swaroop81

I am looking to upgrade the fuel injectors on my '93 FD.

Currently, it has the stock 550cc primaries and 850cc secondaries. My local shop is suggesting I keep the primaries at 550cc but upgrade the secondaries to 2200cc BOSCH injectors with an aftermarket rail. Apparently, their fuel rail does not require changing the fuel pump regulator. I also plan to set this up with a Supra TT fuel pump.

Currently, my car produces 264hp at the wheel, and has the following basic mods:
Downpipe, Mishimoto radiator, Power FC, Apexi Noir Exhaust.

I plan to, in addition to the fuel injectors, also install a M2 intake (bought from a member here), an aftermarket SMIC (nothing very large), and a Supra TT fuel pump. So expecting this will yield some additional hp.

She is primarily a street car, and I do little else, so drivability is important.

My questions are as follows:
1) Is there any advantage to putting in larger stock primary injectors? Any concerns from a drivability perspective if these are larger?
2) Is upgrading the secondaries at this point somewhat advisable given the additional hp over 264hp that I might be pushing?
3) Any thoughts or comments on the advised setup of 550cc primaries and 2200 secondaries?

As always, appreciate your advice and expertise in the matter!

armans

iTrader: (2)

Stock injectors and the pump should be good for 300-350whp.
Interesting why your local shop is suggesting bigger injectors.. Is your car running lean?

swaroop81

Not at the moment. I think this is in anticipation of potentially over working the injectors after the new mods are done. Thanks.

lOOkatme

iTrader: (19)

Bosch EV14's are a great way to increase fuel capacity and I think it is a good idea to always have "too much fuel" and avoid "not having enough".

that would be a great upgrade and will not effect any driveability or anything.

I am guessing you are running a PowerFC ECU.

The powerFC controls fuel well when the primaries are 550CC, you can step up to 650CC but you will need to buy a fuel rail for the top mount, this can be done easily on the powerFC. If you run larger than 650CC you will probably need to run negative injector lag to get them to idle lean enough.

I recommend doing just the larger secondaries injectors if you plan on sticking with the stock twins. its always best to have a good bit of overhead room with fuel. you can also upgrade to more power later if you wish.

swaroop81

Thanks so much for your response! That is spot on with what I was told by the shop as well. And they are suggesting the EV14s as well.

I do have a Power FC, fuel management should be fine. Thanks again!

Scott Stone

I've been told you can run almost 500rwhp on the stock injectors. Not sure how accurate that is since I've had some other issues with that shop, but.. Mazda overengineered the FD a bit, and in a good way.

Sgtblue

iTrader: (16)

It's not accurate...not even close.

0P.... Nothing in your initial post suggests a need for larger injectors as long as you stay at stock boost levels. If that's the case I can't think of any advantage for the expense of all those changes.

swaroop81

So I ended up going ahead with the 2200cc secondaries. You are right, I didn't need them right away, but this gives me more room down the line for additions mods if needed. Also, my current secondaries were leaking fuel a little bit. So figure that isn't getting any better with time either. Will get my 850cc secondaries services and kept as a sister in case I have to press it into service down the line.

After all I am in it with my FD for the long haul
Thanks again for all your expertise.