Rebirth of Monster Mudder

One thing I would add to that list, doesn't take long and saves a bunch of headache down the road. Pressurize the system and do a boost leak check.
 
Well, less than 12 hours till the first race, I'm wide awake so I thought I'd give an update. Still don't have a good working tach signal, I'll mess with it some more tomorrow and see if I can get it better. I had a lean in the wastegate mounting, got that fixed, the stainless steel line for the exit gasses was pulling on it, ended up taking the part of the nipple I cut off to make the bung into the downpipe and added half an all thread nipple to it by welding it together and that gave me the right length then. I lengthened the downpipe 4 1/2 inches to get it to clear the transmission mount. I then had to shorten the straight pipe about 3 inches to fit all of it back together.

I got all the vent lines ran and attached up high. Cleaned all the junk out of the bed and cab, checked the air in all the tires, and zip tied all the lines up out of the way. I attempted to get the radiator to seal up, got it partially, but I'm going to have to pull it out and have new gaskets put in each side of the tanks to get it to seal.

Truck runs awesome, took it for a few test takeoffs and runs down the county road, she's strong and will be a blast tomorrow.

All and all, the truck is as done as it's getting done before the race tomorrow, almost everything is done and finished, only thing outstanding is the tach and the radiator.

Here are some pics I took tonight of it.


Untitled by NakeDiesel, on Flickr


Untitled by NakeDiesel, on Flickr


Untitled by NakeDiesel, on Flickr


Untitled by NakeDiesel, on Flickr


Untitled by NakeDiesel, on Flickr


Untitled by NakeDiesel, on Flickr


Untitled by NakeDiesel, on Flickr
 
Afterbirth

Guess this post would be titled the afterbirth of the mud truck. Today was the first race of the season at Cedar Vale, KS. It was rainy and about 40 freaking degrees outside. I ran last in Class 2, and placed 3rd in it with a time of 6.00 seconds. In class 3, I ran 9th with a time of 5.77, I didn't place in class 3, but was .67 seconds slower than my brother who placed 4th in class 3. All in all, big smiles from me and my wife. Truck did wonderful and was a blast to drive. Would have been better if the radiator wasn't leaking like a sieve and the tack worked, so i'd know where I was shifting at. Never had time to look at the pyro or boost gauge, I know I spooled to about 10psi at launch on the first one, truck left hard and never bogged down anywhere in the pit.

I did get out of the throttle a couple of times I saw in the video from the second run. So I'll have to be more cognicent about that on the next race. I also had problems with the steering wheel lock, anyone know how to get that out of the steering column?

Truck turned alot of heads at the race and everyone seemed to love the runs, was a way different show than all of the standard gas trucks.

here is a video of the second run my wife took with a little digital camera, and after it, I'll post some pics of the truck.

http://www.youtube.com/watch?v=OTzsmS8eRoQ


Untitled by NakeDiesel, on Flickr


DSC00595 by NakeDiesel, on Flickr


DSC00602 by NakeDiesel, on Flickr


DSC00600 by NakeDiesel, on Flickr


DSC00594 by NakeDiesel, on Flickr
 
It was definately heartening to not have anything break. Last year at this first race, I blew the tranny out of my 99 hauling the truck up there, got through the first race, and in the second, melted a piston, bent a valve and blew the head gasket.

The pit is about 2' deep or deeper at the end, and it's thick nasty stuff, I spent 5 dollars at the car wash last night just getting some of it off, i'll wait for it to dry and then hit it again to get the rest off. If you will notice on the pics I have on the turbo side, that black canister is my air filter. It's the same style as the BHAF, but with a solid cover around it and openings only on the outlet side. This reduces the exposure to the mud flying, and there isn't a whole lot of mud that actually makes it into the engine compartment considering what we are doing. It flows like 50 to 100 cfm less than the open BHAF does.

