Worlds Fastest Comanche

I have a D44, but it will be eaiser to change ratios on the 9". It is eaiser to find a disc brake setup to work on the 9" as well. As fpr the weight, i will prpbably have to put some ballast in the back for traction.

Yes, thats the thread about the trip to the Archives. Let me give you a little update on what's going on. I picked up a 2000 xj motor at a junkyard, $200.00. Looks like the guy never changed his oil. #1 main bearing was spun. It came with a HO head that was in great shape, although we will be using a Hesco aluminum head. The engine is at the machine shop, they have to measure the deck height, and see how thick the cylinder walls are. based on that information, we will figure out bore and stroke. Looks like custom pistons and custom rods. The crank will be from a 232 and it will be offset ground to get the correct stroke. The engine will have to turn about 7,500 rpm and produce in excess of 400hp. For the rear axle we picked up a 9" ford. we will change the rear suspension to be like the mid 60's chevy pickups. this is also the same style suspension that Nascar uses. It's 2 arms that run from the axle to a crossmenber at the front of the bed. Chevy used coil springs, we will use airbags. For the front suspension (2wd) we will use a axle out of a later model cherokee with WJ brakes. We will relocate the attachment points for the arms 3-4" lower. this will keep the front end geometry the same, but get the truck down. The tires we will be running will be about 25" in daimeter , the stock tires are 28 or 29" so 2 inches lower because of the tires, 3 inches due to suspension drop, so 5 inches total, maybe more with the front airbags. this should get the truck slammed. Work is also progressing on the timing belt setup. A custom intake manifold will be used with 2 throttle bodies. The trans will be a Tremic, we will probably use a T5 for testing, then get a TKO for the Bonneville run. I n currently funding this out of my pocket, so some things have to wait until i get the money.

We did not see any full size Jeep pickups, you would expect to see at least i J truck. Not very many dodge pickups either.

I will try to answer some of your questions, first we were very lucky to be allowed into the Chrysler archives. This is a place where they store not only cars but other important information, like sales brochures, designs, press releases, stock photos, Etc. It is like an Area 51, it does not have a street address. They have about 300 cars there, and about 75 more are normally on display at the Chrysler Museum. They rotate the cars to the museum and also to special events. GM has a similar storage facility ( also not open to the public) called the Heritage collection. This summer my son and myself were at Bonneville as spectators, We thought ir would be fun to run a truck in the pickup class, and since we have a few J trucks lying around, we thought we would run one of those in the 260cid class. I contacted several firms about building a 6 cylinder engine, one of the firms was Hesco, Lee Hurley the owner wrote me back saying that he had already built a Bonneville engine for a jeep truck. I emailed him back and said "What truck?" That is when i found out about the 87 Comanche. 87 was the first year for the 4.0l and the jeep marketing people wanted to prove how powerful it was. the 258 was only rated at 112 hp and the 4.0 was rated at 175. So the 4.0 was a huge jump in HP and it also had MPFI, which was not very common for 1986. So the engineers slapped something together and set 14 speed records ( top speed 144mph), I will post them when i get time. GM was not very happy about the jeep pickup being regarded as a hi-performance pickup. So GM hired Gale Banks to erase the Jeep name from the record books. In 1989 Gale banks took a modified S15 pickup to Bonneville twice, once to break the jeep records in the 3-5L classes sanctioned by the USAC and FIA. He used a 5.0L engine for these runs and went 198mph. They then took the same truck back to Bonneville for Speed week with a different engine in it and set a record of 183.9 MPH in the E P/MP class that is limited to 261.99 cid. In 1990 Banks returned with the Syclone , and set a record of 204mph in the 5.0L class. So somewhere in my research i found out that the truck was at the archives, and i requested permission to see it, because we were thinking about modeling our truck after this one, maybe even having the same number. My request took several weeks to be answered and has to be approved by "upper management" . The Archives was just one stop on the journey back to Bonnevile, it will be 20 years since Banks set the record in the E P/MP class come next august. We have purchased a 1989 Comanche and are currently working on the engine, we will need a little more than 400hp to break the record. I will keep you posted on our progress.

Here's the problem, torque comes from your stroke times the power pushng down on the piston. If you go with a long stroke to make more torque, then you piston becomes smaller ( to keep the same cid), Smaller piston, then smaller cylinder, then smaller valves, so less airflow. Since HP is torque over time, then the more explosions per second you can have, the more power you can make. Until you start running out of air ( turbos would help) The bonneville engine will probably peak around 7,500 rpm and over 400hp. The block and pistons will be similar to stock ( better quality) but the power will be made with the intake, head and cam.

the forums link on the first page does not work, you have comancheclub.com/comancheclub.com/forums

the tires have to be rated for the spped you atee running, you can use V or Y rated tires up to 200 mph. Over 200mph you need to run a special tire for land speed racing, or get permission to run a specific tire. Goodyear makes an Eagle tire for land speed racing rated for 300 MPH. You can run steel or Alloy wheels, Steel is prefered, and over 16" the center has to be welded to the wheel both front and back.

