Do I Need Afpr

deathb4dismount · Jul 14, 2014

Hopefully my engine will be complete on Friday. I am making one final order to round everything out.

So as the title says, do I need a fuel pressure regulator? Also, will the 24#rs be enough?

Setup is TFS 170s, Stage 1 cam, 1.6 RR, ported cobra lower, 70mm TB, 73mm MAF, shorties, off road h, flowmaster 40s

84Ttop · Jul 14, 2014

Adjustable regulator can't hurt. 19lb injectors are enough for your setup, tried and true

deathb4dismount · Jul 14, 2014

84Ttop said:
Adjustable regulator can't hurt. 19lb injectors are enough for your setup, tried and true

Already have 24s in the intake so they are staying for now. Any particular brand, I have heard kirban is good?

TOOLOW91 · Jul 14, 2014

i have a kirban on my car no complaints

toyman · Jul 15, 2014

You need a FPR. However, you don't need an adjustable one. Just stay with the stock piece.

Onefine88 · Jul 15, 2014

Yes a Kirban adjustable FPR is a good piece. "And important in my opinion."

2000xp8 · Jul 15, 2014

You should have an afpr and if that meter is a c&l, get a new pro m 75 or bigger.

Dave2000GT · Jul 15, 2014

Keep the stock piece, spend $250 on a moates instead learn to tune. Then you can get the most out of it, and in the process you'll figure out if you do need a AFPR, 90% chance that you dont and stock pressure with the 24s is fine. If anything maybe a new pump to keep up at high rpm.

madspeed · Jul 15, 2014

I'll say that IF you need to buy a fpr, might as well get the Kirban adjustable unit. If you have a stock one, feel free to just keep it. No reason to change fuel pressure from the factory setting of 39 psi

deathb4dismount · Jul 15, 2014

madspeed said:
I'll say that IF you need to buy a fpr, might as well get the Kirban adjustable unit. If you have a stock one, feel free to just keep it. No reason to change fuel pressure from the factory setting of 39 psi

Hmm ordered one yesterday with a gauge....my stocker was working just fine. Maybe I will just return it.

Onefine88 · Jul 16, 2014

Here's my .02 cents. I believe in adjustable regulators. I've used them as long as I've been playing with these toys. "Its just me"
Anyway, The stock pressure of 39psi is based on stock components and 19lb injectors. If you throw 24's in the mix, there's a chance you will have a slight rich condition. "Maybe not", but with a cheap Kirban regulator the air/fuel ratio can easily be dialed back in. Also if you are doing a new top end kit as you mentioned in your 1st post, who knows where your a/f ratio is gonna be.

After you do all these upgrades, are you planning to take your car to a local dyno for tuning and also see how much power your new combo makes? Heck that's the FUN part!
If so, how is your tuner gonna dial in the a/f ratio and maximize the power? If you do have a afpr he can easily do it simply by adjusting the afpr and the timing with the distributor.

That's my '02 cents.

84Ttop · Jul 16, 2014

Onefine88 said:
Here's my .02 cents. I believe in adjustable regulators. I've used them as long as I've been playing with these toys. "Its just me"
Anyway, The stock pressure of 39psi is based on stock components and 19lb injectors. If you throw 24's in the mix, there's a chance you will have a slight rich condition. "Maybe not", but with a cheap Kirban regulator the air/fuel ratio can easily be dialed back in. Also if you are doing a new top end kit as you mentioned in your 1st post, who knows where your a/f ratio is gonna be.

After you do all these upgrades, are you planning to take your car to a local dyno for tuning and also see how much power your new combo makes? Heck that's the FUN part!
If so, how is your tuner gonna dial in the a/f ratio and maximize the power? If you do have a afpr he can easily do it simply by adjusting the afpr and the timing with the distributor.

That's my '02 cents.

You make tuning sound so simple. That couldn't be farther from the case. Setting base timing and base fuel pressure is a very small piece of the puzzle. The timing and fuel tables that the car run on are worlds different than what you make them out to be.

madspeed · Jul 16, 2014

those tables should not need much adjusting based on his combo so simply setting the base timing and fuel pressure should get him a well running car. Sure, you can squeeze extra power out of it by tuning, but unless he's going to be getting a tuner or chip of sorts, there's no way they can be adjusted.

To @deathb4dismount , are you planning on getting it tuned by a pro?

84Ttop · Jul 16, 2014

madspeed said:
those tables should not need much adjusting based on his combo so simply setting the base timing and fuel pressure should get him a well running car. Sure, you can squeeze extra power out of it by tuning, but unless he's going to be getting a tuner or chip of sorts, there's no way they can be adjusted.

To @deathb4dismount , are you planning on getting it tuned by a pro?

