[Scott65]

This is exciting for me. I've had a really hard time finding something that is mainstream(for reliability) and suitable to handle the power requirements of a large pump. I'm not sure how other ECU's handle PWM fuel pump control, but MS uses a 50-250 hz ground triggered output. This is, even at 250hz not a high enough frequency to directly drive a motor although some of the MS users do it via solid state relay. I tried it and found it severely lacking. The motor sounded terrible. There are fpdm(fuel pump driver modules) that the OEMs use that would possibly be suitable, except they're mostly made for smaller pumps, and I believe mostly positive triggered. After participating in a thread here on Vaporworx, I contacted Carl. He bent over backwards basically redesigning one of his controllers to work in my application. It's nice to find people like that still out there. He had to not only redesign his controllers, but re think and rewrite an instruction manual. He sent me a purpose built product with excellent peripheral components (wire, connectors, heat shrink, sheathing, and instructions) He was an absolute pleasure to deal with and very helpful and willing to share all kinds of fuel system information. It's early on, today I got it up and running and set pressure vs duty cycles etc. Will make a full on, long drive this evening to check pressures under all conditions. I'd highly recommend if you have fuel system needs, contact Carl@Vaporworx.

[65madgoat]

Another thumbs up for Carl and VAPORWORX!!

[JLMounce]

Big power PWM is unheard of. Lift pumps is/was the game with positive displacement belt drive units.

TBI's won't PWM control anything larger than 340lph, period. That's 800 hp on gas, 600 on E85, but the duty cycles are getting ridiculous at that point.

I'm not entirely sure how the OEM's are doing it. Heck the 2003/2004 Cobra used a PWM controlled dead-head system that was capable of 600hp with the factory pump. A bit more with an FPDM and wire upgrade. You'd run out of injector before you ran out of pump on that deal.

The hellcat pump is similarly perplexing. Mopar runs this thing PWM as a dead-head and it's proven to have spare capacity. PWM controlling the thing in the aftermarket is something different entirely however.

Outside of maybe the MOTEC stuff powering the UG Lamborghini's, I don't know of anyone that isn't running sumps with lift pumps or multi-pump recirc systems for moderate to big power. Certainly not in street driven applications anyhow.

[Scott65]

I'm fortunate to have the capability. But like I said, there was a missing piece. The Vaporworx controller has the frequency to make it happen. The pump is dead quiet even at 50% duty cycle. I tried 50% with a SSR, and it sounded like a rock crusher... I'm going through the datalog of a 30 minute drive all driving conditions right now, verifying commanded duty cycle is following the table, and that fuel pressure stays correct at the reduced duty cycle. I'm about 3/4 through the log so far, and everything looks great so far.

[Scott65]

I put maybe 3 hours drive time on it this weekend and everything seems exactly as it should be after sifting through the logs. I don't know how many people this particular controller will apply to here, but I'm very happy to have it. Kudos to Carl for being willing to explore this option.

[krisr]

Great job man! Welcome to the PWM-dead-silent-pump club!

[CarlC@VaporWorx]

Thanks for giving it a try Scott. It will be interesting to see how far the duty cycles can be reduced for the idle/cruise regime since this is where the engine spends a lot of running time.

My favorite pumps for PWM control are from Bosch and Kafus. Kinda like a well tuned engine, they just sound sweet. Granted in the car one would likely never tell the difference since even a quiet exhaust tone will drown out a PWM controlled pump. Kafus is the primary supplier fuel pump modules to GM. They do nothing aftermarket, but their tech is up there, IMO, with TI Automotive.

Originally Posted by JLMounce

Big power PWM is unheard of. Lift pumps is/was the game with positive displacement belt drive units.

TBI's won't PWM control anything larger than 340lph, period. That's 800 hp on gas, 600 on E85, but the duty cycles are getting ridiculous at that point.

I'm not entirely sure how the OEM's are doing it. Heck the 2003/2004 Cobra used a PWM controlled dead-head system that was capable of 600hp with the factory pump. A bit more with an FPDM and wire upgrade. You'd run out of injector before you ran out of pump on that deal.

