Rotary Rx7 T2

What is the best way to increase fuel in 88 T2? I don't want to spend too much but i'm worried by increasing the boost that it may come to detonation without increasing fuel? I know all of you rotary heads have done this already so if you could just reply what you think. Thanks

RXTASY1

Put 720cc injectors in your secondaries and buy a Apex S-AFC.

TristanTII

How do people feel about doing just adding an upgraded fuel pump. With more pressure behind the injectors they'll spray more when they're open. Would that be enough to feel safe with mild mods (10 psi or less)? And with an S-AFC you could get the most of out the stock injectors with the higher pressure behind them. Then once you mod up a bit more switch over to larger secondaries, and you allready know that the rests of your system is able to handle the load, and you didn't have to plunk down a whole ton of loot at once.


This is my plan, if I erred any where let me know.

Cwaters

get a trailer hitch and attach a couple Jerry-cans to the back of your ca......OH, uhhhhh nevermind.

Cory
mis-led by the vegue question......

HAILERS

I'm ignorant. If you just add a fuel pump how would that add more fuel since you have a fuel pressure regulator in the rail that regulates pressure to approx 40psi. Something is wrong with this picture that I don't understand.

Grimlock

rp fuel pump, safc, fcd. i put a a/f gauge when i put the fuel pump. a/f gauge always reads rich. i have stock injectors. safc comes in handy on idle because i can lean it out. my 88 TII runs rich at idle i mean very rich. when ever i boost 12-13psi she alwasy runs rich. i dont richen things up until 4500 rpm and up and only by 5%. i have been running this set up for a few months and no problem execpt slightly black spark plugs but thats better than lean ones.

my advice is fuel pump and safc.

Grimlock

that i have bonez intake and rb full racing turbo back exhaust.....

TristanTII

I assumed that the stock regulator would give out 40 psi with given whatever the stock pump was putting out. If you increase the input pressure form the pump it would end up delivering more fuel. Unless we have a very consistent fuel regulator that was meant to correct for things like spikes in the input pressure. Again, this is just my thoughts, I have no idea how good the stock regulator is.

HAILERS

Tristan.....the factory pump puts out 71-92psi and the regulator regulates to 40psi. I sort of caught on to why the Walbro is put in. It has more volume output so its unlikely for the 40psi to decay at wide open throttle compared to the factory pump. The part I have not been able to finger out is why a car would run richer at idle or part throttle just because you have a pump with more volume capability. I'm very much a newbie at this. The puzzle parts are not falling in place yet.

1FastT2

iTrader: (1)

When I added my full exhaust I had to add a new walbro fuel pump to keep up the extra fuel needed. It worked great just by adding a new pump and I suggest that is the first fuel mod you do. I then added a S-AFC to tune a little. I am running about 300hp at the motor on stock fuel injectors.

TristanTII

Again, I haven't done this, this is just my plan, and my reasons.

Regulators aren't perfect, they can't take any pressure and turn it into 40. The ones in our cars are made to take the output pressure of the pump (70 to 90) and bring it down to about 40. If you drop in a pump that has an output of 180 (I don't know any of the numbers off the top of my head) the regulator won't be able to bring it down to 40, it justs wasn't made to handle that job. A decent regulator would probably bring it down to like 42-44 or so (I'm used to dealing with compressed gas regulators, so this is a very rough guess, given my imaginery pump numbers) which is like 5% rich at idle, and 10% and WOT, enough to cover basic mods.

If you check out this page about half way down it gives some approximations of how much HP you can run with different types of fuel setups (I think they're all a bit high) IT doesn't give an estimate for upgraded pump only, but if you compare FCON/stockinjectors/stock pump to FCON/stockinjectors/upgraded pump there's an increase of about 20 safe HP. I think that's the extra margin of safety the pump gives you by always supplying a lil more fuel, and not having to worry about it not being able to keep up.

http://www.teamfc3s.org/performance/ecuhints.htm

TristanTII

I just saw 1FastT2's post I guess the estimate from TeamFC3S's page for FCON/stockinjectors/upgraded pump was right on the money.

Makes me happy

Fc3sracer

Hey rotary rx7 t2 i thought you were selling youre car?

Rotary Rx7 T2

i changed my mind i don't want to sell it, First i'll upgrade it a little bit and then maybe i'll sell it. So the best thing would be to get Walbro Fuel pump and s-afc. Now where can i find that walbro fuel pump and s-afc? and how hard is that to hook up?

Brian P

About the FPR, I imagine that it can only regulate so much preasure before it lets its start to climb. Just think of a wategate, same thing. Add exhaust (bigger FP) and the wastegate isn't big enough to relive all boost. So boost goes up. Same with the FPR, increase preasure/flow it can't keep up so preasures are higher.

That makes sense to me. Please feel free to correct me.

HAILERS

Ok. I see now. The higher flowing pump overwhelms the regulator. The regulator can't dump fuel fast enough back into the tank to maintain the 40psi. I have a small problem,( from flat not knowing), with the injectors operating at a higher pressure than they were designed for. Not to worry though, because they've been doing it for years now, I reckon, and if there was a real problem doing so it would have come out by now. Thank you.

RETed

Walbro 255lph fuel pump, nuff said for a little over $100.
This get you rich across the board.




-Ted

Rotary Rx7 T2

ok so since i have now Bonez intake, fcd and Aftermarket Cat back, i also took out the main converter and put that race pipe in and i'm running 8-9 pounds off boost. Now i have to get that fuel pump is that the only thing that will be good in order for me to increase boost up to 12psi or 14? I was thinking later of getting front mount intercooler. Please correct me if i'm doing something wrong.

And once again where can i get that Fuel pump?
Is that one on Rx7.com any good? it says it suports up to 500 rwhp and it won't be rich in idle. It's the only one they have there.

TristanTII

From what I've heard the stock intercooler has a safe limit of like 15 psi, I guess they might actually pop open or something. I'd imagine the usefull limit would be less then that, so if you're planning on running 14, a FMIC would be a good (hell, it's always a good idea)

Also once you start running that kind of boost, most people will say that you need some kind of fuel management. Apex-i S-AFC is cheap and should be able to handle it.

Scott 89t2

10 psi should be the limit for the stock IC. 15psi is the limit for the stock turbo. the stock injectors are good till about 12psi if you have a fuel pump and fuel controller (afc, f-con, etc) after 12 or so you need bigger injectors.

I highly doubt you are getting 300hp with stock injectors. (unless you have AIC..) you can barly get that with a stock turbo.

and to prove a fuel pump runs richer I lost about 30 miles a tank after the FD pump went in...