pissedoffsol

I'm nearing the end of my parts scrounge.... and I'm wondering how necessary this is?
What's the down fall to running the stock FPR on a boosted setup with large 860cc injectors? I have hondata and all the other good stuff... and im wondering why i continue to see FPR's on cars with hondata. From reading the manual, i think it can all be controlled, and maintain a moderate <50 psi rail pressure, from the laptop anyway. So, why run a FPR?

Pros? Cons?

Thanks

ladysman

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pissedoffsol &raquo;</TD></TR><TR><TD CLASS="quote">I'm nearing the end of my parts scrounge.... and I'm wondering how necessary this is?
What's the down fall to running the stock FPR on a boosted setup with large 860cc injectors? I have hondata and all the other good stuff... and im wondering why i continue to see FPR's on cars with hondata. From reading the manual, i think it can all be controlled, and maintain a moderate &lt;50 psi rail pressure, from the laptop anyway. So, why run a FPR?

Pros? Cons?

Thanks</TD></TR></TABLE>

You can't maintain the rail pressure from the hondata (laptop). I have the AEM because I had to raise mine just a little. I have 800cc RC injectors and am running 45 PSI as my static. When I talked to Hondata they told me between 55 and 60 for static on our big injectors. I thought that was too much so I just went at 45. So far it has been fine. I am still tuning but it idles like a champ on the base map. My opinion is get one. If you need to lower or raise it and you don't have it, you are S.O.L.

My $.02. Bottom line, the laptop doesn't do **** for fuel pressure. You need to read the manual again.

BROOD

The oem fpr is not a 1:1 ratio fpr, Hondata with boost is designed to run with a 1:1 fpr. And like said above the adjustability is a good idea. AEM and Aeromotive are examples of common 1:1 fpr's

I'm using the Aeromotive fpr

pissedoffsol

edit


Modified by pissedoffsol at 11:59 AM 6/3/2003

boosted hybrid

The OEM regulators are 1:1, have you personally tested them? I have and they are. Pretty much all modern day fuel injected cars run 1:1 fpr's from the factory.

I dont run any aftermarket fpr's and dont have a single problem with hondata. The fuel pressure on the OEM regulators from 38-50psi from what i have dealt with. It has something to do with year, model from which the fpr came from. On an average though I see 40-42psi when I get the fuel pressure with a gauge. With an intake pump I see a 1-2psi fluctuation from stock setting. The main reason that Hondata tells you to run higher fuel pressure with injectors is the slow response time with large injectors. You need to have them get more fuel out in the lower millisecond range of spraying or you'll obviously run leaner.

ladysman

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted hybrid &raquo;</TD></TR><TR><TD CLASS="quote">The OEM regulators are 1:1, have you personally tested them? I have and they are. Pretty much all modern day fuel injected cars run 1:1 fpr's from the factory.

I dont run any aftermarket fpr's and dont have a single problem with hondata. The fuel pressure on the OEM regulators from 38-50psi from what i have dealt with. It has something to do with year, model from which the fpr came from. On an average though I see 40-42psi when I get the fuel pressure with a gauge. With an intake pump I see a 1-2psi fluctuation from stock setting. The main reason that Hondata tells you to run higher fuel pressure with injectors is the slow response time with large injectors. You need to have them get more fuel out in the lower millisecond range of spraying or you'll obviously run leaner.</TD></TR></TABLE>

Thanks again for the great Hondata info Jeff. I may try to raise mine a bit just as they said to in the first place.

boosted hybrid

I just want to elaborate on the whole "OEM FPR's are not 1:1 in boost" thing.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sdsefi.com &raquo;</TD></TR><TR><TD CLASS="quote">EFI fuel pressure regulators come in various shapes and sizes but their purpose is the same- to hold the fuel pressure at a certain differential above the intake manifold pressure. The inner mechanism usually consists of a sealed diaphram chamber, a spring, a diaphram, bypass valve and a manifold pressure reference port. The valve is connected to the diaphram and the spring pushes against the diaphram from the manifold pressure side. The spring pressure determines the static fuel pressure. If there is vacuum on the port, say at idle, this reduces the effective spring pressure acting on the diaphram and reduces the fuel pressure under vacuum conditions. If there is pressure on the port, such as under boost, this effectively increases the spring pressure, thus fuel pressure. Most OE regulators use a one to one ratio. At one psi of boost, it would add one psi of fuel pressure. This way there is always a constant pressure differential across the fuel injector. Most regulators have a static pressure of between 38 and 44 psi.

