Mud racing with a stroker?

[jonb8]

My wife has been mud racing a few years, and really enjoy's it. First year she raced her 98 cherokee stock with lift and 33's and did really well in the stock class. Last year I bought her a 5.9L zj, built it and it ended up being a epic failure, It was tall, heavy and very unpredictable in the pits. It broke so much I got mad and I sold it.


Now I'm researching next years mud racer for her, she loves the xj but i'm not sure I can get the power out of the 4.0 I need to beat this guy. This is a pic of Morris and my wife at the last mud race, his blazer (with a 4.3 vortec stock) is beating her by 3 to 6 tenths at every event and I can't seem to get anything else out of her xj, no matter what I do.


I'm up in the air between just building her a 4.3 vortec truck with a SAS or a xj with a stroker. I hate to build a chevy but I don't want to loose my butt like I did on last years build. I know this is long, that's why I posted pics (I know you guy's love pics) I don't care about fuel economy or using 87, if I build a jeep it will be for racing only and trailered to every race. I have two motors a 93 and a 94 4.0, I also have a 98 head and intake. Any advice would be helpful to me, I just need to make a decision one way or the other.

[gradon]

With the blocks and parts you have, you could build a nice stroker if you give yourself a $2K budget. You'd have no problem beating that blazer.

[the_wrench116]

2nd

[BADASYJ]

Keep the jeep you could whip him with a stock motor. The key is tires and gearing. Do you have the tranny cpu unpluged to make it a manual valve body?

[jonb8]

Thanks guy's, I don't have the TCU unplugged. I'm running a 8.8 explorer rear and a D30 0pen in the front, with 410's, I'm running 34/10.50 TSL's. I also have a set of 33/12.50 boggers that I run in the deep pits, they seem to pull all the motor out of the jeep in the speed pit though. The blazer is also running a 8.8 and a D30 with 410's, (bad thing is I built the blazer for him) he's running 35/10.50 Tsl radials though. Think I'm loosing some between the 34 and the 35's?

[BADASYJ]

Your not losing anything to his tires unless yours are bald. He is getting more traction then you. The 33x 12.5 boggers are slowing you down cause your trying to push and sling more mud. You are running in 4 low right?

[jonb8]

Yes I'm running 4 low and my tires are about 3/4 tread. Weird thing is he's running 4 hi. Seems to be getting off the line better than my wife too. He's not only beating us but the decent built small block trucks.....

[BADASYJ]

If hes running 4-hi and beating small blocks either he hes got some work done to that motor or hes running some lower gears then 4.10s. I couldn't see a stock blazer being that strong to hold 4-hi in the mud. But on the flip side he might not be spinning his tires as much as you are and getting more bite. It looks like you're racing in a clay pit, you might be just spinning your tires to much on take off. Have you tried running 4-hi ?

[jonb8]

The last mud race she ran 4lo first pass with a 5.3, bouncing the limiter and she said it felt real strong. Second pass I had her run 4Hi, she said it never got over 3500 and felt slow. She was slower, her second pass in 4hi got her a 5.4. We did cut the muffler and cat off tonight and found both were clogged up, I had my suspicions but didn't want to spend the money. It seems to come on alot better, so we'll see on saturday. I'm gonna take the clutch fan off and run on the electric to see if I can pick up a tenth. I'll keep you all posted.

[Mopud]

This is a really interesting thread and I can't wait to see how it goes after your changes.

If it's any use, I've gone with a Novak Conversions fan for my TJ http://www.novak-adapt.com/catalog/cooling_fans.htm at the recommendation of a local jeep expert. I haven't hooked it up yet because my car is not yet running but I can definitely back its quality.. it's freakin badass!

Good luck out there!!

[jonb8]

Thanks Mopud for the link. I'm gonna try to get away with just running the stock aux fan for the two runs tomorrow. Just gonna shut it off quick. I'm also toying around with disconnecting the alt to get alittle extra. Just make it a pulley instead of pulling power from the motor. I know it's all little stuff but I'm only trying to gain tenths of a second. I know this is getting away from stroker motors but I have been doing alot of research, I don't want to put a fortune in a motor that I'm gonna sink in the mud. I can't run a header either so I have to keep that in consideration. Does anyone see any benefit or problems with just running the 4 balance weight 258 crank and rods, some cleaning up of the intake (99+) and head with the rest of the motor running stock 4.0 (New) components? Running a stripped bare bones xj with a added 20HP (from the stroker) and a new set of 35/10.50 boggers on stock steel wheels should put me out ahead enough to not be to obvious.

[Mopud]

How are you going with this Jon? Any luck?

[SIXPAK]

In your case keeping it under 5200 you should be fine with a 4 cw. BUT, For 38 yrs I have allways run a 12 cw and I tried to run a 4 cw crank one time and broke three main caps in two pieces. On a lower HP car and lower R's it should be fine but for ME running in the 5500 to 7000 range I will never do it again. Just my .02. Just to add. My whole purpose was to reduce rotating weight. The 20 lbs saved never showed up on the ET slip the entire year I ran that crank. Just cost me more money and time.

[amcinstaller]

thats an interesting thing to think about sixpak. was the 12 cw worn or was the purpose simply to reduce the rotating weight?

[SIXPAK]

It was not in bad shape at all. It was infact to reduce rotating weight and the same 12cw crank is back in there now--and being abused harder than it EVER has been.