I had a revelation!

[kazzam]

I was sitting around and thinking how to control my fuel pressure with as little money as possible. I was thinking about things like the 43psi stock presure on a 2g, the over-run issues with the 255lp fuel pump. Then it hit me! Since the fuel presure on a 1g is only like 37 or 39 psi or somewhere in that range, couldn't i swap in a 1g fuel presure regulator to make it run at a lower presure then the 2g regulator? And then use the command flow adjustable regulator to increase it from there?

I also had another revelation. I have read that by increasing the voltage to the fuel pump(rewiring) the pump would deliver less fuel. Then why not rewire the pump, put a voltage controler between the power and the pump and turn it down to 10v or 11v so it wouldn't pump over 43psi.

Any of you guys done this? or thought of doing this? Please give me some feedback on my revelation. thanks!

 

[sweet97]

Rewiring the pump INCREASES the pressure. The idea of the Walbro 255 is to have adequate pressure and volume. Why not just get the fullthrottlespeed AFPR if it's still available and adjust the fuel pressure accuratly? Fuel control is critical to keepi ng a proper A/F and I would not want to cut corners on such an important part of the system, just my opinion. Mark

 

[peregrine]

Rewiring the pump INCREASES the pressure. The idea of the Walbro 255 is to have adequate pressure and volume. Why not just get the fullthrottlespeed AFPR if it's still available and adjust the fuel pressure accuratly? Fuel control is critical to keepi ng a proper A/F and I would not want to cut corners on such an important part of the system, just my opinion. Mark

thats actually wrong. the fuel pump rewire keeps the volume stable at higher rpms/boost. only the regulator regulates pressure. thus the name

 

[oldman]

thats actually wrong. the fuel pump rewire keeps the volume stable at higher rpms/boost. only the regulator regulates pressure. thus the name

Actually it supplies the pump with steady voltage (13-14V) under high boost which then keeps the volume stable.

 

[Quasimondo]

The fuel pressure regulator being overrun is a problem only for the low end of the rpm range where the injectors are not open as much and the fuel rail is sending nearly all of the fuel back into the tank. At high rpm's where the duty cycle is around 85-90% all of the fuel is getting sucked up by the regulators and very little is being returned to the tank, which is why the regulator increases pressure with boost. That pressure can only be maintained if the fuel pump is flowing at a high enough rate.

What you intend to do seems to be defeating the purpose of replacing the fuel pump in the first place. By reducing the voltage to the pump, you're limiting how much fuel is being pumped, and ultimately, you're limiting how much fuel your injectors will get when you're at the upper end of the rev range, which is where your injectors need fuel the most.

 

[peregrine]

Actually it supplies the pump with steady voltage (13-14V) under high boost which then keeps the volume stable.

!

 

[DSMJim]

No this will not work.

Fuel pump overrun will happen with either regulator. It's not over running the fpr by a certian amount at a certian RPM. It's happening at varying amounts at varying loads across the entire RPM band. You can not fit it with a stock FPR or any other method even closely related to that.

It's simply a matter that you need a FPR with a larger return to handle the volume of fuel flowing back to the tank that a 255lph pump delivers.

A fuel pump delivers the same amount of fuel from the tank at idle as it does at WOT (except for presusre on a turbo car) so your just returning a lot more, this is where the problem is at low throttle situations.

Making a car run good at WOT is easy, but thats not where you drive all the time.

 

[nanokpsi]

If your car is within the maximums for fuel trims, I don't see the point in doing anyting to stop FP over run

 

[Stapl3]

If your car is within the maximums for fuel trims, I don't see the point in doing anyting to stop FP over run

You've never experienced it then.

 

[DGajre777]

The cheapest way would be to get a 190 fuel pump. If you ever get a turbo that needs more fuel than the 190 can supply, you can get a B&M Command flow to increase the fuel pressure (since it only increases fuel pressure and does not decrease it). This will be a lot cheaper than getting the 255 and then an AFPR (that decreases and increases fuel pressure) to prevent over-run. Anyone disagree?

 

[peregrine]

The cheapest way would be to get a 190 fuel pump. If you ever get a turbo that needs more fuel than the 190 can supply, you can get a B&M Command flow to increase the fuel pressure (since it only increases fuel pressure and does not decrease it). This will be a lot cheaper than getting the 255 and then an AFPR (that decreases and increases fuel pressure) to prevent over-run. Anyone disagree?

because the key word here is volume. a 190 just cannot supply enough fuel for anything over a 20g at max boost in my opinion.

