Shop just rolled the car again showing the fuel pump commanded 100% duty cycle
KPM1000 issue and suggestions
Issue - over 5k RPM I'm not getting more fuel pressure. Prior to this issue, if the car sat overnight it would not start on the first try. It would not the second attempt.
Builder is contacting KPM to see what they have to say. I have posted this issue within Facebook groups and I'm hearing others that had issues and they got no support from KPM. My unit is less than a year old.
If I have to go with something else. Looking for suggestions. My builder like dsx aux pump. I didn't go that route due to tapping the tank. KPM is a drop in solution. However I might be open to whatever at this point. I heard of issues with manual cars and dsx, anyone had issues?
Car info - I'm over 700hp
2016
Manual,
MGW Shifter,
SLIHRM,
Whipple w3.75 pulley,
Monster Triple clutch,
E85,
FIC1200,
KPM1000,
PNP Frostbite - newly installed
CTS-V Sedan wheels / PS4 tires,
PRC Ported heads,
TSP Stage 2 cam,
upgraded internals / CHE,
RotoFab,
Maloo skirts - newly installed
Commodore specialties spoiler(on order)
Builder is contacting KPM to see what they have to say. I have posted this issue within Facebook groups and I'm hearing others that had issues and they got no support from KPM. My unit is less than a year old.
If I have to go with something else. Looking for suggestions. My builder like dsx aux pump. I didn't go that route due to tapping the tank. KPM is a drop in solution. However I might be open to whatever at this point. I heard of issues with manual cars and dsx, anyone had issues?
Car info - I'm over 700hp
2016
Manual,
MGW Shifter,
SLIHRM,
Whipple w3.75 pulley,
Monster Triple clutch,
E85,
FIC1200,
KPM1000,
PNP Frostbite - newly installed
CTS-V Sedan wheels / PS4 tires,
PRC Ported heads,
TSP Stage 2 cam,
upgraded internals / CHE,
RotoFab,
Maloo skirts - newly installed
Commodore specialties spoiler(on order)
Attachments
1 - 10 of 29 Posts
Thanks for the replies. KPM is saying the pump can't support my build. Questions does this pump actually support the numbers they say it can?
I'm thinking dsx. My builder trusts them and does a lot of them. It's the hole in the tank I hate.
@a6d9cmro do you know anyone that has used that hat? Looks nice. 500 and some change.... hmmmm
I'm thinking dsx. My builder trusts them and does a lot of them. It's the hole in the tank I hate.
@a6d9cmro do you know anyone that has used that hat? Looks nice. 500 and some change.... hmmmm
Attachments
I appreciate your time and knowledge for this reply. I ended up adding a DSX. Maybe I'll find the limit of this setup, maybe not. I'm not a hardcore racer by any means and this is all new to me.Manufacturers often will tout their fuel pumping products for being "1000hp capable!" This can be misleading since to make the pump have sufficient output volume to support 1000hp (theoretical) the pressure must be very low, lower than what is needed to support supercharged applications. Also, manufacturers will state a horsepower number based on a Brake Specific Fuel Consumption value that is also not practical.
BSFC is a measure of how much fuel a single horsepower needs per hour. For example, for most naturally aspirated engines need about 1/2 lb/hr of gasoline for each horsepower. 500hp x 0.5 = 250lb/hr of gasoline (units are left out for simplicity.) These are engine/flywheel horsepower values. This BSFC makes sense since a 5hp lawnmower running at full speed/under load will use about 1/2 gallon of fuel per hour. Gasoline weighs 6lb/gal, so 1/2 gallon weighs 3lbs. 3lb / 0.5 = 6hp.
Mild supercharged V8 engines up to about 750-800hp have a BSFC of about 0.6. Using the same 500hp engine as above, 500hp * 0.6 = 300lb/hr. So, 20% more fuel for the same horsepower as the NA engine. This is due to the pumping losses to driving the supercharger.
BSFC goes up dramatically as power increases over 750-800hp. As an example, MOPAR has Hellcat and Hellephant crate engines. These are highly developed and efficient engines. The Hellcat, at 707hp, needs 300lph of fuel. The 1000hp Hellephant makes 41% more power than the Hellcat. But, the Hellephant needs 630lph of fuel, a 210% increase in demand. The BSFC goes from about 0.6 to 1.0. For engines over about 1000-1200hp, the BSFC goes to at least 1.2 on gasoline.
