turboengnr

iTrader: (2)

I recently dynod my car to try and get the daily driver settings all dialed in. I have been running 4 psi for quite a long time now. So i get on the dyno, and make a pass..... and it was running very lean (in the low 14's to high 13's). So i try to tune it a bit. With the injectors maxed out, and the fuel system, i couldnt get it to run richer than mid-high 13's.

I dynod my car on this same boost level about 6 months ago, and it was running in the deep 11's. After checking fuel filters, pumps, and exhaust leaks, i came to the conclusion that my injectors are not flowing as much as they used to. Since these are an internal disc style injector, i believe that the disc may have become bent or warped from the 125+ psi of fuel pressure that the injectors saw when i was running high boost.

I picked up a set of 440 cc injectors about 10 mins ago, and i have a return line setup waiting to be installed at my apartment. Now all i need is time. Until i get these installed, i am limited to 4 psi. Theres no detonation at this a/f ratio and this boost level, but i am still weary of driving my car.......

riceburnrex

iTrader: (2)

That's exactly why rising rate fuel pressure regulators and fuel pumps that do nothing more than raise the fuel pressure for boost (SF) are bad things.

Are you putting together your own return kit, or buying SLP's?

turboengnr

iTrader: (2)

i am actually using the Dyno Works return kit. I have the ability to make my own fuel rail, so the slp one was a little too spendy for my tastes. The Dyno Works one came with 25' of steel braid line, fittings, Aeromotive fuel pressure regulator, and an adaptor you insert into the filler neck of the gas tank. its a pretty nice setup....

4drcivic2k1

iTrader: (2)

A rising rate fuel pressure regulator used as intended will only raise pressure 1:1. This is to compensate for the pressure differential over the injector. They are necessary in all proper turbo setups. The FMU that SF uses raises fuel pressure on the order of 10:1 or something similar. This is extremely hard on the fuel pump. A fuel pump for turbo should be picked based on pressure handling and fuel delivery. If you are running a base fuel pressure of 43, and 10psi of boost, your pump should be capable of supporting 53psi.

opto_isolator

iTrader: (8)

Can't say that I told you so Mike! Sorry to hear about your luck...

BudDyLeEBoOsteD

you dont need a return line as long as you dont swap out the stock Fuel Pump.. I have RC's 310's in mine with a custom Port n Polished fuel rail so the injectors will fit and it works just fine with tunnin from the SAFC II....
you only need a return line when you're swaping out the intake fuel pump and puttin in another one that does not have built in FPR

opto_isolator

iTrader: (8)

Sure thing, new member...

riceburnrex

iTrader: (2)

Do you have a link to this kit? Sounds interesting.

turboengnr

iTrader: (2)

opto, i had never experienced it before with any of my cars nor my friends. Most of my friends with the older civics used FMU's and were fine for years. I guess it caught up to me.

O well... Doing it right now.

heres the link
http://shop.dyno-works.com/catalog/p...products_id=36

it is for an SRT-4, but you just add one more -4 an to 1/8" npt fitting, and it will work with the civics.

turboengnr

iTrader: (2)

i think we all know there is more than one way to do things. He is speaking of the proper way of doing things.

The flaw of using the stock fuel system (even with bigger injectors) is the fact that for every pound of boost you add, you are losing a pound of fuel pressure. Every psi of boost restricts the fuel coming out of the injectors by that much.

Simply saying, if your base pressure is 40 psi, at 5 psi of boost, you only have the equivalent of 35 psi of fuel pressure. Get what im saying? So if you run 15 psi of boost (like i used to) you only have 25 psi of fuel pressure. You would need some rather large injectors to run that.

When you add a return line with a 1:1 ratio rising rate regulator, you increase the fuel pressure to compensate for the amount of boost you are running. That makes sure that you maintain the constant 40 psi (or whatever your base setting is) over the pressure in your engine. This allows you to run a properly sized injector for your application.

Also, the stock pump will not flow a high enough volume of fuel to do what i want to do. So thats kinda outta the question.

Havok2k1

iTrader: (3)

I deleted the disrepectful posts by buddylee

Bud, I would STRONGLY urge you to show respect on this board to existing members, ESPECIALLY for the select few that have vast knowledge and have given back to 7thgen over the years like Opto has.... and if you "dont believe in postin or respectin of any sort..", feel free to take yourself back to Tamparacing....


Edit: sorry for the hijack Mike....

Pedro Lopes

iTrader: (2)

So let me understand you guys. I believe stock fuel pressure is around 43psi. So for every 1psi of boost you have to increse fuel pressure by 1psi aswell. I only plan on running at 8psi so I would have to increase the fuel pressure to around 51psi. Sorry about this guys this whole fuel issue is just a little confusing to me. Thanks.

tfnaaf

iTrader: (2)

Yes you are correct

TheSmuggler

iTrader: (11)

What do you think this is!?!?! A forum!?!?!?

AceAltima

125 psi of fuel! Holy ****..you're lucky you didn't spring a leak someone on your system!! Talk about putting your injectors to the test! lol

FMU = Yuck

Do it the right way this time, for your safety!

turboengnr

iTrader: (2)

Thanks Havok

Pedro, You have to remember that all things are relative. The fuel pressure is relative to atmospheric pressure (which is what is SUPPOSED to go into the motor). So when you look at your fuel pressure, you have to take into consideration what is going into the motor. If you are looking to boost your motor, then you have to calculate what the fuel pressure is going to be.

Fuel going into the motor = fuel pressure in the rail - pressure in the motor

So when you have 55 psi of pressure in the rail, and you add 13 psi of boost, you actually only have 42 psi worth of fuel pressure going into the motor.

Think of boost as a fuel restrictor. For every psi of boost you need an extra psi of fuel pressure.

2K1Civic17"Gabe

iTrader: (9)

So I am gonna have issues with TSIs kit? Im still getting it, but they have new injectors, and TSI FMU. So this is gonna suck for me? I will upgrade my fuel system pretty quick than, this made things so much clearer for me. Good info, thanks a lot people!

turboengnr

iTrader: (2)

doesnt the tsi kit use extra injectors?

Though adding injectors isnt as efficient as using larger injectors with an engine management, it wont compromise the integrity of the stock injectors. It adds fuel via secondary injectors, and keeps the same fuel pressure level.

It should be safe.

Pedro Lopes

iTrader: (2)

This is so confusing. So let me get this clear, that's why you want a return line so you could pretty much bring back the fuel pressure to around stock pressure. Stock pressure is around 42-43. So in my case I would adjust the regular to around 50-51, since you have to adjust 1psi of fuel pressure for every 1psi of boost. So whats happening is boost is taking away fuel pressure so were back to around stock fuel pressure. I hope this is right.

turboengnr

iTrader: (2)

i just wrote a FAQ

http://www.7thgencivic.com/forums/sh...d.php?t=196632