Difference between the 255 and the 190 Walbro fuel pump
 

Hi guys,

Sorry to start a new thread for this but I need to ask if given the same price, would you get the 255 or the 190 Walbro fuel pump? I can get them both at the same price and will use it together with a Walbro FPR...

I am getting it shipped to me at USD169.99, any comments anyone? Thanks in advance!!

The only problem with the 255 seems to be that it overpowers the stock FPR and keeps the fuel pressure at idle too high. This causes trouble trying to get a decent idle. Some have put a bypass line around the FPR before the AFPR to remedy this.

Thanks for the prompt reply Olderguy!!

The 255 will over power the stock FPR, but if I am using an additional Walbro FPR, the 255 should be fine right? If the Walbro FPR is able to drop the fuel pressure...

As long as the Walbro FPR has been installed in place of the OEM FPR and can drop the pressure, you should be fine. If the OEM is left in the circuit, you could have problems.

$169.99!!!!!!!!!!!!!!! JESUS CHRIST!!!!!!!!!!!!!!!!!!! Try This link, you'll be much much more happy.

http://shopping.lightningmotorsports...&cat=24&page=1

yah I know about lightning, but I cannot get a service person online... there is no e-mail also.. I am located in Singapore and its a pain to get online shops to ship and also accept credit card payments... and 169 is together with a walbro FPR..

I have only seen fuel pressure increase by 5 psi at idle with the 255lph HP. The stock ecu is more than capable of maintaining a near stoich mixture at a factory smooth idle.

One of the good guys at M.net tested a 255lph pump on half-a-dozen OEM FPRs and found it overpowered 2/3 of them.

Why take the risk when the 190lph can supply enough fuel for ~350hp at the crank? The 255lph is unnecessary for 98% of folks running Miatas.

I wonder if honda FPRs fit our rail.... I know they are fine with the 255s. Then I could use a B&M FPR also... I'll test it and get back to you guys (on the fitment stuff).

What happens when the 255 overpowers the stock fpr? Does it run like shit or just not idle?

Well, the ECU can handle a couple of extra psi of fuel pressure at idle. The 255lph pumps a lot of times overpower the FPR so much the idle pressure goes from ~35-40psi to ~50-55psi, and the ECU cannot get it to idle of cruise correctly.

Exactly, I don't get this either. There is still so much love for the 255 from the supercharger crew. But haven't you noticed a trend with most supercharger owners and knowing nothing about fueling? I have.

At 50psi of fuel you have enough flow to supply 350BHP with the 190, 480BHP with the 255.

If you are using an FMU, the 190HP provides better flow at higher PSI levels and the 255 drops off eailer.

40-50psi idle with the 255 may cause lumpy idle and rich AFRs.

Its funny you mention this, I just now found out what the dead fuel pump was thats in my car that originally came with the JRSC kit that was on the car when I bought it... I bet you can guess what it was. The 255lph HP version no less. Just a little overkill don't you think?:eek4:

a tad. espeically if a FMU wasn't used.

Yes, although it must be said that the fellow who conducted the FPR tests is a JRSC owner. He's an old-school kinda guy in the same vein as Pop.

i did say most.

hey guys, first post for me!
sorry if this has been covered, but im a little unclear on this and i've read through all the info i could find on here.
if i get a 190 hp walbro, do i also need to get an afpr, or a peirburg..or any of those things? or can i just bolt in the walbro and leave it at that?
i've got a 1.6 but will be using the injectors off the 1.8 NB (230cc i think), and aiming for about 8psi boost (with hopes of a very occasional increase to about 12psi), with a megasquirt.
i was directed here by "aussie driver" as he says you guys know your stuff, and it sure seems so reading through this info. it's great, cheers.

With the 190HP and 1.8's you will need an AFPR to boost your fuel pressure. You should shoot for about 80psi of fuel for 8 psi boost with 1.8 injectors. The difference is that the 190 HP can put out good flow at higher pressures, but you need to restrict the return to tank flow to get the pressure up there.

