6100, TTspec, T2, Baja Truck only thread

MTPyle

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MG is right a properly tuned LS3 525 in a 6100 should get just above 3mpg. 3.5mpg is good.

we had our 430hp LS3 getting 4mpg

Our LT1 on E85 only got 2mpg at the m in Laughlin. At the Mint400 this year we got 2.7mpg.

that being said the terrain and course type plays a large roll in mpg. If it’s silty or sticky your mileage can go down. I wish is was a stable number as that would make fuel planning way easier.

I bet the fleet is getting on average 3mpg

Edit- I see the Brenthal claims above and I am surprised by that. If they are only getting 2mpg on race gas they have something wrong.

Mike
 

MTPyle

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There isn’t any trash talking in this thread yet so I will start. Hehe

if the Brenthel g3 is using 2mpg of liquid power they sure are not putting it to the ground.

we lined up next to a brand new G3 at last years Mint 400. I thought oh man this guy is going to smoke us. Haha Nope.

this was the old 6100 rules. We went half way on one tank and I think we got 3.6 mpg.

Mike

 

cynicwanderer

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fuel consumption depends on a lot of factors. driving style, gearing, terrain, etc... also, engines have different efficiencies at different load points/RPM. so at max power, it maybe not actually make the best power/fuel (specific power) consumption there. this maybe at a different RPM/load. so gear selection has a major role in loading the engine at different RPM. if you constantly stomp the gas and brake hard, you will not get the best mileage (obviously), but you might be faster in that section.

in order to drive smart, you need to know your engines, max horse power point, max torque point and best specific fuel consumption points for different loading, which will vary with different terrain styles. ideally, an automatic transmission controller could be tuned to pick the best gear for the a specific driving condition, based on what the desired optimization is (mileage, speed) at a given part of the course. this of course, assumes the engine/transmission/drivetrain is in best condition/efficiency already. ideally, you'd want a CVT for this if the inefficiencies outweigh the gains, and you can make it rugged to withstand off road racing. or a transmission with a lot of gears, with a spread optimized for a specific course. I.e. if you knew the max. top speed you plan to reach and the lowest speed you need for technical stuff.

a good driver can (used to be able to when things were less complex) do this in his/her head. obviously, the issue is the speed/fuel consumption trade off. i.e. at better mileage, you maybe going a tad slower, but won't have to pit as often (which saves time), but at higher speeds you can go farther in the same time. F1 has taken this (optimization) to the limit of technology available, and are now being limited by the rules more then anything.

I don't have a feel for how advanced some of the pro trophy truck teams are with their optimizations for speed/mileage in off road racing, if not there could be some significant gains for teams who are willing to figure this out for trophy trucks. of course, off road racing is so variable, that it's hard to be repeatable and predict. so even if you had the best running truck/strategy/optimization, some random event can change the outcome significantly, but I suspect over time some of the random events average out and you could be pretty consistent if you optimized.

much of this optimization can be learned through experience. I.e. with reference to the schooling vs hard knocks learning style thread. a veteran knows how to tune, select gears and drive smartly, because he/she adapted over time. I.e. build a truck based on "tried and true" and apply what you have learned but only incrementally try new things and then run for a while averaging out all the random effects that can happen.

I think the current thinking in trophy trucks is that overall speed over a variety of terrain is the winning solution, if you can make it reliable.
 

MTPyle

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Cynic,

You are right there are lots of variables.


If I am worried about fuel mileage as a driver we did something wrong. Mileage should be figured out and the driver is told he has plenty.

You have to push hard at all times on the race course. There is no hypermilling going on in Offroad racing. Haha.

maybe I am wrong and there are drivers doing what they can to stretch mileage.

Mike
 

cynicwanderer

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Cynic,

You are right there are lots of variables.


If I am worried about fuel mileage as a driver we did something wrong. Mileage should be figured out and the driver is told he has plenty.

You have to push hard at all times on the race course. There is no hypermilling going on in Offroad racing. Haha.

maybe I am wrong and there are drivers doing what they can to stretch mileage.

