Super Lean, I need advice

[chris712vt]

Ok guys, first of all thank you in advance for any help you may be able to give. Some of you may know I turbo'd my car about a month ago. Well I finally hit the dyno this weekend and got a rude awakening. I will list the key parts of my turbo and fuel setup below, as well as post my graphs. Then my questions at the end.

Engine:
Howell stroker motor including JE/Eagle combo in the bottom end, P&P head with the Crane cams and so on up top, you all know what it's got. And if not, just look at my profile, I've got most of it listed there I think.

Turbo:
Turbonetics T3/T04e 50-trim. It's a custom setup based on a Star kit platform. I'm running 8psi via my TiAL wastegate's spring pressure only, no boost controller. NGK BKR7e plugs gapped to .028 if that is important to know as well...

Fuel:
Stock injectors, new Walbro 255lph high-pressure fuel pump, used Vortech 12:1 FMU, and a Synapse missing link also used.

In case it matters, I run the vacuum line to the FMU from a vacuum distributor block. The block gets its vacuum source from the brake booster port on the IM, and distributes to 4 lines - my boost gauge pressure sensor, my bov, my FMU, and my brake booster.

The graphs are self explanatory. First is horsepower, second is torque, and third is my air fuel ratio. All three pulls were in 3rd gear. Blue is my first run with my usual setup according to everything I described above. Red was my second run, which I stopped short on because my AFR jumped just the same as it did on my first run and didn't want to risk it. The only change I made for that run was swapping the FMU vacuum line to the port on the throttle body where some vacuum source comes from in case it had a stronger vacuum signal, perhaps making the FMU give me more fuel (didn't help, actually got worse). And lastly, the Green was my third run. This time I completely took off my charge pipe running to the throttle body. This was just a test run just to see what my AFR would do without any boost. I didn't do any more pulls for obvious reasons, I didn't want to blow up my motor or anything.

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Alright, now that you have seen those awful graphs... yay I broke past 200 whp and wtq!! But in all seriousness, I'm definitely scared by that air/fuel jumping to 15:1 at peak torque. I learned a valuable lesson - when I got all my turbo parts, I was (and still am) on a tight budget and couldn't afford a wideband. I sure regret that decision because it would have been nice to know how dangerous the car was running these past 3 or 4 weeks. Granted, there is a slight chance the sniffer wasn't getting a good reading... but it was within a half a point of the wideband gauges on the other 2 turbo cars that dyno'd with me, so I'm afraid it was pretty accurate.

Now I guess I need to do my best to stay out of boost whenever I drive the car until I can solve this problem. It's my DD so I can't just let it sit, I do need it every few days.

Questions:
Could this be an issue with the FMU not working properly? This is an extremely common fuel setup for us turbo 420a guys running 8psi or less, right? That's why I felt safe until after the dyno. I would expect we run 40-43 fuel pressure stock, then add 8psi x 12 (FMU rate), that's an additional 96 psi... can the Walbro support almost 140 psi of fuel pressure when at full boost? What's going on, how is this such a common fuel setup yet I'm so lean?

I have run smooth and strong, seemingly perfectly fine this whole month until Friday night. I never encountered a problem since I went turbo till that night. I was at the 1/8th mile track, and unfortunately I split my fuel return line between the fuel rail and FMU. I only got to make 1 run before I noticed the fuel pouring out below the car. I replaced the line immediately. I don't know if that has anything to do with the situation or not, but in case it might, I added it into my story here. I went to the dyno the next afternoon, Saturday.

Solution?:
So... what do you think I should do now? Remember I'm a college student with practically no money left to spare. I will be working in 2 months, hoping to grab the Plug & Play MSnS when it is released, but right now I'm almost broke.

Could the FMU be malfunctioning somehow? Is there any way to test it? Can I get larger injectors and an SAFC-II or something (don't know much about them yet) and run the same 12:1 FMU + Walbro setup and be safe then still at 8psi? What are my options while still on a strict budget to get to a safer fuel level?

