ustolemyname??stevieturbo

iTrader: (1)

I think that the exernal wastegate allows more controlled flow, and better control of the boost pressure. The built in wastegate design, I think came about for cost, and compact design reasons for packaging, as outright performance isnt alway required. For production cars etc, the built in design is much more cost effective, and works very well. Most high performance/high power output turbo engines seem to use the external wastegate design. eg most of the Rigoli cars seem to use them, as do a lot ( if not all ) WRC cars. Id guess that the whole turbo installation is more efficient when using this method?

Andy.F

Once you start making big power, the integral wastegate can become a restriction to exhaust flow and boost control becomes ineffective.
Up to an extent, porting of the integral wastegate channel and fitting a bigger disc will help.
Agree big power generally requires a separate unit....mind you, the RS500's made good power on integral Garret T4's

Pavlo

the old TPS sensor with 4 wires integrates a switch for zero throttle. It would be possible to either add a mechanical switch, or create some solid state switch, and use the 3 wire sensor on the new manifold.

You might be able to get a 4 wire version of same switch, as I don't believe it's a subaru item, proabably denso or something.

Is there anything else that prevents the use of the later manifold?

Paul

David_Wallis

Injectors? (not really a problem..)

Edited to add that as far as I am aware there are three manifolds

92 - 96 97 - 98 99+

Not quite sure about the years... roughly correctt... first two are ok but later one has idle control valve built into the throttle body... their are also three throttle bodys... second (98 - 99 ) being shorter...

Im sure someone in the know will confirm.

David

[Edited by David_Wallis - 7/26/2002 1:56:07 PM]

ustolemyname??stevieturbo

iTrader: (1)

Yea, thought about adding a closed switch, but it would be messy. The big hassle is that the TPS sits on the opposite side on later manifolds, and would rotate the wrong way, otherwise I would k=just make one of them fit ( assuming it sends the same signals to the ecu ) The MY00 type manifold does have a 4 terminal switch, altho I think that only 3 wires are actually used, but again it rotates the wrong direction

Pavlo

So would I be right in saying the 94-96 and 97-98 engines, termed 'phase 1' have the same port/stud layout on the head. The 97-98 engines have the coil on the the manifold too, but if I am putting the later manifold on (I am thinking front entry turbo here)with injectors and rails, can I use the existing throttle body, or do I need a newer one to match?

Pipes and so on are not a problem, get a newer header tank and PS resevoir (or locate current one remotely). Raise intercooler a bit too, or maybe a later throttle body fixes that.

David_Wallis

Studs are the same on all, and throttlebodys can be mixed and matched, might have to be creative with gaskets... All very simple compared to front entry on the turbo... The 97-98 manifold has more clearance under it as far as I know as the inlet tubes (or whatever you want to call them) have a higher whatever = more room under... (92 - 96) can be done with about 30mm of spacers..

Im just wondering what effect this would have on the injector spray pattern as the manifold and port look matched?

David

Pavlo

worked fine on andy's

David_Wallis

I know... just wondering

David

ustolemyname??stevieturbo

iTrader: (1)

Throttle bodies are not interchangeable. The throttle linkage/TPS are reversed on early/late manilfolds. The early TB wont fit the later manifold, as it fouls the ISCV. Never looked at putting the new on onto an old manifold, but see no reason why anyone would need to. And as ive said before, the TPS has 3 wires on the new, and 4 on the old, and also rotates the opposite direction, ( but dont think that should matter )

David_Wallis

I Know what you mean... but I didnt say it right well.. what I meant is it would fit (bolts would allign) other than that...

David