Mike
yeah, I find all this really interesting (i.e. I would rather work on this than my real job). I don't know what the top teams are doing. obviously, that is part of the "secret sauce". you're right all this can be figured out based on knowledge of the course and vehicle and by adding some margin. however, the margin in fuel is the thing that is going to make your truck heavier, so it's a trade off. a heavier truck is a bit slower until you burn off some gas and harder on the suspension. it does make the driver's job easier when they don't have to worry about the fuel consumption and can just focus on driving as fast as they can, without breaking the truck or getting flats.

you can see this happening in motorcycles. I think a couple of years ago the winning moto team in V2R had huge/multiple fuel tanks and hardly ever stopped. on the other hand, you have 2 stroke bikes that are super light and go super fast, but they stop every 50 miles for gas. 2 strokes haven't won overall moto for a while on long course, I think. moto racers always worry about range on long courses, especially when they get into sandy/silty, or head wind conditions, dirty air filters, etc...

so here is a question I don't know the answer to... do trophy trucks even have a fuel level sensors in the tank, or do they just use fuel consumption data from the ECU ? I suspect the ECU gives accurate data, and no one is running carbs any more. how do they know how much fuel is actually in the tank ? does the co-driver keep track of how much fuel was used and how much was added, etc... to estimate how much fuel is in the tank, or does no one look at it and it's "no worries" and assume they have been topped off at the last pit enough to make it and just go.
 

michael.gonzalez

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Whoa now. Everyone knows the heavier a TT is, the better they handle. Don't stir the pot with this lightweight is better crap!

I don't think there is much need for the driver to know the tank level. It's not his decision to fuel up or not anyways.

Pit-boss should know how much gas is in the truck more than anyone.

Nobody should be running close to empty if they play it smart.
 

cynicwanderer

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Whoa now. Everyone knows the heavier a TT is, the better they handle. Don't stir the pot with this lightweight is better crap!

I don't think there is much need for the driver to know the tank level. It's not his decision to fuel up or not anyways.

Nobody should be running close to empty if they play it smart.

lol... ok, so bigger fuel cell is better and just keep it full ;-) just curious on the trucks. in moto ironman I do make the decision. I may decide to take less fuel if I know the next section is really technical and I want my bike to be light, but may take more fuel, if it's particularly dry/slity or muddy that day, since I will use more fuel.

OK, not being in control is going to be a "deal breaker" when I get tapped to race a TT ;-)
 

Vdrive

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I drove away from a pit at Vegas to Reno before I was done fueling My 7200 truck in order to keep track position. Then I had a “hybrid” foot on the gas pedal until the next pit in an effort to stretch what I had. It worked the guy behind me blew his motor after the pit trying to pass this rabbit. We topped off at the next pit and went on to win. Some sections of track use more mpg than others. Especially when your going 55 in sand fully floored vs 110 mph across a lake bed. We calc fuel mileage based on 2.7mpg with LS3 430hp.
my 7200 truck had a 3.5 eco boost motor and ran 39” tires, running lower air pressure at the blue water race we got 1.2 mpg

The turbos could normalize at any rpm and start pumping fuel like a big dog.

we’re going to full fuel at SilverState somewhere and not worry about mpg!

Vegas to Reno is fun cause you have so many options on when to stop.
 

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Ikaika

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I don't think there is much need for the driver to know the tank level. It's not his decision to fuel up or not anyways.

Pit-boss should know how much gas is in the truck more than anyone.

Nobody should be running close to empty if they play it smart.
[/QUOTE]

In my opinion,........it is imperative that the occupants of an off-road race vehicle know ( via a gauge ) or have an educated assessment of fuel levels on board........AND........furthermore, I very much have the opinion that the occupants should have the last word on the option to "top-off" or "splash & go" during scheduled & non scheduled stops.
The disclaimer here is that the occupants can only gain the option of decision making AFTER many years of data logging, course knowledge and understanding vehicle dynamics.

It "takes time" to learn a new girlfriend, puppy, job, Boss etc.........likewise it "takes time" to learn about the race vehicle, changes made ( and the effects of said changes.....ie rear axle ratios, transmission ratios, header length effects, air/fuel & tuning ratios etc... ), driver consistency, course knowledge etc...all with the assumption that there are "constants"....such as fuel quality & availability.
One "constant" is that the weather is constantly changing and plays a role in fuel consumption.

There are a huge amount of variables that can be averaged with relative accuracy over a long "study period".....and as such, once the "study time" has been spent, I feel it is in the best interest of the team to leave the race vehicle occupants to ultimately make decisions on the "to fuel or not to fuel".

Cheers !
 

