edomund

I'm in the middle of overhauling my engine (87 T2) as well as a few other mods and I want to ask for your guys opinions about what kind of fuel setup I need.

1. I'm street porting the motor while it's apart.
2. I'm having bnr upgrade my s4 turbo to a stage 3 (to4 wheel and housing plus generous wastegate porting)
3. I'm getting the corksport catback as well as a cone filter intake

I have already bought the s-afc and am going to get a fcd and walbro pump.

My main question is what size injectors should I go with, with the mods I'm doing?

Let me know if I forgot anything I need.

Thanks, Ed

madaz07

at least 720cc secs and get a full turbo back system otherwise you will be chocking it

chris-reedtn

check out fc3s-pro.com Ted has an awesome fuel rail setup with a dual inlet fuel press reg, Do this mod!

-Chris

dvls-7

ditto.....since u have everything apart just go for the full monty with 1600 and the fuel rail to support it.....that way u wont have to go through it again when u want to upgrade again. Also get a FPR, and why not consider the greddy emanage it does a lot more than the s afc for about the same $$$.....jus my .02.......good luck man.

edomund

I already bought the s-afc. I don't really want to hassle with the 1600 secondaries. I probably wont upgrade much more than the mods I'm doing now (I'll be broke after this)

So does anyone think that 720cc sec. (along with the other fuel mods) will be insufficient?

ed

edomund

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edomund

The turbo upgrade that I'm getting has a 60-1 compressor wheel. Thats about the biggest hybrid I can get.

Should I go with 720's all around?

ed

edomund

what do think about bosch injectors?
are the greddy ones better

BlackFC

You will probably need 720's all around. OPEC on this board was leaning out with just 720 secondaries before the stage point on his stock turbo (this was tested with a wideband not just what SHOULD be ok). He was able to get his car tuned in pretty well on the S-AFC and 4 720's.

Daniel
1993 Kawasaki ZX7 - Slow
1989 Mazda RX7 Turbo - Slower
2000 Honda Civic DX 2Door - Slowest

Ryde _Or_Die

Ya just go with 720s all around. For the stage 4 thats what Bryan told me I'd need so you will need probably need 4 as well. Contact him, he can tell you what all you need.

edomund

so what about the bosch injectors are they as good as the greddy 720s?

Ryde _Or_Die

Well the GReddy's aren't even GReddy's. GReddy doesn't make them or anything. I forget what company GReddy puts there name on though. Bosch is a pretty good brand, are they a whole lot cheaper? Because I thought $110 a piece is pretty cheap anyways.

RETed

Yes, those GReddy 720 fuel injectors are just rebadged ND (Nippondenso) fuel injectors.&nbsp I believe the Japan-only 12A turbo engine ran a pair of 720's stock.


-Ted

TristanTII

I just went over to RX7.com, and used their fuel calculator, and it gives about 240 flywheel HP for 4x720 injectors, which seems very low to me. Of course for 4x550 they give 183 hp, which is barely stock levels.

So, is that calculator junk, or just paranoid?

Ryde _Or_Die

Probably making certain they don't get any lawsuits I guess. With 4 720cc injectors and a walbro pump I think you should be good for like 350rwhp with proper tuning.

RETed

Does it adjust for fuel pressure?

My rule of thumb is 250bhp flywheel for stock 4x550 @ 85%, 325bhp flywheel for 4x720 @ 85% - both running at stock ~35psi of fuel rail pressure.



-Ted

edomund

I can get the bosch for 95 each or nippon denso for 110 each. What should I go for?

ed

edomund

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edomund

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edomund

anybody have any suggestions on which injectors I should buy

ed

Ryde _Or_Die

I don't know anything about the bosch ones is why I haven't replied. There ARE 2 types of top-feed ones though. I know that the GReddy ones will work, but I don't know anything about the bosch.

edomund

Those of you who tune with the s-afc, do you use a air fuel ratio gauge to aid your tuning or just by feeling?
I'm thinking about getting a gauge, but I'm wondering how acurate they are?
Does anyone have one, do you like it?

ed

Ryde _Or_Die

I used my EGT gauge to do some broad tuning. Most a/f gauges are nothing more than a light show. BUT, I've heard the GReddy one is not too far off of a wideband.

No7Yet

The GReddy one is okay, as is the DIY WB O2, with their linear response curves. The only way to be really sure, however, is to use a real, heated wideband. You should be tuning on a dyno anyway, and the dyno place will have one that you can rent.

DO NOT TUNE YOUR CAR WITHOUT A REAL A/F AND EGT (if tuning timing) SENSOR.

The light-show stock-O2 sensor "A/F gauges" are crap for tuning, but can be nice for everyday, around-town monitoring.

Brandon