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New fuel system

GlacierSean

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I think your all familiar with my cat but for those who aren't I have a 1987 BR100 with a Chevy LS V8. It has taken a couple of seasons to find and fix the small issues we have had with the modifications. Last season I was having no throttle on steep hills. I would have it floored and it wasn't making any power. Someone at the Vail Jamboree suggested that the in line pump was having trouble pulling gas. And that I should put in a second pump so the in line pump didn't have to pull fuel. It helped and I had barley enough power on steep hills. So we tried to do a full day of cat skiing and about half way thru the day it died on a very steep hill. Once I got it started it would only go about a mile and it would die and need about 15min to restart. The gas tank was under negative pressure. So I did some research and found that the issues with throttle, power, and tank vacuum were probably being caused by the stock gas tank. With the EFI v8 you need a vent so the tank won't make a vacuum. The pump works the best if in the tank. And the in tank pump wants a foam bladder to keep the fuel around the pump from sloshing. So a company called Areomotive makes a system that solves all of these issues without replacing the tank. Basically you have to cut a hole in the tank "replace shorts" and install a foam bladder and fuel pump. From there it's just fuel line and wires.
 

GlacierSean

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Here is a picture of the old fuel system, you can see the two pumps and the tank before I started this project.
IMG_20171016_164221.jpg

IMG_20171016_164205.jpg
 

GlacierSean

Member
SUPER Site Supporter
Hole cut, foam bladder installed, ready for pump assembly. IMG_20171106_143347.jpg

Pump assembly installed, the return is plugged because the tank already has one.
IMG_20171107_103202.jpg

Everything installed and hydraulic radiator put back on. Notice the fuel filter on the tank vent line to keep debris out of tank. Good idea?
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Blackfoot Tucker

Well-known member
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I'm not sure the in-line pump was the problem, but rather the way it was installed. I'm quite sure they are supposed to be installed below the level of the gas tank - so fuel gravity feeds to them.

I have two vehicles that have LS series engines in them and in both cases they were engine swaps. Both setups have in-line electric fuel pumps and I have had zero issues with them. The LS fuel injection system requires something like 55-60 PSI of pressure which is much higher than that required for a TBI system. Many in-line pumps don't put out that much pressure.

Another option for a gas tank vent would be to use a marine style vent.
 

GlacierSean

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Thanks for the advice Jim and Blackfoot Tucker. If I have an issue with the fuel filter as an air filter I'll try that paint filter. Good idea on having the in line pump mounted below the tank level. The best I could have done is put it in the engine tunnel. I would have just been a little worried about heat. If the new system doesn't work I'll give it a try. Blackfoot Tucker you mentioned that you have done a couple of LS swaps. Did you also put an LS in a snowcat?
 

Blackfoot Tucker

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Sean, the answer is yes... and no. My snowcat buddy and I did install a different engine in our project Tucker, and I counted it as an LS series engine in my post above as it has an LS-like fuel system, but technically speaking, Chevrolet calls it a Vortec engine. To me that's somewhat confusing because the original Vortecs used a CSFI (Central Sequential Fuel Injection) system (with the somewhat problematic spider). The LS series engines used a more advanced system, as did the later Vortecs, but they're still called Vortecs.
 

GlacierSean

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A vortec V8 in a Tucker sounds like fun. I bet it makes a cool noise, my little cat makes a hilarious noise. I would like to see a picture of your vortec sno cat, would you put a picture of the cat and the engine on here?Thanks
 

Blackfoot Tucker

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A vortec V8 in a Tucker sounds like fun. I bet it makes a cool noise, my little cat makes a hilarious noise. I would like to see a picture of your vortec sno cat, would you put a picture of the cat and the engine on here?Thanks

Sean, not quite a year ago I started a thread about the machine. It's been a very long-term project and my snowcat buddy and I took it out for some testing. Our plan was to make the various modifications to the 'cat, then verify satisfactory operational performance before disassembly for paint, interior, etc. We found some issues that needed to be corrected, and of course more testing for performance validation.

As I write this the Tucker is up in Idaho being painted. My intention is to post more complete photos after we have it reassembled. Please indulge me for a few more months on engine and other photos. I will say it's the most comprehensively modified Tucker I'm aware of. Here's a link to the thread:

http://www.forumsforums.com/3_9/showthread.php?t=75527&highlight=testing+thundercat
 

GlacierSean

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Blackfoot Tucker-Cool pictures, it looks like you were giving it a good test. Thundercat is an awesome name, are you aware of the cartoon of the same name? You could use the Thundercats emblem on your tucker. I would like to see your cat in person sometime when it's ready. Maybe we could have a friendly race.
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Blackfoot Tucker

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Blackfoot Tucker-Cool pictures, it looks like you were giving it a good test. Thundercat is an awesome name, are you aware of the cartoon of the same name? You could use the Thundercats emblem on your tucker. I would like to see your cat in person sometime when it's ready. Maybe we could have a friendly race.
View attachment 94135

Sean, I've never heard of the Thundercat cartoon series. The inspiration for our Thundercat name is aviation related:

As you probably know military aircraft are typically named, and this tradition goes way back; B-17 "Flying Fortress", P-51 "Mustang", F-14 "Tomcat", etc. One of my favorites belongs to the Republic F-105. It was officially called the "Thunderchief". That is such a cool name, but didn't really have a snowcat connection, so I modified "Thunderchief" into "Thundercat".

Tuckers have many wonderful qualities, but one thing they're not is fast. While the engine swap added significantly to the machines capability, it really doesn't increase the top speed as you're somewhat RPM limited. Honestly too, above a certain speed the rotating mass of the rubber belted tracks becomes disconcerting. If something were to come apart - it could get ugly.

The RPM limitation is related to the Vickers hydraulic pump. Vickers recommends a maximum pump RPM of 2,500. That means the geometric relationship of the pump's driven pulley and the drive pulley mounted on the harmonic balancer will limit the maximum engine RPM.

I'd love to see your LS powered BR-100!!!
 

GlacierSean

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Blackfoot Tucker - I'll pm you whenever we have some real snow so we can get together and compare builds. My cat doesn't like going over its stock top speed either. But it sure gets to top speed in a hurry. I have found with all off roading it's nice to have a bunch of power on hand to get out of or into trouble.
 

The Sweet Wbj1

Active member
We spend a lot of time on the Western slope. There are a couple guys on here with cats that are very close to us. Was hoping for one more!
 
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