i am about halfway into a twin PARALELL turbo setup, and i have been looking around for stock turbos that would be fitting and i think that i would like to find out more about the t-25g that comes stock on the rb20-det found in the skyline gts-t, but its hard to find any information on it, i have found some on the t-25, but i was wondering what the "G" designates.


anyone with info on where to buy (im in the states) that turbo/ or any links to info on it, or suggestions for other turbos, i would appreciate your feedback, i think nzconvertible said something about it in the long long ago, maybe if he is at large i can glean more info from him.

im looking for about 400hp range

and dont try to dissuade me, i have decided on twin so this THIS IS NOT A THREAD TO DEBATE THE ADVANTAGES AND DISADVANTAGES OF PARALELL SETUP

thanks in advance
liquidferrum

 

It's a bit interesting how you can be halfway into a twin setup, but don't know what turbo's you are going to use (which makes me think more along the lines that you're about halfway decided to do it). But anyway, expect some pretty slow spool, and pretty much anything over 15psi is going to turn it into a giant hairdryer, and that they'd probably run out of useful power at ~350. Pretty much a waste of time and money

 

why does it have to be off some skyline?

why not jack a decent sized turbo off a car you'll actually be able to find. Or better yet just get a couple diesel turbos from a junk yard, everythings going to have to be a one-off anyway, why not go big.

 

Probably because you couldn't spool two of them?

 

why are they going to run out of useful power at around 350? on the rb20 they make around 200 stock, and i am "halfway into it" because i have been silently doing about as much research as i can do, while slowly getting the money for this thing, i dont want to jump headlong into anything without knowing what i was doing... would you have more respect for me if i had already bought 2 random turbos?

 

rotary needs "more" turbo to make the same power as a piston engine.

 

*sigh* i know, but what is the basis for the number 350? just a guess, or do we have a formula somewhere? do we know what the max hp of the t-25g is? X 2? X the mystery formula? is that how we got 350?

 

How about using two stock HT-18 turbos or hybrid variants of them that still utilyze the special straight bladed "impact" turbine unclipped for good spool AND more power potential.

If you run the turbos parallel with one rotor feeding each turbo without a crossover you will have even more "impact" effect over "reaction" effect than the stock systems and so even more reason to use the "impact" style turbine, though I don't recommend this set-up.

I would suggest a crossover in the twin set-up to double the pulses to each turbine for a faster spool. If you used dual '89 TII turbos you could get tricky by feeding each turbo with exhaust from the front AND rear rotor like stock.

If you run the standard single turbo style large runners off the exhaust ports and then split each runner to two smaller shorter runners feeding the turbos with a good velocity stack incorporated into the reduction/split then you should have good exhaust velocity for good spool.

Since they are internal wastegated turbos the complexity of the exhaust manifold is bad, but at least you don't have to deal with the external wastegate dumps

I would suggest putting a divider between turbine flow and wastegate flow in the downpipes as you are starting to see more of in the aftermarket.

 

And this is supposed to mean what? You do know that the rotary needs more air than the 2 liter?

 

Why pick something as obscure as turbos on a JDM car? That's a waste of money.

DSM 13G or even 14B. They'll be easy to find and cheap. VR-4s make 500+awhp with 14B's. The stock twin setups on most cars out there are just tiny.

 

thanks bluetII and arghx... to bluetII's comment, wouldnt i be looking at a considerably higher ammount of turbo lag with 2 ht-18's.. the original idea was to get fast spool up with minimal power loss... and the reason i picked a turbo from a skyline is that i heard somewhere that they are ceramic ball bearing? and spool up incredibly fast, sadly i dont know a great deal about the specifics of different turbos and effects of thier construction, and i dont seem to be learning fast enough.

 

Hurrah for 60lb/min at less than 60% efficiency... (14B), the 13G wasn't even big enough for the car it came stock on! The *LEAST* you could do is some Big 16G's, at least those would be up around 71% in the area you'd use them, that's a start!

