SCCA Turbo 5.0L MJ (Comanche Eliminator Project)

[TurboTom]

Cool project.
What size exhuast housing is on your T-3?
What are your HP goals?

[Plechtan]

Here is an idea for lowering it.

Bonneville 2009.jpg

[nick]

Cool project.
What size exhuast housing is on your T-3?
What are your HP goals?

T-3 has a 2.25" ex it's a A/R .60
After the rebuild I should be making 450hp by 4800rpm, but my real no bullcrap goal is 600 HP and 650lb/trq with 16 psi

I know, I know your kidding right? NO I AM NOT! I am building this like no one has ever built one before with chromoly offset ground crank, roller cam and lifters and it will be done right.

Here is an idea for lowering it.

NICE. I saw this a while ago thanks for reminding me how low you went. I am curious about your suspension setup.

My plan was to get custom made 800in/lb de-arched leaf springs and lowered coils in the front with same strength. I'd also use really short bilstein shocks.

[Plechtan]

4 link.jpg

You probably can't get low enough in the back with leaf springs, you would also need to add a traction bar with all that torque. We went with a 4 link. 2 straight bars and the uppers angled towards the diff. Then coil overs in back of the axle.

We ran out of room and the coil overs and had come through the bed. I will post some picts. We had the "metric ton" option on the comanche that came with a Dana 44 rear. You may be able to find one over at http://www.comancheclub.com They also put dana 44s in some xj s, but the leaf springs are on the wrong side.

The front was lowered by making a dropped axle. ( see here http://www.jeepstrokers.com/forum/viewt ... f=8&t=1031) The suspension attachment points are all in the stock locations, the C pieces were moved up about 4". We used rear GM springs that had the pigtails to fit in the stock location. for your application i would recomend putting in adjustable spring buckets in the front ( available here: http://www.speedwaymotors.com/) and using the 9.5" stock car springs. The stock springs are about 12" with the truck sitting empty, 16" extended. they have a 200lb rate (so about 800 lb load per side). So a 600lb spring would get you down about 4". Watch the oilpan!

You can use Srt 8 Grand Cherokee brakes. I think they have 15" rotors or bigger. You have to change your knuckles to the 2003 and up, then redrill your rotors, or redrill the rears to match. I would redrill the rears so you could use stock replacment rotors. There are several articles on the internet talking about putting the stock grand brakes on a XJ or TJ. I used an electric vacuum pump and a 94 XJ brake booster for my setup. The hydroboost looks nice, but i did not want the engine to drive anything.

We did not go with the SRT8 brakes because it would have required at least an 18" wheel. We wanted to be as low as possible, so we have a 15" wheel with a 22" diameter tire.

[nick]

Plechtan, thanks for the tips. I was debating whether or not to do the 4 link or not, but I took off the leaf springs the other day to do some test measurements with jack stands. I definitely agree with you that the 4 link is the way to go. I will also have much improved suspension for my track days and autocross.

[MA2LA]

I will definitely be following this build. I have a short be 4 banger 2wd mj that i plan to build as a replica to the scca trucks. the biggest thing I am running in to is the front suspension. I also have a 2wd xj that i'm building and have been playin with the front end and when i was able to get it as low as the scca ones i was pretty much on the frame rails with the bump stops removed.. I have tried many time to find any info on the originals but no one has the info. i know there is one sitting in a museum and i have been tempted to make a raod trip and as them for permission to climb under it for some good pics.

[nick]

I will definitely be following this build. I have a short be 4 banger 2wd mj that i plan to build as a replica to the scca trucks. the biggest thing I am running in to is the front suspension. I also have a 2wd xj that i'm building and have been playin with the front end and when i was able to get it as low as the scca ones i was pretty much on the frame rails with the bump stops removed.. I have tried many time to find any info on the originals but no one has the info. i know there is one sitting in a museum and i have been tempted to make a raod trip and as them for permission to climb under it for some good pics.

Nice to know there are a few others who want to copy the SCCA build. Let me know if you make it out there for pictures. Plechtan was able to get his Bonneville pretty low, maybe he has better insight for you. I plan to chop a lot off in the front end. Trying to distribute weight a little better and increase strength.

[Plechtan]

I will definitely be following this build. I have a short be 4 banger 2wd mj that i plan to build as a replica to the scca trucks. the biggest thing I am running in to is the front suspension. I also have a 2wd xj that i'm building and have been playin with the front end and when i was able to get it as low as the scca ones i was pretty much on the frame rails with the bump stops removed.. I have tried many time to find any info on the originals but no one has the info. i know there is one sitting in a museum and i have been tempted to make a raod trip and as them for permission to climb under it for some good pics.

