in 1.02, 1.16, and 1.30 A/R. The Tial housings are also hands down higher quality than the BW EFR housings.

I'll actually be fitting this setup to one of our 20Bs thats on the engine dyno as soon as I can get back into the shop as well as give it a couple hours of break in. I actually haven't seen anybody try to run this config, just a lot of folks parroting that it is a poor choice for peak power numbers. If I'm wrong and anybody has seen some real dyno sheets (don't care about peak) with a boost reference I'd love to see them.

Hi all, quick update on the 20b and 9180 marriage. Sorry its been so long:

Santa Barbara was hit with a fair bit of natural disasters/fallout after the Thomas fire so I've been super laggy on running this setup. Also Jim Hagerty, formerly of Mariah Motorsports, passed away due to complications from, again, the Thomas fire. As such my partner (Dr. Wayne Graham formerly of Rotary Engineering back in the '80s) and I have been racing around figuring out where we'll be doing our work/builds etc and had pushed off this testing. Long story short a letter of intent has been signed and we will be the owners of the old Mariah building. So...on to the good stuff:

The 9180 and a 20b rocks if you're interested in a long lasting, reliable, V8-like torque machine. It will never be a dyno queen or top end screamer though. At this point we haven't done anything more than 18 psi (I'm still trying to convince Wayne that boost pressure doesn't matter, only IAT and combustion chamber pressure matter, but I digress) and so we've been pretty low on our peak power numbers (635hp 480tq). Whats VERY cool is the fact that even with a 1.45 turbine housing we're seeing target boost pressure at around 3500 RPM and I'm certain once a 4 port solenoid is fitted we'll see at least 100-150 horses more at 26ish PSI.

I'll post up some photos/sheets once all data is in and if anyone has any questions, suggestions or ideas regarding testing and/or development please feel free to respond here, pm me, or email me at david@machine-ep.com


Thanks much! Sorry for the delay.

P.S. We may be seeing target boost pressure before 3500 but honestly, in a tube framed race application, who gives a shit?

I'll have to get back to you on turbo speed but with regards to a larger divided housing VS an undivided vband housing I'll just say that we're not hurting with regards to spool, we have full boost by 3500 (we'll have to tweak lower RPMs at the track, the older Superflow, even though its rated for 1000 horsepower/whatever torque equation they're using is, it doesn't want to load well below 3500). We are certainly hitting stall at the moment due to a low spring pressure desire for torque modulation and using a 3 port solenoid though I'm sure I could try out some other power delivery control strategies that aren't as intrusive as trac control. The thing hits a brick wall at 7500.

Somewhat back from the dead but another small update. Engine config/tune is finalized on the dyno and we'll be shoehorning this beast into its chassis over the next month. Still very conservative due to the fact that this will be the most power/weight my client has put on the street and we're eschewing the use of any 'nannies' (traction control) for the time being. Still going through some logs but here's some pertinent info:

Power at peak : 700 / 514 @ 7000 RPM and 20 PSI
Timing at peak torque/combustion temp: 11.5*
Intake temps at peak torque/combustion temp: 103* F
Water/Meth Injection at peak pressure: ~900cc's
ECU: Motec M800
Turbo: EFR 9180 1.45 turbine
Port Config: Moderate to large side port


Still hitting a wall at 7500 however not as bad. It's not the end of the world as we're making 500 ft/lbs of torque from 5000-7000. We didn't bother doing any more power pulls below 5000 but I'm sure its very usable, 2000+ RPMs of that much torque should be enough to deal with the vette and viper crews we've had trouble with in the past. And if not time for 25+ psi if the turbo will make the boost.

That turbo will be a LOT more efficient over 25psi of boost. Excited to see what happens from here.

Are you monitoring turbine speed? I imagine you will hit max turbo RPM before 25psi on a 20B

I agree, but since I'm not writing the checks I figure we hit our target and potentially have room to grow.


This pass we didn't however channels are set aside and there's an optical sensor sitting on my desk. Obviously we'll stop feeding boost before the turbos redline!

