33 replies to this topic

[Chasersaurus]

Heyo,

Was trolling through some random reading on the inter-webz and discovered twin-scroll turbos.

Has anybody heard of these or gone down this path. Quite an interesting read, take a look below.

http://www.modified....sign/index.html


Cheers,


Tim8o

[Chasersaurus]

Also another interesting read.

http://www.modified....gine/index.html

More relevant to us 1JZ guys.

[MaXim]

To implement a twin scroll turbo you need a split pulse exhaust manifold and a twin scroll turbine housing. The only split pulse 1JZ VVTi manifold I know of is the cast iron one by 6boost. Expensive, but supposedly the best money can buy, and you get a lifetime warranty. For non-VVTi there are cheaper stainless manifolds.

In regards to suitable turbos for the 1JZ, I guess anything goes as long as there is a twin scroll turbine option. Lately I have been looking at the Garrett GTX3076R and Borg Warner EFR 7670 which both support twin scroll turbine housings. Of course I doubt I can ever afford a custom turbo setup so I'll just settle for a kit turbo that bolts onto the stock mani In the end it just comes down to how much you have to spend.

I think that Toyota never saw the need to use a twin scroll setup because they had the parallel twin turbos in the 1JZ. In the JZX100 engine there is peak torque at 2400 rpm due to VVTI and a higher compression ratio. The CT15b is sized adequately but not too large to provide decent response. So again, no need for twin scroll.

There was an instance in which Toyota used a twin scroll turbo. MR2 turbos used a twin scroll CT26 and later CT20. I am guessing this is because the CT26 used in the 3S engine uses a very similar if not identical compressor to the CT26 used on the 7M-GTE. There is no way that the original 7M CT26a would give adequate response for a small 4 banger such as the 3S so they changed the turbine housing to a smaller one with twin scrolls and smaller turbine wheel.

Edited by MaXim, 19 June 2011 - 12:27 AM.

[HIZOKU]

Had one stock on the EVO with a good manifold i had tomei one seen boost increase sooner and also more top end turner was shocked when i pumped out 240 vs the standard 220ish just due to having a good exhaust manifold dump setup

[Cuts]

7m ct26 have a bigger: compressor wheel, exhaust wheen and exhaust housing, as well as being single entry. (core and compressor covers are the same)

1st gen ct26 (st165) was single entry (same flange as the 7m ct26) but smaller then the 7m in pretty well every way.

2nd gen ct26 (st185, rev1 sw20) was twin entry, otherwise identical to gen1 ct26

3rd gen ct26 (called ct20b by most) (st205, rev2 sw20) twin entry, is size wise closer to the 7m ct26 in regards to wheel sizes, rear housing is obviously smaller and wheel profiles are different.

4th gen ct26 (also called ct20b by most) (st215, st246) technically single entry, the exhaust housing and exhaust manifold are single piece of cast iron, otherwise the same as the 3rd gen ct26 (all caldinas are ceramic wheeled however, where as some 2nd and 3rd gen ct26 have steel. eg Group A Rallye, WRC, Carlos Sainz, RC)).

Twin entry does make a difference, so if you can get the housings to suit i say go for it.

[Chasersaurus]

hectic you guys sure know your yota's, i love your depth of knowledge.

I am still a relative n00b, I know little about how it works etc inducer size, A/R etc. But I'm trying to learn through reading excessive amounts of info like the links posted above.

It is comforting to know that these twin-scrolls are used in porsche's as it does have a significant reputation behind it. I guess if its good enough for porsche..... They info listed on Borg Warner however talks it up rather well.

also being a n00b i wasn't aware that the Garrett GTX series was a twin-scroll system. All in all it does seem like the way to go in terms of upgrading a turbo. Hopefully I can save enough to get a twin-scroll system.

[Chasersaurus]

one more interesting read

http://www.procharge...es-new-products

[Alehandro]

My T04Z is a twin scroller with split pulse manifold,
highly recommend it for street cars, spools up super fast for a big huffer. .82 exhaust

[Nyphe]

Got a GTX3076 0.82 twinscroll with a 6boost mani and twin gates going onto my engine in about 6-8 weeks, at least that's the plan. So keep an eye out for my results, though I'm going from stock turbo, so it won't be a back to back test against a single entry of similar size unfortunately.

[Chasersaurus]

Alehandro, on 20 June 2011 - 08:17 PM, said:

My T04Z is a twin scroller with split pulse manifold,
highly recommend it for street cars, spools up super fast for a big huffer. .82 exhaust

Oh really!? Show how n00bish I am, didn't even recognise it.

How much did you end up paying for the manifold? Cause I have heard they're expensive as hell!

When does your boost hit?

Nyphe - would love to see how it goes. I'll hunt you down in members rides!