liquidferrum

hi, i would like to first apologize for wasting people's time, but i have searched and i get alot of results for this and after reading about 5 pages worth of threads i get tired of it

anyways, i have an 88 TII, with an 89jspec in it right now, and i would like to start building a new engine (a really good one) with ceramic apex seals, those teflon/silicone water seals etc, and i really dream of doing some sort of twin turbo setup. what i am looking for is maybe somone who has done this, or who would know what i am in for, right now i am pretty much sizing up how much trouble it is going to be, but i am going to do it, the question is just how long will it take me =Þ

anyways i would like to know where to get manifolds for something like that, if they make them at exhaust shops,etc or if there is a special place where you can get a manifold made, and some things about engine management, does a microtech lt-8 support something like this, otherwise what would you suggest for engine management etc.., also for anyone who has done this/knows about this what other things am i going to need to consider, i have seen that twin turbo purple fc that runs the 9.66 1/4 so i know this can be done, but i realize he has more money and time than i.

thanks, and once again sorry for wasting time with my dreams =D

liquidferrum

rx7_turbo2

I know a few Australian guys run a twin turbo setup using stock turbo's.

Check out www.dysonrotary.com.au
I know they have a few interesting manifold designs, check in the product section under adapter plates. There are a couple other Aussie shops that do similar work, search around.

As for engine management, that's tough to answer, I would think any of the big names Microtech, Wolf, Haltech, AEM etc would be capable of running such a system, you'll have to do some research on each one to find which one works best for you in terms of budget and wanted auxilary features

Scott 89t2

there is really no advanage to running twin turbo as they would just come on at the same time. unlike stock systems that start with one and then the other.

just get a big single. it's the same airflow in the end. but alot cheaper and less work.

rx7raca

ya a single turbo is a much better idea, i used to think the twin turbo was better because u *think* it pulls harder in the low rpms. but a single does a better job, and its less crap to worry about.

NZConvertible

Very untrue. People were running twin parallel turbos for many years before Mazda first tried doing it sequentially. If there was no advantage, it wouldn't have been done. Airflow depends on turbo sizing, not how many you've got. Besides, you completely miss the whole point of twin turbos. Two parallel turbos will spool up much faster than one big turbo that can flow the same amount of air. Rotational inertia increases with the square of radius, so even though each turbo is only getting half the exhaust flow, their much lower rotational inertia means they spool faster.

Big turbos may be great at the dragstrip, but when you don't get meaningful boost until 4000rpm, they're can be a real pain to drive on the street. Smaller turbos make street car torquier, more flexible and faster in anything other than high-rpm work. How often do you really spend above 4000rpm on the street? Very little...

True, but if you wanna play, you gotta pay. You get a better end result. Besides, there could be considerable savings to be made when you consider the cost of a big turbo plus it's external wastegate and more complicated manifold compared to a couple of smaller internal wastegate turbos picked up from a wrecker and rebuilt.

Twin parallel turbos are not complicated or difficult. If you understand one turbo, you understand two. Usually the biggest challenge is fitting it all in, but I've seen done to FC's so it is possible. Care to explain?

rotary>piston

it does pull harder in the low rpm. That's what a sequential twin turbo set up is for. It's better for street driving because it's always ready to boost. If you just want to race, then a single makes sense because you spend all of your time in the high end.

Scott 89t2

hmmm ok. I always thought it was only faster if they were sequential.

Evil Aviator

You should post in the 3Gen section for 13B-REW support.

Lots of turbo stuff here:
http://66.216.67.51/subcat.asp?0=220

I agree. However, the AEM EMS only works in conjunction with the 3Gen wiring harness, so it probably wouldn't be such a good idea to use it with this project when compared to the universal EMS products from Microtech, Haltech, Wolf, Electromotive, etc.

NZConvertible

Sequential is faster than parallel (only one small turbo to spool initially), but for equal airflows, two always beats one.

Somethin needs clearing up here. He asked about custom making manifolds, so I'm presuming he's after a parallel arrangement, not the 3rd Gen sequential set-up. In that case EMS selection is irrelevant, because there's no computer control over parallel turbos (other than boost if you want). As I said, it's no more complex than a single turbo. It's just more pipes.

Scott 89t2

I belive AEM has a stand alone "race" unit with it's own harness and sensors.

