I am having a conversion done on a 1995 Impreza L. A USDM 2.5 STI block is currently being installed at at the tuner. One person has told me (vaguely) that my sensors off my 1.8 manifold can be disconnected and reconnected on a 98 RS 2.5 intake manifold. Also supposedly my cam sensors (I think I am using the right terms) can supposedly be mated to 98 2.5 DOHC cams.

Can any of you chime in on this subject. Before I lay out the $$$ for the parts to have them sent to the shop I want to make sure this is scenario is possible.

Thanks,

Jay K

Okay a lot more information is needed. The main thing that matters when it comes to sensors and manifolds is the heads that are being used, not the block. Also why a 2.5 STI block? Are you going with an aftermarket turbo kit? If your doing a long block from an STI then you really should be doing a straight up swap and rewiring either with the STI harness and ecu or with a stand alone ecu.
Joshua

Yes a turbokit is being installed on the USDM sti block. The engine management is a greddy e-manage unit utilizing an optional MAP sensor to cope with the high boost the application will see. A wideband 02 is also being installed to keep an eye on the vitals.

Since many people nowadays are just swapping longblocks or making hybrid EJ20 head / sti shortblock motors, I suppose this question would have best been asked years ago before the advent of US wrxes when people were swapping RS motors into Ls.

Does anyone have any comments on the compatibility of the sensors with RS heads and L sensors. I heard after 98 the answer was no. But 98 may work. Before I go drop money buying 98 RS parts and pay the tuner shop for an attempted install I would like to stand on some firmer ground as far as research on this particular matter.

Anyone ...?

The answer is yes. If you go with any of the DOHC 2.5 NA engines you will be fine. They were first made in MY96 in automatic outbacks and were still available in the legacy and outback untill MY99. The impreza and forester only used this engin in MY98. I don't fully see the purpose of this swap though. The money you will have to put out to purchase the Sti block, the emanage, the turbo kit, and the 2.5 engine since you don't have it would all be better spent on a WRX swap. It will make more reliable power probably cost less in the end and be easily upgradable. I talk from experiance. I have had an MY98 2.5 RS and then and MY97 impreza L 2.2 both with turbo kits. The L recieved and MY97 2.5 and was also turboed. I just did a swap to an MY05 LGT drivetrain.
Joshua

So wait, are you doing a MY98 EJ25 but using a STI shortblock???

All I need is a bigger intake manifold and heads with more flow. So yebokmj are you essentially saying that the intake manifold from a DOHC EJ25 and the heads will be compatible with the sensors off of my current EJ18 engine?

Yes, thats what I'm saying. I'm also saying the money spent on this project could be better spent. An Sti block at minimum is what 1,500 dollars? Then you need to get a 2.5 DOHC engine that's going to be the very least 300. Then you need the emanage, I don't know what those go for but lets go with 300, then the widebad o2 another 300. Then a turbo kit worthy of the sti block is at least 2500. Lets say you went used with the kit 1,500. Either way your looking at the same amount of money as a swap with untold relaiblitly and other unforseen problems. Having already gone the turbo kit route back before swaps were a more affordable option (5 years ago) I have and would now go with a swap from a WRX or other.
Joshua