The picture to the right is the Jeep factory truck that set 14 records at Bonneville in 1986. It is currently located at the Chrysler archives in Detroit. The archives are in a unmarked building on a street with no name. They keep about 400 cars there including cars made for car shows. I was lucky enough to tour the archives and examine the 1986 truck first hand.

I did see at least one of the Scca truck s while i was there, all the cars are under covers so you kind of have to hunt for things. The archives are not open to the public, but you may be able to get information about the truck or go take a look if you have a legitmiate request. I would suggest calling the chrysler Muesum and getting the number for the archives. They may send you pictures, or maybe let you in. If you are lucky enough to get in ( not easy), they will only let you take pictures of the 1 vehicle you are interisted in.

You should also try posting on the Hesco Forumhttp://www.hesco.us/forum/ Lee did allot of work on these trucks and he may be willing to share some of his experience.

[MA2LA]

I may try to contact Chysler but i doubt they will do anything, i did call archer racing but no one there had any info on what they did.. the one thing i have come up with to get it lower is to notch the front frame rails. I just finished up a 10 " notch on a suburban and this one would be much easier.. the hard per of it all is getting the geometry to work right. I have lowered my XJ a couple inches in the front and now I have some interesting handing issues and i'm not sure if its the track bar height or if by some od chance my steering box went bad. also the oil pan on a 4.0 may need to be modified to get much lower.i saw the axle setup on the the other mj and i'm not a big fan but it may come down to something like that.

[Plechtan]

I may try to contact Chysler but i doubt they will do anything, i did call archer racing but no one there had any info on what they did.. the one thing i have come up with to get it lower is to notch the front frame rails. I just finished up a 10 " notch on a suburban and this one would be much easier.. the hard per of it all is getting the geometry to work right. I have lowered my XJ a couple inches in the front and now I have some interesting handing issues and i'm not sure if its the track bar height or if by some od chance my steering box went bad. also the oil pan on a 4.0 may need to be modified to get much lower.i saw the axle setup on the the other mj and i'm not a big fan but it may come down to something like that.

This is why i went with moving the C pieces up, no need to notch the frame and the suspension angles all reamain stock.

[Plechtan]

Maybe you guys should go with a Mustang II suspension. Check here http://www.fulltiltstreetrods.com/cross_members.htm

[Plechtan]

I posted on the Hesco board asking what suspension was used on the SCCA trucks.

Lee Hurley Replied:

The rear springs were leaf and lowering block were used.

The front axle was cut and dropped

[MA2LA]

humm I'd like to see how they did it. I swear at one time they used to sell drop spindles for these front ends but i tossed the catalog years ago. I want to say t was trail master that made them back when they played with lowriders aswell.

[nick]

So several updates...

Lots of new pictures on the 4th post here
Engine specs also heavily updated here

I removed the rear leaf springs and set the rear on jack stands. I'll start mocking up the 5 point suspension. I haven't decided if I will be notching the frame or going into the bed at all.

Gradon started working on the '95 0630 head. So far he has clocked almost 7 hours on the port and polish. We are aiming for 64cc combustion chamber (going to be tough). Of note, we are already at 60cc due to the tulip Ferrea valves. Getting an additional 4cc shouldn't be too difficult.

I have decided not to go MSD and will be using the 2001 coil packs. I will use the 36 -1 tooth for the pickup on the harmonic balancer. I also like the 32 -1 over the dizzy due to less stress on cam gear.

I am purchasing a TIG welder soon and will start stiffening the frame and doing lots of fabrication. Below is the location of where I'll make the fuel cell fit (I removed the spare tire lowering rig).

[TurboTom]

Just a couple of thoughts...and I am just trying to help.

The 2001 coil pack works a little weird compared to most others. It has a common ground and you have to switch the power on and off for it to fire.
Also it not really a strong sparker either. That's what I found out attempting to build a stand alone ignition for the coil pack.
There is no more load on the cam gear as you have to run the oil pump anyway and the dizzy takes nothing really.
Coil packs do not make anymore power than a dizzy.

That turbo is a waste of your time for your goals. It is sized for a 1.6 -2.0 liter
It will probably make boost at just above idle, and blow up at 4000 rpm.
Then little bits of turbo wheel will go into your newly built engine.
I know you already own it, I own a hornets nest, but I'm not installing it in my car.

Build your exhaust to take a birficated housing and take advantage of the firing order.
My split housing is a 1.15 A/R

Good luck, I like your build.