What size turbo would you use to make 400 - 450 WHP (max) with a 1JZ...

[6BOOST]

What manifold was this done on buddy? Just curious... thats all.....

Haha, mine of coarse

Question. would a 3082 with a 1.06 be a better option than a .82 rear housing?
im not really clued up on the A/R business, will having a larger exhaust housing A/R help since its a relatively small turbine to begin with?

A 3582 with a .82 will outspool the 3082 with a 1.06. If you read above, 2 of my Rb30 VL customers have upgraded from a 3082 to a 3582 and couldn't notice the difference. I would personally forget the 3082 and go with 1 of the following options.

If you can lower your target to say 415-420rwhp, use the 3076 with a .82, chuck in some cams and cam gears and I think you'd go very close to 440-450rwhp on 23psi pump fuel with full boost around 3200-3400rpm, faster than the stock turbo's by a huge margin.

If 450rwhp is just your starting target and you may end up wanting more, go straight to the 3582 with a .82 and get some cam gears and spend a lot of time on the dyno optimising them for spool, keep the dump pipe around 3" and step up to 3.5" under the car with as little restriction as possible, I think on the right manifold you'll get full boost down to around 3800rpm and walk 450rwhp in. Once you get used to the car and want more, you can start to dial some spool out of it and optimise cams for hp and make upwards of 500rwhp on the stock bottom end. I for 1 wouldn't be pushing the engine this hard on pump, but make sure you have very very reputable and safe tuner. MAny a engine has gone kaboom shortly after with the tuner blaming the power output with stock components rather than the detonation that killed the cat.

6BOOST

[o_man_ra23]

I would use a pair of GT20 or GT25 series Garrett Turbos. A lot of research needs to be done to find the exact turbos which will work perfectly, most of it can be done off the graphs if you know what you are looking at though. You should also increase compression ratio, install improved cams, use a highly advanced ECU and apply very tight control on your engine's tune and all the other bits associated with a high expectation engine build.

Before people bag the twin setup, I say keep with twins, as they spool VERY quick, and its the torque curve which will improve acceleration, NOT max power. Cars that get built for max power runs generally get trailered everywhere because they are too much of a pig to drive on the road... me personally, I like to have my cake and eat it too It is however a lot of work to setup, as manifolds will probably be quite custom.

[/RANT]

[Norbie]

It is somewhat debateable that a pair of small turbos will spool any quicker than a well-matched single. Certainly that was the idea with the original 1JZ, but modern turbochargers have changed the game. After all the updated 1JZ went back to a single turbo.

[petespipes]

well i have always believed that 2 smaller turbos with the combined output of one larger turbo will always spool faster [all other things being equal] due to the inertia multiple involved in getting the bigger wheel up to speed.

please read above comment as- "less force required to spin two small wheels than one big one"

problem is two turbos cost double of one plus manifolds etc.

Anyways,back on to puspose of thread-

for what its worth i tried gt3040 [3082] after stock turbos with some mods doing 302rwhp and found it comparitively laggy.[compared to stock] without a retune.

pulled it off and fitted gt3076 to be happy with response like stock with no tuning.Jampac has done 300 rwkw plus with gt3076 and others here have backed those figures as obtainable with this turbo.

I originally tried 3082 as i had read SLYLUX's results [300rwkw] with manual gearbox and 3082.At the time nobody was playing with smaller singles....

Now i have read all the posts in this thread and it seems there is something not quite right.OR something i dont understand more likely.

"a 3582 with a .82 will outspool a 3082 with a 1.06"

accepting that both turbos have a 82mm compressor wheel

the 3582 has a 68mm turbine
3082 60mm turbine? with opening up the rear housing on the gt30 what makes it slower to spool up to full boost than a turbo with a larger rear wheel?
\
Also it has been suggested to use either 3582 [bigger than 3082] OR 3076 [smaller than 3082] but no support for 3082 which should be in the middle? or am i deluded

anyways,good thread and useful input by many.

[The Real Roadrunner]

the main reason i dont support the use of the GT3082r is due to the fact that it is a compromised turbo (much the same as a GT2876r).

have a read around on the garrett site and there are alot of usefull formulas to work off, or just take kyle's and my word for it.

it basically comes down to the efficiency and flow of the turbine side versus that of the compressor side, if they aren't well matched then you wont get great results.

as far as the twin versus single arguement goes yes twins could be better but not many ppl want to fork out for the R&D to get it 100% right when a single setup is proven and costs alot less.

cheers
linden

[pato]

hurry up and get something, then based off your results i can pick mine

[JZA70 R]

assuming the 3082 is a 'mismatched' turbo, it does seem logical that it would be less efficient than other turbos since the compressor will be trying to pump more air into the motor than the exhaust housing of the turbo can flow.... is this on track?

[The Real Roadrunner]

in simple terms yes, there is a fair bit more to it but would be more like an essay than a reply.

efficiency of both sides comes into play, power you need to drive the compressor versus power supplied by the turbine, max flows for both sides etc.

the best advice i can give would be to read through the turbobygarrett.com tech articles and it should give you a better understanding of the way a turbo is designed and how to chose the appropriate 1 for your needs.

as you can see kyle and i would both be chosing the same turbos to do the job but it depends on the exact number your chasing, 400whp=GT3076r or 450whp+=GT3582r.

cheers
linden

[petespipes]

well im convinced,made a few calls today re changing my very low k gt3082 into a gt3582.[a lemon into a rose hehe]

Brett at GCG is preparing a quote for me and offered to swap some parts etc,they seem very organised and on the ball.