Here is probably the best calculator page http://www.wallaceracing.com/Calculators.htm Just a note on all the corvette and other car top speeds, they are probably limited by their gears. A land speed record car usually has to be pushed off the line by another vehicle because it is geared so high. This would be unexceptable in a performance car, also rember if you are using all your hp to fight wind restisance, then you have no power to accelerate. Again for a sports car to accelerate at very high speeds, it need extra HP to do it. The choice that the car builders make is to gear a car somewhat low so it has power off the line. Putting a 6 speed trans in helps with top speed.

Ok here are some calculators to help out. The 1986 jeep did 16.986 in the quarter mile, at 80mph. If you run this through some of the calculators available on the internet it will say that you have about 140 rwhp. Which would make sense if the 1986 truck had a basicilly stock engine and about 20% in driveline and other loses. So the old truck set a record of 141 mph in the flying mile, and if we figure it took 140 hp to do it, you can run it through this calculator to figure the new hp required http://robrobinette.com/top_speed.htm I come up with about 316 rwhp, so again assume that is only 80% of the HP you need, it comes up to about 400hp at the flywheel. Here is a calculator for calculating speed depending on engine rpm and gears http://www.catherineandken.co.uk/sti/tyres.html

The head has to be the same configuration as stock, I take same configuration to mean 2 valves per cylinder, no overhead cam, etc. Everybody ports and polishes the heads, so moving an intake port a little should not be a big deal. My problem is that i will need to produce about twice as much airflow and fuel flow as a stock motor. The intake area will probably need a lot of work. I really question if the stock intake will flow enough air. We will probably have to use 60-75 lb/hr injectors

You are making assumptions that the rated HP of a Corvette motor is available at the rear wheels. When you Dyno a motor, it does not have a fan, or alternator, or power steering pump. You also have transmission loses of at least 20%. The GMC/ Banks S15 went 183.9 MPH with a 4.3 L motor. The also ran a 5.0L motor in the same car in 1989 and went 198mph. In 1990 they returned to the salt with a different truck and went 210mph on a one way pass. If you read the press releases on this, the qouthe Banks engineering as saying the 1990 motor had a little over 500HP.

I need a factory bumper for my Land speed record truck, the Jeep parts book shows a tube bumper for an eliminator. I have never seen one , and would like to buy one, but i would settle for some pictures.

A couple of notes, I got a copy of the press release of the records the 1986 Comanche set. One of them was a standing Quarter mile in 16.9 seconds. and of course the other one was the Flying mile at 141mph. The Comanche did have a run at 144 mph. If i run some numbers on this , it tells me that the truck had to have around 145 RWhp to do the quarter mile time stated. This assunes a 3,500 LB weight. I know the curb weight is less than that, but a roll cage was added and a fire supression system. You also have to add the weight of the driver. So if you make the assumption that the truck has had the same horsepower when it made the flying mile run, then you can figure a drag factor. So if you know the spped you want to go, and you know the drag factor, you can come up with the amount of horsepower you need. So doing all that, i came up with a figure of 350 RWhp to go 185mph ( one mile per hour over the current record) So it looks like the engine will have to dyno out at about 400hp if i want to set the record. That's a lot to ask a 4.3L inline 6 The other thing was that people have been telling me to see "The World Fastest Indian", Finally got a copy and saw it last night, I would recomend it, gives you a good feeling of Bonneville, and it also shows wahat you can do if you put your mind to somthing.

here is a link to the an article on the conversion http://jeep.off-road.com/jeep/article/articleDetail.jsp?id=257864

Another way to go would be to use a Moroso part number 63745. this is an piece that goes into your upper radiator hose and lets you put a radiator cap on. You then use a later model heater control valve, and get rid of the plastic tank completely. The Moroso part cost about $30.00 you also need a cap, about $10. you can probably find a coolant recovery bottle in a junk yard, or convert your old plastic tak to one. If you look around the web there are several write ups on converting from a closed to an open system. you can get the heater control valve part number and the repiping instructions from those articles. One note, the radiator cap should be installed at the higest point possible, to let the air out of the system.

I bought a expansion tank on Ebay http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&sspagename=STRK%3AMEWNX%3AIT&viewitem=&item=270282791043 for $75.00 I plan to replace the factory plastic tak with this and do some re plumbing. seems eaiser and cheaper than a new radiator.

Got a big envelope from the Chrysler archives today, it had 6 xerox copies of photos of the 86 Bonneville truck. they were poor quality and black and white. From a previous conversation with the Chrysler historian, i know that hte truck was red with white lettering. It has a big "140" on the doors. On the upper side of the bed it says "Jeep Comanche" on both sides. It has a racing stripe down low near the rockers, the stripe is broken near the front of the doors and it has "LSR2" in white letters the same height as the stripe. I assume that LSR2 stands for Land Speed Record #2. I wonder if there was a LSR1? Was it a truck, or maybe an Eagle product. When i spoke to the Historian eariler, i had requested to see the truck, in the letter wirh the pictures he said that i could come and look at it and gave me the contact. I will probably head over next Friday with my son. It is stored in a building with 300 other "signifigant" chrysler vehicles. Should be a great trip

There is a book called "Common sense not required" by Evan Boberg. he was an engineer with AMC then Chrysler. He worked alot on the XJ suspension, they had some Chief engineer who wanted the Cherokee to steer easy. they ended up with 11deg of caster, when it should only have about 4. If you want the detail, you can probably get the book used on amazon cheap.

