Turbo Choice for single on Gen 3 1GGTE - TD05 18g/Td06 18G etc

[eightsixboy]

Hi all,

Before I get flamed yes I have searched, but most threads about single turbo upgrades are pretty vague regards what turbo will actually suit the 1G.

I'm basically going to be running a Y-pipe up to a t3/T25 flange so turbo choice for me is pretty much limitless. I would prefer internal gate purely due to cost/room.

I'm tossing up between these

TD05 20G
http://www.ebay.com.au/itm/271285065...84.m1423.l2649

TD05 18G
http://www.ebay.com.au/itm/271285065...84.m1423.l2649

TD06 SL2 18G
http://www.ebay.com.au/itm/281172485...84.m1423.l2649

My aim is 220-250rwkw but the number doesn't really matter, I'm after something that is very good in the midrange and top end but without excessive lag. Looks like the stock twins make 14psi by 3,700 ish so even the stock twins are pretty laggy, I would be happy if with a bigger turbo I had 16-18psi by 4k or there abouts.

What do you guys think?

[Kedderz]

220 rwkw = 2871r
250rwkw = 3071r (or 76r)

what other supporting mods do you have? anything over 200rwkw in a 1g will require a large turbo, thus lag.

[eightsixboy]

Will be upgrading fuel pump and injectors, car already has a larger intercooler, exhaust and emanage blue.

[e30-323ti]

Not sure how prolific late model Evo turbo's are over there? But would also be a good one to consider.
They are twin scroll, so would work well with your Y-pipe design.

The other one I'd look at is an STI turbo, VF 37 or 38, are twin scroll also, with a real simple flange design.

[eightsixboy]

Not sure if a twin scroll turbo would work without a split pulse manifold though?

I thought about going down that route but not sure how well it will work.

[e30-323ti]

Well the Y-pipe is split pulse if you don't merge them together!!
The front & rear 3cyls are pulsed appropriately.

[eightsixboy]

Yea I just realised that the firing order is like 1-5-3-6-2-4 or similar to that, so that would mean that indeed the manifold is already split.

I'm surprised know one has tried this before on a 1G.

Glad I didn't buy anything yet as this opens up a lot more possibilities.

[maj]

If you go for a VF series turbo, stay away from the VF38, they aren't one of the best ones out there and probably would be a restriction at top end, even TD04 twinscrolls are a slight improvement.

The holy grail of STi twinscrolls are the VF36, ball bearing and big enough to provide enough power through the range.

equal length manifold and split up-pipe issues aside, be prepared to find it a little tougher finding a good tuner who can work with a twinscroll to get the most out of it.
Most people don't go twinscroll because it's just cheaper to whack on a big single entry and go from there. Twinscroll you can advance your timing much more though and get a lot more midrange.

[SHEPPO3930]

[snip]
equal length manifold and split up-pipe issues aside, be prepared to find it a little tougher finding a good tuner who can work with a twinscroll to get the most out of it.
Most people don't go twinscroll because it's just cheaper to whack on a big single entry and go from there. Twinscroll you can advance your timing much more though and get a lot more midrange.

Can you elaborate on this further? How does the twin scroll turbine housing have an effect on ignition timing? I am keen to know more.

[maj]

Plenty of info available for this if you google further on how twinscroll differs from single entry.

Only thing is I might have jumped the gun a little, because you need exhaust VVT in order to also take full advantage of less pulse interference in your manifold with a twinscroll design. Maybe that's why no one has tried it on a 1GGTE before?

[eightsixboy]

So it wont correctly without vvt or just not as well as it could?

I guess the main reason for twinscroll would be less lag with the benefit of running more timing?

[eightsixboy]

If you go for a VF series turbo, stay away from the VF38, they aren't one of the best ones out there and probably would be a restriction at top end, even TD04 twinscrolls are a slight improvement.

The holy grail of STi twinscrolls are the VF36, ball bearing and big enough to provide enough power through the range.

equal length manifold and split up-pipe issues aside, be prepared to find it a little tougher finding a good tuner who can work with a twinscroll to get the most out of it.
Most people don't go twinscroll because it's just cheaper to whack on a big single entry and go from there. Twinscroll you can advance your timing much more though and get a lot more midrange.

I wonder if the stock twin scroll turbo's are big enough though for a straight six?

[maj]

Same engine displacement as the EJ20 boxer, so I don't see why not?

[maj]

So it wont correctly without vvt or just not as well as it could?

I guess the main reason for twinscroll would be less lag with the benefit of running more timing?

On a 6cyl, you're bound to run into pulse interference in your manifold, it's just a fact of life the tuner will have to deal with on a single entry turbo.
With a split design running all the way to the turbo you are already improving that flaw, it's just the twinscroll will be able to take advantage of it, faster spooling because the entry size is smaller and thus ease of spinning the turbine (twinscrolls usually have a 60/40 entry split, or something along those lines, one for spool, the other for power), but the pulse stream of exhaust gases hitting the turbine is also more even once you hit the power band.

By using VVT and advanced timing, you can create more overlap on the exhaust cycle due to the reduced pulse interference by design, that's where you can make further gains.

As mentioned I don't know how well it can transfer directly to the 1G. But considering you have the option to do it, as long as the budget is there and you have a tuner who can work with it, I don't see any other downsides to it.

[eightsixboy]

Same engine displacement as the EJ20 boxer, so I don't see why not?

I was always under the assumption that the rexy turbo's were pretty small to accommodate there poorly designed up pipe, to help with spool etc. I know the td04's are to small, but not sure how the vf turbos would compare to say an aftermarket td05 or similar.