Garret on the other hand were obviously not used to dealing with the public [me] although they tried.

Will post results as its probably on topic for many following this thread.

[6BOOST]

For anyone following this thread, I will give you the following information on twin turbo VS single turbo setup. Although I have dyno graphs of all 3 cars somewhere, I'd be stuffed to find them, but take my word on the following:

I have done much back to back testing on GTR nissans in the past 2 years with Mercury Motorsport in brisbane, as we shared a workshop and they do quite a few GTR skyline upgrades. 3 Cars come to mind, each one was fitting with various modifications, some had plenums, some were bone stock with cam gears, ALL had Apexi management, good fuel systems, and upgraded turbo's. The lowest powered example fitted with hks 2530's, supposedly the pick of all twin setups for spool, made 313rwkw on 20psi of boost, stock engine, pump fuel, full boost was around 4400rpm.

Second car had 2540 turbo's, hypertune intake, massive ARE cooler, 3.5" exhaust, good dumps, good fuel system, all the supporting mods, and made 330rwkw on 18psi, full boost 4600-4700rpm

Third car was R34 with T518z trust turbo setup, fuel system, cams, head work, good cooler etc etc, and made 341rwkw on 22psi, full boost 4500rpm

All cars were tested in rwd mode, as 4wd mode can get a wavy line from the attessa. All cars without any other changes switched to my GT35 single turbo kit, with a .82 rear housing and tial 44mm gate. All cars had a 3.5" dump pipe made that went back down to exhaust that was on there. No cam gear changes, no other mechanical changes.

Car 1 Went 398rwkw on 21psi, pump fuel, ran 128mph on 17psi full weight

Car 2 went 378rwkw on 18psi

Car 3 went 413rwkw on 22psi

Every single car made full boost between 4000rpm and 4100rpm, each car had more power everywhere, by massive margins, more torque, earlier torque, nice boost curves(most of the twins fall a psi or 2 up high), every single one was more responsive, and the best case scenario was car 1 that picked up 85rwkw within 1psi of boost pressure.

In my experience, and these are just a few, twins are ALWAYS laggier than a well chosen and well thought out single on a decent manifold. I have nothing to gain in coming to this conclusion, I sell twin manifolds and they are $100 more expensive, so I make more money if I built a twin setup for you. Simple fact is the twin turbo "legend" so to speak no longer holds true. Maybe in the days or plain bearing T4 truck turbo's we started using compared to twin T28's, but not in this day and age with TO4Zs and GT35 etc.

6BOOST

[1JZ.747]

well im convinced,made a few calls today re changing my very low k gt3082 into a gt3582.[a lemon into a rose hehe]

Brett at GCG is preparing a quote for me and offered to swap some parts etc,they seem very organised and on the ball.

Garret on the other hand were obviously not used to dealing with the public [me] although they tried.

Will post results as its probably on topic for many following this thread.

pete, GCG are garrets public relations basically, they sell the garrett product. garrett dont like selling direct to the public.

brett is great on the phone but from my experince buying my first 2 single turbos from them, service is not great and getting a true answer can be a challenge. their repair work is excellent.

have you tried ray hall turbos in qld, he is the local garret dealer up there i believe.

[petespipes]

GCG price for altering gt3082 to 3582 $1000+ ray hall $1500+
in ray hall's option the turbo would be done by garret in sydney using all new parts where GCG could utilise parts on hand.

At these prices its definitely sell the turbo and buy again provided i can get $1200 for a gt3082 with under 500ks use? then pay 1800 for a 35.............money down the drain lol

note-rays price option on buying a new 35r was the best price and i would happily buy my third new garret from him.If i had taken his advice initially i would have purchasrd the right turbo first time around.

[o_man_ra23]

Ray Hall may be more expensive, but him and his old man have been working on performance cars since Fred Flintstone added rubber soled shoes to his feet for better braking. They were innovative and ahead of the field when turbos first started getting used in cars, and they really know their stuff.

Ray's old man managed to get a plumber I know's HZ 1 tonner an added 30% torque all round with a fuel consumption decrease while pulling a full load back when it had less than 1000kms on the clock (read 1979), and their reputation in Cairns and over the country has only gotten better since.

Dont know anyone who has personally dealt with GCG, so cant comment on that.

[Danners]

JZA70R - Thanks for the thread (minus the little fights in the middle )

i'm looking for a garrett solution for my 1J as well, and the information in here has been very informative... although I still can't make up my mind! I think the extra lag from the 3582 concerns me, but it has all of that extra "headroom"

gah!

[The Real Roadrunner]

although I still can't make up my mind! I think the extra lag from the 3582 concerns me, but it has all of that extra "headroom"

gah!

best advice i can give is find ppl with both and go for a drive in their car to see what you prefer.

i doubt you would be unimpressed by either if theyre setup/tuned correctly but it all comes down to how you like a car to drive.

cheers
linden