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Topic: Bonneville MJ

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Worlds Fastest Comanche
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Bonneville MJ
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about 22 years ago, Jeep was going to introduce their new 4.0L  MPFI engine.  The 258 of the time had about 120hp, the 4.0  had about 175 hp.  So the smaller engine actually had 50 more hp.  Some of the engineers had an idea, so in the summer of 1986, the Jeep factory team took a 1987 MJ to Bonneville and set 9 US speed records and 4 international records.  the most impressive one being a speed of 141mph in the flying mile. 
GM of course did not like the idea of Jeep as a performance vehicle.  So GMC motorsports hired a guy named Gale Banks to break the Jeeps records.  So in 1989 Banks went to Bonneville and broke the records set by the Jeep, ( he also broke a Porche record).  He used a S15 pickup and went 198mph with a 5.0L engine.   He also returned to Bonneville for Speed week, with a 4.3l engine in the same truck and went 183.9 mph in the E P/MP class ( production mini/mid pickup) That record still stands today.  

To make a long story short, my son and myself were at Bonneville this year as specators, we thought about returning in 2009 with a Jeep pickup,  we were going to run a J truck, but then found out about the MJ.  So we changed our plans and found a MJ in Texas  which will be our 2009 Bonneville entry.

We started working on it in October, and the plans seem to change daily.  We were originally gong to run a 4.3L engine,  but due to some issues with the 4.0 Crankshaft design, we are now building a 5.0L engine.  The 4.0 block will be bored to 4.0"  and the crank will have a 4" stroke ( too many 4's) Hopefully we will get between 450-500 hp out of it.

Some of the other things we are working on are:
Aftermarket EFI controller
Timing belt drive for Cam
Custom Intake
Hesco Aluminum Head
Shaft style roller rockers
Billet roller cam
Lowering the truck 5"
SFI Bellhousing and flywheel.

I am sure there is more , but i can't thnk of them right now. 

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Peter Lechtanski The worlds fastest Comanche project.
dogwonk
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Now THIS is exciting! clap.gif

I cannot wait to hear more about this! Please keep us updated on all the progress.

Oh, and you should know, we REALLY like pics around here! biggrin.gif

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choppergar
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WOW!!!!
The best of luck and keep us posted.

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Gar Pratt
aci4369
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That would be awsome if you get that much HP out of it.

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Worlds Fastest Comanche
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That kind of HP is not unheard of, but it is rare for a engine without a turbo or supercharger. Back in 2001 there was a dragster that ran a 4.0 that had somewhere near 500 hp. Barney Navaro had a Indy car based on the AMC 6 that produced around 650 hp. The engine was only 188 CID!

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Peter Lechtanski The worlds fastest Comanche project.
ChevelleSSLS6
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I don't know your level of expertise, but I do have some links that may be helpful...
http://amccars.net/cgi/yabb2/YaBB.pl or www.amcforums.net
http://www.go.jeep-xj.info/
http://www.jeep4.0performance.4mg.com/
http://jeep.off-road.com/jeep/article/articleDetail.jsp?id=257969



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My Fleet
1996 XJ "Snowball"- 3.5" lift, bunch of little mods.  I hate pegleg rear axles!
1974 AMC Javelin "Jade Grenade"- 360v8, 4sp, green inside and out. Underfunded Project.
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Worlds Fastest Comanche
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My level of expertise? I don't know that either. Have i built race engines? no. Have I built race cars? NO. I have built some nice vehicles, some Jeep some not.

What i have found out is that search is eaiser than research. allot of very smart people have done a lot of work through the years,, and hopefully i can build on their experience.

I am always working with a group of knowledgable people to come up wuith the best solution to a problem. I will check out those links. the best one for 4.0 performance i have found so far is this one :

http://www.jeepstrokers.com

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Peter Lechtanski The worlds fastest Comanche project.
Worlds Fastest Comanche
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Checked out the links, Dino's site was one of the first i visited when i started the project. The other articles seem to talk about moderate increases to a stock engine.

My project is totaly in left field compared to these builds. if you run some basic numbers, it is quick to see that you need 50lb/hr injectors, one huge or 2 small throttle bodies. the stock intake just can't flow enough air.

I thought people on this board might have an interest to see how much performance you can get out of a Jeep 6. From the work i have done so far, it looks like the most performance gains you can get are related to airflow. Get a Hesco head, 99+ wj intake bored out throttle body, good header and good exhoust. Throw a good cam on top of that and a chip, and you could probably get 100hp or more.

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Peter Lechtanski The worlds fastest Comanche project.
dogwonk
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I think I can SAFELY speak for most people on this board when I say... "WE ARE VERY INTERESTED IN WHAT YOU ARE DOING!!!"

Expert or not, you are doing something very special, unique and interesting. It just so happens to involve one of our FAVORITE vehicles. clap.gif

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aci4369
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Heck ya, keep the good stuff flowing.   So how much have you done?  I know in the first post you listed what your goals are.  How far have you gotten in reaching those?   Is it a 5.0 already?

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bmyohn
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ive never heard of the WJ TB swap before. is it a direct bolt on? what do you bore it out to? and what kinda gains could you expect over just a regular bored out XJ TB?

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xjryder
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I vote for pics and play by play info

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To build something that can run over the idiot driving 45 in the passing lane ,Now Thats Talent!
Worlds Fastest Comanche
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ive never heard of the WJ TB swap before. is it a direct bolt on? what do you bore it out to? and what kinda gains could you expect over just a regular bored out XJ TB?

The throttle bodies are the same, the performance come from the new intake .

Just search Ebay for Jeep 99 intake manifold, I a sure a few will pop up


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Peter Lechtanski The worlds fastest Comanche project.
bmyohn
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oh i gotcha, i have an 01 so its got the better intake. i thought you were just talking about the throttle body specifically

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Worlds Fastest Comanche
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The later XJs really are set up pretty good from the factory, almost 200hp. Adding a chip and Borla exhust would help with another 20 or 25, but it may cost you $800 for parts , not counting labor. If you have a pre HO XJ 86-90, you shoud find a HO head and put it on along with the newer intake and 22lb injectors. As long as you have tha head off you should probably add a RV cam. You should be able to get the Cam, lifters, and springs for about $350.00 or so.

I recently picked up a siezed 92 4.0 at a junkyard for $200.00 All i got was the block and head. It was a HO head of course, so not really a bad deal. Looks like whoever owned the car that the engine came out of never changed ther oil, it was like tar. The number 1 Main bearing was spun. We did some checking at the engine shop and determined that we could go to a 4" bore. The would let us use stock chevy pistons if we wanted. We will also be using a 258 crank stroked to 4". What we found out was that to get the numbers we wanted for compression, we had to go to custom Pistons and Rods. We will end up with about $2000 in custom pistons and rods, but we will also have a 5.0 instead of a 4.0, 12:1 cr



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Peter Lechtanski The worlds fastest Comanche project.
 
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