Running sequential turbos on a 4G63T engine?

[awdstreettuner]

I am wondering if anyone has ever tried to run sequential turbos off of an twin turbo rx7 or supra? I have only seen one 4 cylinder with this and it is a local guy with a civic hatch. He had it dynoed at 293whp at 12psi on stock engine. I was wondering if it has been tried by any of us DSM guys.

 

[gritsak]

its even more pointless then running true twin turbos on a 4cyl...its been gone over time and time again...you can make as much power as you want with a single turbo and its a fraction of the cost of doing it any other way....how many fast rx7's or supras do you see with seq. or even twin turbos still..other then the handfull of upgraded twin turbo supras all the fast ones are single

 

[awdstreettuner]

I agree with the Supra's and Rx-7's 99% of the fast ones have the single turbo conversion. I was just curious if anyone has successfully done this and what kind of dyno numbers did they get. I thought the civic hatch had great numbers considering his internals were stock with stock engine.

 

[skier_du]

I heard of a guy that did that a few years back around here. He used to street race here. Never saw him though, so can't really say much about it.
but as far as expensive? Well, the major things could be a couple used t25s shouldn't cost much. and then its just having a custom manifold and downpipe fabricated. Or if your reall good you might be able to fabricate those yourself.
'Supose its possible.
It woulod be unique for DSMs. I'd be interested to see if it could work and how well.

 

[skier_du]

A guy that used to street race around here supossedly had twin turbos on his DSM. I never saw it, though.

as far as expensive? The major stuff is a custom manifold, 2 turbos, custom downpipe, and intake and licp that both split off. The manifold and downpipe shouldn't cost more than a couple hundred from a local shop. Turbos? heck a couple used T25s would probly work OK. Better than 1 would. Most 2g guys have at least one laying around. And if your handy, you probly can fabricate most of the stuff yourself.
Personaly, I'd love to see that setup and see how effective it would be. It would definitly be unique in the DSM world.

 

[ivanr4g63]

But this civic with twin turbo setup wasn't done on a b16 right? Only h22,b18c5, and maybe the h23 I think It'll hold that kind of boost on stock internals not quite sure though.

The thing is that if you try hard you can get a custom Sequential Turbo setup, and probably not spend that much money, but it is a bit more of a pain in the ass to keep the turbos running at a coordinate spool, eventually you'll want to raise the boost and the problems begin, that's pretty much why when it comes to racing people switch to a single bigger turbo, so they'll have more accurate boost. But then again if you want to do this for a show car It'll take you some time, but it can be done.

 

[skier_du]

Just realized that I double posted. I thought the first post didn't go through. Sorry.

Yeah, boost could be a problem. but I bet it would be a lot easier to control with an electronic boost controler that had the capability of controling 2 seperate selonoids.

 

[DSM007]

Marco of magnus ran two t-25's with a custom manifold and NO WASTEGATE,he hit 23 pounds of boost max with no boost controller,they were maxed out and couldnt make anymore boost,spooled fast like by 3500 rpm 23 psi.........just letting ya all know its been done in some type of way on a DSM.

 

[kpt4321]

Running 2 of the same turbo is NOT a true sequential setup, and presents NOT positive side effects compared to running one properly sized turbo.

To do a workable sequential setup, you need a TINY turbo (smaller than T-25) and a medium sized turbo. Then you need to fabricate a complex turbine housing that will first send al the exhaust gasses to the small turbo, and then will transition over to the big turbo as the boost and airflow levels rise. You have to set up a similar system for the charge air.

Doesn't seem like such a good idea anymore, does it?

 

[90DSMTurboFWD]

Actually the only honda motors that would be able to safely hold anything over about 10 PSI would have to be the b18 and b16 series motors, the H22 has week chambers which cause them to litteraly explode under high boost, people with h22 turbo setups tend to put sleeves inside to help strengthen the bottom end. Atleast that is for the DOHC series. SOHC engines on the otherhand have plenty of boost potential and I think you can run something like 12PSI on a stock sohc without danger.

 

[awdstreettuner]

I know that the engine he is running is a D15 or D16 which makes it a SOHC 1.5 or 1.6 liter. I doubt his engine will last long because he is about 200% above stock with stock internals. If I recall correctly the sequential turbos are off a twin turbo rx7. Maybe I can take some pics of his setup to see exactly how he has it set up. I know he raced another friend of mine with an 03 z06 and they tied.

 

[skier_du]

actually, they b series is not stronger than the H series. They both run into a problem iwth the newer ones. 97+ H series has open deck design, as do the B series. That is the weekness and the reason for the sleeves. Sleeves only strengthen the block; they close the deck and can handle more abuse than stock sleeves. The internals on the H22 is actully very strong and people have run 15lbs on the stock bottom end. However what thedy need to do is change the head gasket for a metal one that is thicker, thereby lowering the compression and increasing detonation resistance, allowing for bost levels as high as 13lbs safely and realibly.

 

[DSMJim]

All H22 are closed deck. They sleve because the block is Nikasil like some 2strokes and you can't bore them out. They are considered a non-rebuildable motor by Honda due to this.

293whp on 12psi is not great. We made 298whp at 10psi on a stock GSR so your buddies twin turbo setup is not very great if you ask me. That was on a lame ass Drag turbo kit too which uses pretty crappy parts.

 

[RipperXX]

gritsak, every 3rd gen RX7 was a sequentail setup...

 

[awdstreettuner]

298whp isnt really that bad for a honda. Dont get me wrong there are stronger ones out there. If I may remind you this is a D16 at most which means it is a SOHC 1.6. GSRs come with a 1.8 DOHC vtec. I thought he was quite well considering most people say that the limit for a D16 is 350whp and he is stock block with only 12 psi. I know he has plans to up the boost to 18 psi. I am curious to see what power he gets out of it then. I also know that he better plan on building the engine if he wants it to last over a few runs with that kind of boost.

 

[ChicagoGSX]

Originally posted by RipperXX
gritsak, every 3rd gen RX7 was a sequentail setup...

Yeah he knows that, and he also knows that when upgrading 95% of people go with single turbos

 

[skier_du]

Originally posted by DSMJim
All H22 are closed deck.

Actually, all pre 97 H22 where closed deck. 97+ H22 are all open deck.
http://www.h22a.org/specifications.htm