1jz?? What is the weak point?

[ecko]

the rb..
lol i was expecting u to be having a go at me for bagging nissans lol

[JZA70 R]

i guess aswell being metal head gasket would mean that its less likely to pop a head gasket
meaning more internal damage ...
ie normal gay nissan motors you run to much boost the HG pops u stop...
but JZ's you run to much boost the head gasket doesn't pop you keep going then major internal damage done.... a victim of its own overengineering...
sounds about right guys?

nope. sounds like you just made your own theory up. headgaskets are not designed as some kind of fuse for boost or horsepower.

[ecko]

yeah i pretty much did...
makes a little sense to me like on normal engines too much boost can popp a HG

[Toy77]

Its not the boost that generally pops the head gasket, or the pistons or the rods....

Its the DETONATION that comes from TOO MUCH BOOST on POOR (pump) fuel - which is directly related to the TUNE.

So a good tune on pump fuel and sensible boost to suit the fuel used - like 20psi and all will be good.

You can make more - but the engine is walking a much finer line - a bad batch of fuel and its likely to go bang.

Or if you are actually serious about 550rwhp.... then it will be useless on the street.
May as well get a pump fuel tune around 400rwhp and then a race fuel tune for the big grunt - just drain your tank for when you will run at the track.

Nice and easy.

Cheers
Stew

[Celica RA65]

the problem i've had with my 1jz is the standard turbo's. the ceramic turbines in the standard turbo's are weak. i've blown mine twice now within 6 months. i've had my turbo's rebuilt and the ceramic turbines replaced with steel turbines. the response isn't as good but they're stronger.

[The Real Roadrunner]

Its not the boost that generally pops the head gasket, or the pistons or the rods....

Its the DETONATION that comes from the TUNE being incorrect for the application.

So a good tune on pump fuel and sensible boost to suit the fuel used - like 20psi and all will be good.

Fixed for you.

you can run as much boost as you want with shithouse fuel and the timing retarded to suit without the risk of detonation, but that doesn't mean its going to make good grunt either.

the only thing that will break a 1JZ long motor (that has been treated nicely) is poor tuning or particle ingestion. they are a pretty solid thing if treated well and tuned correctly.

The rod bolts will fail if they are over-revved repeatedly, a problem Kade has run into but at the same time he is running over 24psi through stock turbos and a 100+hp shot of NOS so something is bound to fail.

Cheers
Linden

[renxun]

yeah.. im frm malaysia and using 1jz too ... i found out too that on pumped fuel in my country ron97 the max boost i can run on a t04z is around 24-25psi depending on the intake temp where my datalog will show some very slight knock if i go any higher. definitely can go higher but the timing retards will be too much that IMHO not worth it.

with a better intercooler and methanol mix (toluene was not sold in my town) i can run slightly higher but not too much. so far it had clocked 127k km and if i wanna touch 500whp on pump i guess the only way is to go 1.5j