 

Even if they are ball bearing, their hotside (when ran twin), is quite a fair bit larger than a stock single turbo, so even the benefit of the ball bearing will still make it slower, although allowing more flow for 'top end', but it's useless since the compressors can't keep up.

 

They are all too small, and the turbine A / R is waaaaaay too small - usually 0.4x to 0.6x.
About the only thing you might be able to get away with is the T28's that come off of the S14 / S15 Nissans, but you need two of them; they only come with one per car stock.
You're not going to find these things in the states very easily.


-Ted

 

I assume you have the stand-alone EMS already running or ready to install soon?


-Ted

 

You should do some research on the twins(specs) that Mazda/Pettit/BNR offers(FD3S) and do some reading in the 3rd gen forum. Maybe that'll help you find the size that you are looking for.
Also, you are better off asking the turbo rebuilders/mfgs what they would recommend for twin turboing a rotary.

There are a lot of ~200hp turbo'd cars out there. I understand the 'logic' to grabbing two junkyard turbo$. But, only your trial/error will give you the answer you want if the turbo suppliers' experience doesn't.

Grab two turbos off any car(Audi/VW 1.8, Talon/Eclipse 2.0, VW TDI, Toyota MR2/Celica, Nissan 300zx....) and see what happens. I'm not saying that it is the 'best' or 'efficient' way to 'double up' for 400hp. But, its your time and money.

Good luck and fill us in with your end results.

 

That sure is a bad idea. You can pretty easily determine what will work and what won't just by looking at compressor maps and other specs of the turbo, and most of them you listed would be damn near useless.

 

thanks bluetII and arghx... to bluetII's comment, wouldnt i be looking at a considerably higher ammount of turbo lag with 2 ht-18's.. the original idea was to get fast spool up with minimal power loss... and the reason i picked a turbo from a skyline is that i heard somewhere that they are ceramic ball bearing? and spool up incredibly fast, sadly i dont know a great deal about the specifics of different turbos and effects of thier construction, and i dont seem to be learning fast enough.

Yes, there will be more lag with 2 HT-18s than one HT-18 (depending on rest of the set-up), but the power potential is higher.

If you are "just" looking for 300RWHP one unclipped HT-18 with a moderate compressor upgrade is going to give you the best spool.

Put a '89+ TII turbo with ported wastegates, an unclipped exhaust wheel and an upgraded compressor wheel and housing (possibly with dynamic seal like BNR for better boost response) on a proper equal length tubular exhaust manifold (you were ready to fab something for twin turbos anyways) and a BIG turbo back exhaust (3 1/2" or 4").

This will give you more power and better spool than any homebrew concoction of twin turbos of other cars. Check the Australian rotary forums where they actually have made tubular manifolds for the stock turbo and made 400RWHP. One of the guys there has a big 4" exhaust and other work and his car has awsome low end power- there is a dyno plot overlay of stock hybrid turbos!

There is LOTS of other work to do besides turbo sizing that will increase the turbo response. You should work hard to decrease any restrictions to airflow on the intake side as well. More restriction before the turbo really hurts spool so ditch the stock AFM and ECU and go with a standalone and a big turbo inlet duct/filter. Try to reduce bends/length and restrictions in the intake after the turbo as well as more backpressure means more work for the turbo before boost is seen at the ports.

I was running a BNR stage 4 hybrid turbo and it spooled as well as a GT35R dual ball bearing turbo from what I have read on the forum and has the same power potential - 400RWHP. I had full 17psi boost at 3,500rpm some boost by 2,000rpm. That was due to all the other work to improve turbo response even though I was running the stock unequal length short cast iron manifold. I would spool better with a tubular manifold!

 

Go on ebay and get the Amemiya twin turbo kit fo $2k and be done with it.

I think it said they were TD05H or something(can't remember the crappy pic of the tag).

 

i think this guy is too afraid to post anymore..... nice job once again Sonic

 

I like the idea of running two modified S5 turbos.

 

digi7ech is right
http://cgi.ebay.com/ebaymotors/JDM-F...spagenameZWDVW

 

thanks for all the info everyone, ill sit on this for a while