Is there a chance I'm broken my motor and don't know it?

I apologize for the length of this thread, but I wanted to be clear, and leave no detail unmentioned. If you have any input, please post it. I need your all's help!

Thank you!

 

[VelocitàPaola]

Stock fuel pressure is about 53psi, and no, the Walbro 255 cannot support 140psi of fuel pressure. The Walbro 255 HP can barely support 120psi at maximum output. This is great to finally have some AFR logs of nothing but a 12:1 FMU and Walbro 255, though. I don't think too many people have bothered to "tune" with such a limited setup. I say get a 4psi spring for your TiAL and try again... that way we can narrow down the source of your problem and you can turn up the boost from there.

 

[chris712vt]

wow... well then why does everyone say the Vortech 12:1 + Walbro can support up to 8psi on stock injectors? That's 149psi at max boost theoretically.... Is that why I get so lean? The fuel pump just can't support past 120psi of fuel pressure, or 5.5psi?

Something doesn't make sense. Either the Vortech + Walbro combo cannot really handle 8psi, in which case why does everyone say it can? OR my setup isn't functioning correctly, because it seems like others are doing / have done the same thing as me and have been fine.

 

[Car_guy_09]

wow... well then why does everyone say the Vortech 12:1 + Walbro can support up to 8psi on stock injectors? That's 149psi at max boost theoretically.... Is that why I get so lean? The fuel pump just can't support past 120psi of fuel pressure, or 5.5psi?

Something doesn't make sense. Either the Vortech + Walbro combo cannot really handle 8psi, in which case why does everyone say it can? OR my setup isn't functioning correctly, because it seems like others are doing / have done the same thing as me and have been fine.

Did you check all your basic stuff? Like fuel filter, Make sure all the fuels lines aren't kinked up or anything etc., Always check the little stuff first . But im a little skeptical on the "Vortech + Walbro combo", I think its just more headaches than anything . But im just a poor teenager so im stuck with one too If you must drive it, Do what i did and take the wastegate spring out, Until you figure it out. Yea its gonna be slow but you wont blow your motor

 

[Blitzeclips]

Well son of a bi***. I have the same set-up as you.

I'm scared for my motor now too!

Dude I was reading an article is Super Street from a 2 year old magazine (read each one atleast 10 times!) and their project Civic ran lean on the dyno. When they looked into it they couldn't figure anything out except the fact it was still on stock injectors. They pulled the filter, lines, pump, all checked out. They sent the injectors out for flow testing and 3 of the 4 would flow 210cc and one of the 4 would flow only 173cc!!! The injectors were suppose to be flowing around 230cc! They figure the injector either got clogged or malfunctioned. Regardless, it cracked a piston along the way.

I would seriously check the fuel filter and buy some new injectors. Don't even go bigger buy some relatively new stockers or some aftermarket injectors flowing a stock amount. It may seem pointless if you're upgrading your fuel set-up, but it'll be the only sure fire way to ensure motor preservation and direct problem recognition.

Man, I've been running the same set-up as you for almost 2 years now!! Imagine how I feel after seeing those charts!! Car still drives like a champ, though...

PAUL- What are you seeing for AFR's??

 

[silvreclips]

Chris - Why put so much money down on a motor and that big ass 50 trim turbo when and dip out on the fuel system. I suggest getting rid of the FMU asap and spending some money on a real fuel system. Yea it will cost you more but not as much as a new motor. And then you would be able to actually get some power out of the car.

 

[chris712vt]

I completely agree with you. I swapped the stock motor with the stroker over a year ago when I had an opportunity to get it with plans to eventually turbo it. I now wish I had pieced together a better fuel system ahead of time as well... but after buying all my turbo parts and finishing everything, I don't have enough money left over to go crazy on the fuel setup.

