Tomoya

Okay So in another thread, I talked about needing a better fuel system.



I am making a new topic so I dont jack peoples threads.



I am currently Running 10 pounds of boost on a stock S5 motor and Turbo, stock S5 ECU and stock fuel pump/secondary injectors. The shell is an 88 10th AE.



Mods are:

Swapped S5 motor/turbo/Ecu.

All emmisions Removed (we dont have that regulation where I live)

Racing Beat Downpipe

Mazdaspeed dual cannons

cone air filter (aftermarket cheapie) I think it was called "INTIMIDATOR"......

ported wastegate



I was under the impression I was still running pretty rich considering the smell of gas everytime i go near that car. But it makes more sence that its only rich during Idle...



I do not know much about fuel systems, but I know I need bigger and better ones to be able to support my boost......and that i need to tune it so i dont waste gas when i dont need it the most.



These are my questions:



1. FD pump V.S.Walbro Pump. Differences/pros/cons.



2. How much power/boost can a 720cc injector + Walbro fuel pump handle?



3. If I had a low budget, and could only afford either the 720 injectors or the fuel pump which would be priority?



4. Will I need a standalone EMS if I upgrade my fuel pump to 720 secondaries, and a walbro fuel pump?



5. Which brand of injectors are good? quality wise and price wise. Like bosch/greddy/etc... $$$



Any input will be appreciated!!

1988RedT2

Well, let me share my setup since I don't feel qualified to answer in detail each of your questions.



Stock S4 T2 engine

Denso fuel pump from RX7.com

New stock fuel filter (of course)

Cleaned 550cc primaries, new RC Engineering 750cc secondaries

Stock turbo rebuild and upgrade compressor, ported wastegate

Manual boost controller set around 10 psi

K & N cone filter

Throttle body mod, for simplicity, nothing more expected

Haltech E6X

Water/alcohol injection





I'm sure I'm forgetting something. If you plan on tuning it yourself, get a wideband. I like the Innovate LM-1. Widely available for $350. With this setup, I'm still reading a max. AFR around 9.9 under full boost, though I suspect that's about all the injectors can handle. Naturally, I need to get this a bit leaner. I really haven't had the time to mess with it lately.





One more thing: if you smell gas "everytime I get near the car", check your pulsation damper and the rest of your fuel system for leaks, unless you want the car to go out in a blaze of glory. The pd is very prone to leakage. I replaced mine with a banjo bolt, but my car is rarely street driven.

1988RedT2

I will answer this question: Start with the fuel pump, a new fuel filter, and clean the stock injectors. If you upgrade the secondaries, you need an ECU that can use them. The stock ECU really only works correctly with the stock injectors. Get the wideband and monitor your AFR's as you do performance mods. If you find that you are getttng leaner than around 12:1 under full boost, it's time for more fuel.

j9fd3s

i second that i guess. i ran 2 different setups on my t2, both worked great.



1: stock s4 engine, hybrid s5 turbo, fd fuel pump, stock injectors, and fcon. it happily ran 11psi, little rich in the middle, prolly a tad lean up top.



2: real mild ported s4 engine, stock s5 turbo, 550primaries 680 secondaries, fd fuel pump, FCON+GCC. it was running .4-.5bar of boost. i basically could have gotten rid of the fcon with this setup, didnt bother turning the boost up, cause the car was FUN

Tomoya

hey thanks for the supports.



The denso fuel pump seems a lot better than the walbro pump. It's quoted to be able to handle up to 500HP.



Currently I have no money to invest in a standalone ecu... so I need to do it without. So would JUST getting a better fuel pump affect any readings on the stock ECU?



I just need to know what would most likely happen in three senarios.

and which one will be closer to being safe runnin 10 psi... the car came like that so I didnt have a chioce to run it on 10psi or not....



1. getting just the fuel pump upgrade, on stock ECU and Secondaries.



2. getting the fuel pump and the 720cc secondaires with stock ecu.



3. getting the injectors cleaned (prim and second) and a fuel pump with stock ecu.



Thanks guys!

j9fd3s

at 10psi, assuming everything else on the car is good, any of those 3 would help.



2 is the best option, and it will give you some room to grow



3 is prolly a good idea, 1 is quicker....

Tomoya

Thanks again for the help.



So even with the stock S5 ECU it wont be a problem using 720cc's and a FD/Walbro fuel pump? Nothing serious is gonna screw up?



what would be the drawback of not using a standalone EMS.



Thanks!

1Revvin7

You're going to need an RTEK atleast to use larger injectors. Unless you're going to use a some sort of fuel controller like an SAFC.

Tomoya

will a piggy back be okay for temporary solution?



I have a blitz Multi Fuel Computer system. And yes this **** is beyond ghetto.. old skool whatever you can say about being old. haha

Not much info I can find abou this thing, but it also came with the car when i bought it, and if anyone knew how to use this thing/ tune this thing I would love you forever!





Thanks.



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Tomoya

okay maybe I scared aways everyone by saying "I will love you forever"..... so i take it back. and replace it with a You are my hero!



heh... thanks thats all.