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-   -   Took car to dyno today, have fuel issues (https://www.miataturbo.net/prefabbed-turbo-kits-3/took-car-dyno-today-have-fuel-issues-26766/)

posidon42 10-05-2008 08:59 PM


Originally Posted by Braineack (Post 316097)
search some of POPSTOY's posts on m.net, he went through a few different pumps until he found one that didn't drop pressure.

Good to know. My fuel filter was changed with the 30k maintenance, but that was almost 20k ago. So it is probably about time. My plug gaps were also sitting at 40mm when we checked them. They were at 28 when I installed them. Sean (spelling?) said that turbo cars lose about a thousanth every 1000 miles or so. Guess I need to check those a lot more frequenly than I thought.

On another note, if I am already having issues like this, should I start looking into a dual feed fuel rail? I think there are some DIY methods posted here, I just don't want to mess with stuff unless I need to.

Faeflora 10-05-2008 11:10 PM

Does anyone have a recommendation to hook up a fuel pressure gauge to a returnless (03) system? The hard lines run to the FPR which then has a quick-release. Do you just cut the soft line that goes to the rail and T in with the gauge? I'd think you'd need a new quick release line after that.

y8s 10-05-2008 11:19 PM

when I put in my dual feed rail, I just pulled the quick disconnect fuel lines out (get the tool) and put hoses and clamps on the hard lines. they've got the equivalent of a bead roll on them already.

oh and get a dual feed rail so it's worth your while. :)

samnavy 10-06-2008 07:15 AM

^I agree with Y8s that a DFFR is a good idea, but it has nothing to do with your 95*DC problem.

Your next step is a new fuel pump and filter... then do some datalogging.

posidon42 10-06-2008 11:23 AM

thanks guys. Any suggestions for a good place to buy said fuel pump? I read through some of POPSTOY's threads on M.net and he seems to favor the 255lph Walbro pump. Though I am not sure if that will give me issues with idle tuning or not. Since I have the Hydra, I assume I can meter the fuel enough to adequately control the idle, but I want to make sure. So should I get the 190 or the 255?

Braineack 10-06-2008 11:30 AM


Though I am not sure if that will give me issues with idle tuning or not.
not with an EMS, not with the '99 fuel FPR.

jayc72 10-06-2008 02:19 PM

Lightining motorsports for the pump. Got my 190HP from them and they were good to deal with.

http://www.lightningmotorsports.com/index1.htm

Marc D 10-06-2008 02:47 PM


Originally Posted by boileralum (Post 316090)
He has a bigger turbo - 2871, IIRC. Much more flow at lower boost levels.

youre also forgetting he has a 2001+ NB model, so his compression ratio is higher as well.

posidon42 10-06-2008 03:16 PM


Originally Posted by jayc72 (Post 316469)
Lightining motorsports for the pump. Got my 190HP from them and they were good to deal with.

http://www.lightningmotorsports.com/index1.htm

So this is the link I found at lightningmotorsports for the pumps.

http://shopping.lightningmotorsports..._Kit-p-89.html

Please confirm that I have the right one (they don't have one for 99+). Also, the 255 is only $10 more than the 190. I am leaning toward the 255 unless someone can come up with a good reason that I shouldn't.

cueball1 10-07-2008 02:00 PM

The 190 is all you need. When I was researching the same stuff the general consensus was the 190. It doesn't move as much volume but it pumps at a higher PSI if I remember right.

Braineack 10-07-2008 02:57 PM


There are a few draw backs to a non-return fuel system, that need to be taken into account, the biggest of which is the inability of adjusting fuel pressure. It is fact, not opinion, that only the walbro 255 lph-hp is capable of maintaining 70 psi of fuel pressure above 5500 rpm with my engine producing 159.9 rwhp at 6850 rpm. It is also fact, not opinion, that with a walbro 190 lph-hp that my fuel pressure fell off to less than 50 psi at about 5500 rpm, and despite safe tuning was only capable of 145 rwhp, on the same dyno. Because you already have a return system, that allows use of a afpr, and the fact that the 99 head makes more power with the better atomization of higher fuel pressure, only being possible with the walbro 255 lph-hp, and an afpr, other than heat being transferred to the fuel, and excessive fuel flow being returned, I see no other detriment to using the big walbro, well maybe noise too. Oh, I used a fluidyne afpr, with a vacuum port, adjusting the fuel pressure to 60 at idle with full vacuum, at wot and no vacuum, it increases fuel pressure to 70 psi, a safe limit for injector reliability. Bob
here. POPTOY suggests the 255-hp. Since I have no first hand '99 experience, and he has gone through a few pumps to finally be happy with one. I'd go with the 255-HP. It's not going to hurt anything.

Rishi 10-07-2008 04:04 PM

I have the 255 HP in my car and the 99+ cars do need a pigtail adapter to make the Walbro work. The place below sells the pumps, but sold me the pigtail seperately. Hope this helps!

http://www.aztpi.com/product.php?pro...7&cat=0&page=1

cueball1 10-07-2008 08:09 PM

OK so I'm an idiot talking out my ass. Like everyone didn't know that already. Didn't see the fact he had a 99. Duh...

posidon42 10-07-2008 09:35 PM

Thanks for the info guys. I am going to contact that vendor and see how much they will charge me for the connector.

fmowry 10-08-2008 08:06 AM

I thought injector-rehab who used to be a vendor sold the pigtails and Walbros. I just cut off the eyehole connectors on the pump wire and put on spade connectors and used an NA fuel pump.

Frank

Faeflora 10-08-2008 09:23 AM


Originally Posted by fmowry (Post 317174)
I thought injector-rehab who used to be a vendor sold the pigtails and Walbros. I just cut off the eyehole connectors on the pump wire and put on spade connectors and used an NA fuel pump.

Frank

Did you just solder/shrink them on? If that's all that's involved I won't worry about a pigtail.

BTW thought I'd mention that when I went to the dyno (York Automotive in Mt. Airy) I had a problem with going lean at high RPM irregardless of trying to add fuel in the Hydra map which is why I'm going to be replacing my pump and filter too.

fmowry 10-08-2008 10:26 AM


Originally Posted by faeflora (Post 317186)
Did you just solder/shrink them on? If that's all that's involved I won't worry about a pigtail.

BTW thought I'd mention that when I went to the dyno (York Automotive in Mt. Airy) I had a problem with going lean at high RPM irregardless of trying to add fuel in the Hydra map which is why I'm going to be replacing my pump and filter too.

Yes. Granted I haven't had the car on the street yet, but it shouldn't take more than changing the connector to the NA.

Frank

posidon42 10-09-2008 01:24 PM

Well I ordered that pigtail from the link above. $8 plus shipping is acceptable for me not having my personal soldering and shrink tubing involved in my fuel tank... I am also going to order the 255 walbro today. Let's hope this fixes all of my fuel problems.

posidon42 10-10-2008 11:32 PM

Pump should be here Wednesday!

BamBam 10-11-2008 09:04 PM

dip me in pig shit for asking
 
and plugging into this thread but I was always told or seen it on vendor pages not to run over 12 psi on stock internals on a NB, especially 2001 and up.

I would much prefer 14 psi -vs- 12 psi... so ..? don't really know what my question is.. but am I in the 'danger zone" if I up my boost to 14 psi? and tuned good?

Buck


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