Turbo Exhaust Housing 1JZ Question.

[Soarer_D00D]

Hey guys. As some of you may or may not know i blew the ACME T70 ebay special i had running my 1JZ after i boosted it upto 22psi. I recently purchase a garrett T04 turbo for my 1JZ Soarer. Now, it has a 1.1 A/R exhaust housing on it, obviosuly suited more to a 13BT rather then a 1JZ. The ACME T70 had a .84 rear housing, but didnt spool till around 4000rpm, hitting full boost by around the 5000 - 5500rpm mark. Ideally, i'd like boost to come on a little earlier, say around the 2500 - 3500 mark.

Now, im not sure this is entrirely possible with the T04, but i would like it to be alot earlier then 5000rpm. Im sure it was just the shithouse design of the whole T70 turbo blades/compressor housing. Now, being a much better, more researched blade design on the garrett item, im unsure of which rear housing to swap to. I was thinking a .84, but i dont want it to be as laggy as the old turbo.

What rear housing would you's reccomend with this new turbo for a better spool rate on my 1JZ. A Detailed spec list can be found in my members ride thread. What are you guys running in regards to rear housings on your 1JZs. Also, what power would i be expecting? It made 325rwhp on 18psi with the old ebay turbo. What power on around 18psi would i be expecting with the genuine garrett turbo?

Any help/info would be muchly appreciated lads/lasses.

Cheers
Shannon.

[Draven]

some wheel sizes would help (there are a lot of T04 variants). if you want it earlier than 5000rpm, the .84 or .9x would work well (if the T04 has a .9x rear housing)

18psi is 18psi (measured at the plenum) - a genuine turbo probably won't make a whole lot more power (unless the e-bay special was particularly hotter, increasing your inlet temps)

[The Real Roadrunner]

a .82 split pulse rear in a t3 flange should be the go for a daily, from previous experience it shoul start building boost at 3500 and make full boost at around 4200. a rough power output would be arond 280rwkw through a manual at around 18psi with a safe tune in it.
at the end of the day it depends on lots of things but these would be rough figures to go off.
dont try a .63 as you will lose alot of mid and top, the gain in low end wouldn't be worth it

cheers
linden

[chris davey]

^^

I have a non split pulse .63 t3 flanged turbo on mine now. Starts making boost at 2600 from memory and full boost at 4000rpm. I am confident it would make about 270-280rwkw@18psi as it made 235rwkw at 14-15psi. Surprisingly it didn't drop off at the top end at all.

Having said that, matching up the exhaust to the compressor is very important so going too small can stuff things up. I think it was the 440hp GT28 which was notorious for this. (small exhaust wheel, big comp wheel and still mega lag)

I would probably go with the .8 as it seems to work for most cars.

[The Real Roadrunner]

had a .63 on a customers jza70 and we changed to a .82 as it wasn,t pulling the numbers we wanted (320kwatw) and after doing so the engine felt better as it came on (700rpm later) and had an extra 30kw from 4000rpm up. fuel economy was better aswell during the daily grind.
this was just what we experienced and others may vary, but why choke a motor up if its capable of spooling a big turbine and already has so much off-boost torque.

if running a stock converter a small housing may feel better but if you want more performance the stock converters are shite, even on stock turbos.

the gt2876 is a pos unless used in twin applications and i believe the garret site even states such (could be good on a 12000rpm 1litre bike though)

cheers
linden

[Soarer_D00D]

I believe it had a 60mm compressor wheel, and a 75mm turbine wheel. So a .84 or .86 would be the one to go, even though it spooled quite late on my old T70

[Draven]

you've got a good chance the genuine T04 item will spool quicker than the ebay job - better bearings etc

[The Real Roadrunner]

you've got a good chance the genuine T04 item will spool quicker than the ebay job - better bearings etc

i dont think so much better in the way of bush/journal design but tolerances would be better.
thrust race in the the chra is probably better but the main thing that you probly will notice is that the assembly would be balanced properly.
most china turbos arent balanced at high speed causing quite a few probs.
1 lower shaft speeds = less airflow = less power
2 decreased bearing life
3 more lag

could bitch for weeks.
if you grab an .82-.86 i dont think you will have any prob just a that youll have a hard time getting rid of.
cheers
linden

[Dieseltrain]

if running a stock converter a small housing may feel better but if you want more performance the stock converters are shite, even on stock turbos.
cheers
linden

Stock convertor is shite aye even on stockies??? WHy have i managed a 1.68 60 footer ( consistent 1.70's) and 12.18 @ 113mph in a 1710kg race weight Jzz30 soarer? That was pushing just under 18psi and on a stock ecu hitting the speed limiter on the 400m mark.

I am aiming for lower 60 footers once i start pushing it harder off the line.

I think the stock one does fine Some people just dont know how good they can be i guess.

[Soarer_D00D]

I sent the turbo away to Precison Turbochargers today to get the rear housing swapped. Its being swapped out for a .84 rear housing with a V-band flange. Should have it back in the next couple of days.

Can't wait

[Draven]

make sure you put the "Depends" undies on

[Soarer_D00D]

make sure you put the "Depends" undies on

Hahaha, yeah. John from Precision reccmended a .84 rear for best spool vs power. Any smaller woudla choked the engine, any bigger woulda lagged