Evil Aviator

They decided not to produce it.

Scott 89t2

I think I'll keep my mouth shut now in this thread.

0 for 2

Evil Aviator

LOL

I disagree with your scoring. You ARE correct in that the AEM Race is a universal EMS. It's just not being produced for retail sale.

liquidferrum

sry yes i want paralell turbos, i thought i could get away with running a bit smaller of a turbo, for faster spool, and then since there are 2 in the end i will get more boost than having that one small fast spooling turbo, am AM NOT interrested in sequential turbo setups, and about engine management, doesnt that control the wastegate actuators, and if so, wouldnt i need 2 actuators to be controlled, or could i somehow have one actuator going to 2 wasteguates, also is it a better idea to run the turbos into a Ypipe that combines them, and then into one large intercooler, before a single throttle body, or to keep evertying seperate (2 intercoolers, 2 throttlebody's)

i also have no problem with dual 3" exhaust =p

also would i be should i go for lower compression rotors (87-88TI) or high compression rotors (89-91NA) because i wondered if the power gained due to higher compression rotos would outweigh the benefits of being able to boost higher, would this give me better low end power? or is it a better idea to be able to boost a little more

edit: intercooler, not into cooler

rx7_turbo2

That was my assumption as well.

I was unaware AEM decided to not release the "race" harness to the public.

I'm not totally convinced the twin setup is more money. If your going single you need a new manifold anyways so no real savings there. And how many of us have a couple stock turbo's lying around? Good lord I have two, and I know of a half dozen others I could get my hands on with a couple phone calls. Running the coolant and oil lines would be a pain in the ***, but not impossible. Then you have to worry about a custom downpipe, depending on the single turbo you choose you may need one anyways so once again no real savings. Worst case senario it probably works out to be in the same price ballpark as an average single turbo project. If I'm missing anything I'm sure you'll bring it to my attention

liquidferrum

i am already getting a custom downpipe made for my setup....stock turbo, because the s4 dp hits the switching valve actuator on my 89 engine

liquidferrum

bump again, anymore info on TT setup, or know anyone who has done it?

how would the wastegates work

Scott 89t2

you need 2 and a vac line to each if you are using internal ones.

NZConvertible

You're right that you'll be able to use two small turbos that spool very quickly. That's the whole point to twin turbos. But that doesn't necessarily mean more boost. Theoretically boost shouldn't change because they're running in parallel, but it'll depend entirely on turbo selection.

I've seen a couple of Aussie 13B's running twin stock turbos, but that wouldn't result in quicker spooling than stock, only a helluva lot more airflow potential. It would definitely spool a lot quicker than one turbo that can flow the same though. I imagine you could pick them up for a fraction of the cost of one big aftermarket turbo.

Personally I'd look at slightly smaller turbos than stock, as ours have quite big exhaust sides. If you think of any turbo car that made ~200hp stock, then two of those turbos have the potential for ~400hp, more if you raise the boost. What does a 400hp turbo/wastegate combo cost?
Wastegates don't need to be electronically controlled. Look at the S4's turbo for example and you'll see there's only a short hose going from the compressor to the wastegate actuator. That's all that's needed to control each turbo. If you want to control boost electronically, the hoses are simply tee'd together. Most of the small turbos suited to this type of installation use internal wastegates, so they're a non-issue. Again, this is much simpler than most people seem to think.
Wow, two TB's and intercoolers is defnitely getting far more complicated than is necessary. Just join the two compressor outlet pipes together and send them to the intercooler. Simple.
Hell yeah!
Like I said, boost level has nothing to do with the number of turbos. Boost will be whatever the turbo's wastegates or your boost controller allows. A high-comp, low-boost engine will always be more flexible and drivable than a low-comp, high-boost one, because when you're off boost that extra compression makes a big difference. But if you plan to crank the boost up just stick with the rotors you've got.

BTW, I forgot to mention before, the Nissan Skyline GT-R's RB26DETT, probably the most famous twin-turbo engine ever, only ever used non-sequential parallel turbos and most of the 1000+hp engines you see over there still are.

liquidferrum

thanks alot NZ, very good info

rx7_turbo2

I've always liked the idea of a twin system on a 2nd gen. I think it would work very well. In fact I know it will, there are more than a couple Australian guy's running a twin system on all kinds of rotary powered vehicles.

