EFR Internal Waste-Gate Discussion

[Turblown]

I thought a few of you guys might be interested in some of the latest on the BorgWarner EFR turbochargers, especially the viability of the internal waste-gate turbine housings. The 7670 and 8374 are pretty well suited for most 2 rotor applications. The 7670 is particularly nice for a sub 400rwhp car looking for ultra fast response, and the 8374 for the 500~ish rwhp cars. Anyhow here is part 1 of the 7 EFR turbo systems we are building( some we are also tuning in house too).

http://blog.turbosource.com/2013/11/...rotary-engine/

[Monkman33]

What kind of response are we looking at with the 7670? Equal or better than sequential bnr stage 3s?

[RETed]

All this does is make turbo exhaust manifold design and building easier...
If these turbos take off for 13B applications, I see a whole lot of simpler turbo exhaust manifolds being offered in the near future; it's going to be pretty easy to design and build something with just two runners versus every piston engine turbo exhaust manifold.


-Ted

[Turblown]

Originally Posted by Monkman33

What kind of response are we looking at with the 7670? Equal or better than sequential bnr stage 3s?

One owner has reported 1 bar by 2200rpms using the 7670 on his 2 rotor.

[TitaniumTT]

Originally Posted by Monkman33

What kind of response are we looking at with the 7670? Equal or better than sequential bnr stage 3s?

An properly sized single with a good (re:LARGE) exhaust will out perform the sequentials in terms of TORQUE response, not boost response.... I wish I had access to my old dyno charts, the torque comes up faster and lasts longer with my single (Turblown GT35R Stg V with a billet wheel, 1.0 a/r exhaust) but I also fabricated an equal length extremely short runner Mani with dual TiAL MVS gates and a 4" exhaust that splits into two three inch sections back to the bumpers. If you want boost response, nothing is going to equal what is basically a GT28 but if you want torque response.... A properly sized single built and tuned properly will outperform the twins..... Sooooooo do you want to see a boost gauge going crazy, or do you want to put torque out? I would prefer to make power, not just crazy boost.
In terms of numbers, at 2500rpms I could see 17psi with my old BNR's, with the Stg V I'll see > 10 psi, however, at less boost I'll make more power. Most of it has to do with EMAP and how efficient everything is. At 10psi on the BNR's I would see about 15psi of EMAP, by 14.5 psi of boost I was seeing 29psi of EMAP and I was making ~378RWHP. By comparison with the GT35R STG V, at 14 psi I see ~ 15 psi of EMAP, and I was making 405 RWHP with more in there given more tuning.... I spent 45 minutes tuning that car the morning we left for DGRR. So, here's the thing, think of an engine as an airpump, boost ( MAP) goes in, EMAP comes out. MAP/EMAP = efficiency, which setup is more efficient?

[Monkman33]

Originally Posted by TitaniumTT

An properly sized single with a good (re:LARGE) exhaust will out perform the sequentials in terms of TORQUE response, not boost response.... I wish I had access to my old dyno charts, the torque comes up faster and lasts longer with my single (Turblown GT35R Stg V with a billet wheel, 1.0 a/r exhaust) but I also fabricated an equal length extremely short runner Mani with dual TiAL MVS gates and a 4" exhaust that splits into two three inch sections back to the bumpers. If you want boost response, nothing is going to equal what is basically a GT28 but if you want torque response.... A properly sized single built and tuned properly will outperform the twins..... Sooooooo do you want to see a boost gauge going crazy, or do you want to put torque out? I would prefer to make power, not just crazy boost.
In terms of numbers, at 2500rpms I could see 17psi with my old BNR's, with the Stg V I'll see > 10 psi, however, at less boost I'll make more power. Most of it has to do with EMAP and how efficient everything is. At 10psi on the BNR's I would see about 15psi of EMAP, by 14.5 psi of boost I was seeing 29psi of EMAP and I was making ~378RWHP. By comparison with the GT35R STG V, at 14 psi I see ~ 15 psi of EMAP, and I was making 405 RWHP with more in there given more tuning.... I spent 45 minutes tuning that car the morning we left for DGRR. So, here's the thing, think of an engine as an airpump, boost ( MAP) goes in, EMAP comes out. MAP/EMAP = efficiency, which setup is more efficient?

