• We are no longer supporting TapaTalk as a mobile app for our sites. The TapaTalk App has many issues with speed on our server as well as security holes that leave us vulnerable to attacks and spammers.

mbarryracing's Apex fuel system upgrade

mbarryracing

TY 4 Stroke God
Joined
Aug 31, 2007
Messages
1,922
Age
51
Location
Springville NY
Country
USA
Snowmobile
2006 Yamaha Attak Turbo
2015 SR Viper RTX-DX
1996 Vmax 600XT
Figured I would share some more of my learning curves from trying to make my Turbo Apex trail reliable, after burning up two Bosch 044 fuel pumps in a row.
If you guys remember a few years ago after I originally had fuel starvation issues with my FPP stage 2 secondary fuel pump setup using the stock in-tank pump as a lift pump to an external Walbro 255 Hi Press pump, I deleted the in-tank pump with a Hurricane Performance stock fuel pump delete kit after I finally figured out it was faulty and was puking out when the fuel got too warm.
At that time I also upgraded to a big Bazangha Bosch 0-580-254-044 fuel pump that could flow 300LPH of flow (488 lbs per hour!!!) and operate up to 72.5 PSI, just in case I ever wanted to run big Bazangha boost levels. Mounted it in the nose of the sled, I felt like a real man with this huge fuel pump buzzing away.
However, for two seasons I chased inconsistent fuel pressures and eventually intermittent fuel pump operation, failing two different pumps that weren't cheap. You could always hear they sounded erratic like they were pumping carbonated soda...

I had heat issues where the exhaust heat was baking the gas tank and wicking into the fuel, resulting in boiling fuel issues. The hot fuel was definitely a contributor to inconsistent fuel pressures, and pump cavitation, but still struggled with that even after I rectified my thermal management issues.

After an ah-ha moment while doing some much needed research on other reasons for pump cavitaion, I now understand that with big fuel pumps that produce big fuel flow, they need to be able to be fed big fuel flow too. That means the fuel pickup and supply lines have to be able to support that kind of fuel flow at a low restriction. I finally determined that the stock Yamaha in-tank fuel pickup / cloth filter (that is re-used with the Hurricane Performance's stock pump delete kit) was good for stock fuel pump flow levels but much too fine / restrictive for bigger pumps. Since Yamaha used it as the sole fuel filter in the system, it's more like a 10 -30 micron filter.
NOTE most race fuel pump manufacturers s recommended to not have a pre-pump filter anything less than 70 microns or it can lead to fuel pump starvation issues, leading to cavitation and failures. A smaller finer filter, like 10 micron, is OK for post-pump but not before the pump.

Aeromotive Tech Bulletin #101 : "When a fuel pump has to pull through a restriction to get fuel from the tank a vacuum develops which lowers the fuel’s boiling temperature, cavitating the fuel and turning it from liquid into vapor."

So long story made longer, that stock in-tank filter sock was causing my big fuel pump to starve and cavitate, causing inconsistent fuel pressures and eventually wear it's internal vanes and burn out.
Well I'm a little smarter now, that Bosch 044 was TOO MUCH fuel pump for my needs after all. Reality slapped me that my GT2860 can't produce enough boost to need that much fuel flow anyhow, and 99% of the time I'm trail riding on pump gas NOT at 50 lbs boost.


20150228_123256.jpg
View attachment 115915
 
Last edited:

I decided to completely redesign my fuel supply system, from the tank pickup to the fuel pressure regulator, to provide low restriction / free flowing fuel supply to the pump.