That's why I'm asking your all's opinions on both why I'm running so lean when others (like Blitz) have done the same exact thing and been fine, and how I can change what I've got to be safer.

My goal is to do MSnS with bigger injectors when I can afford it like I said, but I need some sort of middle-step right now that I can still afford but will be better than what I've got. Can I get rid of the FMU and get an SFMU with slightly larger injectors? Would that setup just run on a certain SFMU disk or does it need to be tuned with an SAFC or something as well? SFMU + injectors + SAFC-II is already adding up if that's an option. I know that comment sounds ridiculous but I've still got to afford rent, food, gas, and other expenses for 2 more months of college before I start my job and get a steady income - that's why this is so tough/frustrating right now. Fuel is my weak spot knowledge wise so I need some help understanding what all is needed with this setup to run boost safely.

 

[Blitzeclips]

Well, I could be driving with a couple cracked pistons right now, and depending on their damage, it could even be not enough to notice. So I'm certainly knocking on wood here.

I was discussing this with some friend last night to come up with some ideas. I realize you broke a fuel line the night before. I think this might, of anything, have something to do with this. I'd seriously check every part of the line you replace for leask. Fuel is tricky because it will evaporate befoe you can notice it sometimes. If you started the car and checked it out while puel pressure is being applied you might find something. Did you loop the line around any parts or would there be kinking anywhere because you installed it in a rush??

Have you checked your plugs? Can you post pics of them?

 

[chris712vt]

Well I mounted my FMU back behind the battery and strut tower. I had to extend the stock fuel return line with new fuel line, as well as add the new line off the fuel rail to reach the FMU. I found the small split where fuel was leaking out under pressure, and it was close enough to the end of the line I was able to cut that part off and reconnect it to the FMU. There are no kinks and I couldn't find any other leak.

I'll pull the plugs and take pictures as soon as I get some free time.

I might as well double check just to be 100% positive - the fuel rail return line goes into the side of the FMU, and the return line back to the tank comes out of the bottom of the FMU, right?

 

[Blitzeclips]

Well I mounted my FMU back behind the battery and strut tower. I had to extend the stock fuel return line with new fuel line, as well as add the new line off the fuel rail to reach the FMU. I found the small split where fuel was leaking out under pressure, and it was close enough to the end of the line I was able to cut that part off and reconnect it to the FMU. There are no kinks and I couldn't find any other leak.

I'll pull the plugs and take pictures as soon as I get some free time.

I might as well double check just to be 100% positive - the fuel rail return line goes into the side of the FMU, and the return line back to the tank comes out of the bottom of the FMU, right?

I mean you should also check the voltage going to your pump. It may not be up to par with what your vaccuum demands when you are in boost.

 

[4UH8ERS]

8psi being ok is merely an average figure and also depends on what size of turbocharger you are using. 8psi flow characteristics of a 14b and a Hahn s20g or your 50trim are not comparable. Just so that you know that. Either way though, if that FMU is working correctly and you have a clean fuel filter as well as good voltage to the pump. You should'nt be experiencing that with a 12:1 FMU. Just due to the mere nature of where thre A/F ratios are lean and the inconsitency in it leads me to beleive that its not a capability problem, but more a functionality problem of the current parts.

 

[We're on Boost]

Here are some Walbro flow vs pressure charts. 140psi? Yeah, at 2 gallons per hour .

Gary

 

[Blitzeclips]

My question now is, HOW can you tell the difference in the 255lph High Pressure system versus the 255lph FLOW sustem?

Well, ooks like the 255lph FLOW system drops off around 90psi. But, correct me if I'm wrong here, a simple re-wire kit can sustain the voltage and inprove fuel pressure torwards the upper psi..

In other words, wouldn't a re-wire merit a 255lph FLOW into basically the same pump as the High Pressure. And again, how can you tell the difference between the two?

 

[chris712vt]

Well I bought the 255lph HP, and that graph still makes me feel pretty uncomfortable now...

