Find me a turbo that fits these critera
 

I am terrible at mapping out stuff on turbo compressor maps.

Basically, I am looking for a turbo that is extremely quick spooling to make 10PSI (ish) as fast as possible at 2-3k RPM and is efficient while doing sowhile ALSO being able to flow an easy 5-6PSI at 7.5kRPM. The PSI it would be pushing out of the compressor would be a linear down curve starting at about 10PSI at 2-3k RPM to approx 5-6PSI at 7500RPM.

Large external wastegate will be involved so turbine housing choke is not a big deal since a huge majority of exhaust gases will be bypassed at high RPM. So a small quick spooling turbine housing is a must.

Pls and thanks.

(if you think there is a tuburbo that has an internal gate (ported gate obviously) that would also meet this criteria I would be open to it.

So far I'm thinking a GT2550R meets this after briefly looking at the compressor map. But which turbine housing would be best?

Am I right in thinking that if it is efficient in flowing 10PSI by 2-3k that it will have no problem with the 5-6psi at high RPM? I'm guessing here that the high rpms stuff doesn't really matter?

so basically you want this in red?

https://www.miataturbo.net/attachmen...ine=1332953505

More or less. What turbo is that?

a t25 off an SR20, thats running around 9.5psi to redline.


basically a GT2554.

Yeah that's what I meant to say in my original post... 2554R. But those aren't available in v-band are they?

A GT2554 with a .86 turbine housing on a VVT engine would be pretty bauce.

I agree. Would make a really nice 225-250rwhp turbo.


also looks like if you have access to a machine shop, you could make the same happen.

need to go to GT28XX to get the cool Tial v-band housing or the one with integrated EWG.

I think the GT2860rs is still a viable option for daily driving, especially if you're using a tubular manipheould.
I have a GT2860rs .86 turbine housing, slight overbore, low compression, and 99 head and I'm seeing about 200wtq at 2700rpm. If I had a VVT head on that car, man it would be crazy low. I realistically feel like the car "moves" at 2250rpm even with the trailer on it. When I'm cruising on the highway, I leave it in 6th unless we go below 2500rpm because it just looks weird and it's not a Corvette, lol.

Yeah, looks of the milled v-band housing is not a big deal because it will be for the most part completely hidden away. I just want it for the reliability and not having to deal with turbo studs. Downpipe studs I think I can deal with.

This is just for an idea I have working in my head right now, we'll see if it ever comes to fruition.

well you can always bolt on a vband adapter on the outlet...

true... would that solve the problems that some people have had with down pipe studs backing out? I dont really see it being THAT big of a problem?

The only think that I'm somewhat concerned about is the fact that while the turbo may only be pushing 5-6psi out of the compressor, there will be exhaust gasses coming out of the motor will be equivalent to 300+whp on a flowed, cammed head. This is why I'm thinking a big 44mm tial would be a solution.

i dunno, just saying.

That's not really how it works, lol.

You don't know what I'm doing ;)

Lets just say that the motor will be seeing a substantially higher amount of boost than what the turbo will be pushing out.

so you're using the turbo for lowend and rotrex for topend. different from how its "normally" done but I can see it working

As long as you don't choke out from the small turbine wheel, this plan should work just fine :).

yay twincharged miata

5PSI at the turbo = 1.34 PR
feeding into something else making 12PSI or 1.81PR

1.34 x 1.81 = 2.42 - 1 = 1.42 x 14.7 = 21PSI.

:)

Get 1 giant (or 2 large) ewgs to vent that ish and you should no problem with turbine choking.

In for teh win. Falco mentioned this in another thread many moons ago, I'm hoping this is for the reals?

Yeah, more or less. I want to take the great efficiency that the Rotrex has in the upper RPMS and keep that as is. Adding a turbo to feed into the Rotrex. Thinking of running a big wastegate with it's vaccum source off the manifold for 20PSI or so. At lower RPMs the turbo would be boosting more, and lowering as the Rotrex comes into it's own. The large wastegate should be enough to keep the flow without choking the motor at the small turbine housing...


Anyways... this is still all int he planning stages and I have to figure out packing as well. Bottom mount but I don't know where to put the wastegate.

Lol, yeah I did. I've been living in Germany for the last 7 months and am heading home this Monday. I am itching to get wrenching on something again and since the motor and Rotrex stuff is all done I need to think outside the box.

Right now though, I'm just trying to think of how much boost the motor can really take. 20PSI? 25PSI? Who knows... Crank it up and see? Lol...

If you decide you want something bigger than that C30-94, I may know someone that's interested in your old one.

Its built. Number of "PSI" is irrelevent. What is relevant is correct setup and tuning.

You can have the wastegate on top of the turbo if you're going bottom mount.

The torque curve shape should be interesting to see on a 1.6. I'm predicting an LSx replica.

Haha, if anything I may go down to a 74. Right now the Rotrex is pushing 16PSI at 8k and with a turbo, even pushing only 5psi it would make 26-27psi at the motor which is a bit out of my comfort zone. We'll see I might just put a bigger pully on it and gear it down a bit.

https://www.miataturbo.net/attachmen...ine=1332970130

I sense a pending trade in your future...

Yeah, but there is the inlet to the Rotrex. It can't be completely blocked I need a bit of space to make piping from the exit of the turbo to the inlet of the Rotrex. And the wastegate needs to be placed where I can still route it back into the exhaust. I'm getting old and atmosphere dumped gates are no longer something I want... haha.