Read my faq for a little bit more understanding (or tons of consfusion) about the fueling situation. But yes, a FMU be required to raise the fuel pressure in the rail effectivly raising the fueling potential of said injector.

thanks olderguy. so do you think it might be better just to get some bigger injectors and not use an afpr? i have already purchased these injectors but i should be able to send them back and get some bigger ones.
as i said i'm aiming for about 8psi at the moment but would like to eventually get to 12psi boost.
so of the 3 combinations below which do you think is best for that target
1 - 1.8 injectors + 190hp + afpr
2 - bigger injectors (supra?) + 190hp
3 - bigger injectors (supra + 190hp + afpr
4 - something else ? ?

I'm probably going to earn a(nother) handslap, but no, you don't want any sort of FMU/RRFPR/AFPR or other fueling bandaid with MS. You may need to substitute a higher pressure regulator to get enough flow from the injector though.

I suppose there might be some fun to be had with higher PWs at idle and therefore better resolution, but I'd just get the right size injector for your HP goal and go from there. You can get pretty good idle resolution by fiddling with the squirts per cycle, etc.

thanks guys.

braineack, i'll re-read your faq and try to get my head around it. but i think i'm starting to get a grip on things.

yes you can do alot on the cheap by just running more FP. look at andy floyd 300whp on 300 cc injectors and stock ecu. alot of us do it but ultimatly it is alot claener and mroe flexible to go with something that can run injectors akin to your power goals. also i noticed my idle pressure has gone up to about 45 and fluctates to 48 or so psi at idle ocasionally with my 255 fitted. once i throw in the 460's it should drop a couple of psi esp if i can get it to run. for 8 psi pon the smallish turbos we run the 1.8's + extra FP should be fine even at 12 psi. but a ms can run huge injectors so your only concern there will be how much the injectors cost and cooling effeciency

just thinking about this... is the regulator from the 1.8 engine a higher pressure unit, or the same one? could it do the job?

it is totally different, and wont fit the 1.6 rail. you need a aux regulator that raises the fp dependent on boost. say 12-1 or 4-1 depending on your fueling needs and resolution. there are adjustable fprs on the market from begi etc. as well as several cheapo single rate units that can be custom rebuilt to meet your specs.

Are you sure he should run an RRFPR with standalone EMS?

i guess i could just get one of the new multi role begi units:

"Multi Role Regulators
The new Multi Role regulator from BEGi is designed to provide complete adjustability to your fuel injection pressure. The MR series takes all of the features found in our rising-rate regulators and adds the extra functionality and convenience of allowing you to adjust your base fuel pressure (the fuel pressure at fuel rail during idle conditions). This allows you to replace your factory fuel pressure regulator with a fully adjustable, easy to mount, single unit.
Patent Pending

Price $309.00 (Fittings included)"

not cheap tho

how about a combo of the walbro 190 HP and this aem regulator... ?
http://shopping.lightningmotorsports...cat=717&page=1

says it's a "universal" regulator... reckon this will work in the miata ?

All I can say is, figure out if there is any reason for a RRFPR. If you do, please post back, because I just don't see it.

Then find out what the OEM FPR is and if it's suitable for your injectors and your power goals.

Skip the mad tyte JDM nonsense. There is plenty of stuff in the JYs that can be retrofitted.

ok thanks. just that everybody seems to say that the oem fpr can't handle the pressure and will fail.
so as you say there is plenty of stuff that can be retrofitted (but what do you mean by JY's sorry) , i just need to find the best / cheapest option.

i figure once he went ems he would just run bigger injectors the fp tricks are just ways to work around the limitations of the ecu you are using. the ms is your cheapest option esp since you seem to be handy with a soldering iron get that and some 500-600 cc injectors and be set to make 300 whp on the stock fp and system. for 8-12 psi the stock ecu and cheapo fpr will suffice. but the ms given good tunning and setup will give an ultimatly better ride and control it just scare alot of people like me who dont like ot go poking around where the space is so limited on electronic solutions or solder on circiut boreds. it is all in what you have the skill for.
Also the aforementioned aem fpr will only allow the adjustment of base pressure so it is no more usefull than your stock fpr unless you are runnig a 255 hp and need more flow to keep the pressures down at idle.