 

[VelocitàPaola]

My question now is, HOW can you tell the difference in the 255lph High Pressure system versus the 255lph FLOW sustem?

Well, ooks like the 255lph FLOW system drops off around 90psi. But, correct me if I'm wrong here, a simple re-wire kit can sustain the voltage and inprove fuel pressure torwards the upper psi..

In other words, wouldn't a re-wire merit a 255lph FLOW into basically the same pump as the High Pressure. And again, how can you tell the difference between the two?

They have different part numbers. They're different internally, so simply rewiring the power supply won't render the two equal.

 

[We're on Boost]

For that lower chart you have to have a part number reference to make use of it. There is a good one here on the FP site - open up the pdf application guide and look for the mitsu section in the guide:
Forced Performance: Walbro Fuel Pumps

The rewire should keep your voltage up to about 13 or 13.5 volts. Without the rewire, I don't know, I think I've heard about 11 volts. I don't think that rewiring a low pressure 255 is enough to get it up to what you guys are talking about here. It just drops off too fast above 60 psi.
I think somebody in here suggested adding a walbro inline high pressure pump to whatever you have in the tank. So you would have 2 pumps in series. Now that would do it. It is a little expensive. But I think it's kinda cool because the inline pump would not be inside your tank, it would be strapped down somewhere outside the tank. Nice little add-on.
Forced Performance: Walbro 255LPH High Pressure Inline Fuel Pump
These high fuel pressures are a little scary to me. You wouldn't want to chintz on your fittings and hoses and stuff, that's for sure.

Gary

 

[chris712vt]

Thanks for the help so far guys.

I've decided to upgrade to an SFMU and 315cc injectors and see how that works for me. Hopefully I can richen it up to a safe AFR, maybe even up the boost a little, but first thing's first getting the car to run safe at 8psi.

 

[totaleclipse_05]

Read this:
2GNT.com - 420a_Sleeper_Part_5

 

[BigRand]

That jump in the AFR is a result of the FMU not responding to the boost immediately.....look how it spikes. And with that 50 trim running the dyno in third gear, your not gonna really see boost until 3500-4000, and the graph shows how the AFR's are dropping.

I have a feeling that your used 12:1 FMU may not be funtioning properly, or may not be a 12:1 disc inside.

Back in the day when I ran that setup, my dyno had me in the 10's and 11's for AFR's, but it would spike up for a second right when you enter boost (not that high). I wish I had afr's to show you guys from back then, but its been a long time.

 

[Car_guy_09]

Mine dips down in the 9's when i floor it then climbs back up to about 10.8-11.3 at 6psi. (with hahns FMU setup)

 

[chris712vt]

Alright, I've got an SFMU and 315cc injectors now, and my new Innovate LC1+DB wideband will be here tomorrow. But before I start installing the new parts, I'm wondering if I should get even larger injectors? I figure with the 315s I can run my 8psi safely, and possibly 10-12psi? Maybe not, but I was going to start at 8 and work my way up while monitoring the afr.

Anyway, if I did get larger injectors, I was planning on getting stock 4g63 450s. I've got 4 friends in town with awd dsms that I thought would have some laying around - turns out none do. I know 450s could be done with the SFMU... maybe not too smooth of an idle but it would be possible. But what about 550s? Is that just too much for an SFMU to control? Reason I ask is because one of my buddies does have a set of 550s he's not using. I could probably go on up to 15psi with them, but I don't know if it's feasible considering idle and cruising.

Any input?

 

[ILLegit420aT]

i have a 97 with 4g63 450's a walboro 255hp and an safc...i run -50% on low thr. and +50% on high thr. and i stay in the 11-11.6 range until high rpm then i will hit 12.2 and 12.3, but im running 16psi on a garret a/r .50 t3/t4 hybrid setup. custom log manifold mild p&p in the head, kometic head gasket and i think if you get 550's you'll need to run around 16-18 psi, and deff invest in msns-e...just my opinion