Bumping this up - Trying to see whats the new turbo Meta for a fairly aggressive streetport 20B for the same general format albeit more for canyon duty. I am not limited by space at all.

Quick specs - D series 20B, Street port, solid dowels and oversized studs, lightened /side clearanced rotors and race balanced.

Im putting it back on the dyno Monday for a health check before the first race since our shutdown so I'll let you know. That said if I have to swap turbos I'm going to be playing with the 9280, car still is doing great, easy to modulate throttle/torque without having to plan ahead.

Looking forward to the results @dguy . I have a supercore 9180 with the original plan of going with the bulleye or tial vband exhaust housing. Had thoughts of switching to a 9280 or perhaps something from the G series before I get the manifold fabricated. What you're describing thus far should suit my needs.

Slight delay, having to take apart the back half of the car as well as the shroud on my dyno hubs. Still dont have the clearance until I whip up some spacers:

https://cimg8.ibsrv.net/gimg/www.rx7...461be569c2.jpg
https://cimg0.ibsrv.net/gimg/www.rx7...4b017d32b4.jpg


Edit: No idea why the second photo ended up being small. You get the idea :P

@vqturbo i do have a tial housing for the 9180/9280 . brand new. bought it and changed my plans as i wanted to use it on the hks t51r manifold

@R-R-Rx7 I'll consider it for sure, what AR? Holding out until I figure out if I continue with the EFRs or not. I have a bit of time - waiting on the rest of my chassis to be fabricated. I scooped up @Davin s Chips short runner flange for it.

https://cimg8.ibsrv.net/gimg/www.rx7...7d4cc9f29f.jpg
https://cimg9.ibsrv.net/gimg/www.rx7...5306788b4f.jpg

That’s a nice flange, are they readily available.

That looks like Chip's flange. His stuff is nice, but damned pricy!

https://chipsmotorsports.com/product...st-flange-13b/

just adding this link for content and future readers; 9180 1.45 A/R result on pump gas from the past

https://www.rx7club.com/single-turbo...45-ar-1127000/

Bumping this up - Added a billet turbo elbow to match the billet collector and my proposed parts - Turbosmart 60mm gate and Tial gt42/45 vband housing. I havent found a general consensus on exhaust manifold length on the forum or in my search engine results - seems to be a split consensus between short runner vs. long runner manifolds. Any recommendations on research material I may had missed? As a quick reminder, I'm not limited much by space.

Also anyone happen to play with fresh air anti lag strategies on rotaries? I'd like to plan for air inlets if needed earlier vs. after the manifold has been fabricated and shoehorned. I have only seen Kyle Mohan use it on his 20B Miata drift car

https://cimg4.ibsrv.net/gimg/www.rx7...d817a62472.jpghttps://cimg3.ibsrv.net/gimg/www.rx7...d07a413a94.jpg

I havent tried it, but here is the antilag strategy I dreamed up for rotary.

Feed high flow solenoid to high flow SS check valve from lower intake manifold close to injectors for fuel in your air.

Output your high flow SS check valve to the port air flange on the middle side housing (13B, IDK 20B).
Air and fuel delivered to exhaust ports through the holes in the exhaust sleeves.
Mileage may vary....

I think at the end of the day either a short or long runner manifolds is going to work really really well. I did think this was a interesting short read on the subject:

Long tube vs Short tube header manifold Design

Never thought of using post fuel compressed air as a source, I believe I've only seen post intercooler/pre throttle body air being used for fresh air anti-lag strategies. My plan at this moment is to use turbosmarts ALV and run hard tubes to the exhaust runners. If anyones tried it on a rotary - I'd love to check it out. I dont think it would differ much to piston applications but I'm on the fence if its worth the time. Obviously ignoring the additional strain the turbo will see - seems like the best time to plan for it before we get further down the line.

Thanks for sending the link over - I think i've stumbled on this site once before but always good to have additional references. I plan to do a long-runner manifold and coupled with the 9180EFR I have, I think transient response will not be much of an issue on a 20B.