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RWDboy
Forums Junkie

Location:
South Australia
Registered:
July 2002

Re: GT4 modification and performance ...

Fri, 20 May 2005 03:17

Okay first thing, when I say bottom end sometimes I'm not including pistons in that equation - this is my fault because I do realise that I should include the pistons in any comment regarding the bottom end - I will concede (obviously) that the gen 2 pistons are better than the gen 1 pistons, but aside from that the bottom end is just as strong in either - including oil starvation issues with #1 big end bearing.

Quote:

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.

What you mean is that the older *head* not the older 'block'. All this talk about 'block' is getting to me, what you mean by 'block' is usually the 'whole engine'. When I say block I mean the lump of iron that has four holes in it for pistons and a few other things. Not the head + turbo + manifolds + everything else....the blocks are for all intents and purposes (aside from oil pump and maybe the water pump) identical.

As for the better oil cooling system on the Gen 2 'block' - I presume you mean it has some kind of remote oil cooling - or that the engine's water cooling system is more efficient (ie the radiator)? The Gen 1 has no oil cooling system at all - all of it's oil cooling is done via the water cooling system of the engine. If you could elaborate on this I'd be appreciative! I'm only here to learn - if I'm wrong (which isn't unusual - hehehe

)

Quote:

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.

Depends what upgrades you are talking about Razz

Yes, it is a bit of extra work to get as much HP out of a Gen 1 head as you would get out of a Gen 2 head, but I'm talking about economical modifications - which I will get to in a minute.

Quote:

The gen2 has a different oil cooling system, and you will also find that the blocks are different.

How so? I don't have the money to go out and look at the differences between the two but from my experience with looking at 3S-GE's (non turbo) from gen 1 and gen 2 is that the 'blocks' are both identical (bar the fact that 3S-GTEs have oil squirters etc). I *have* noticed however that at approximately late 1993 Toyota made some changes to the block - I'm not sure whether this popped up in the CS edition or the SW20 MR2 but I'm 90% confident that in at least the first two years of production the cast for the ST185 block is the same. I'm open to correction on this because, as I said, I'm not big with money and don't have the resources to check all of these out.

Quote:

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

Changing over the oil pump is not a huge deal, and I'd love to get my hands on one from a Gen 2 if they actually are a higher flow unit - as this was an area i was looking to improve upon with my car.

Anyway, in regards to getting a Gen 2 and fitting that, and it being "half the cost" - I utterly reject that. Fitting some new pistons and upgrading the head gasket and head studs are all the modifications you need to do to the internals of a Gen 1 to get it ready for some 'serious' boost. That's never going to cost as much as getting a Gen 2 and fitting a metal head gasket and installing it (and if you must, the manifolds and ECU, which may not even fit in the ST165's engine bay). Even if you sell the Gen 1 motor afterwards.

Let alone the fact that if you buy the air-to-air intercooling system you have to bugger around with your bonnet to get any decent intercooling.

Sure if you are looking to the very far flung future with your engine and you want to get even more horsepower out of it later, you *might* want to think about biting the bullet and sticking the gen 2 or gen 3 engines in, but in reality the difference at this low end of the performance scale doesn't justify the cost (ie 200-300hp at the flywheel). Any car running 200kw @ the wheels is going to have some SERIOUS modifications (ie ECU, fueling, intercooling etc) and really isn't a useful comparison.

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