Starting with fabricating the in-tank fuel pickup, I elected to go with the Walbro snowmobile 5/16" check valve style pickups MP-12 and MP-13, same that Arctic Cat racers and Rock Crawler trucks use.
These have a fine mesh screen that when submerged in fuel, the fuel will pass through the mesh with ease. When fuel sloshes away from the pickup, the mesh will hold enough fuel to fill all the tiny holes. That mesh full of fuel acts like a solid. At this point, the pump, sucking on the pickup will cause the mesh to suck shut, closing a check valve and preventing the pump from sucking air. When fuel covers the pickup once again, the valve will open up and transfer fuel. The inlet side of the pickup has a 70 micron mesh and can flow 40 gal per hour.
Walbro suggests that one pickup in the system should have a bleed hole. If your system doesn't have a bleed hole, it can become totally closed if all of the pickups close at once. If that happens, the closed pickups can take many minutes to re-open, depending upon how much vacuum the fuel pump has pulled. In extreme cases, you may have to open your fuel tank and remove a fuel line to break that vacuum. On the side of the trail, that would "suck", literally...

So I used two pickups to make sure I had enough flow capacity, plumbed one MP-12 non bleed hole in the rear of the tank and one MP-13 with the bleed hole in the front of the tank so if under low fuel conditions the fuel sloshed to the back of the tank under a wheelie or under hard acceleration, the front would suck shut and close but be able to open back up again.

20150228_001431.jpg
20150228_001424.jpg
MP_bottom.jpg
 
Last edited:
I redesigned the tank plate, tossed out the original 5/16" brass elbow and 1/4" fuel line and welded in a 3/8" aluminum bung to use 3/8" brass barbed hose fittings with the intent to keep the fuel supply lines as large as possible feeding the pump with as little restriction as I could.
I used good Gates 5/16" submersible fuel line #27093 inside the tank so wouldn't have the risk of the fuel line swelling shut or splitting, spit off and ran in a 'Zoro" pattern to the pickup in the front right corner and to the left rear corner. Used good Oetiker clamps.

20150227_231727.jpg
20150228_003407.jpg
20150228_121155.jpg
 
Last edited:
I elected to try an Aeromotive inline EFI fuel pump #11109 (rated 325 lbs per hour, little lower flow than the Bosch 044 (488 lbs/hr) but still good enough for 375 HP under boost) pushing through an Aeromotive serviceable 10 Micron in-line fuel filter #12301 with AN-10 fittings and then a JEGS fuel check valve.
I compromised after the guys at FPP reasoned with me. This new fuel pump rating now more matches my current GT turbo power rating. If I'm going to run 400-500 HP in the future, I will upgrade to a bigger fuel pump or dual pumps when I upgrade to a larger turbo... if I EVER go that route. Now in hind sight, this makes more sense because I am almost 100% only ever running pump gas boost levels.

Wasn't sure if the inconsistent fuel pressures were all due to the pump cavitation, or if the inexpensive Tomei adjustable FPR I had previously installed (replaced stock FPR on rail with an adapter plate and nipple) & had mounted on the headlight pod bracket above the engine was getting baked in the heat from the exhaust was a player, too. It use to get so hot I couldn't touch it, obviously that was adding even more heat into the fuel...

DSCN0118.JPG


So as a precaution I tossed that fuel pressure regulator and went with the adjustable (and rebuildable...) AEM rising rate FPR #25-302BK that I mounted up front in the nose with the fuel pump and MoTec ECU. Plumbed the fuel lines out away from the heat of the engine for more consistency. Set FP to 43psi, now nice and consistent.

Used a variety of 6AN, 8ANand 10AN fittings and adapters.

20150223_220507.jpg
20150223_220524.jpg
20150228_130932.jpg
 
Last edited:
With just the fuel system changes, the first test ride out the sled was super fat rich more than 10:1 AFR under WOT 14 psi boost, misfiring and gurgling. I had to pull fuel out of the secondary boost fuel map to lean it out to 11.5:1 where it started running clean. This reconfirms that my monster Bosch Fuel Pump wasn't keeping up under boost and I was unknowingly compensating for it with the fuel mapping.
This new system is flowing more freely and more efficient, not working as hard to maintain 57 psi fuel pressure at 14 lbs boost. Its much more happier than that Bosch 044 pump trying to suck 488 lbs per hour of fuel thru a bar stir stick...
 
