Turbo Choice for Track Supra..

[2jayzgte]

I'm thinking along the lines of a Garrett GT30 as Im looking for response not out and out power.The reason being for the smaller turbo is the fact is that I believe we'll be getting full boost at 3000 rpm and it will give me best use of the factory rev limit.Don't think a bigger turbo is worth it as it will rob me of to much of my power band.I am hoping by not raising the rev limit I'll get away with the standard internals.

I am going to use a Bosch 044 in tank pump.
A Link G2 ecu to run it all
Supra 550 cc injectors
US/U.K Spec Cams.

Power well if with this setup I am hoping for 500-550 Hp at the flywheel.
The car weighs 1580 KG with driver and 1/2 a tank of gas but we have a plan to reduce weight to about 1250-1350 kg well thats our aim anyway.So any helpful responses would be much appreciated...

[Si]

being the larger of the GT30s, and because Liths is pretty cool..........GT3076R
not sure on the AR, .82 may suit better than .63.

What turbo(s) are you using now? stock?

[strx7]

what is the stock rev limiter set at?
JZ bottom ends seem pretty well balanced etc as a factory motor. If you just balanced the whole factory rotating assy you should be able to use 7500. I think the guys on the supra forums concluded that the factory valve springs are more the rev limiting factory std rather than the bottom end. Get longer duration cams, degree them for midrange power, it'll broaden your powerband for sure.

[Lith]

I have a GT3076R with a .63a/r turbine housing on my R33, its already done 274rwkw "not even trying" - I can cruise up Nguaranga gorge in 5th gear at 80kph (~2100rpm) at low throttle and it will be sitting on 2psi. That is with a 2.5litre in a car weighing 1360kg, so I'd imagine with a 2JZ breathing through it - it'd be huge fun. Go no less than .82 if you do though!

[2jayzgte]

We are using the factory ceramic turbo's in parralell at the moment but they will not last.Basically we don't want to touch the head or cams at this point.Just get a nice driveable power and torque curve going with this setup.I believe with this setup and 500 odd HP put the car on a diet we'll have a real sleeper.As I believe no one has done a small response setup with the Supra so I really think we can get the car going quite well.

[JustinSpiderholden]

T04z

[2jayzgte]

To4z good turbo but since we don't plan on raising the rev limit it will kill most of our power band which with a Garrett GT30 we'll be making full boost at between 3000-3500 rpm whereas with the To4z we won't make full boost till 4500-5000 rpm so for us theres not enough useable power band for us to be any good.Now if we were to increase the rev limit then the To4z would something that we would seriously consider.

[flygt4]

i thought you had US spec steelies on there?

why not use big twins? if response is what you want then twins would be ideal. they are used often on gtr's, with great success. doesnt seem as common on supras seeing as they have 3L displacement with which to spool a big single, but i reckon a 2jz with large twins would just rocket out of corners from any rpm.

[2jayzgte]

i thought you had US spec steelies on there?

why not use big twins? if response is what you want then twins would be ideal. they are used often on gtr's, with great success. doesnt seem as common on supras seeing as they have 3L displacement with which to spool a big single, but i reckon a 2jz with large twins would just rocket out of corners from any rpm.

Its not actually mine its a friends just trying to get some info before he makes his decision.Twins are no good as they wont start to spool untill about 4000 rpm.This is why our thinking is at a small single and better use of the factory power band.

Basically looking for the response of the factory twins with about 100 more HP.I no this goes against what most other 2JZ powered cars do but we reckon for a track-day car response and low weight is the way to go.

[Lith]

Its not actually mine its a friends just trying to get some info before he makes his decision.Twins are no good as they wont start to spool untill about 4000 rpm.This is why our thinking is at a small single and better use of the factory power band.

Basically looking for the response of the factory twins with about 100 more HP.I no this goes against what most other 2JZ powered cars do but we reckon for a track-day car response and low weight is the way to go.

Depends on how small the twins are actually - a pair of GT2560-7s would probably be pretty insane, but realistically I think the GT3076R will be the punchiest and easiest to apply setup. Going for a big single allows for an easy upsize if needed in future as well

[strx7]

Twins are no good as they wont start to spool untill about 4000 rpm.

so you must also know how long a piece of string is if you can make that statement.

Ever thought of using a Pair of TD04 or TD05's on it?

[matt dunn]

Twins are no good as they wont start to spool untill about 4000 rpm.

We use twins on the 2JZGTE in the Enduro race levin as they come on way sooner than our older one that now has a single,
and gives a much wider powerband, and also as the power comes on much smoother you can actually drive it out of the corners to get more speed doen the straight.

[2jayzgte]

My bad guys I was referring to the aftermarket twins with regards to spool up.Again lack of experience with the smaller aftermarket twins is why we have chosen not to go in this direction.Also I think for the money spent it would be cheaper to go with the single.

We actually think that the factory twins for what we want are not to far away from being really good.I have been using the U.S spec twins in sequiential mode for about 4 years now and really like them.

What we do want is in a ideal world is match or better the factory power and torque curve with about 100 odd Hp more hence our goal of 500-550 hp.

The biggest problem we are running into is user experience no one to bounce ideas off as no one in NZ has bothered with a small single on the 2JZ some people may think we are wasting our time but I think our experiences with the factory twins reckon a small punchy single is the way to go for a track-day car.

I was influenced by the dvd footage of the Amuse Supra on that Best Motoring 5 DVD just the way the car was so responsive off the bottom and all the way through the rev range.

[strx7]

what duration are the cams you are running at present?

[2jayzgte]

We intend on using the U.S/U.K spec Supra cams.I cannot tell you the exact duratiion and lift I think there about 233 degrees on the inlet side and 8.25 mm of lift.

[strx7]

something around 256 degree, timed to the right degree would give you as nice midrange power boost and broaden the torque curve up

[matt dunn]

My bad guys I was referring to the aftermarket twins with regards to spool up.

The standard twins lasted approximatly 3 laps before the exhaust wheels disappeared out the tail pipe.

It now runs what looks like two T25 type turbos and makes 510hp atw.

Other than the external mods and the US spec injectors, the rest of the engine is JDM factory spec.

[Lith]

I reckon a GT3076R with a 1.06a/r hot side and 1.2-1.4bar i would be pretty tough on a 2JZGTE. Problem is it'll run out of compressor efficiency, though the stockers will be doing that as well.

Especially if you pump something more exotic than 98octane into it, I'd not be surprised to see over 350kw @ wheels and an absolutely insane power delivery with that kind of setup.

[2jayzgte]

I reckon a GT3076R with a 1.06a/r hot side and 1.2-1.4bar i would be pretty tough on a 2JZGTE. Problem is it'll run out of compressor efficiency, though the stockers will be doing that as well.

Especially if you pump something more exotic than 98octane into it, I'd not be surprised to see over 350kw @ wheels and an absolutely insane power delivery with that kind of setup.

Mate what do you reckon of a GT 30/82 with the .83 exhaust housing we can get this turbo from the NZ Garrett dealer for a good price and it sounds abouyt right for what we are looking for????

[Lith]

Mate what do you reckon of a GT 30/82 with the .83 exhaust housing we can get this turbo from the NZ Garrett dealer for a good price and it sounds abouyt right for what we are looking for????

Yeah man, I can't remember if I mentioned it the other night but it'd be a bit laggier than the GT3076R but still better spooling than the GT3540R. The compressor won't choke on the 2JZGTE like the GT3076R will in the higher (>6000rpm) revs, so it should be able to rev just that little bit better

One of those should be good, and easier to find than a 56Trim GT3076R.