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Went to the dyno today and my tuner said I'm running out of fuel and need to up grade to a bigger fuel pump I do have 255 in tank pump. What's brand and sized fuel pump I should get look for fuel pump that can suport 800whp
Here's my thoughts, and theory.
The problem I could see with a single pump is, to hook it up in the stock bucket you need to run it to the jet syphon that picks up fuel from the left side of the tank ( because of the saddle shaped hump). It's going to be the only thing feeding the bucket incase of low fuel right hand turning. I'm not sure the limitations of the single line and the siphon, but in appearance it looks like it would be one in higher hp situations.
Dual pumps with a y block to a larger line, would alleviate that problem. The second pump bypasses the syphon, therefore bypassing that restriction.
I had a single aeromotive 340 with bap, in theory should have supported quite a bit, but after thinking of the stock bucket, I wasn't so sure. I imagine even if the syphon allows for enough flow the restriction would raise the pressure from the pump, possibly limiting life.
The bigger the pump the worse it would be.
Like I said just my theory.
You will need a regulated return set up to support that hp.
I'm not sure how much hp the stock system would support hooked up to the syphon jet, with a return. But you may find it a limitation.
Also food for thought, would running a single large 460 pump heat the fuel too much causing vapour lock with a return?
Maybe others can chime in shedding more light.
There haven't been too many definitive answers to your question and I have done much reading and theorizing on the subject.
Right now I am redoing my whole fuel system.
Maybe this will help a bit. I have been looking into fuel pump upgrades and contacted vapor worx about their aftermarket PWM system. Carl, the owner/operator, did some testing of our stock buckets using an upgraded fuel pump (DW300 to be exact). This is what he found.
Our bucket with the DW300 in a stock configuration.
Our bucket, DW300, and with modified pressure regulator and restricter.
Based on these findings and his experience with fuel systems his recommendations were:
1) Low budget single pump and stock regulator. Keep the liquid level in the tank high enough to cover the module when WOT occur for more than a few seconds. Will work just like stock all the way to tank-empty.
2) Dual pump low budget with stock regulator. Same as above but have the second pump triggered with a Hobb's switch + relay. If holes are added to the lower module section I highly suggest always keeping the liquid level above the fuel module. The unknown here is exactly what the flowrate would be. Worst case is 2x that of a single. If the regulator could not bypass enough fuel when both pumps are running then line pressures will go up. I don't believe this is happening to the V1 dual pump module that was outlined in the forums.
3) Same as #2 but add restrictor and plug + pwm. In this case the maximum flowrate would be the restrictor chart values plus the full DW300 flowrates. Since the primary pump is feeding the jet pumps the full volume of the second pump can be utilized.
He has tried none of these solutions but offered them as likely best paths forward.
The issue with #1 is you do get elevated fuel pressure at idle (I am seeing 60 to 62 psi).
The issue with #2 is the same as #1 + you may have an issue with elevated fuel pressures at odd times. Fuel demand depends on more than just the MAP pressure. However the Hobbs switch only reads pressure so in low rpm high boost situations you could see fuel pressure increases (not a deal breaker to me as the worst case is a rich condition with performance limitations rather than a lean condition and a trashed engine).
#3 is likely a good solution for most but with the DW300 and boost it is right in that border area in terms of a solid solution. Most are shooting for 500 hp + for boosted motors. A boost a pump plus the DW300 is likely a good way to go with this as the PWM controller can eliminate the over pressure situations generated due to the limitations expressed in solution #2.
I will be trying the just to see how viable it is but my eventual permanent solution will be two DW300s in tank controlled by Carl's PWM FPR system.
A lot of you may say why not go with a return style system? TO ME it is important that I limit fuel heating and limit current draw on the system. These are two of the advantages of a PWM system. As I am an electrical engineer having an additional electrical component in my trunk is MUCH preferred over adding another run of fuel line down the car with all the potential leaks that come with that run. THIS IS MY PREFERENCE and I am sure others may feel differently.
Kudos on you guys working on an intank solution.
Having too much pump is not always the best solution, having enough pump for your hp goals is.
I'm wondering why you guys are choosing the dw300 pump?
I could see using it for a single pump solution, but not for dual, unless your shooting for 1000+ rwhp.
The amp draw on them seems pretty high. That's why I'm going with dual racetronix 255 pumps, which should support well over 800 rwhp, which is more than most are setting goals for.