Last edited:
Awsome write-up, if someone wants to build an solid fuel delivery system, this is how to do it.
 
I love the looks of the install, very clean!
 
How much power are you running on pump gas on the trails?
kinger,
Running 14 lbs boost with 91-93 pump gas it's definitely 290-300, or more, at the engine. I haven't engine dyno'd it with the Motec yet, but the last time I dyno'd it with the old piggy back fuel controller and same 2860 turbo at 12 lbs boost it was tickling 280. Since putting the Motec on I had to add clutch weight from where it pulled the same boost with the piggyback, so it's making even more power. I'm pretty sure there is more left on the table with higher boost and timing, but not going to gamble with it unless I can test it first on the dyno since I didn't buck up $ for the knock control option.
Honestly it's pretty darn sufficient at 14 lbs, been running that way for 2 seasons now without hurting the motor, so not the time to get too greedy. LOL
 
Last edited:
That is a pretty cool set up. I run a egay 255lph in tank and make 255-260 hp but may convert to a mid mount impulse turbo this summer. I was hoping to just plumb a external 255lph walboro and call it a day. This is great info.


Sent from my iPhone using Tapatalk
 
kinger,

I have had ZERO issues with this fuel system since I did it, other than a year ago having to tighten a worm clamp on the fuel return line fitting to the tank that was occasionally dripping. Still all the original components... I have actually not had any issues with the sled running at all.
I fully believe the key to fuel pump durability is the low restriction fuel pickup in the tank / low restriction on the suction side of the pump. I found a scan of my original "bar napkin" sketch of the in tank pickup showing where each component went, if that would help you.
 
Last edited:
I would take any drawings. I have the same thought process with the placement of the pick up screens and one with the hole in it. Did you anchor the pick ups down at all or do they just slap around in the bottom by the strength of the hose? Is your FPR after your rail? How did you connect the hose to the rail? Thanks for the help! Also I think I'm doing ID 1050x injectors so hoping Martin has a fuel map for those. I think last time it was all based on ID1000.
 
kinger,
I did not have to anchor the pickups down, they don't flop around. They stay in place because the submersible fuel line is rather stiff so the plumbing is rigid and keeps the Walbro pickups planted in the corners of the tank. Sorry the sketch is crappy, but should answer some questions on the positions of the fittings. I can't find my notes on the exact lengths of each hose section but mocking up is the best method.
Apex Fuel Tank Pickup sketch_01.jpg



Yes my AEM FPR is plumbed after the fuel rail. I ran fuel line from the outlet of the fuel rail down the right side of the hoop to the regulator in the nose then back up to the factory fuel return fitting on the gas tank.
The fuel line is attached to the outlet of the fuel rail via a 90 deg brass barbed fitting in an aluminum adapter plate from a Subaru in the place of the factory fuel pressure regulator . See pics. I think I posted the particulars on this adapter in one of my original buildup posts.
P35.JPG


Capturefitting.PNG


As far as the ID 1050 injectors, Martin is usually pretty busy and I hate bothering him so I have had pretty good Motec support from the guys at T1 Race Development with dialing in their ID injectors. Was told that if you have the most recent Motec update that the ID1050 data should already be in the ECU already so should be able to select it from the injector list and the Motec will adjust everything in the file accordingly. None of our Motec's had that so when we upgraded a drag race SkiDoo 1200 from ID1000's to 1050's we used the same Motec cal / maps for the ID1000 by adjusting the injector battery comp to match and then slewed out about -5% overall fuel trim because the flow difference between the ID1000's and the ID1050's is only about 5%. Minor tweaking of fueling tables from there but that was likely more attributed to the simultaneous upgrade to bigger a GTX turbo and change to different fuel...
 
Last edited:
Awesome, its in your original post as well! Good reference! Can't wait to get this thing powered up and getting the data logs. Toying with adding the GPS speed to see real speed at launch compared to time vs just track spin. So many cool things to control.
 


Back
Top