RWHP Limit of Single Bosch 044
05-14-15, 05:30 PM
#26
...........So far my pump has been doing "ok". When the car hits around 200F and heatsoaks in the traffic, the pump gets louder and the fuel pressure comes down about 5-7psi. After doing some more hunting around it seems its possible that this drop in pressure could also be attributed to the Regulator spring warming up and expanding and/or the density of the fuel changing.....
temp!
I think the effect of heat on the FP regulator spring is probably negligible. It is much more likely that the change in fuel temperature (hence its density and viscosity) is affecting the regulation curve characteristic slightly vs its calibration temp.
Additionally, as the pump motor warms up, its windings will increase in resistance somewhat which reduces pumping power slightly. The density & viscosity of the fuel as well as the speed of the motor will influence the pump's sound.
I personally think modulating the pump voltage, thus speed & capacity is a good way to help control fuel temp.
One other note: IIRC, a stock FD had a solenoid that would momentarily increase the fuel pressure during hot restarts (by cutting the vacuum to the FPR) to improve engine operation following the restart. Interesting that the factory experienced what seems to be a similar problem.
05-14-15, 09:17 PM
#27
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We have one guy running an AEM fuel pump on his RX7. Works just fine, even after extended use. He origionally had a knock off (what we deemed) supra denso FP, the car would get around 300-320WHP and it just would flop. changed to the AEM FP and we were able to go much higher PSI at much lower AFR's. I think he bought it for like $80-90 bucks.
found it.
found it.
05-14-15, 09:33 PM
#28
On my single 044 with 4 ID1000's at 52psi base pressure and 900cc of 50/50 water/meth I have hit 548 rwhp on a ported 13b with a T66 at 26lbs of boost on pump 93 gas. I am pretty sure by my calculations that any more psi and it would start loosing pressure towards redline, I currently high speed data log the fuel pressure. When the fuel gets hot the pump will cavitate and will lose 5 to 10psi of fuel past 6500rpm.
05-16-15, 08:11 AM
#29
I have been using dual 044,s on my 500 rwhp setup for a few years . I have observed that these pumps get louder and cavitate as the fuel and pump itself get warmer. This typically happens when driving for extended periods especially on a low tank of gas.
05-20-15, 02:15 PM
#30
Its very good to hear people coming forward on the cavitation issues with these high flow pumps.
This information is valuable. Alot of folks claim they never have any issues with a Walbro 400, 044, etc...but I'm beginning to think alot of folks don't monitor fuel pressure and/or don't push their pumps to the brink and/or don't drive long distances in hot weather frequently.
At this point, I'm thinking its just the nature of the fuel system to start building heat, especially with the heat of the 20b, and the full voltage to the pump.
A PWM fuel controller, like the speed controller by Aeromotive seems like the solution. Run the pump at low speeds under 3k rpm, but not so low as to drop pressure, just enough to reduce flow significantly, then bring it back up to full volume over 3k rpm.
This way, pump isn't circulating 400lph @ low loads unnecessarily
This information is valuable. Alot of folks claim they never have any issues with a Walbro 400, 044, etc...but I'm beginning to think alot of folks don't monitor fuel pressure and/or don't push their pumps to the brink and/or don't drive long distances in hot weather frequently.
At this point, I'm thinking its just the nature of the fuel system to start building heat, especially with the heat of the 20b, and the full voltage to the pump.
A PWM fuel controller, like the speed controller by Aeromotive seems like the solution. Run the pump at low speeds under 3k rpm, but not so low as to drop pressure, just enough to reduce flow significantly, then bring it back up to full volume over 3k rpm.
This way, pump isn't circulating 400lph @ low loads unnecessarily
05-20-15, 04:56 PM
#31
Yep, in temps above 80 and driving times in traffic cavitation can happen pretty fast (10-15min). Before the summer hits I have a walbro 255hp inline that I will be installing to feed the surge tank and will use a regulator on the surge tank to fuel tank return line to pressurize the surge tank/bosch 044. I am thinking that 25psi should help cure the cavitation and extend the flow of the pump some so I can bump my base pressure up if needed.