Going to take some measurements and see what Abe can come up with. If anything I doubt this being completed for a few months so don't get all excited just yet guys! :P

Oh and I need a job first... haha

Your engine bay will look like a plate of spagetti

Yeah pretty much.

For reference, what it "kind of" looks like right now, sans piping.

https://www.miataturbo.net/attachmen...ine=1332970750

4th Reich?

A turbo for low RPM, and a supercharger for high RPM is really going to confuse the super/failcharger crew. You should get a couple 60mm TiAL wastegates.

What about having the compressor feed directly into the mouth of the rotrex?

...but then you might have supercharger surge ( LOLWAT)

Why not just run a turbonator?

^^ Thats kind of the plan, but there will be a blow off valve of some sort in there.

And Hustler, you know me... all about making people go "why the hell did he do that?"...

c'mon who else spends a ludicrous amount of money building a 1.6L motor then putting a Rotrex on it?

people that wished they drove a honda

So I can put some boost in my boost, so I boost while I boost.

http://t2.gstatic.com/images?q=tbn:A...S8WvSKuCf1GnzQ

I hate Hondas.

yet you replicated their power and torque curvehttps://www.miataturbo.net/attachmen...ine=1332971324

In a RWD, light and much better chassis.

hehe, look what I found. C30-74 w/ Holset HX40. 4AGE

Personally I would just wait a few months till the TSE borg warner EFR turbo kit comes out. Great spool, great top end, far less piping, weight and complexity.

Uhhh.... yea, ok?

Lol... because I'm totally looking to spend like 3k on a EFR and associated parts in a kit. Did you read the thread at all?


Anyways, for all of you wondering I've decided to go with an SR20 turbo for simplicity with the ATP external 44mm wastegate housing.

ftfy

Farking nuts that Toyota. I'm not quite going to go to the same level he is (well maybe one day). For now a solid 20-22psi ish. If I can make 330whp and break 250wtq I'll be happy.

Oh, and he too is blowing the turbo into the Rotrex. Same plan I have.

So I have found a solution to all my problems. The stock Nissan GTi-R SR20 turbo has the same turbine wheel as a GT2871R and therefore the Tial housing will work. Now, finding one of these turbos is proving difficult (one that's priced realistically).

So, what I am looking for is a turbine wheel (just on it's own) that is a 76 trim with a 53.8mm wheel. I have a s13 turbo sitting here and if I can find a new turbine wheel that is that size (for a bush bearing turbo obviously) then that will work too. But again, I'm having problems finding what I need.

Then again if you sold the rotrex setup you'd get good coin for it then the EFR kit wouldn't cost you 3 grand price difference. I admire you for even trying just a complicated setup, but I've also seen it done before. A local guy has a twincharged setup in a civic that's very competative in One lap of America.

The tuning is a pain, the car still has weird issues, and still doesn't run 100% the way it should. You also now have 2 major systems that can fail instead of one, and all the extra weight.

If the car sees any track time I do not see how you'd profit from this setup versus a properly setup turbo. Either way I wish you luck, sounds like a badass build.

I'm aware of the Enmo Civic.

I am not selling the Rotrex. Thanks for playing.

I don't think you quite understand. For me it's not about slapping something on, making big power and that's it. For me I enjoy building more and doing something different than everyone else. It's either keep the Rotrex as is, put a 3'' exhaust and large IC and call it a day or twin charging. Not "just" turbo. I've been down the turbo route on this and many other cars. And, if I DID want to go EFR why wait for TSE? You can buy a manifold/dp from Abe, buy the turbo and make your own IC. Instead of waiting months. So yea, for now no turbo. Future... maybe, which is one of the reasons I'm going to go v-band (for future upgrades if wanted) but for now, no.

Dam, broken link.

Dann

It's from Finland ;)

crazy finns

we are used to drive fast lightweight rwd cars:

Turbo -> water-to-air intercooler -> rotrex -> front mount air-to-air intercooler -> throttle body. Profit?

why the w/a interheater?

Wouldn't it be more efficient to cool the charge coming off the turbo as it generates a warmer charge than the rotrex? If not delete my posts since I could be going full-retard right now.

Yeah it would help, but due to how little the Rotrex heats air up compared to turbos it will only be marginally hotter. Coupled with a quality intercooler (likely upgrading to the 600hp Precision) it will be fine.

What kind of post-compressor temps are you seeing from the Rotrex? I can't find anyone that's actually logged it. I'd be great to have the datapoints...

I'd have to go find some old logs. Give me a few minutes I'll see what I can find.

Just so I have this straight, you're planning on running somewhere between a GT2554 and a GT2871, and blowing directly into the rotrex, with the pressure between the turbo and the rotrex being ~10psi at the low end, and 5-6psi at peak power?

If this is accurate, you are going to need some sort of secondary inlet to bypass the turbo going into the rotrex, or you will have to significantly overspeed any of the turbos you mentioned to get the mass flow rate at the PRs you are talking about. While you should easily have enough exhaust gas to drive the turbo that fast, you'll be getting into the territory where a wheel bursting is a real possibility.

And also how do you plan on the compressor housing of the turbo not choking the rotrex?

Dann

I do love the twincharging idea, but whenever I've thought about it, it seems like it's really best implemented on a bigger engine, which probably wouldnt need it anyways. The sizing with engines this small seems like it could just be a surging nightmare to find the right fitment...but if VW can do it from the factory, there's obviously hope.