 

[sweet97]

An AFPR adds a tuning aid also. I realize for pressure there needs to be resistance like as in the regulator but I am quite sure my Walbro is a 255HP as in high prerssure. RRE has some info on somne different pumps on their tech site. Mark

 

[boostedinaz]

So with out all the E arguing, why not just put it how it is.

You can save a few bucks to make your half assed fuel system that wont work and that 50 bucks you saved can be a nice starting point for you engine rebuild fund. You car, your money, your call.

If you do things the right way you only have to do them once. So get a 255 and an GOOD AFRP and call it a day.

 

[sweet97]

^Agree^

 

[peregrine]

^Agree^

here, here^^^^^^

 

[98evoIIIpwr]

So with out all the E arguing, why not just put it how it is.

You can save a few bucks to make your half assed fuel system that wont work and that 50 bucks you saved can be a nice starting point for you engine rebuild fund. You car, your money, your call.

If you do things the right way you only have to do them once. So get a 255 and an GOOD AFRP and call it a day.

Couldnt of said it better myself. amen

 

[biglady112]

I also hate to burst your bubble here. But a 1G regulator will not bolt to a 2G rail. Tha flanges are way different. If you had a 1G rail by all means go ahead. But your idea won't work.

Don't be cheap. Save one more pay check and get a real regulator and fuel pump. The full throttle regulator is junk. My best friends duaghter's car has had two fail. We put an aeromotive on there and have had no issues since. I run the SX and love it. Of course you need a 1G rail for it as well.

Steven

 

[kazzam]

well, there goes my moment of brightness. thanks for all the feedback guys!
One question, i got a rewired 255lp fuel pump on stock system otherwise and i don't really have any driving problems. My car did stall before when it failed to catch idle during gear changes or stops, but i just adjusted my driving to compensate for that. I use heel and toe technique. Other then that, i have never had any other problems. Is this the so called over-rum symptom i have dealt with? Also, i noticed that after doing the rewire, i lost some mid rpm power but gained more high rpm power at the same boost(16 psi on the 50 trim). Any other problems now or in the future i should look into that has to do with the over-run issue? THanks

 

[never2muchBoost]

im gonna get bashed for saying this but u dont need a afpr unless your anal about stuff like that. u can tune fine with a 255 pump and no afpr. i threw a fuel pressure gauge with sending unit on my car without a afpr and with a 255HP pump and i had no overrun issues and tuning is fine.

 

[boostedinaz]

well, there goes my moment of brightness. thanks for all the feedback guys!
One question, i got a rewired 255lp fuel pump on stock system otherwise and i don't really have any driving problems. My car did stall before when it failed to catch idle during gear changes or stops, but i just adjusted my driving to compensate for that. I use heel and toe technique. Other then that, i have never had any other problems. Is this the so called over-rum symptom i have dealt with? Also, i noticed that after doing the rewire, i lost some mid rpm power but gained more high rpm power at the same boost(16 psi on the 50 trim). Any other problems now or in the future i should look into that has to do with the over-run issue? THanks

Yes these are all the problems that come along with a big pump and the stock FPR.

im gonna get bashed for saying this but u dont need a afpr unless your anal about stuff like that. u can tune fine with a 255 pump and no afpr. i threw a fuel pressure gauge with sending unit on my car without a afpr and with a 255HP pump and i had no overrun issues and tuning is fine.

Like I said before there is always one guy that likes to do things half ass. When people get aids do they feel it right away? No, but guess what they still have a problem. It isn't a matter or a pressure problem it is to much flow and the FACT that the stock FPR cant deal with it.

I would be interested to know hot you "tune" the 255.