05-20-15, 11:23 PM
#32
Yep, in temps above 80 and driving times in traffic cavitation can happen pretty fast (10-15min). Before the summer hits I have a walbro 255hp inline that I will be installing to feed the surge tank and will use a regulator on the surge tank to fuel tank return line to pressurize the surge tank/bosch 044. I am thinking that 25psi should help cure the cavitation and extend the flow of the pump some so I can bump my base pressure up if needed.
Was toying with doing the same thing but with something like a carter black supplying maybe less than a bar to the surge tank but shelved the idea due to lack of precedent and not being 100% confident in the concept amd too lazy to do the experiment lol - basically chickened out.
I ended up using a veyron pump which is allegedly more efficient than, and outflows the 044. Can comfirm it is quieter than the 044 it replaced but yet to see how it really performs after the powertune (soon) or if it tries to boil the fuel tank like tje 044.
Also i think a large part of the overheating problem apart from all the friction of a big pump doing so much work pushing fuel through a regulator and back on an engine sitting in traffic is that you're circulating all your fuel through a pair of hot fuel rails at a rate of 350lph or whatever.
Im thinking it would make sense to control the pumps electronically and/or run a cooler on the return line maybe.
05-21-15, 10:01 AM
#33
Wow yes! Gooooodd info.
So many have told me that I've setup my fuel system wrong, that there's no way my fuel temps would get hot enough to cavitate.
Been hearing the pump do the same loud pitch whine and the pressure gauge drop in hot weather now for months. Gone through 2 walbro 400's at this point, multiple socks. Removed a sock in hopes that it would help and then clogged my fuel system with debris....list goes on. In the end its just normal cavitation as suspected!!!!!!!
Solution:
Just ordered a brand new Aeromotive Fuel Pump Speed Controller. Going to run the pump down to lowest speed possible to where pressure begins to drop and add fuel to the low end of the map to compensate. Switch over will be set around 2k rpms. This should bring the flow down from 400lph to hopefullyly WAYYYYYYYY less
So many have told me that I've setup my fuel system wrong, that there's no way my fuel temps would get hot enough to cavitate.
Been hearing the pump do the same loud pitch whine and the pressure gauge drop in hot weather now for months. Gone through 2 walbro 400's at this point, multiple socks. Removed a sock in hopes that it would help and then clogged my fuel system with debris....list goes on. In the end its just normal cavitation as suspected!!!!!!!
Solution:
Just ordered a brand new Aeromotive Fuel Pump Speed Controller. Going to run the pump down to lowest speed possible to where pressure begins to drop and add fuel to the low end of the map to compensate. Switch over will be set around 2k rpms. This should bring the flow down from 400lph to hopefullyly WAYYYYYYYY less
05-21-15, 10:25 AM
#34
Do you have a fuel cooler installed? I did this do help solve this same problem. I used an old oil cooler (ghetto, I know)placed in the return line beneth the car.There are several versions on the market. I think this helps greatly . I seldom hear cavitation now, but the pumps still get louder after a long drive and low fuel.
Last edited by jetlude; 05-21-15 at 10:31 AM.
05-21-15, 08:43 PM
#35
Yep, in temps above 80 and driving times in traffic cavitation can happen pretty fast (10-15min). Before the summer hits I have a walbro 255hp inline that I will be installing to feed the surge tank and will use a regulator on the surge tank to fuel tank return line to pressurize the surge tank/bosch 044. I am thinking that 25psi should help cure the cavitation and extend the flow of the pump some so I can bump my base pressure up if needed.
The tank pump is only to keep the surge tank full. Ideally, you want a tank pump that will flow just enough to keep up with the external pump at full demand. Even the oem pump has more than enough flow at 0 psi to keep up with most after market hi flow fuel pumps because it isn't under pressure. Too much pump in the tank will also just add more heat because your just circulating more fluid. I would try to mount a top to bottom site tube on the surge tank to see if the level holds at full demand. Who knows, maybe you could see some little bubbles when the cavitation starts.
05-22-15, 09:41 AM
#36
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time to put the fuel pump speed resistor back in
05-23-15, 06:39 PM
#38
I love this idea, let us know how you go with it. I'd imagine that you want your lift pump to be able to match or exceed the flow of your injectors though. Also i dont think it will help with your 044 acting as a fuel heater in traffic, more likely exacerbate it.
