im tryng 2 get some injectors but dont know what to use for the primary and secondary

 

550cc primary, 850cc secondaries are stock. You can mill a primary rail to accept 850cc or you can get 1680cc secondaries. Those are the two main routes unless you want to go your own way.

 

Why are these the two main injector sizes people are using? 850cc for the primary seems to be a little big for street cars, maybe maybe not? Would like the thought on this and way.

Thanks

 

850's are fine as long as you have some sort of ems to tune with. I think upgrading the primaries is really only for really high HP (450+) as I've seen many people with 1680's and stock primaries doing quite well.

The 1680's are used because they fit and they are usually bosch (i think almost always), so they are good quality and reliable. And they can support high hp numbers.

Check this link out

 

850 primaries aren't a good idea, alot of times it makes it difficult to get a good idle. I run 550's even with lrg turbo's and porting. Just do some searching and find some setups similar to what you'll be running. That will give you a good place to start.

Brent

 

Its quite easy to make 850's idle. If i can do it, any tuner worth their salt won't have a problem. I've also seen 1000cc's idle effortlessly.

 

O.P what are your mods or future plans for the car?

If u plan on keeping your twin setup 1300cc secondarys should be enough fuel.
if u plan on going single 1600cc secondarys should do the trick.
the 550 primarys will be fine either way.

 

what computer? future mods? money? mech skill? all play a part in what u choose.
I have 1600 sec and reused the stock sec in the primary rail(mod to rail required)or for 90 bucks you can order one and 2 walbro 255 pumps or the kits offered at rx7 store are a good setup for the price.
no such thing as to much fuel in a rotary. 400hp is a safe number for stock primarys and 500hp for a single stock style pump
do your own homework

 

I don't think a single pump setup is good for 500hp unless you are displacing a lot of fuel with methanol injection.

I have just gone through a ton of research myself to get my car ready for 500whp, and pretty much hands down everyone recommended a twin pump setup (walbro or denso), or a single and then use the Ken Belle Boost-a-Pump. Either would work fine, but everyone has their own preferences.

I actually found a great deal on the Aeromotive Tsunami pump, looks kind of like a walbro, but flows twice as much, so I'm going with a single one of those.

When I was on the 1300 secondaries (modified OEM) and stock primaries, i had low 80% (you don't want more than 85%, you may be perfectly fine, but reliability could become an issue) duty cycle readings right around 375-380whp. I'm taking out my walbro this weekend, if you want it pm me.