 

[oldman]

One question, i got a rewired 255lp fuel pump on stock system otherwise and i don't really have any driving problems. My car did stall before when it failed to catch idle during gear changes or stops, but i just adjusted my driving to compensate for that. I use heel and toe technique. Other then that, i have never had any other problems. Is this the so called over-rum symptom i have dealt with? Also, i noticed that after doing the rewire, i lost some mid rpm power but gained more high rpm power at the same boost(16 psi on the 50 trim). Any other problems now or in the future i should look into that has to do with the over-run issue? THanks

Yes, what you're experiencing are typical overrun symptoms, pig rich conditions during idle and part throttle until the system is able to use up the additional fuel cause by the overrun. I don't think it matters though because you don't seem to be interested in finding out the facts as you're ignoring advice given by some of the best on this site. You're simply looking for approval for not running an afpr and you're not going to get it, well not from serious DSMers anyway so just go ahead and do you have already decided to do before you posted this thread.

u dont need a afpr unless your anal about stuff like that.

Yes most of us are extremely anal about stuff like that, especially when the solution is as easy as bolting on an afpr.

im gonna get bashed for saying this

When you decide to bandage a problem instead of fixing it such as in the case of afpr, then post on a technical forum in a techical thread and present your half assed solution as the right thing to do, you should expect people to dissagree with you. I'm not going to bash you but I would like to know a few things.

i threw a fuel pressure gauge with sending unit on my car without a afpr and with a 255HP pump and i had no overrun issues

What was the fuel pressure? I'm assuming 43psi since you're claiming no overrun.

but u can tune fine with a 255 pump and no afpr.

Since overrun is load based, not rpm based, I would like to know what kind of adjustments you did to whatever you're tuning with (fill out your car profile) in detail.

You made a statement, now back it up with facts.

Edit: Too late, Micheal beat me to it.

 

[kazzam]

Yes, what you're experiencing are typical overrun symptoms, pig rich conditions during idle and part throttle until the system is able to use up the additional fuel cause by the overrun. I don't think it matters though because you don't seem to be interested in finding out the facts as you're ignoring advice given by some of the best on this site. You're simply looking for approval for not running an afpr and you're not going to get it, well not from serious DSMers anyway so just go ahead and do you have already decided to do before you posted this thread.

Reason i started this thread was because i had some ideas i though i would share with the dsm public and get some feedback.
I am not looking for approved to not running an afpr. I already know that i need to get one and will do so when i have the money. I realize that EVERY fast and streetable dsm has an afrp.
Another reason why i started this thread, is because i am looking for information about various fuel problems and solutions. When i start moding my fuel system and helping my friends mod theirs, i will have the most reliableinfo possible.

 

[oldman]

Reason i started this thread was because i had some ideas i though i would share with the dsm public and get some feedback.
I am not looking for approved to not running an afpr. I already know that i need to get one and will do so when i have the money. I realize that EVERY fast and streetable dsm has an afrp.
Another reason why i started this thread, is because i am looking for information about various fuel problems and solutions. When i start moding my fuel system and helping my friends mod theirs, i will have the most reliableinfo possible.

If those were your intensions, I'll take back what I said in the last post and offer my apologies for misunderstanding your last post. I thought you were set on not using afpr despite what everyone else said. Get that afpr on there as soon as you can, you won't regret it.

 

[peregrine]

Reason i started this thread was because i had some ideas i though i would share with the dsm public and get some feedback.
I am not looking for approved to not running an afpr. I already know that i need to get one and will do so when i have the money. I realize that EVERY fast and streetable dsm has an afrp.
Another reason why i started this thread, is because i am looking for information about various fuel problems and solutions. When i start moding my fuel system and helping my friends mod theirs, i will have the most reliableinfo possible.

thats bullshit. you wanted a cheap solution for a problem. at least be honest. all dsmers are cheap. but there are some things you cant skimp on.

I was sitting around and thinking how to control my fuel pressure with as little money as possible. I was thinking about things like the 43psi stock presure on a 2g, the over-run issues with the 255lp fuel pump. Then it hit me! Since the fuel presure on a 1g is only like 37 or 39 psi or somewhere in that range, couldn't i swap in a 1g fuel presure regulator to make it run at a lower presure then the 2g regulator? And then use the command flow adjustable regulator to increase it from there?

I also had another revelation. I have read that by increasing the voltage to the fuel pump(rewiring) the pump would deliver less fuel. Then why not rewire the pump, put a voltage controler between the power and the pump and turn it down to 10v or 11v so it wouldn't pump over 43psi.

Any of you guys done this? or thought of doing this? Please give me some feedback on my revelation. thanks!

 

[kazzam]

If it isn't everybody's goal to make the most use of their money and get the most power with the least investment then perhaps a civic is in order. peregrine