edomund

I did a search and read all of the results for like 3 hrs. But I still have a question.

My question is when do I need to upgrade my secondary injectors?

I have a 87 TII. For now I'm just going to get an intake, exhaust, walbro pump etc. Just the basics, no upgraded turbo or anything, yet.

With the bacis mods are the stock injectors ok?

I used rc engineerings fuel injector/ hp ratio thing and it said 550 cc injectors are good up to 300 hp. I don't think I'll be at 300 hp with my upgrades.

Thanks, Ed

Ryde _Or_Die

Well I did alot of posting and searching to find out myself. I am going to make sure that I have enough fuel. I have intake and a 3" DP/MP now. Before I get my full exhaust or do my custom TID I am getting some 720cc injectors and an s-afc. I really couldn't afford an engine right now, and have to be safe. Will full exhaust and intake its usually said that the walbro can get you by(especially if rewired), but every car is not the same. And one bad boost spike could kill the engine.

Zaxfire

I am thinking about putting TII Secondaries in my 86 N/A along with a TII Fuel Pump...What kind of gains would I be looking at if I did this...???

edomund

Thanks ryde or die, where are you getting the injectors from?
I hear the gen 1 injectors work and some are 720.

Ryde _Or_Die

Well I initially bought some used gsl-se injectors(680cc) and sent them to RC Engineering to be cleaned and balanced...BUT one of them had an external leak they said and it needed to be rebuilt. So the other one would have to be done as well which was going to cost $360+. So I decided just to buy the GReddy 720cc ones from rx7store.net.

Ryde _Or_Die

Ok what will you gain?...Well you will gain the amount of times you will have to get gas in any given time. Oh and you'll lose HP Seriously though, the NA fuel system is fine for all BPU mods DEFINITELY, and even streetports, etc. When you start going to bridgeports, large shots of N2O you might want to look into upgrading some fuel components. But even then you might just need a TII fuel pump OR TII injectors and a way to control it. Bottom line, the best fuel mod you can do to a moderately modded NA would be to get an s-afc and some dyno time and lean some fuel out.

edomund

I found a pair of 680, 85 gsl-se injectors. Will these work for my secondaries? Are all gen 1 injectors low impendence?

Ed

Ryde _Or_Die

Yes.

edomund

I decided I will just go ahead and go with bigger injectors in my secondaries. Your right it's better safe than sorry.
I have another question though.

Do you think those 680cc injectors with a walbro pump and afc are sufficient. What type of mods would this fuel setup be safe for?

Ed

edomund

Second question is, can I run 4 denso 720cc injectors if I tune them with the afc? Would this be a good setup? I found a set of four that I might buy.

Ed

Zach McAfee

I think its funny that one might think more fuel would help, but, in the NA world, we're usually running too rich with the stock injectors, and actually need less fuel for more HP.

Anyone selling 400cc injectors?

By the way, I just bought a set of rebuilts from some place in CA over the phone. I guess it doesn't help much since I can't remember who it was. If you want to know drop me a line and I'll give you the # off the packing slip when they get here. $45 per injector, not bad.

Ryde _Or_Die

I believe with that setup you will have enough fuel for as much as the stock turbo can ever put out efficiently. You will prolly have to lean it out some with the s-afc, but its better safe than sorry. Plus you'll have the ability to tune the vehicle for maximum performance and gas mileage.

edomund

Thanks for the info, but what about the 4 720cc setup?

Ed

Ryde _Or_Die

Either way you'll have enough fuel. You'll prolly have to lean some of it out.

edomund

Can I run 89-91 550cc high impendence injectors as my primaries? How do I correct the impendence?

Ed

Ryde _Or_Die

You could but you'd have to wire in resistors. Why would you want to use S5 TII injectors? They are 550cc injectors, just like your S4.

HAILERS

No, he would have to wire around the solenoid resistor, not add resistors.

Ryde _Or_Die

My mistake.

edomund

I asked about the s5 injectors because I have a TII that caught fire and I need to buy all new injectors. I found some TII injectors thats why I asked about them.
Anyway it's possible then, right?

edomund

Are all 84-85 gsl-se injectors 680's or are some 720's. I found some that state they are 720's, just wondering if this was true.
Also if anyone has any 720's or 550's I'm looking.

Thanks, Ed