Project Hellraiser

Page 16

   
 
 

Previous Page


The recent club road trip exposed a few problems on the buggy.  The first was a failing alternator.  In the past I had experienced issues with the motor cutting out at wide open throttle.  I have since replaced all sorts of sensors, a fuel pump, added grounds, swapped ignition modules and tried disabling the boost bypass valve in order to narrow down the culprit. The hills at the cinders in Flagstaff turned out to be a great diagnostic tool, due to the inclines and altitude the engine was working hard and consequently I had all three cooling fans running full speed most of the time.  This heavy electrical load exposed the dying alternator when the buggy stalled while trying to climb one of the hills, a lucky glance at the voltmeter at that moment showed 8V. After having the battery test good that evening I bought a new alternator and haven't had a hesitation since.

I had my doubts that the alternator was the problem because I had never seen the voltmeter dip below 12V when checking it. The moral to the story is if you are not seeing 14V when charging you may have a weak alternator.

Img_0543.jpg (32434 bytes)

The next issue involves my fuel system. I re-used all of the lines and parts from my last setup but missed one important part,  the fuel lines I used for connecting the in-tank fuel pickups were not rated for submersion in gasoline.  I admit I asked the parts counter guy if the hose in question would work in a fuel tank and he said yes which is partially true.  Almost any hose will work but for how long? As it turns out the particular brand I bought lasted about two years before the gas permeated the outer layers causing the hose to collapse.  I also found chunks of a gooey substance in the tank, another by-product of the hose break down. 

So this go around I did some homework and discovered I needed a hose that met the SAE 30R10 rating which states the hose "is capable of handling fuel, alcohol-extended fuel or diesel fuel in fully immersed, mobile, stationary and marine applications."

Source: Gatesrubbercompany.net

It turns out this stuff is not common and even Gates primarily sells it to oems.  I did eventually discover a part number, Gates #27093 gets you a 12" long piece of 5/16 fuel hose and it is available online from Napa and Checker although you should expect a few weeks wait to get it as they don't readily stock it. 

IMG_3842.JPG (38069 bytes)

My fuel pickups also looked a little worse for wear, you can see all the black bits of material caught in the screen and I suspect the darker portion of the screen is also partially blocked with even smaller particles. When I went to order new pickups I discovered that there is a new revision of the pickup, P/N MP-10 has been replaced by MP-12.  The -12 pickup has a larger mesh than the older -10 (70 micron vs. 30).  This change was brought about due to new formulations of gasoline over the years that caused a residue build up in the plastic tanks these pickups were used in (primarily snowmobiles).  Auto Performance Engineering is now also recommending you have at least one pickup in the system with a bleed hole (P/N MP-13), this is in case the pickups all get shut the bleed hole will allow them to open up quicker.  Without the bleed hole it could take a long time depending on how much vacuum the fuel pump has pulled.

Since my pickups did not have a bleed hole I suspect I experienced some of this "pickup lock" as the mesh got filled with debris.

IMG_3850.JPG (70030 bytes)

So the first step in my fuel system re-fresh was to pull the fuel tank and clean it out real good to remove any of the broken down hose goo and fuel cell foam debris. Here is a list of the components in order that will go back into the system starting inside of the 8 gallon RCI fuel cell:

2 Fuel pickups,  # MP-12 & MP-13 connected with 3 pieces of the ##27093 gates submersible fuel line. 

The fuel cell is connected to a low pressure 30 micron fuel filter (Summit # EDL-8130) via some 3/8" fuel line (doesn't have to be EFI hose as this is the vacuum side of the fuel pump but I used EFI rated hose anyways).

The fuel filter feeds an Vortech VOR-8F002-265 (Summit Racing) 70gph, 85psi inline fuel pump.  I suspect my old MSD-2225 (Summit Racing) would have worked fine but due to the fuel lines breaking down I thought the MSD pump was not providing enough flow (it is rated for 43gph). I am hoping the old fuel pump is ok, it was pretty loud in Moab but I suspect that was due to it trying to pull fuel thru the clogged pickups/lines/filters. If it is toasted I have another MSD-2225 I plan on running.

After the fuel pump everything has to be pressure rated, so for hose I am using some EFI fuel line I purchased off of e-Bay.  The line meets the SAE 30R9 standard (high pressure & high temperature) and cost about $2.80 a foot.  The next component in line is a pressure rated 5 micron fuel filter #MAA-3160 (Summit Racing).  I did not have this second filter in the system before but should have to further protect the injectors from smaller particles.

So to sum it up, a decent fuel system for a buggy that will support 3-500 hp will run you roughly $500 and change.  You could save a little by buying generic fuel filters off the shelf but either way do it right the first time to avoid damaging more expensive components. 

While in Moab I hit the scales just south of town and discovered the buggy weighed 3700lbs without water in the tires.  With water in the front tires (filled halfway) the buggy weighed 4095lbs.  I still need to weigh the tools and spare parts I carry but I'd guess with a full cooler I have about 80lbs of cargo onboard. I thought the buggy crawled and climbed better with water than without so I guess lighter is not necessarily better.

4-1-07_0016.JPG (77957 bytes)

And finally a quick update on tire wear.  The 9 day road trip put more wear on my tires than the last 30 outings here in AZ combined, but to be fair the rock in Farmington and Moab is like sandpaper.  Anytime you spun your tires you could see a small black cloud of tire dust which symbolized a few miles of life coming off the tire. I am hoping for over a year of tire life and I think it will happen.  As you can see the lugs are starting to get the typical chamfer often seen on comp tires and this is how they work best.  Seat of the pants tells me the grip is getting better but still not quite on par with the bald Krawlers everyone else on the trip were running. If tire grip can only get better I am totally satisfied with these tires.

Update 4-24-07 - So maybe I didn't escape major carnage on the road trip. 

IMG_3846.JPG (25735 bytes)IMG_3853.JPG (48449 bytes)

This is the short side axle from my rear end.  Basically an alloy 35 spline axle that most people said wouldn't break. It broke on Saturday as I attempted a climb on Saw. It was either a fatigue break or I twisted it on the road trip because It sure didn't seem like it should have broke at the time. The long side also has a slight twist in the splines so I went ahead and replaced both with another set of Dutchman alloy axles. 

I also had to file down some of the splines on my spool on the broken axle side.  In hindsight I should have stopped and pulled the broken axle before driving back to the trailer as it looks like splines got a little chewed up from the broken bits grinding around in there.

IMG_3851.JPG (49508 bytes)

My fix for the leaky diff covers is holding up well.  Here you can see I had to cut away the reinforcing plate to remove the diff cover, a small price to pay to be leak free.

Next Page