I agree completely.

Onefine88 said:
how is your tuner gonna dial in the a/f ratio and maximize the power? If you do have a afpr he can easily do it simply by adjusting the afpr and the timing with the distributor.

I was referring more to this part of his statement than anything else

Onefine88 · Jul 16, 2014

Hey , I'm not here to argue with you guys. OP posted a question. I gave my .02 cents, as I feel an adjustable regulator is important. My Tuner asks that I provide one on my combo so its there if he needs it or not.

That was my .02 cents. If OP decides to use one or not that's his decision.

deathb4dismount · Jul 16, 2014

madspeed said:
To @deathb4dismount , are you planning on getting it tuned by a pro?

Absolutely. I never understand the "do I need a tune" threads after something like a new top end or forced induction. Why spend all that money to then have your car run like crap.

If it will help with tuning I will stick with it. I understand there is more to it than just fuel and timing, but I also know that it's beyond my expertise, which is why it's going to the dyno. They do mustangs pretty much exclusively where she will get dialed in. I am hoping it hits around 270ish , we will see.

toyman · Jul 16, 2014

If your tuner is adjusting fuel pressure to achieve the desired AFR you need a new tuner. The amount of fuel is properly adjusted by adding or subtracting the injector pulse width. Injectors are engineered to provide a spray pattern at a specific pressure. Too high a pressure and the spray is irregular and may not burn completely. Read up on flame kernel propagation.

90lxwhite · Jul 16, 2014

toyman said:
If your tuner is adjusting fuel pressure to achieve the desired AFR you need a new tuner. The amount of fuel is properly adjusted by adding or subtracting the injector pulse width. Injectors are engineered to provide a spray pattern at a specific pressure. Too high a pressure and the spray is irregular and may not burn completely. Read up on flame kernel propagation.

So the moral of the story is if one brings his or her car without an adjustable regulator they can still dial it in with the computer? Someone correct me if I'm wrong but isn't using adjustable regulators kinda the old school way of getting it "dialed in" and now it's primarily done using computers?

TOOLOW91 · Jul 16, 2014

90lxwhite said:
So the moral of the story is if one brings his or her car without an adjustable regulator they can still dial it in with the computer? Someone correct me if I'm wrong but isn't using adjustable regulators kinda the old school way of getting it "dialed in" and now it's primarily done using computers?

Yes . we didn't touch my regulator not even to put a gauge on . I set it at 42 , tuner asked if that's where it was I said yes and that was the last of it

Onefine88 · Jul 17, 2014

These AFPR's are "old school". Nowadays most people are using some type of software for tuning. My 88vert is tuned on an SCT chip. I used 60lb injectors this time around and using injectors that large require the use of software.
When I got done bolting the new HCI, blower, and supporting parts together I took it to the dyno for tuning. The first thing my tuner did was set a base FP he was happy with using my adjustable regulator. Then he did the rest of the tuning on the laptop. That may very well be the last time that AFPR will ever see action. "Who knows"
But,, there are alot of folks out there that don't want to spend the money for tuning software to tune their car.
Therefore, the "oldschool" method of adjusting the FPR and distributor is how its done to achieve a safe acceptable A/F ratio. Basic and primitive I know but it works.
I have a friend right now with a supercharged '94 Saleen S351R code. His car is currently making 561rwhp/565rwtq. He doesn't use software, just an oldschool AFPR and distributor. A/F is perfect.
I rode around in my supercharged '89SSC for more than 10 years with no tuning software whatsoever. Just basic A/F adjustments made on the dyno from the AFPR and distributor.
It ran flawless, made 450 at the tires, passed emissions, had cold A/C, and was blast to drive. There's something to be said for "old school"
Hey, its all fun guys! We all do things differently, that's all.

Some say I'm long winded. NOT MEEE! . LOL

Do I Need Afpr

deathb4dismount

Crap, didn’t realize my crotch was in that picture

84Ttop

They make new pistons every day, so why worry?

deathb4dismount

Crap, didn’t realize my crotch was in that picture

TOOLOW91

If you're the village idiot what's that make me?

toyman

Onefine88

Previously 89SSC18

2000xp8

Dave2000GT

Active Member

madspeed

Colonel Mustard

deathb4dismount

Crap, didn’t realize my crotch was in that picture

Onefine88

Previously 89SSC18

84Ttop

They make new pistons every day, so why worry?

madspeed

Colonel Mustard

84Ttop

They make new pistons every day, so why worry?

Onefine88

Previously 89SSC18

deathb4dismount

Crap, didn’t realize my crotch was in that picture

toyman

90lxwhite

I'm kind of a She-Man

TOOLOW91

If you're the village idiot what's that make me?

Onefine88

Previously 89SSC18

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