Was toying with doing the same thing but with something like a carter black supplying maybe less than a bar to the surge tank but shelved the idea due to lack of precedent and not being 100% confident in the concept amd too lazy to do the experiment lol - basically chickened out.
I ended up using a veyron pump which is allegedly more efficient than, and outflows the 044. Can comfirm it is quieter than the 044 it replaced but yet to see how it really performs after the powertune (soon) or if it tries to boil the fuel tank like tje 044.
Also i think a large part of the overheating problem apart from all the friction of a big pump doing so much work pushing fuel through a regulator and back on an engine sitting in traffic is that you're circulating all your fuel through a pair of hot fuel rails at a rate of 350lph or whatever.
Im thinking it would make sense to control the pumps electronically and/or run a cooler on the return line maybe.
Was toying with doing the same thing but with something like a carter black supplying maybe less than a bar to the surge tank but shelved the idea due to lack of precedent and not being 100% confident in the concept amd too lazy to do the experiment lol - basically chickened out.
I ended up using a veyron pump which is allegedly more efficient than, and outflows the 044. Can comfirm it is quieter than the 044 it replaced but yet to see how it really performs after the powertune (soon) or if it tries to boil the fuel tank like tje 044.
Also i think a large part of the overheating problem apart from all the friction of a big pump doing so much work pushing fuel through a regulator and back on an engine sitting in traffic is that you're circulating all your fuel through a pair of hot fuel rails at a rate of 350lph or whatever.
Im thinking it would make sense to control the pumps electronically and/or run a cooler on the return line maybe.
05-26-15, 10:12 AM
#41
The fuel is not getting excessively hot, the 044 is just very prone to cavitation and force feeding it should cure the problem of the cavitation. Stripped all of 3rd gears teeth off again and will install the new lift pump when I do the transmission, hopefully sometime next week should have the answer to whether it will work or not. I have done a test of putting 3 to 5 psi of pressure on the 044 when cavitating and it immediately cures it, however this is done at idle and not full boost.
I'm running the 20b around 550rwhp with fear of increasing on the street to the 700rwhp tune as I'm hearing alot about these 3rd grears letting go over 500rwhp!
05-27-15, 09:59 PM
#42
I am installing the 4th transmission in 14,000 miles. Tires are 255/40/17 Direzza Z2's 200 tread wear, with a 3rd gen torsen retrofitted to the rearend. I do boost alot though, I have around 10,000 full boost pulls on the truck with in the time frame. I would blow 3rd about once a month with my 3rd gen running 28psi on a t88, I was using enough fuel for 700 crank hp and the car was weighing in at 2,527 lbs very close to the trucks weight of 2,510. They will hold for a while sometimes, then with usually no warning it will blow right as it hits full boost. The up side is, when it does blow you can just keep on driving to your destination.
05-28-15, 12:17 AM
#43
I am installing the 4th transmission in 14,000 miles. Tires are 255/40/17 Direzza Z2's 200 tread wear, with a 3rd gen torsen retrofitted to the rearend. I do boost alot though, I have around 10,000 full boost pulls on the truck with in the time frame. I would blow 3rd about once a month with my 3rd gen running 28psi on a t88, I was using enough fuel for 700 crank hp and the car was weighing in at 2,527 lbs very close to the trucks weight of 2,510. They will hold for a while sometimes, then with usually no warning it will blow right as it hits full boost. The up side is, when it does blow you can just keep on driving to your destination.
05-28-15, 08:49 PM
#45
Faceplate. The also strengthen all the gears themselves. I've done quite a bit of 3rd gear roll freeway racing at over 600whp without issue. What type of clutch are you using? Breaking the gear on a roll seems pretty excessive but you've done it on multiple trans so something is definitely going on. Give them a call and tell them your situation. They are definitely very knowledgeable and should be able to help you out.
05-28-15, 10:07 PM
#46
In the truck I am using a ACT 6 puck sprung with a stock rx8 pressure plate, in the 3rd gen I had both sprung and unsprung 6 puck with the ACT extreme pressure plate. both on 10ish pound flywheels. I will give them a call, as I am kind of torn between what trans swap I want to do on the 3rd gen.
