Face

I have a '90TII with some mods. I have been told that I should be running bigger injectors. Can I swap in bigger injectors directly into this car with the stock computer?

My mods are: hks exhaust, 2 1/2 down pipe, upgraded stock turbo. I have a hks fcon but it is not yet installed.

NZConvertible

How much boost are you running?

The first thing you should replace is the fuel pump, not the injectors. The pump cannot supply the necessary pressure past ~10psi on the stock turbo (maybe less on an upgraded turbo), so bigger injectors won't help.

There is only one way to determine if you need bigger injectors. Have it dyno'd and see what the mixtures actually are. If you're running lean with an upgraded pump then you should look at a fuel computer (or aftermarket EMS) to add more fuel at high load. If you reach 80-85% injector duty cycle and still need more fuel, then you need bigger injectors. Not before.

Face

I have a toyota supra pump in there. I am planning on running 1bar at the track and about 8-10 lbs around town. I am installing a ft. mount intercooler as well soon.

Can the stock computer compensate for the larger injectors? I do not want to go to a stand alone system. Since I am not going to go to a bigger turbo, the hybrid is fine for me.

Face

I have a toyota supra pump in there. I am planning on running 1bar at the track and about 8-10 lbs around town. I am installing a ft. mount intercooler as well soon.

Can the stock computer compensate for the larger injectors? I do not want to go to a stand alone system. Since I am not going to go to a bigger turbo, the hybrid is fine for me.

NZConvertible

Nope. You need a fuel controller (e.g. S-AFC) or a new EMS.

Face

Won't my Fcon system work?

All I need to know is if the stock computer can handle bigger injectors (1990 TII)

NZConvertible

Yes it will work. You need something that can tune the amount of fuel being injected. The S-AFC was just an example (that's what e.g. means ).
Once again, no!

RETed

You'll need a GCC for the F-CON to work with the larger fuel injectors. Last time I checked, it was priced at around $400.


-Ted

Donn Hecht

Well my personal opinion is you can run GSL-SE injectors on the secondaries, and leave the stock 550's in the primaries. Face just in case you dont know what GSL-SE injectors are they are from the first generation RX7. Sorry to insult your intelligence, im just letting you know this because there are some people on this forum that didnt know that. By the way theres something that NZConvertible forgot to mention, "Im really surprised by this, as NZ is one of the very few, and I do mean very few guys here on this forum that know what there actually talking about". If you need some expert advice by all means ask NZ as he defenitly knows his ****. Well getting back to the subject you should defenitly take the time out to rewire your fuel pump to make sure your pump is getting the proper voltage it needs, especially under boost. If your F.Pump is not up to par than you can just simply say bye,bye to your motor. Face I would like to know what mods you already have on your T-II ?
Like I said you cant go wrong with the GSL-SE injectors as many people have used this setup with great success including myself. By the way Face if i were you I would sell that HKS FCON, and go Microtech. Microtech is the way to go.

NZConvertible

Good point about the rewire. Rewiring the stock fuel pump is a good idea as soon as you start increasing boost through intake and exhaust mods, and should definitely be done if you're upgrading the pump.

RETed

Uh, no.
The stock ECU can't handle the larger secondaries and will usually hesitate slightly on the crossover at around 4,000RPM. I call that something going wrong...


-Ted