The amp draw in the pumps are considerably less to psi ratio. Plus with smaller flow, less chance of sucking the bucket dry, and less heated fuel coming back from the return.
I am also adding an inline cooler to my return line, setting the second pump at 3psi, so hopefully fuel heating shouldn't be a concern.
I also already have a bap, so in going to use that as voltage stabilization, set on low. I'll be adding a second bap to the second pump for the same reason. There is dual bap but they only run on full voltage, so I decided to add a second instead.
It seems from the flow tests that my theory is correct, that the syphon is limiting the flow.
Oh ya, I'm no electrical engineer lol.
Last edited by tommycompton; 03-11-2015 at 10:51 AM.
I am using the DW300 because that is what I selected initially for a one pump plus BAP solution. The second pump will be a DW300 just for form factor. Fuel heating should be minimal with PWM controller as it will adjust duty cycle to only run as necessary. I am interested in your cooler. Can you share a link?
For another data point I always log fuel pressure at the rail.
With a KB BAP and DW300, 6,400 rpm, 10.8:1 afr, (too rich I know), 58% injector duty cycle, 10,100 MAF hz (ls3), map 180 kPa (11.5 psi boost), airflow 75 lb/min (fuel flow ~1.165 gal/min at 6lb/gal) rail fuel pressure 48 psi. This is stock bucket and lines. 40A BAP maxed out. This is 560hp to the wheels. Blower should be eating 130 hp and probably 100 hp to drivetrain loss so 790 at the crank. I haven't checked that math. Looks like bsfc is .75 at wheel hp, .63 at drivetrain, or .52 with blower loads.
At 1000 rpm and the BAP on the fuel pressure is 70psi (must be out flowing the regulator), at 2000 rpm it is at 58.
The original setup was BAP on the stock pump. With the BAP on even on the lowest setting it would outflow the regulator at idle.
With no BAP it was 30 psi or less rail pressure at redline wot.
The BAP is nice because just throwing a huge pump on there is for sure going to outflow the regulator and cause issues. The BAP will minizine it since it only comes on at high load.
The right way to do it is with a boost referenced pressure regulator. At least the 07 computer cannot compensate for boost pressure in the injector calculations so it is fudged. This is exaggerated by lower rail pressure than the 58psi the ecu is expecting. Ie the computer is calculating the pressure differential between map and rail pressure. This is what the injectors see and the pressure is used to calculate the flow of the injectors in that environment. The 07 computer maxs the map at 14.7 psi so the injection delta pressure is always off. A boost referenced regulator cleans all that up!
There are a lot of race car fabricators around here so maybe I'm spoiled but it just seems like it would be easier and probably not that much more cash to cut out the spare tire well and put a fuel cell in the back of the car that would give you the freedom to do whatever you want.
Unless you're intent on running full size spares, this would be the safest (and easiest) way to deliver fuel in a car with the horsepower levels some of you are making. It would also improve the weight bias of the car significantly...
I am using the DW300 because that is what I selected initially for a one pump plus BAP solution. The second pump will be a DW300 just for form factor. Fuel heating should be minimal with PWM controller as it will adjust duty cycle to only run as necessary. I am interested in your cooler. Can you share a link?
I just picked up this heatsink, there are dual pass ones too, that would probably perform better, but the inlet and outlet are on the same side. So for ease of installation I just got the single pass. I've heard of guys using them on return lines, so I'll see how this works out, something has to be better than nothing. http://m.summitracing.com/parts/der-13254
I am running a boost referenced regulator, to up the pressure under boost.
The right way to do it is with a boost referenced pressure regulator.
Yes and no. IMO the best way to do it is manifold referenced (to account for vacuum as well as boost). You may have meant this as well but some folks do not...
At least the 07 computer cannot compensate for boost pressure in the injector calculations so it is fudged.
I believe there is a patch available in HP Tuners to allow the 07 ECU to compensate for boost pressure.
However, all the calculated compensation in the world is not as effective as holding the pressure differential across the injectors constant throughout all MAP levels (like we both said boost/manifold referenced is the best).
A lot of guys also replace the feed line from the tank and go up one size in diameter.
