Forgive me as the search function doesn't work. Anyway my question is should I upgrade the secondaires to either a 1300cc or a 1600cc injector? I am thinking about keeping the primaries at the stock size but just upgrading the secondaries. The reason for asking is that I want to be prepared incase my turbos go and have to buy some BNR's. Also how hard is it to change out the secondaries?

R.K.

 

If you go with 1300cc secondaries, they just drop right in to the existing fuel rail, no modifications required. That should be plenty of fuel for the BNRs...if you ever need more, you could install 850cc stock secondaries in the primary slots with little modification.

To install the 1600cc secondaries, you will have to buy a new fuel rail and fuel pressure regulator and completely redo the secondary fuel system. You will also have to remove the ACV, so you won't be able to pass emissions. Also, some people have a harder time getting the transition when the secondaries come online smooth with the 1600s.

My advice is to go with 1300s.

 

Thanks for the info. Another question; how hard is it to change out the injectors and should I replace the fuel regulator while i'm in there?

R.K.

 

Also are the ones from rx7store.net bored out 850's or are they true 1300's because I heard that the ones that get bored out have a crappy flow pattern.

R.K.

 

There is no such thing as true 1300 cc/min side feed (stock style) injectors. They are all bored out 850s. That is my understanding, and I've been playing with these cars for a long time and have been active on the forums and email lists the whole time. I've seen some reports of larger-than-850 side feed injectors coming new from various sources, but I've never seen proof that any were real. I think the stock 850s are indeed the largest side-feed injectors available without modifying them.

The top feed injectors that you use with an aftermarket fuel rail are available in 160 lbs/hr (=1684 cc/min) sizes directly from the injector manufacturers.

See what kind of power various fuel system options can support here:
http://maxcooper.com/rx7/how-to/fuel_system/calcs.html

-Max
stock 850 secondaries in stock primary rail
bored-out 1300s in secondary rail

 

Thanks for that info Max. Can anyone else answer the other questions I have?

R.K.

 

unless your ECU can manage 1300cc injectors you are wasting your time. sounds like you are running a stock ecu?

 

Your going to need some sort of ecu uprgrade, ie.....PowerFc.
Next, your right the stock primaries are good up to around 450rwhp. The secondaries, I would go with the 1600cc's. You can get the fuel rail, fpr, and injectors from Keith at www.kgparts.com
This way if your twins go up, you can go single or BNR route and your fuel system will already be done.
Good luck,
Ernie

 

Actually I have the Pettit ecu. I can trim the fuel down with the AFC controller when I put in the bigger injectors. Ernie; you don't think that the 1300's will be abel to handle the BNR's?


R.K.

 

Haven't there been some reliablity questions with the bored out 1300's?

Personally, I went with the 1600's.

Also, before the 1600's I ran 850's in all 4 spots. I was putting down 360 to the rear wheels with no fuel issues. You may want to consider that route to start.

 

Supposedly 1300's can have fuel issues, (Stuck Open or closed) if left sitting for a period of time, after they come back from being modified. Something about the way they do it, it needs fuel and pulses put through it or else the grease / lubricant starts to make them stick, once in, and run for a couple of min/hours they're supposed to be fine.... I personally didn't want to take the chance, and ended up Like Jesuscookies, and went with stock 550's and a 1680 secondary rail. But I also have lots of issues getting my AEM system tuned... and the transition is a mess ! But hopefully with more $$ it'll all work out (Cough Haltech, cough cough) Maybe....

 

NO!

Sell the Pettit (and the S-AFC if you've already bought it) and get a PFC. You need a true tunable standalone ecu if you want to run more than just bolt-ons and at higher boost.

Depending on what boost you run with the BNRs, the 1300s should cover you. Like I said above, if you start running really high boost on the BNRs, you may want to upgrade the primaries to 850cc.

 

The only problem is that here in Edmonton, Alberta Canada there is no one able to tune the pfc so you are limited to what you can buy.

R.K.

 

Actually I had the 1300's lock up on me when I used to have stock twins. Like stated prior, they are bored out 850's. Your much better off with the 1600's. And sell the Pettit chip and afc. Not a good route to go with the FD. If your worried about maps with the Power FC, don't be. There are plenty of maps with your exact setup around. Buy it from somebody like Gotham Racing and tell Steve what your mods are. Im sure he'd load a map to get you pretty close.

 

^^^Thanks. Is there a lot of modifing to get the 1600's and the fuel rail in? Does it just hook right up to the fuel pressure regulator?

R.K.

 

crazyrx7,

The S-AFC is good for "fine-tuning" a rechipped ECU, but not good for adding more fuel. The two best ways to add more fuel are:

a. Full programmable ECU (PFC, Haltech, etc)
b. Secondary Injector controller (and add more injectors not upgrade the stocks ones).

While most people don't opt for option B, it's more of any "old school" way of doing things, but it still works.

 

You'll need a new regulator and you will have to redo the fuel lines as well.

 

I have been running 1300cc on my TO4R and no issues what so ever, you dont need 1600's that would be overkill unless you plan on going up to 500 HP.

 

Its very easy. It bolts down right into your lower manifold. You can even use your stock fuel lines if you choose. And as I stated myself and many others have had failures with the 1300's so I'd shy away from them.

 

Ya I don't want to risk and engine just to do it half assed. Its definitely a cheaper alternitve in the long run.

R.K.

 

I have 550's and 1300's with BNR stage 3's. I have plenty of fuel for my modest 15psi.

 

Oh yeah I bought the new 850's that where bored out to 1300's (and flow tested). They were more expensive but I felt safer that way.
No problems here so far, going on 2 years.

 

I will have some time to decide what to do. I think this will be my winter project. Right now I think I will just drive my car and have fun with only 322rwhp at 12psi. Next year I will shoot for high 300rwhp with the new fuel setup no matter which way I will go.

R.K.

 

How do I go aboutg modifying the stock primary for 850s? Wider hole or deeper? or both? I would have searche dbut this site is dying lately.

 

http://www.newwave.net/~flanham/wlan...el/850pri.html