The fuel pump always puts out an excess of fuel volume. The regulator controls the pressure in the fuel rail by bypassing any fuel not used by the engine back to the fuel tank once the control pressure is met. At idle, perhaps 95% of the fuel delivered to the fuel rail is returned to the tank. At full power, perhaps 5% to 50% of the fuel delivered is returned back to the tank. Fuel is generally routed from the pump to one end of the fuel rail which feeds the injectors. The regulator is usually mounted on the opposite end of the rail. This arrangement allows any hot fuel in the rail to be immediately purged back to the tank after a hot start to reduce vapor lock and fuel boiling. A similar arrangement should be used if you are fabricating your own fuel system.</TD></TR></TABLE>

That bit of information was taken from http://www.sdsefi.com, it applies to all fuel injected cars that are made today. It makes sense physically with how the fuel pressure regulator works, much the same way a wastegate works.

BROOD

Hmm, I must have had bad test results when I was verifying the oem fpr ratio. I'll have to check it out again. Thanks for the correction.

pissedoffsol

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted hybrid &raquo;</TD></TR><TR><TD CLASS="quote">The OEM regulators are 1:1, have you personally tested them? I have and they are. Pretty much all modern day fuel injected cars run 1:1 fpr's from the factory.

I dont run any aftermarket fpr's and dont have a single problem with hondata.</TD></TR></TABLE>

Thats what i was thinking too... according to hondata's site, since all 240cc's in b-series supply different vilume engines, they use more of the duty cycle, and different pressures.

Now my question comes up, I'm going to be running an 84mm gsr bottom end with an Sir2 b16 top... and for now, stock b16 fpr on a GE rail. I'm wondering if this will offer me the proper pressure, as its deisnged for a motor .4 L smaller?

krazy

id also like to know. so, what he said.

krazy

g2turbo

good thread

i have stock regulator now with 550's, hondata, Walboro HP255. No problems here as of yet. Just recently ive been thinking about going for more power and wondered if id have to bump base pressure to get the injectors to spray correctly. WIth say 720's?

boosted hybrid what size injectors have you done on stock regulators?

boosted hybrid

I have done 900cc with the stock fpr and no problems. As far as you trying to find your proper fuel pressure for your 2.0 liter engine, if you are using larger injectors than you have no reason to mess with the fuel pressure. Strickly adjust the pulse width not the fuel pressure.

pissedoffsol

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted hybrid &raquo;</TD></TR><TR><TD CLASS="quote"> Strickly adjust the pulse width not the fuel pressure.</TD></TR></TABLE>
Which is what i was trying to get at in my first post- having hondata control my fuel- not some device

Do I have a 2nd opinion?

ladysman

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pissedoffsol &raquo;</TD></TR><TR><TD CLASS="quote">
Which is what i was trying to get at in my first post- having hondata control my fuel- not some device

Do I have a 2nd opinion? </TD></TR></TABLE>

It doesn't control the pressure though which is what you were referring too in your original post. He is saying it controls the injector pulse width. 2 totally separate things.

pissedoffsol

right... but by controlling the pulse, you don't need to control the pressure. That's what i was getting at

ladysman

But increasing the fuel pressure can lower the duty cycle of your injectors. Pulse width cant do that. In other words you can make your 440's 480 by going up a certain amount in the fuel pressure. I don't recommend it but it can be done. That was my point.

pissedoffsol

right on... but with my 860's, i probably wont be anywhere near 80% duty cycle anyway....

ladysman

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pissedoffsol &raquo;</TD></TR><TR><TD CLASS="quote">right on... but with my 860's, i probably wont be anywhere near 80% duty cycle anyway....</TD></TR></TABLE>

Same with me and my 800's. I have the AEM and probably couldn't get **** for it if I sold it. I guess I will keep the bling bling look for now. Who knows, I may need it someday. I still want to know how to control the pulse width in Hondata. I PM'd Jeff about it.

pissedoffsol

have him psot up what he knows, or paste it to me... i'd like to know as well

-B