I'm running the np205 in low range, so that's 2.0:1 ratio, and I'm running 3.55's in the rear ends, a th400 for a transmission with 37" boggers on the truck. I really need to get the tack working on it, I'm pretty sure I wasn't getting up to max rpm on it yesterday, and I need to practice in a few more pits to get used to it. This new engine was night and day compared to last year, I couldn't make it to 3rd last year in this same pit.
 
I'm just making suggestions purely off of the sound of the motor, but it sounded like a little taller gear would have loaded the motor a little more and used some of your massive torque advantage.

I know mud racing is a different situation, but when drag racing, the faster I get my truck into overdrive, the quicker it runs as long as the turbo(s) don't snuff out from short shifting. I've tried running it up to 3000, 3100, 3200, RPM etc on the lower gears and it always resulted in slower elapsed times. I now shift at 2600-2700 rpm which is brutal on the locked up torque converter but really launches the truck down the track.


Does your TH400 have a lock-up converter or is it 100% fluid coupling? I hear that fluid coupling based converters are more efficient as RPM increases so you might be driving perfectly running it through to pit mid 3000 rpm range like in the video.
 
I'm already running the highest gear out there I think, most are 4.56:1 or lower. I definately need some more seat time practice in the pit, and was full of nerves yesterday, since I'd already blown the truck up once. I was in and out of the throttle too much, I just need to hammer it and keep it there. Once I get a working tach, I'll atleast be able to start getting consistant shifts.

The TH400 is 100% fluid coupling. I have the stall set to 22/2400 rpm of stall. I did raise my final ratio when I switched from the 241dld to the np205, the 241dld is 2.72:1 low range ratio vs. the 2.00:1 low range ratio of the np205 transfercase.

I also only foot braked the truck and launched at low psi's, and haven't been brave enough to test the transbrake yet.
 
Nice runs and great job! Its always a great feeling to go out the first time and be competitive and not have big problems or tear anything up. Keep it up!
 
Great job on a great build man!!!! Looks like all you need to work on is fine tuning your truck and you'll be showing the gassers how a real truck runs the hole!! Keep up the good work man!!!
 
More Fuel and little higher gear. You cleaned the smoke up nice. I think most of the gassers run a lower diff gear, but they are twisting them much higher rpm. Looks good thou.
 
I think I do need more fuel, next step will be upping the delivery valve size, just have 181's in there now. I don't think I was maxing the truck out speed wise as it sits. Also, the pit sunday was pretty cleaned out for that run. They get much worse than that. I'll know more once I get the tach working on the truck
 
SWEET! If weight is an issue...ever consider a hood stack? It may shave a chunk a weight off. You could always run a 5" like your single stack, with the flapper to keep the much and crud outta the inlet....
 
Going to a hood stack I saved a bunch of weight on my puller. 5" pipe is heavy.

Looks like you could use more fuel, check the classifieds for a sweet CDS 13mm pump w/ an ag gov. However, I'm not sure you could run a hand throttle, shift your trans, and steer all at the same time :hehe:
 
I can't run a hood stack in class 2, you can in class 3 and up. I'm planning on moving up classes probably when I do the rebody to the 46 powerwagon body.
 
NakeDiesel said:
The TH400 is 100% fluid coupling. I have the stall set to 22/2400 rpm of stall. I did raise my final ratio when I switched from the 241dld to the np205, the 241dld is 2.72:1 low range ratio vs. the 2.00:1 low range ratio of the np205 transfercase.
Click to expand...

Do you need to run low range? I'm not a mud bogger, so I don't know if I'm asking a dumb question. Wouldn't you want your tires spinning as fast as possible? Instead of a gear swap go high range. The only thing I would worry about then would be the input shaft when you're staging.
 
Here are some pics I took yesterday of the engine compartment before I pulled out the radiator to get it fixed. *This is after 2 runs through the pit


Untitled by NakeDiesel, on Flickr


Untitled by NakeDiesel, on Flickr

Yes, wheel speed is king in mud racing, the faster you turn your wheels, the faster you claw through the mud. *
 
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