This means that at about 850-900hp the amount of gasoline needed starts to exceed what is needed for e85. The cooling effect of e85 is quite helpful for timing and detonation resistance, whereas more gasoline needs to be applied to help cool intake charges and avoid detonation. BSCF for e85 is about 0.85.
Voltage also has a large influence on pump performance. For brushed pumps, a pretty good estimate that for every 1v of change at the pump will result in a 15% change in pump output. That means going from 12v to 13.5v at the pump results in a 22.5% increase in pumping capacity. There is falloff on this as the voltage becomes quite high, but for non-voltage boosted applications it's important to keep all power connections in good condition and sufficiently sized.
Example:
The big "H" company states that their newest brushless fuel pump is good for 2000hp. After digging deep into how they came up with this, the pressure is 35psi, the input voltage is 18v, and the BSFC is 0.5. When spec'ed using 65psi/13v/0.85BSFC, it becomes an 850hp pump. This is a true example, and may lead to someone putting a pump that is woefully short on pump capacity.
The true measure of what any pumping system will do is proper data and/or proper flowrate chart.
From a practical standpoint the KPM1000 or the VaporWorx Super ZL1 are good for about 750-800FWHP on gasoline. There is flowrate data available here: Gen5 Camaro ZL1 Super Fuel Module - VaporWorx
There is little advantage to change the pump in the ZL1 fuel module to a 525lph pump. First, it won't come close to fitting. Second, the pump in a stock ZL1 module is basically a TI 450lph pump, and the VaporWorx Super ZL1 a TI 525lph/F90000285. Both are so close to their TI counterparts that the graphs almost overlay each other. However, the real measure of the fuel module performance is what comes out of the top hat connection. There are fuel volume losses inside of the pump module that are needed to drive the jet pumps. All too often folks take the raw fuel pump output (525lph pump output) and think that's what comes out of the fuel line connection. That's a hard nope.
For most builds up to 750-800hp the Super ZL1 is a great option. It keeps all of the OEM fuel handling, filtering, and connections in place. Basically, it's plug and play. It does have a check valve just like the stock ZL1. In fact, none of those parts are changed. Just the electric pump and jet pump feeder hose are replaced.
For those looking for more capability the KPM Streetfigher is, for now, my first choice. It is very well thought out and is in line to go into my car shortly. However, there are some additional parts and labor needed to make it work correctly.
1) It will need a check valve near the outlet at the hat. If the check valve is not used it will cause fuel drainback and long crank times.
2) Since there is now a check valve near the outlet of the pump a safety overpressure valve must be installed. Imagine driving the car on a hot day and you pull into the 7-11 to get a soda. You head back and try to start the car but it it won't fire. It acts like it is out of fuel. It is. Heat soak from the engine has caused the fuel line pressure to go up. We have observed 200+psi pressures in these cases, which is no bueno for lines, fittings, rails, etc. From a practical standpoint, once the fuel pressure goes over about 100psi the injectors stop working, hence the engine won't start. The safety overpressure valve can be done with a Radium Engineering 20-0014 regulator holder and a 6bar pressure regulator available from VaporWorx. This safety overpressure system is the same as what is in the stock ZL1 fuel module. That's what the silver cylindrical device near the bottom is, a safety overpressure regulator.
3) An inline fuel filter is needed.
4) It is highly suggested to use a PWM controller to slow down the pumps. The way the SF1500 is designed both pumps must run all the time. Imagine the heat generated by driving twin 450lph capable pumps (it uses Bosch pumps) full speed all the time. That's a lot of heat going into the fuel load along with the added electrical demand to the vehicle. This kit reduces idle/cruise power by 83% and keeps the OEM Fuel System Control Module functional. KPM Streetfighter 1500HP Ally PWM Fuel Pump Controller - VaporWorx
Matt Carlson has the SF1500 using all of the above. If memory serves he's near 800RWHP on e85. This same setup has been used in Australia/Holden chassis for several years @ 850RWHP e85 without issue.
Basic plumbing layout:
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