Fuel System Upgrades
 

I haven't found much on the site regarding fuel system upgrades beyond injectors and a fuel pump. I've seen people question how effective a stock FPR is with an upgraded fuel pump, but haven't seen any real consensus. Is there a point at which fuel lines need to be upgraded? Is there a point that a 255 walbro isn't enough? Any other issues to address?

I've still got hopes and dreams of 400whp (probably 350 realistically) and considering a switch to E85, which will add additional strain to the system. Right now my plan is for 1300cc injectors, mtuned fuel rail, fuelab FPR, and walbro 255 with the stock supply/return lines. Are there other mandatory upgrades or significant weak points in that setup?

I know vlad ran >300whp on e85 and dw1000's or something, no problems. Soviet runs >400whp on stock fuel lines, albeit a crazy fuel pump and big injectors. But stock tank/lines IIRC.

I don't think lines will be your problem, and i really think that fuel pump will flow plenty for 350whp with 1300cc injectors even on e85. There is only one way to find out though, Do it and get back to us.. for science.

As for the wally 255 + stock regulator, I too have seen this debated. I just slapped a wally 255 in my car, and the fuel map needed NO retuning, so I'm guessing it's not (yet) overpowering the stock FPR. Although FPR's are cheap, and for a big power setup it would probably be a good idea to get one for peace of mind.

PS, i always loved reading your build thread and was wondering what happened with your car. Did you ever get it to make decent power?

Not dw....ID1000 ftw :party:
Also I find the wally to be nearly tapped out at just a bit over 400 on e85. Soviet basically ran into the same issue. I'd go dw300 or something more serious. Also I'd stick with the smaller injector and bump up the pressure if you're only shooting for 400, because better spray/atomization.

That's basically it.

I'm sure others (the 400+ crew) will chime in with much more helpful info.

Silly me, i definitely knew that. Master race ID injector owners... :giggle:

Seems like I wasn't overlooking anything too major, so that's good. I also realized 1300's cost almost double 1000's, so 1000's it is!

I felt like problem after problem with my car was making me look like a 'tard so I kinda shyyed away from updating the build. It finally looks like it's coming together again though, once I've got something I'm not embarassed to post I'll get the build caught up. I hope to have it on the road again by Thanksgiving.

That's great man, good for you.
In for 400whp glory

Ha! Don't worry about that man. I sure don't think you are a tard, I've loved all the different miatas you have had (especially the teal NA, lol) and always enjoyed your videos. You've built some respectable machines thus far, i have no doubts this current one will fall into place.

Wally400E85 (wally 465L) or bust. They're so fracking cheap, and like silent.

the stock FPR has been known to handle the 255, the stock FPR has also been known to fail with the 255, but just like stock bottom ends at 300rwhp, your FPR is on borrowed time. (as recently as the last 60 days, someone with the 255 + stock FPR came to us with fueling problems - in his case, the 255 killed his stock FPR in about a week) I know of no documented cases in which a 190lph HP has overwhelmed the stock FPR. I would recommend 190lph as a limit for the stock FPR. Your lines shouldn't have problems with gasoline, as it's pressure, not flow, which would cause them to rupture, and while any larger pump you add will certainly add flow, you're generally going to replace the injectors with higher flowing units before you start fiddling with the fuel pressure.

Well then, that just added a part to my winter shopping list. LOL, what aftermarket FPR do you guys recommend, and how do you bypass the stock one when going to an aftermarket setup?

I guess i have some research to do.

The easy way to bypass the stock FPR is to run the MTuned fuel rail. When I looked I never found an adapter plate that had our FPR flange on one side and any sort of thead on the other.

FPR wise, fuel lab or aeromotive. The AEM is serviceable but I'm still awaiting the day that the seal blows and it starts leaking fuel all over my engine bay.

TL;DR

I run a Walbro 255hp, stock lines, stock fuel rail, stock regulator, ID1000's and E85 and make 360whp. I think I am at like 40% duty cycle, Vlad will have to clarify that number for sure.

Yep lol. I have no idea how or why its so low. Its a sign we should just re-tune for 40psi :party:

I thought that the general consensus was that a 255HP would overpower stock FPR's, and the 190HP would be sufficient.

or?

Whenever we talk about fuel systems, I wish we could all mention what year car or other modifications they have done. A returnless NB with a non vacuum sourced regulator @ 60psi in the tank is a bit different than a NA8 @ 43.5psi with a legit return system and vacuum sourced regulator under the hood.

I'm running a 190HP on factory parts in my NB, no issues I am aware of with pressure or regulator. It is noisy, but I'm also a wuss about such things.


Like this:
Profile says you are driving a 90 with a 1.6, truth?

^ Agreed on your first point... when I was new and learning I was all the DIY FAQ stuff, but didnt realize till later down the road that it all pretty much applied to NA return style fuel systems. Stock NB stuff sucks. I'm at 20psi and hitting 70+ duty cycle already with Wally 255 and ID1000s.

Pdextra, keep your build thread going! No need to be shy about the fail.... I need someone to relate to.