Evil Aviator

Oh, I think I misunderstood the original post. I thought you wanted to use a 13B-REW. IMO a twin-turbo 13BT is a waste of time, money, engine space, and weight. A modern ballbearing turbo is going to spool up very fast. If you want quick boost, then simply use a very short exhaust manifold, run low to moderate boost levels, and match the ballbearing turbo and wastegate to the engine.

FYI "V" and horizontally opposed piston engines use twin turbo setups in order to reduce the length of the exhaust manifold plumbing. Since the cylinder banks are on opposite sides of the engine, a twin setup makes more sense if you want to reduce the plumbing length in order to spool the turbos with as much exhaust pressure as possible. This makes a big difference in performance, as evidenced in the superiority of the S5 RX-7 TII manifold vs. the S4 manifold that is only slightly longer. Parallel twin turbos don't do much for inline engines with very few cylinders or rotors to feed.

BTW, a 20B-REW swap would be about the same cost and complexity of that monster of a parallel turbo setup that you mentioned.

liquidferrum

i think a 20b swap would be alot more

$150FC

Evil Aviator, with all due respect to a mod/rotary guru, I think you're incorrect

Really. Say you take two HT-18 units, rebuild them with a turbine clip, ported wastegates. For theory's sake, they're S5 turbochargers. So the units and rebuild will cost you, say, $1300.

After that, you go to your exhaust shop of choice (but you make sure they don't suck) and have a manifold welded up. Or, even better, if you've got the mad skillz, fabricate one yourself. There are plenty of people who've done that and if anybody is seriously considering making a custom parallel twin setup, they should have most of the skills necessary. (That's also why, incidentally, I'm /not/ doing a twin setup :P) I don't know how much a manifold would cost, but if you do it yourself, I can't see how materials would be much more than $300. That number may even be way high.

After that, you need boost control. If you're running standalone, you basically already have that (and again, if you're going to have twins on a 13BT, you ought to have a standalone). If you really want, you can go out and buy a nice electronic boost controller: An E-Boost, $500, or a Profec A, about the same price.

After that, you need some air filters and some more welding skills to make a Y-Pipe. If you already have a FMIC, then the Y-pipe shouldn't be too much of an issue. Figure $400 to have somebody custom make it.

Lastly, the exhaust. Downpipes and the rest of the full (true) 3" dual system shouldn't be more than, what, $1000? Custom made, of course, since there is no supplier for that. :P

So that's about $3500, or the cost of a long block J-spec 20B in need of a rebuild out of a Cosmo that some japanese fool drove until he wrecked the car

Corrections, anyone?

Evil Aviator

I think you are looking at about $10,000 either way, which also happens to be about the price of a quality large turbo setup (although few people admit this). Both the 20B conversion and the custom parallel turbo 13BT are going to require a lot of the same parts. The main difference is that the 20B will need an ignition upgrade (standard if the MTX12 or TEC3 is used), custom engine mounts ($275), and some type of oil pan or suspension modification for clearance. The twin turbo 13BT is going to need two smaller turbos (twin HT18's are too big for the quick spooling requirements), a custom exhaust manifold ($1,000 to $1,800), and the "monster" specs I was referring to included the twin intercoolers and two throttle bodies on a custom intake manifold. The cost would be even higher with new aftermarket turbos with external wastegates.

For a good price and layout overview, see this Twin Kit for the FD:
http://66.216.67.51/product.asp?0=220&1=362&3=720

Hehehe, custom parts cost more here in the US than you realize. A good custom 321 SS turbo-back RX-7 exhaust is about $1,400-1,600, plus about $400-500 per muffler, and $100-400 for a high-flow cat if required. A $100 Rainbow Muffler press-bent Y downpipe plumbed into the stock TII exhaust is probalby a better idea for a ghetto junkyard setup like you mentioned.

A good custom intake manifold can be as much as $3,500.
http://www.hogansracingmanifolds.com

Like NZ Convertible mentioned, a boost controller is not required, and is probably not even needed because a quick-spooling setup is going to have low boost, which is easily handled by the wastegate spring. Also, the newer EMS products like the Wolf3D 4.0 and Haltech E11 have built-in 3D boost control (PWM solenoid sold separately) which lets you set the max boost level past the wastegate spring setting at different rpm intervals.