I agree but what confuses me is that they typically due it with the flexible lines. Everything I have read says that the friction coefficient of the hard lines is lower than the flexible (hard for me to believe) and so an upgrade in diameter using flexible lines only provides marginal improvement. I may go to a larger hard line but it will be down the road and only if the fuel system can't keep up.
I've heard of guys using them on return lines, so I'll see how this works out, something has to be better than nothing.
I saw those when looking for an oil cooler solution. I guess my concern with those is where to put it. If you put it on the return near the gas tank then you might be near the exhaust. Obviously a big no no. That leaves you with mounting it near the rail which is likely a PIA if you don't have a lift (jack might crush the fins). I thought about doing something similar and going with a return line but by the time you figure in the cost of the line, the fittngs, and cooler you are over what it costs to buy the PWM module. IMO the PWM module is very likely to deliver better results (in terms of fuel heating) as it shouldn't impart nearly as much heat to the fuel to begin with...
EDIT: Sorry but I moved my mouse before taking the screenshot above. The help message in the box should read:
"[ECM] 121 - Manifold Vacuum Boost Patch: OS Patch to enable the Manifold Vacuum to read negative for boost. Used to make the Injector Flow Rate table read into boost."
Yes and no. IMO the best way to do it is manifold referenced (to account for vacuum as well as boost). You may have meant this as well but some folks do not...
I believe there is a patch available in HP Tuners to allow the 07 ECU to compensate for boost pressure.
However, all the calculated compensation in the world is not as effective as holding the pressure differential across the injectors constant throughout all MAP levels (like we both said boost/manifold referenced is the best).
I agree but what confuses me is that they typically due it with the flexible lines. Everything I have read says that the friction coefficient of the hard lines is lower than the flexible (hard for me to believe) and so an upgrade in diameter using flexible lines only provides marginal improvement. I may go to a larger hard line but it will be down the road and only if the fuel system can't keep up.
I saw those when looking for an oil cooler solution. I guess my concern with those is where to put it. If you put it on the return near the gas tank then you might be near the exhaust. Obviously a big no no. That leaves you with mounting it near the rail which is likely a PIA if you don't have a lift (jack might crush the fins). I thought about doing something similar and going with a return line but by the time you figure in the cost of the line, the fittngs, and cooler you are over what it costs to buy the PWM module. IMO the PWM module is very likely to deliver better results (in terms of fuel heating) as it shouldn't impart nearly as much heat to the fuel to begin with...
I found a place to mount it away from exhaust under the car, which should be safe from a jack, as long as you dont put the jack right on it lol. I'm using teflon braided lines so leaks, fumes, and friction shouldn't be a problem.
I am looking forward to the pwm module results and if they are favourable i would consider swapping out my set up. Not 100% sold on twin dw300's, I'm sure I can always add my pumps to whatever you guys figure out.
I can't wait for a better solution, but if one comes along I'd sell off what I got.
A lot of good stuff here. IF you have a return line, why would you install a cooler on the return? The return line itself mitigates vapor lock - the PWM would further mitigate heat by controlling the fuel pump.
Again, it's good to see new stuff but the need for a fuel cooler flew over my head.
A lot of good stuff here. IF you have a return line, why would you install a cooler on the return? The return line itself mitigates vapor lock - the PWM would further mitigate heat by controlling the fuel pump.
Again, it's good to see new stuff but the need for a fuel cooler flew over my head.
The return is recirculating heated fuel from the fuel rails directly back into the bucket, not something I want. Is a cooler needed, maybe not, but it definitely won't hurt.
Yes and no. IMO the best way to do it is manifold referenced (to account for vacuum as well as boost). You may have meant this as well but some folks do not...
I believe there is a patch available in HP Tuners to allow the 07 ECU to compensate for boost pressure.
I agree but what confuses me is that they typically due it with the flexible lines. Everything I have read says that the friction coefficient of the hard lines is lower than the flexible (hard for me to believe) and so an upgrade in diameter using flexible lines only provides marginal improvement. I may go to a larger hard line but it will be down the road and only if the fuel system can't
EDIT: Sorry but I moved my mouse before taking the screenshot above. The help message in the box should read:
"[ECM] 121 - Manifold Vacuum Boost Patch: OS Patch to enable the Manifold Vacuum to read negative for boost. Used to make the Injector Flow Rate table read into boost."
Agreed on the manifold reference and hell ya thank you for pointing me to the patch!
03-09-2015, 04:35 PM
Fuel pump 