Uhh, if that last VD is correct you are near 400whp?
In which case 70IDC on a wally and ID's is actually right on the money

I've used 255's on all my NB's. Haven't had FPR issues yet, and they all had/have stock FPR's.

Whatever that's worth.

That is the truth 1990 fully built 1.6l. MS2 tuned by Vlad, using an O'Reillys fuel filter. Stock return style system. The only thing added was the Walbro 255hp, ID1000's, and the MS2

^ Agreed. have you seen my rotrex fail thread? Of course, I DID bury it in the thupercharger section for a reason.

Magic 1.6 FPR ftw! I'm rocking my original 90 FPR with 170k miles on it and a wally 255 with dw800's. I was originally planning on using this exact fuel system for my new build and ~300whp goals, but I'm starting to worry about the FPR.

What will happen if this thing fails? Will my system go pig rich or lean out? or will it fluctuate? Any reason not to rock this setup until if/when it fails?

look up the meaning of "overwhelm" ;)

I don't think I can get much more out of it though. At 20psi boost, and 60psi fuel rail pressure 60-20= 40psi effective...problem is if I try 25psi boost, now my 900cc injectors rated at 43.5psi now only have 35psi of effective pressure. With that inverse relationship going on, you start running into high duty cycles quicker than expected. I guess 400whp is nothing to complain about though! Honestly I don't think I want any more, stuff starts breaking and it can already be scary at times.

At a certain point you must upgrade a LOT of things to keep going. I think that point is somewhere 350-400. Below that, so far at least, I've not had any issues with the setup I posted.

And if you're really making 400 like your VD says, I don't think you'll ever be bored and want more......:party:

:jerkit:

So basically it will increase my base fuel pressure if it overwhelms it. I guess the problem comes when/if it fluctuates like mentioned earlier in the thread. If it overwhelms the stock FPR and raises the base fuel pressure 10psi consistently, than good for me i guess. If it fluctuates than your tune will never be right. Mine is sure holding up fine for now at least.

Subscribed. I'm running the 255HP pump with stock '92 lines and aeromotive AFPR, E10 gasoline. I figured I would have to switch to a new pump and fuel lines to hit my >400rwhp target but the plan is to see if the current fuel system works before spending the money on something that might not be required.

I think Savington replaced the fuel system on Thesus, there must have been a reason. Unless I am getting confused with a trackspeed V8 car.

Gimme a pic of the stock FPR. I'm pretty sure i know what you need, and it costs like... $15 shipped.

Just google. The flat face on our FPR is not the sealing surface, a little clit that goes into the hole on the rail has the sealing oring. I was just going to make a plate like I have on other cars/bikes out of some scrap but it was gonna be too much work for this one.

https://www.miataturbo.net/attachmen...ine=1383235227
90-93


https://www.miataturbo.net/attachmen...ine=1383235227
94-97


https://www.miataturbo.net/attachmen...ine=1383235227https://www.miataturbo.net/attachmen...ine=1383235227
99-05

Right. Same setup as KL and F2T. The adapters are all over Ebay for none of the money.



[edit]

Just saw the pics.

Yep, same piece.

Here's a fancy one. Knockoffs are all over the place if you change your search words slightly.

http://www.ebay.com/itm/TurboSmart-F...db6a67&vxp=mtr

Where were you last year? :vash: The next problem would be finding an elbow tight enough to clear 99+ intake manifolds.

I'm a little surprised this is new information... these have been out for a LONG time, i've been using them on my MX6 for about... 4 years? KL guys for probably a decade, and Mazda isn't really known for using eleventy billion different regulators.


I actually even used mine as a blockoff plate. Bought that thing, stuck a plug in the threaded portion, then cracked the nut off the end of my rail, which i then threw an adapter to -6 into, ran that to regulator, back to factory return line on firewall. I didn't like the factory FPR placement, how it sat between cylinders 1 and 2.

You mean this tight?
http://thmb.inkfrog.com/thumbn/txaut...2-1014.jpg=450
Turbosmart Fuel Pressure Regulator Adapter for Mitsubishi EVO TS 0402 1014 | eBay

That's gotta be threaded in there. $23 to find out ;)

So hold my hand a little, i think i'm right i just want to double check.

For my 95 engine / fuel rail / FPR i'm going to want this thing
Turbosmart Fuel Pressure Regulator Adapter for Subaru Nissan Mazda TS 0402 1001 | eBay
That Ben posted, along with something like this.

Fuelab Adjustbale Fuel Pressure Regulator - Modern Automotive Performance


From what i understand, that FPR would just adapt to that adapter. But the adapter doesn't say in which means that happens. Is it just a universal? I see the return is -6an and i can choose between -6an and -10an inlet.

Also from what i'm reading about my DW300 pump, is that this regulator should be able to handle it's output. Which at 14.2a will do 100psi.

Lastly, im sure it's possible to connect a -6an line to the stock hardline. Is this a thing that people do? Would would it take to do that(besides the obvious -6an lines) some kind of hardline to braided line adapter?

Flare the hardline to -AN.