fuel pressure regulator

[240sxproblems]

I am trying to get a little more power out of my ka right now I am running a safc with 370cc injectors. I made 280hp and I was wanting to try and make it to 300. I was told that I might be able to do it with a fuel pressure regulator, but I am not sure if I should use a rising rate fuel pressure regulator or just a normal 1:1 adjustable. If anyone has any ideas I would greatly appericate it.

[KATwo40]

If you use the 1:1 adjustable, you can tune out the rich condition you'll find off-boost.

The purpose of the 1:1 regulator is to maintain the same delta P across the injectors, regardless of manifold pressure. Using an FMU will not provide this.

Personally, I wouldn't want to run my injectors at 100% duty cycle. It's more risk to injector failure, and you don't want to blow that motor. The best solution would be to purchase a larger set of injectors.

[mkory]

I never thought 370cc injectors would make it past 350hp?

[crzycav86]

I have an adjustable fpr(1:1), but if I had to do it again, I'd just get a rrfpr. That way you aren't putting extra pressure on the injectors until you need the extra fuel(in boost). It is not as easy to tune as and adjustable fpr, but it's safer.

The amount of boost and how much power you want will determine the ratio you will want for the rrfpr. Use the pressure-flow formula to solve for the new flow, and match that to your desired power goal and duty cycle.
Modified by crzycav86 at 9:43 AM 5/18/2006

[KATwo40]

The amount of boost and how much power you want will determine the ratio of the fpr. Use the pressure-flow formula to solve for the new flow, and match that to your desired power goal and duty cycle.

I don't get it...

A 1:1 adjustable FPR only adjusts the base fuel pressure, not the ratio at which the pressure rises.

[j-z]

actually yes it does and you even said so by saying 1:1. for every pound of air pressure, you get one one pound of fuel pressure. so if youre boosting 8 psi, youre fuel pressure will be bumped up by 8 psi at 8 psi of boost. and yes, it does adjust base pressure as well.

[j-z]

and also you souldnt push those injectors any more past where youre at right now. acutally i wouldve dropped them about 20 hp ago. get some 550s and youll be set.

[crzycav86]

I don't get it...

A 1:1 adjustable FPR only adjusts the base fuel pressure, not the ratio at which the pressure rises.

I'm talking about how he should select a rrfpr. I edited my post to clarify.

[KATwo40]

actually yes it does and you even said so by saying 1:1. for every pound of air pressure, you get one one pound of fuel pressure. so if youre boosting 8 psi, youre fuel pressure will be bumped up by 8 psi at 8 psi of boost. and yes, it does adjust base pressure as well.

You still misunderstood...

I said the RATIO at which the pressure rises remains unchanged.

[crzycav86]

240sxproblems:If you want to flow 490cc/min, which is enough for 300whp, you will want to increase the fuel pressure by 25 + boost. if you are making your desired power at 10 psi, then you should use a fpr with a ratio of (25+10)/10, or 3.5:1.

If you are making that power at 15 psi, us (25+15)/15, or a 2.7:1 rrpfr(you will want to use 3:1).

..then you will want to tune it.

[j-z]

OK i gotcha now. and 240sxproblems (LOL@yourname) youre just gonna have problems trying to do what youre asking. cough it up for some bigger injectors. deutchworks 555s are $300 and nico members get %10 discount so thats $270 for brand new 555s. sell your 370s on here for 75, and itll only cost you 200 versus a fried motor cause you tried to do something half assed.

[240sxproblems]

I have 550cc but I don't have anyway to tune them. I am thinking about an e manage ultimate. The safc has a hard time tuning them.

[180sx]

u guys forgeting 1 thing while calculations walbro has higher fp than oem BY about 10psi ... so walbro+ afpr is a different story than 370's AND OEM PUMP.do u have walbro?

Why e-manage get biki or doughter board will be easy to run 550's and also tweak ur Map's