The hellcat pump is similarly perplexing. Mopar runs this thing PWM as a dead-head and it's proven to have spare capacity. PWM controlling the thing in the aftermarket is something different entirely however.

Outside of maybe the MOTEC stuff powering the UG Lamborghini's, I don't know of anyone that isn't running sumps with lift pumps or multi-pump recirc systems for moderate to big power. Certainly not in street driven applications anyhow.

As long as the injector is fed a sufficient volume of fuel at the intended pressure it does not care if the fuel system is return or returnless.

Every OEM uses PWM returnless systems to control pressure, even most of the lower horsepower models. The OEM's are not doing this because it costs less than a simple mechanical regulator and a return line. Long term reliability comes first into play. Second is emissions. I'm a bit of an oddball, but I consider modern emission requirements to be the best thing that has happened to automotive performance in the last 5 decades. ECM's, sensor technology, CFD for intake/head/combustion chamber/exhaust port, etc. has all lead to quiet revolution in power production.

GT500 are at 750hp on returnless
C7ZR1 750hp
Demon 840hp

At VaporWorx, we've been at the PWM gig for 13 years. Again, I'm the oddball because I wanted something for my 1968 Camaro that did not exist and nobody wanted to make, a stand-alone returnless PWM controller to work with the OEM intank fuel modules (which are worlds better than anything in the aftermarket.) We're now up to 1850hp using triple F90000285 525lph pumps on e85 and have not found the top end yet.

Generating a PWM signal is pretty easy. It's what's done afterward that is more challenging.

So the question then becomes, if every OEM manufacturer abandoned full-return systems decades ago, why do the big aftermarket companies still push them?

[krisr]

Originally Posted by CarlC@VaporWorx

Thanks for giving it a try Scott. It will be interesting to see how far the duty cycles can be reduced for the idle/cruise regime since this is where the engine spends a lot of running time.

My favorite pumps for PWM control are from Bosch and Kafus. Kinda like a well tuned engine, they just sound sweet. Granted in the car one would likely never tell the difference since even a quiet exhaust tone will drown out a PWM controlled pump. Kafus is the primary supplier fuel pump modules to GM. They do nothing aftermarket, but their tech is up there, IMO, with TI Automotive.



As long as the injector is fed a sufficient volume of fuel at the intended pressure it does not care if the fuel system is return or returnless.

Every OEM uses PWM returnless systems to control pressure, even most of the lower horsepower models. The OEM's are not doing this because it costs less than a simple mechanical regulator and a return line. Long term reliability comes first into play. Second is emissions. I'm a bit of an oddball, but I consider modern emission requirements to be the best thing that has happened to automotive performance in the last 5 decades. ECM's, sensor technology, CFD for intake/head/combustion chamber/exhaust port, etc. has all lead to quiet revolution in power production.

GT500 are at 750hp on returnless
C7ZR1 750hp
Demon 840hp

At VaporWorx, we've been at the PWM gig for 13 years. Again, I'm the oddball because I wanted something for my 1968 Camaro that did not exist and nobody wanted to make, a stand-alone returnless PWM controller to work with the OEM intank fuel modules (which are worlds better than anything in the aftermarket.) We're now up to 1850hp using triple F90000285 525lph pumps on e85 and have not found the top end yet.

Generating a PWM signal is pretty easy. It's what's done afterward that is more challenging.

So the question then becomes, if every OEM manufacturer abandoned full-return systems decades ago, why do the big aftermarket companies still push them?

Thanks for the comments Carl! PWM is definitely the way to go. I've been PWM'ing my Ti fuel pump in my fuel cell for many years now, originally started using a Jaguar controller sending it a 100Hz PWM signal from the ECU, now with Haltech PD16 it's PWM straight on the power wire now. I've seen your products and they definitely look great, for me it was a case of what was available to me locally (Australia) which influenced my decision. My pump is dead silent and only use a mechanical fuel pressure regulator as a safety (set at 65psi) should anything go wrong and it gets 100% DC. Run my pumps and regulator are in the trunk, single line to the fuel rails, just like the OE.