hey guys i've found some high imp. 460cc injectors from a '88 rx7. the wire harness is a different shape to the miata ones, but i don't imagine it would be a big job to fit them onto the car?
reckon these would be a good way to go? i'm just a bit worried about going any larger, in regards to how the car will run at low rpm / idle etc. ? is this a silly concern, should i just keep looking for some 550cc's ? ?
finally, do these puppies fit ok? it seems others have use them in the miata.

Attachment 217278

Holy sh!t dude, are you just grabbing parts? 4x460cc = 300HP at 85%DC. I'd be worried about getting the right idle resolution. 550's would make it even worse.

Why not get MS and WB running on your 1.6L in NA, then see how much room you have? Start slow, up the boost a bit, and then increase pressure or injector size.

I'm all for gathering parts up in advance, but you really aren't going to jump right to 300HP.

You really should use the smallest injector you can, without overdoing the duty cycle. And even then, heck, I ran 4x300ccs at 110% DC for a while with zero adverse effects.

From http://www.megamanual.com/v22manual/minj.htm#size
"Injectors that have too large a flow rating will make it difficult to tune the engine at idle and cruise."

hey the ms can run 800 cc injectors no problem it is one of the most versatile engine managment systems out there hell i hope to run those very same 460's with just a rx7 afm and safc if i can get low impedance injectors ot run pon just the rx7 afm then the safc in the mix i should be able to get the 460's to run just fine throw in 80-90 psi of fp and i have all the fuel i will ever need for this tubro anyway. now all i need to do after i get it figured out is find a better rear end and a six speed. your bigger injector notion is only true when you are limited by ems a ms is not limited a link is limited to about 600 or so a emanage blue 330's and an ultimate has no real limit that we have seen so far on it compensation. as do the tec3, hydra, etc. heck markp runs 800's i believe with his tec3.

hey man, yeah, i am just grabbing parts :lol:
but i did check with my megasquirt guru (aussiedriver) when i was looking at some 550's and he reckoned that things should be ok , that the idle tuning might be "interesting" to use his words, but would be ok.
hmmm. but yeah maybe i need to slow down a bit eh ? ?
i already have some 230cc's sitting here ready to go, maybe i should start with those like you said.

Hi Magna - it's not a question of what MS can do, it's a question of how much fuel his car is going to drink. If you go too big, you can't get the idle pulsewidths low enough for a stable idle, ditto for lean cruise. Running static fuel pressure has its drawbacks, I suppose. Still waiting to hear if anyone actually runs a RRFPR with MS....?

Hee hee! 4x300's got me to ~220HP (modest guess) at 100% DC, and 4x400's did the trick at 85% give or take. Just get'r'done, then drive it. The DC gauge will tell you when you need more injectors.

ms has done it on other miatas as well though that is all i am at. heck cccpull runs 650's with a clocked ecu, rx7 afm, and vafc. it has been done why limit yourself on fuel when it has been established it can be done. i dont mean to argumenative just throwing my opinion out there. fatty if you like the idea of cutting the and splicing the injector clips the 460's and MS should work. and like i said before if i get enough time i should be running 460's by sunday.
We'll see. ohh yeah btw the stock clutch is only good for about 150 or so whp.

woops, my hand slipped on my keyboard and i accidently bought them :eek:

so i guess i have 2 sets of injectors to play with now :cool:

i'll start with the 460's and have the 230's as a backup, in case i can't get the idle and cruise sorted out.

good luck

yeah man i know the clutch issues. i will be getting a 1.8 clutch and flywheel (maybe an aftermarket cro molly fly, not sure yet).
then the brakes...

then the diff...

and so on and so forth

Btw... I eyeballed a Honda FPR the other day... and it should work. They don't have issues with the 255 pumps if you desired to use them. I'll probably use one with a B&M adjustable on it when its time to reassemble my car.