Yet another injector discussion...

[Obscure411]

OK, I've been following all the threads for months regarding various fuel system modifications and ideas to get more power without leaving the injectors static and losing control of fuel delivery.

So far, I've heard of two solutions : STi injectors ($800 from Jan Shim -- am I correct?), or RX-7 injectors (2nd set from used RX-7 TT). Are there any additional alternatives that have made their way out since then? I'm not against paying good money for quality parts, but $800 for 4 injectors seems rather steep. There must be a way to upgrade this for cheaper... have I missed any alternatives?

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[bsquare]

Shiv has 550cc injectors, but I don't know if they fit the WRX. PM or email him. You can also try taking your car to a local fuel injection shop and having them machine some injectors to fit. Believe it or not, it will probably be cheaper than just buying STI injectors, and you can get however much flow you want (how about some nice 850cc Bosch injectors?).


ben

[DeliciouSpeed]

Or if you know someone who is going to Japan, you can pay JDM retail which is just under $400 for all four STI injectors . Thanks Sactown! Hope you have fun, can't wait till you get back. Tell Arika I said hi.

Ken

[ellisnc]

just wait, there'll be about 8 choices inside 2 years

[bsquare]

I visited a good local fuel injection shop this morning to discuss options for getting 650cc+ injectors in my car. The best solution, imo, is just to have the injector cavities machined out to accept Bosch-size injectors and then using, you guessed it, Bosch injectors. You get rid of those annoying pintle injectors and get to use lots of quality, cheap Bosch injectors that far outflow the STI parts and cost about 2/3rds.


Ben

[Obscure411]

Durn, now if I can just find a place like that in Jersey...

Anyone know how the Bosch injector spray would compare to an STi injector spray?

I know alfried (or someone) had originally brought a set of STi injectors and a RX-7 one to a shop who had told him the spray patterns varied quite a lot.

[RiftsWRX]

Spray pattern is really only going to matter on the low end and with part throttle smoothness.

Frankly on the top end the air is moving so fast that the fuel stream is going to be pushed and pulled and squashed so bad that it won't matter.

Jorge (RiftsWRX)
www.ProjectWRX.com

[bsquare]

Ball or disc style injectors like Bosch give a much better spray pattern than pintle style injectors like the ones I believe are used by Subaru. www.dsm-performance.com has some comparison pictures of pintle and disc/ball injectors on their site.

The fuel injection shop said they would send the manifold out for machining (no doubt to one of the endless local supply of ancient Boeing machinists), so that part could be accomplished by any competent machining shop, assuming you have the injector dimensions. The fuel rail modifications (you should just tear the stock ones out, really) can be done by a decent fuel injection shop.


Ben

[bsquare]

I agree 100% with Jorge that the spray pattern only matters at lower duty cycles, but that is exactly where it matters most if you want your car to idle well with big injectors.


Ben