05-29-15, 06:34 PM
#47
Your truck is an animal on wheels!!!!! I've seen the videos, holy sh*t man. I still don't understand how you go through transmissions. no issues hammering the gears on slicks (KNOCK ON WOOD). Using an exedy twin disc...its a hell of a lot smoother engagement than the 6 puck on last engine. I wonder if using a dampener on the slave cylinder would help?
If your 4.9 sec 60-120 is legit, that's one of the fastest vehicles around on the interstate. 1200hp GTR are barely scratching 4.5 seconds IRRC
If your 4.9 sec 60-120 is legit, that's one of the fastest vehicles around on the interstate. 1200hp GTR are barely scratching 4.5 seconds IRRC
Last edited by Monsterbox; 05-29-15 at 11:26 PM.
05-29-15, 06:43 PM
#48
Update: Aeromotive Speed Controller = LAMEEEEEE
Its great quality, but the RPM system is subpar. This gadget is suppose to drop to low speed under a threashold RPM and pop back up to full speed. Well, at low speed mode with the car running, the device is oscillating between full speed and low. Essentially, the RPM signal has noise and/or the device doesn't filter well enough to distinguish the square wave. It does pop up to full speed the threshold, but it doesn't maintain its low speed operation.
Options I'm considering:
1. wiring the OVERRIDE switch (which jumps it to full speed) into the ECU auxillary output and triggering manual override based upon MAP/Load or RPM from ECU
2. wiring in resistor/capacitor to filter the square wave before it reaches the controller.
Aside from the issue, this controller has potential. The little pot adjustment allowed me to bring the pump down to around 10v before it would stall on revving. Sounds wayyy deep pitch and humming, and fuel pressure drops around 10psi. AFR's came down around 1.0 at idle and rev up to 2k.
Once the triggering issue is solved, I will add a global percentage correction to the fuel map at all breakpoints below the 2.2K rpm threshold. This should keep AFR consistent at the lowered rail pressure until it returns to nominal base.
Ill let you guys know soon how it works out.
Also have a Craig Davies EWP on the way, which I'm going to control with a solid state relay and PWM off the ECU.
Its great quality, but the RPM system is subpar. This gadget is suppose to drop to low speed under a threashold RPM and pop back up to full speed. Well, at low speed mode with the car running, the device is oscillating between full speed and low. Essentially, the RPM signal has noise and/or the device doesn't filter well enough to distinguish the square wave. It does pop up to full speed the threshold, but it doesn't maintain its low speed operation.
Options I'm considering:
1. wiring the OVERRIDE switch (which jumps it to full speed) into the ECU auxillary output and triggering manual override based upon MAP/Load or RPM from ECU
2. wiring in resistor/capacitor to filter the square wave before it reaches the controller.
Aside from the issue, this controller has potential. The little pot adjustment allowed me to bring the pump down to around 10v before it would stall on revving. Sounds wayyy deep pitch and humming, and fuel pressure drops around 10psi. AFR's came down around 1.0 at idle and rev up to 2k.
Once the triggering issue is solved, I will add a global percentage correction to the fuel map at all breakpoints below the 2.2K rpm threshold. This should keep AFR consistent at the lowered rail pressure until it returns to nominal base.
Ill let you guys know soon how it works out.
Also have a Craig Davies EWP on the way, which I'm going to control with a solid state relay and PWM off the ECU.
Last edited by Monsterbox; 05-29-15 at 11:28 PM.
05-29-15, 08:54 PM
#49
Seem like for a turbo car you would be better off to use MAP sensor signal instead of RPM.
I know when I maxed my injectors when WG line came off it was 3,000rpm and ~30psi boost.
You need to cover your *** for boost and not rpm. As a bonus MAP signal is a nice linear 0-5V signal.
I know when I maxed my injectors when WG line came off it was 3,000rpm and ~30psi boost.
You need to cover your *** for boost and not rpm. As a bonus MAP signal is a nice linear 0-5V signal.
05-29-15, 11:30 PM
#50
Used the aux ecu output to trigger off map at vaccuum levels on the override function and it worked well. The pump was able to run at 9.5v and keep afr similar at idle and in the vaccuum areas. This should hopefully stop the cavitation