This really making me rethink my setup... Sadly.

I love the idea of keeping my 95 FD with sequential twins for nostalgia's sake. But this sounds like it would suit my driving better...

Who knows. I'll probably just stick with what I have for now, finish the build with twins. And if I don't like it, then switch over. The only additional expense I'll have to deal with that I haven't already bought and paid for is the solenoid set for controlling the twins.

[speedjunkie]

^Pretty sure you're referring to me lol.

I have the EFR 7670 with two Tial 38mm external gates, one on each runner, with a short runner manifold. I had the runners built as short as possible out of 321 stainless. This turbo has RIDICULOUS spool. Mine starts around 2k rpm, and I'd say reaching full boost by about 3300-3500. The problem is I haven't been on an actual dyno yet to get any info, and I've had this turbo on since early last year. It also sounds like a jet engine, but that's just an added bonus lol. Anyway, the only thing I've done is virtual dyno, and I'm not sure how much stock I put in that. Supposedly it's within 5% accurate, but having not been on an actual dyno yet, I couldn't tell you for sure. And since all dynos read differently, I'm not sure it would make much difference anyway. All I know is if you want response similar to stock twins but more top end, the 7670 is perfect. I can't speak to the 8374, but I was thinking of possibly stepping up to that one next time. I wouldn't say for sure you can't break 400whp with the 7670. I'm at 6000 ft altitude and I'm already pretty close to 400 (according to the virtual dyno anyway), and we lose quite a bit of HP up here. Although the spool is so fast and strong that I have to turn down the duty cycle on the boost controller in the first couple gears, and a little in third gear, or I'll spin all the way through. That's why I was thinking about going with the 8374 next time. I imagine it spools just not quite as fast but probably pretty close, but will still get you more whp. Here are some pics of the when I was installing everything.

[speedjunkie]

My concern with internal gated housings is if there will be enough room between the engine and firewall/strut tower. I'm already pretty close with my external gated housing, but part of that can be manipulated with the manifold of course.

More pics...







This is something that really bugs me. My manifold came out with a 5 degree forward slant, although this pic makes it look worse than it is.


Here's how it turned out before I powdercoated everything black.


A couple problems I ran into were oil drain and coolant feed and return. For the coolant feed and return I had to go with a banjo fitting on both sides, and one side needed to be angled.


This is what the turbo drain needed, to be modified to angle out as soon as possible to avoid the line contacting the turbine housing at the flange.


Both of those problems could probably also been managed a little better with a different manifold too.

[speedjunkie]

[JhnRX7]

I am very interested in this as well. When I make the switch to single I am planning on going this route. It solves the issue of having to reroute the waste gates which for me is a must.

Speedjunkie, do you have any shots showing how close the exhaust housing is to the LIM? Maybe one looking straight down on it?

[speedjunkie]

I don't think so but I'll take a pic for you.

[RENESISFD]

Turblown, who wrote that article?

[RETed]

Sounds like he did.


-Ted

[TitaniumTT]

And Eric's car is fucking sexy, love that sled. I though you were running the internally gated BW though?

[jacobcartmill]

has anyone actually put one of these on a rotary yet?

i would absolutely love to ditch my water cooled dual wastegate setup and go with an internal gate, but only if it can waste enough exhaust to allow me to run low boost (10-12psi).

i have turblown's dual wastegate manifold on my car with both wastegates recirculated, with water lines running to/between/from the wastegates back to the engine, and 7 vband connections that don't seal perfectly (yes, 7 vbands) and two air lines running to each wastegate.

i dread even thinking about removing my downpipe.

i would love to switch to this EFR turbo and run 1 air line, 1 vband, and add 2 water lines for the turbo...