I have a question that im not too sure about. And hopefully we can get some tuners and anybody that knows any information about this to chime in. Basically i was trying to find out if a Twin Scroll setup is better then a standard scroll setup (T3/T4) housings? I have tried to find information on this topic but really havent been able to pull up much. Here is the only thing i was able to find. Any info will help! Also we are talking about upgraded turbos and not stock. On stock turbo and can see it helping but on the bigger turbo's would it become a restriction??

Thanx Guys!

A twin scroll turbine housing uses dual side by side passages into the housing. When coupled with a pulse converter manifold that separates exhaust pulses as many crank degrees in the firing order as possible, a twin scroll or divided housing works to reduce lag, decrease exhaust manifold backpressure on the top end, reduce the potential for reversion, and increase fuel economy. The twin scroll is based off the same reasoning a tri-Y header uses: keep spent exhaust gases out of an adjacent cylinder drawing in fresh air. At high rpm on a turbo car, exhaust backpressure is usually significantly higher than atmospheric pressure, and often higher than intake manifold pressure as well. A divider between each of the two volutes allows the cylinders to expel the exhaust gases without it interfering with the fresh air for combustion. Since there are two openings, each a smaller overall volume than a single scroll design, the exhaust velocity of each pulse can be maintained. This also spins the impeller more easily because lag is a function of the scroll area. A single turbine housing opening isn't as efficient since cylinders on the exhaust stroke of the 4 stroke cycle contaminate the cylinders that are on overlap with exhaust gas. A conventional turbine housing is not as effective in using exhaust pulse energy to help spin the turbine up to speed as it does not exploit the energy contained in the pulses as well.

 

I'm curious as well

Tho IMO the t3/t4 single scroll when mated to a t3/t4 turbo hosuing should flow and spool faster. However, as we've discussed, the twin scroll seems to spool faster.

 

You have to mention the design of the Mitsubishi turbo VS the garrett turbo. The t3/t4 design is a bit old and does not wear as well as mitsu turbos. Garrett BB turbos, however, are pretty much the best.

 

technology filters down from turbodiesels believe it or not!

variable compressor nozzles are next. actually-- I think the beetle turbo might have one! don't quote me on that but I thought I read it.

 

I've seen some variable vane, and hear some about variable nozzle.. your right, all the innovation comes from the Diesel turbocharger technology..

 

Huh well thats crazy. Variable compressor housing huh? How does that work. ANyway back to the main topic. So basically im taking it that nobody really knows how the twin scroll compares to the single scroll setup. Ill give you a for instance. Im running a GT35/40R with .63 housing with a Twin scroll exhaust housing and a twin scroll exhast manifold. So if i were to take that exact setup and change the exhaust housing to a t3 and change the manifod to a t3 manifold what kind of changes would i see? Slower spool? More top end power? Anybody know?

 

variable nozzle is the same as variable vane.
http://www.egarrett.com/technology/t...&l2id=2&l3id=4

 

oh regarding the full T3 instead of GT3540... um that's easy. the old T3 would suck in comparision. bad. you have a very nice, very modern turbocharger-- why would you even wonder if something from the 70s could challenge it?

 

I would love to hear from some venders regarding the twin scroll vs. standard scroll. How come few venders (only one that I know of) utilize the twin scroll technology, which mitsubishi uses as a selling point for the cars turbo.

?

 

why listen to vendors? :huh: the ctrl-v that is the second half of the first post in this thread has it exactly right, wherever it came from-- and here's more information from garrett:
http://www.egarrett.com/technology/t...&l2id=2&l3id=1

as to why there are still continuous flow turbos in use? they're cheap, plentiful, and "good enough". they are not better. go for the simple answer until proven wrong. in this case it's "cheap".

 

I would love to hear from them also. And to the other comment about going to a T3 turbo i wasnt saying i would change the whole turbo. All im trying to say it would a standard scroll setup be better then a twin scroll setup. From what im reading now i dont see how it would at all. But just looking at the setup of the manifolds you would think that the twin scroll would be more of a restriction then the standard scroll setup. But after reading some of these posts i see know how it is very benefical to have a twin scroll setup. I really appriciate everybody helping with the information. And as far as the vendors i was wondering the same thing why only a very few of the vendors are using the twin scroll setup. A couple of the main contendors (AMS & RNR) are running the standard scroll setup. Why would they be doing this if it had downfalls? Maybe Cost? We need to hear from some of the companys and get there outlook on things.

Thanks Agian Everybody for lending your info.

 

prepare for lame excuses about their inferior technology, or them pointing out that their product is less costly and is good enough. sometimes the good enough claim is true, as just the existence of a fancy turbocharger isn't enough to win the day. the kit needs to be well engineered or else it is just wasted potential.

 

Im in agreement that the t3 housing is too small. BUt the t4 housing is what I want to know about.

The equal length manifold will act as a pulse, as the twin scroll is designed to do, from what I've heard. So maybe that's why neither is worse nor better because they are the same.

Technology or not, old vs new, airflow is airflow.

 

equal length manifold on a standard turbocharger doesn't change anything. please read some of the links. here I'll help-- this is from one of them.

 

complete with their typos, lol.