Class10DAN

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I don't think there is much need for the driver to know the tank level. It's not his decision to fuel up or not anyways.
if hes Robby Gordon then you're sadly mistaken
 

MTPyle

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Made some changes on our Truck for Silverstate.

new fuel vents and larger filters.We went to larger filters for better flow and less resistance.

new sheet metal around our new larger air filter. When we put the LT2 intake we moved the filter back into the cab so we went with a way larger filter.

we put a new brake bias valve. And added shut off valves to the front and rear brakes. So if we lose either we can shut it down from the cab and keep going.

we moved our PS cooler in front of oil cooler to get air flow from the oil cooler fan at lower speeds. In the technical stuff our PS system was getting hot.

new brake pedal and master cylinder. Old brake pedal was getting worn.

also added a drive line safety loop to contain the driveline if the front fails. At the Mint the yoke failed and took out our limit straps loop. Then the yoke flopped around taking out our coolant lines. And the driveline came down and grabbed into the sand bending our 3rd member yoke. So we upgraded the loop to steel.

also got our shocks back from SDG. Finally decided to bite the bullet and get the best suspension set up we could.

Always improving and pushing the truck forward. The guys at Misfit garage in South Jordan UT have really stepped up with some great work. It’s great to have some guys willing to help and be fair on pricing and do great work. We could not do this without them.

Mike
 

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mebedb1

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I'm surprised you passed tech without the drive line hoop. It is in the rule book, They're not looking for these?
 

MTPyle

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We had limit straps for a drive line loop. Many trucks have them. It does not require a metal loop like short course. But our limit strap system failed. Hence the upgrade.

And don’t get me started on what gets thru tech. I am often shocked at what they let thru.

Mike
 

Vdrive

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Made some changes on our Truck for Silverstate.

new fuel vents and larger filters.We went to larger filters for better flow and less resistance.

new sheet metal around our new larger air filter. When we put the LT2 intake we moved the filter back into the cab so we went with a way larger filter.

we put a new brake bias valve. And added shut off valves to the front and rear brakes. So if we lose either we can shut it down from the cab and keep going.

we moved our PS cooler in front of oil cooler to get air flow from the oil cooler fan at lower speeds. In the technical stuff our PS system was getting hot.

new brake pedal and master cylinder. Old brake pedal was getting worn.

also added a drive line safety loop to contain the driveline if the front fails. At the Mint the yoke failed and took out our limit straps loop. Then the yoke flopped around taking out our coolant lines. And the driveline came down and grabbed into the sand bending our 3rd member yoke. So we upgraded the loop to steel.

also got our shocks back from SDG. Finally decided to bite the bullet and get the best suspension set up we could.

Always improving and pushing the truck forward. The guys at Misfit garage in South Jordan UT have really stepped up with some great work. It’s great to have some guys willing to help and be fair on pricing and do great work. We could not do this without them.

Mike
Nice work! Be careful with the brake bias if you lose pressure on one circuit or shut one off it can articulate the bar too far and break stuff...
 

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jon coleman

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Whoa now. Everyone knows the heavier a TT is, the better they handle. Don't stir the pot with this lightweight is better crap!

I don't think there is much need for the driver to know the tank level. It's not his decision to fuel up or not anyways.

Pit-boss should know how much gas is in the truck more than anyone.

Nobody should be running close to empty if they play it smart.
i did, almost ran out, 32 ga fuel cell, 5 mpg 150 miles However , jeep was ssssputering comming into Parker python,/ pitts, stoped at first pit i saw & they gave me a little bit of juice( thanx by the way!, who ever you were), so my 5mpg was off because cell took all30ga,no pick up issue, sooo i sent chase guy ahead to midway, had to change strategy on the fly, woulda worked out b tchen until i broke control arm in the rock garden,Always cut your testing milage by at least a third ,testing you get 5 ?, no, for race its 3.5 Max!
 

43mod

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Mike. Brake valves will probably be a bad idea. When you shut down one end it can lock up that m cylinder and not allow pedal travel for the other m cylinder. A center valve will fix this and let both m cylinders push on f or rear until repairs. Try your setup first and decide
 

jon coleman

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balance bar becomes a REALLY bad leverage fulcrum, had issues with rear & master cyl. locking up , then All pedal travel is to front w Bad leverage, its super hard pedal& no brakes to speak of
 

MTPyle

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Good points. But at least you have a chance of brakes with a shut off valve. Without one you are totally screwed. I would rather have to be easy with some brakes than have none. We have lost our rear and fronts and had to stop and block off the line which took a while. Would rather limp to the pits with some brakes and have the pit crew fix it. At least now we have the option.

Mike
 
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