We will use a post 91 xj 2wd front axle. The early ones had screwed up geometry. 2001 wj brakes and similar year brake booster and master cylinder. We thought aout putting a Mustang II front suspension kit in, but the XJ axle is eaiser. There are many mustang II suspension kits for street rods that could be put into an MJ. We only have to go in a straight line, so handling is not super important. You can run Racing gas, No other fuels are allowed in this class. We will be running about 11:1. You do have to run a bed and all stock body panels and bumpers.

Nope, not done yet, Maybe i should start part II, Last week i received a copy of the AMC press release where the announced the records. It reads in part: "Southfield Mich. -- The Jeep Comanche pickup truck, only in its second year on the market, already has beaten the competition to the proverbial "Quick" A specially -prepared 1987 2 wheel drive Comanche powered by a modified version of American Motors' new 4 liter, fuel-injected 6 cylinder engine set 9 US and 4 International records late in 1986 in the trials at the Bonneville Salt Flats. The highlight was the the Comanche's record adverage speed of 141.381 mph in a two way dash over a 1 mile measured course at Bonneville. It's peak speed was 144.028 mph Not only did the comanche set seven speed marks for trucks, it also established six national and international records for vehicles of any kind, including passanger cars." The international records were set in the 3-5 liter class, this just goes to show how powerful the 4.0 was for the time. the 4.2l ( the old motor) was only rated at about 120hp, and the 4.0 was 175hp with the MPFI The comanche was and is a great product, even today, it is hard to find a mini pickup with a 2200lb payload capacity.

Did you see the bed for sale in Classifieds? St Louis area, you could probably pick it up.

There has been some discussion in the pub about rear axles in the "Worlds Fastest Comanche" thread. the need for a land spped car are different than for a street or trail truck. I though here i would share my experience with rearends and what i think would work best and cost the least. Many years ago I called up Randys ring an pinion trying to buy gears for a D35. The tech guy said "don't waist your money on that axle, i wouldn't put a nickel into it" Ovet the years, i would have to aggree with him. I think everybody knows the the best swap for a MJ is the D44 out of the metric ton package, These are hard to find, next choice, D44 out of a Cherokee with a tow package. Number 3 in my mind would be the Chrysler corporate rear used in the later cherokees. All of Cherokee axles will require welding on new spring perches. Number 4 is the Explorer rear used after 95 with disc brakes ( Ford 8.8 ). you can get these for about $300. You will have to do some work cutting off all the brackets and stuff, then welding on the spring perches. Try and get the drive shaft, this rear has a flange, so you need the part for the U joint. They are usually 3.55 or 3.73, you can find a 4.10 but they are rare. Next would be a ford 9". you can find them out of old Mustangs or Broncos. you will end up with way more money in it than if you used the Explorer axle. The ones for sale are usually drum brakes and it's big dollars to switch to Discs. Probably the bolt pattern will be wrong too. I think anything bigger, like a D60 is just overkill for an MJ.

I have been in a similar situation with cars, not getting ripped off, but having to deal with tons of rust. allot of times you are better off looking for a different body. I have some J trucks i bought in Oregon, and they have no rust. Oregon seems to be better than Texas or Arazona, because the sun is not so intense. I just bought a MJ on ebay for the Bonneville project, it has 275000 miles and was a little beat up, but it cost me $900.00 and about $400.00 to drive it home. it has a 4.0 2wd AX15 with a D44 rear end. Has air and power steering. Here is a link to the Ebay listing http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&sspagename=STRK%3AMEWNX%3AIT&viewitem=&item=330272004324 My general rule, don't buy a car from a state wher they have snow and salt the roads. It may look great, but you have no idea what's underneath. I bought a truck from PA, looked great, but it was pretty rusty once you got all the bondo off. You have to look at the cost of repairing the rust VS finding a good body and swapping you parts into it. I think you can find a good body in the 1-2k range, if you have it shipped figure about a buck a mile. Best is if you can get a cheap ticket and drive it home, big risk if it breaks down though. If i had shipped my truck back form Texas it would have cost $1000. My son was in texas on business so we had no cost to fly down, it cost about $350.00 for gas, and $80.00 for 1 night in a hotel. He had a bad ujoint, so he had to stop to fix that. So it was probably $500 to drive it back VS $1000 to ship it. So even if it had 2k in it , it think it would be money better spent that patching the old body.

I think your comments relate to the eearly NWC ( Non World Class) transmissions, they were used until the mid to late eightys. the NWC treanmissions were still used, but in the high performance cars they went with the WC transmissions. Here is a link to find out what kind of trans you might have and which vehicle it was used in http://www.britishv8.org/Articles/Borg-Warner-T5-ID-Tags.htm actually, if i did not need a scattershield, i would go with a NV 3550. great trans, and the 2wd units do not go for that much money. plus since it came in the cherokee, it goes right into a MJ. Problem is that you cannit get a scattershield for it.

And about 5 grand too!