I have a 88 gxl mazda rx 7 and I want to put TII injectors in my car instead of the stock injectors. I would first like to know if this is possible and if it is what does it take to do this conversion. do I have to get the TII computer? I figure its just gonna take the injectors, fuel rail (do i even need that?), TII fuel pump and some work. how many of you have done this? Are there kits that would upgrade my injectors what are some prices on these? Here are the mods ive done for your info: streetported engine, Intake, RB headers and RB presilencer, lightened flywheel.

Thanks alot guys and gals

 

No need. It would run hella rich, even with the SP. Just get a S-AFC.

 

There's no point unless your engine is heavily ported, you are making more than 250HP, or you run forced induction of some kind. Do what Rico said and spend the money on an S-AFC to get the most out of your existing injectors.

 

WOW!!! Aaron actually agreed with something I said!!j/k bro!!

Yeah, those 550cc injectors are WAY overkill. Mabye if you are using N20, but still, there is no reason for them. A Apex S-AFC is an injector controller that allows you to control injector output throughout the fuel map, in 500 RPM incriments. They usually run $275ish new, but check www.thepartstrader.com they usually go for like $200-$250 used there.

 

If you already know the injector flow rate, you can calculate the maximum safe hp available with the following formula: injector flow rate in cc's per minute multiplied by the number of injectors divided by 7 equals maximum hp at 85% duty cycle. 460 X 4 divided by 7 = 262 hp.

To learn more about EFI goto www.sdsefi.com and read the tech pages. Lots of good info.

 

what if i got a carb would that be better then that fuel controller thing?

 

NO!

 

My s5, ported N/A is about as modded as it can be, and I am still leaning out the stock 460's by an average of 5-10% to get the most power.

Why did you want to do it in the first place anways?
If you are looking for intake gains, you can port your existing intake manifold. Probably a good idea given your engine porting probably opened up the intake runners on the block a bit, so it doesn't mate perfectly with the manifold...
You can also get the pineapple racing aux port sleeves.
Getting an S5 VDI manifold is good for power too- but you will only get a high end gain, and loose some low end unless you get a way to actuate the system (not hard, just takes an rpm activated switch, and air pressure from the air pump)

And contrary to what NZ says, you can get a great power gain by going to a weber sidedraft carb with it's own manifold. He just doesn't want to accept it because it doesn't make sense!!! J/K!
The reason is that the manifold flows better- but the carb itself is much more ineffeceient, finicky, and just a PITA compared to good old EFI. While it'll basically drive fine, It will never feel as refined as the EFI. (or EGI as Mazda calls it). Plus, I don't know what the hell you do with the computer... since you need it for timing....put in a distributor I guess.

 

Hey, I never said that! He asked if a carb would be “better”, I said no.
I know you can make more peak power (mainly because of the removal of the AFM), but like you’ve pointed out, the trade-offs are so many.
The downdraft IDA's are better anyway...

 

Ah yes grasshopper....downdraft...

 

So what if i just put in the TII injectors in the secondarys? Ive heard of people doing that.

 

Dude, you're not listening. You don't need them. There are no advantages to doing it. In fact without spending even more money on a fuel controller to tune them it'll run worse because it'll be too rich. If you want more power, you need more airflow, not fuel.