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Forums Junkie

Location:
Brisbane, Queensland
Registered:
January 2004

Re: GT4 modification and performance ...

Thu, 19 May 2005 21:46

Ok first mistake that i made was calling a T66 turbo a CT66.... My bad. T66 being a 700hp turbo that would flow shitloads more at 12psi then your humble CT26.

And in your previous statement about 'the gen1 is as good as the gen2' i will point out where your contradicting yourself.

Quote:

Headgasket must be changed for anything above about 10 psi

The gen2 has a different designed head (introduced better ribbing) and headgasket which reduced this problem. Gen2's are known to hold out until around 22psi of 'boost' pressure until they let go. But are common to let go on older blocks around the 14psi area. The heads differ in the valve area. The Gen2 having more lift. Any upgrades to the Gen1 valve area requires new springs and head modifications to make it work.

Quote:

The ST165 pistons are pretty lame, I think there is weakness in the factory cast and they tend to crack when the boost goes up, anything above about 12 psi and you should look at new forged pistons.

Quote:

If you read my posts then you'd notice that I mentioned the Gen 1 pistons suck (that's what you would have with an ST165, which is what you asked about in your first post?) - so yeah best to have a look at them when upping the boost.

The gen2 with an uprated Metal Headgasket has been known to survive upto 200awkw before letting go and thats reliably as well. This is around 21psi on a highflow. Depending on trim of course. Show me a ST165 that has done that.
The pistons and the bottom end are quite sturdy, your saying quite the opposite about the Gen1.

Quote:

One thing that I would DEFINITELY look at with the ST165 in particualr (when upping the boost) is the factory intercooling system, and even a remote oil-cooler kit would be a good idea. The water temps frequently went up on my car on warm days when i had it under load

The gen2 has a different oil cooling system, and you will also find that the blocks are different. The ATA intercooler system was used until TTE complained to Toyota about the bonnet lifting the front of the car at highspeeds, hence why we got the CS a) as a special model b) to reduce this problem by using a more efficient WTA intercooler.

The oil pump on the Gen1 was inferior, as it was updated in the Gen2 with a higher flowing pump.

NOW... after saying all that, lets bring everything back down to earth. We arn't top high dollar rally teams. So lets face the reality.

Quote:

Currently I'm looking at new pistons and a copper head gasket for my car and because I can't afford a better fueling system nor intercooling sticking it at about 11 or 12psi.

Gen 1 block is dated. Its old, and you could spend the money rebuilding it. Better pistons, better oil system (using gen2 pump) rebuild the head with better cams and valves etc... To do what the gen2 does STOCK...

OR
you can kill 2birds with the one stone.

Replace the engine/drievtrain package as Ive suggested already. Half the price, and you get the slightly better gearbox to boot. The already good flowing head. The better oil cooling system. The Better ECU, i'd argue the better ATA system (unless it was a groupA halfcut). The better turbo. All round, a better engine.

I know which one i would do.

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