whooprunner
NAXJA Forum User
- Location
- Orange County, CA
Hi All,
Upon reading alot of the posts, it seems like it would be helpful to have a single thread that can answer the frequently asked JeepSpeed related questions. Here's some sections that might be of interest. Feel free to add your own opinions to be incorporated into this FAQ.
JeepSpeed Rules
http://www.jeepspeed.com/store/1700%20Rules.pdf
Jeepspeed bases all rules off the SCORE class 3 rule book
BITD Rules
http://www.bitd.com/images/stories/p...CTRuleBook.pdf
Suspension
Front Suspension
Rules:
Currently Approved Suspension Manufacturers:
Long Arm vs Short Arm Opinions?
Rear Suspension
Rules:
Most teams use Deaver G9 Leaf Springs with a boomerang Shackle from Rubicon Express, JKS etc.
Shocks / Bumps
Rules:
Current Major Manufacurers
Front Shock Length: Due to the restriction by the JS rules and space in the front wheel well, the front shocks are generally 10" in length. Most are using T & J style mounts with support being tied into the engine cage. Due to the restricted space shock manufactuers sometimes weld heims directly to the shock shaft to reduce overall length.
Rear Shock Length: The Length of shock is typically unrestricted, however at least a 14" shock is a good idea with.
Should I run a 2.5" Bypass or a 3" smooth body?
This is one of those questions that have people on both sides.
2.5" Pros:
2.5 Cons:
3" Pros:
3" Cons:
Drivetrain
Transmission / Transfer Case
Front End
Rearend
Rearends currently in use: Dana 35, Dana 44, Chr 8.25, Ford 9", Ford 8.8"
The gear ratios for JeepSpeed usually run into 5-6 ratio which tends to rule out stock axles. The most common axles used are the Ford 9 inch and the XJ Dana 44. Both have a large number of ratios available and have a larger ring gear.
* Here is a idea of what a basic (Currie) JS rear is going to run a team.
Housing and Axles Retail JS team
* EXTRA HEAVY DUTY HOUSING - MIG WELDED TO YOUR SPECS... 399.9500 379.95
* CURRIE PERFORMANCE 35 SPLINE AXLE PACKAGE...................... 459.9500 436.95
* SPRING PADS - 3.00 INCH X 2.25 INCH - PAIR ......................... 19.9500 18.95
3rd member
* 9 Inch Ford (9IN) 5.14S Ratio - 35 Spline - Spool (SP) Diff. - 9+ Nod Race [R] Case - Currie Alloy [C] Pin Sup - 1310-Short 9+ (A) Yoke .................................................. ..1257.65 1194.77
[NRT_Chris]
Steering
Unibody Frame / Cage
Cage
Material: Recommended 1 3/4" .120 DOM Tubing.
*Jeep Cherokee XJ 8 Point Cage - Weld-in Kit - starter cage
*Jeep Cherokee XJ Stage I Chassis Stiffeners
Engine
*62mm Throttle Body - you can buy from NRT_Chris or myself (support our sponsors)
*1987-2001 Jeep Cherokee XJ Motor Mount Brackets
*ATK crate engine or Jeeptricks engine (another sponsor)
Electrical
Lighting
Fuel System
Fuel Cell
*Current Manufacturers Jaz, Fuel Safe
*Current Types: Under the Floor in Stock Location or In Cab Mounted
-Fuel Pump
Body
Body Style
2 Door or 4 Door Cherokee?
No real competitive advantage with either. One opinion is that the extra door pillar of a 4 door may help with body stiffness. Choice is really up to personal preference e.g. driver accesibility, driver vision, looks, accesibility to rear etc.
Front Fiberglass
*Current Manufacturers: Hanneman, Trailer Products...
*Rear Fiberglass: Hannman makes rear fiberglass for the MJ that can be addapted to the Cherokee. Most others are using flares rather than fiberglass.
*Fiberglass is not really needed to stuff 33" tires. More for weight savings in the hood area or just for looks.
Safety
Seats
Current Manufacturers
There is an on going debate regarding over the safety of Suspension seats over Shell type seats. Some say suspension seats contribute to back injuries and advocate Sparco type shell seats. A majority of racers are currently using suspension style seats for now.
Wheels / Tires
*The most common tire size is either 33x10.5R15 or 33x12.5R15
*American Racing or stock only
Upon reading alot of the posts, it seems like it would be helpful to have a single thread that can answer the frequently asked JeepSpeed related questions. Here's some sections that might be of interest. Feel free to add your own opinions to be incorporated into this FAQ.
JeepSpeed Rules
http://www.jeepspeed.com/store/1700%20Rules.pdf
Jeepspeed bases all rules off the SCORE class 3 rule book
BITD Rules
http://www.bitd.com/images/stories/p...CTRuleBook.pdf
Suspension
Front Suspension
Rules:
- Maximum front wheel travel is 10"
- Stock frame lower front control arm brackets may be cut, bent, modified or removed from the unibody models.
- Suspension components must attach to the stock control arm brackets on the front axle.
- Axle control arm brackets may be strengthened by adding material, but must remain 1"radius of original location relative to axle centerline.
Currently Approved Suspension Manufacturers:
- Currie Ent.
- Skyjacker
- Rubicon Express
- Full Traction
- Poly Preformance
- Fabtech
- Rockrawler
- Nth Degree
- TerraFlex
Long Arm vs Short Arm Opinions?
Rear Suspension
Rules:
- Maximum rear suspension travel is 12"
- Stock frame spring mounts may be strengthened by adding material or replaced but must remain in original location.
- Axle leaf spring brackets may also be strengthened by adding material, but must remain in original locations relative to axle centerline.
- Leaf springs may be of any manufacture, but may only have a maximum length of 55" eye to eye measured along the curvature of the main leaf.
- Rear shackle length may be 6” maximum when measured eye to eye.
Most teams use Deaver G9 Leaf Springs with a boomerang Shackle from Rubicon Express, JKS etc.
Shocks / Bumps
Rules:
- A single shock absorber per side is allowed with a maximum diameter of 3" with non external bypass or rate adjusters, or 2-1/2 inches with external bypass or adjustment.
- Bumpstops are required to attach in the original locations and may be of any material.
- Air/Hydraulic bumpstops are allowed.
- Mounting locations on frame may be modified only enough to allow mounting of new bumpstops, but bumpstop angles may be changed.
Current Major Manufacurers
- King
- Fox
- Sway A Way
- RadFlo
- Bilstein
Front Shock Length: Due to the restriction by the JS rules and space in the front wheel well, the front shocks are generally 10" in length. Most are using T & J style mounts with support being tied into the engine cage. Due to the restricted space shock manufactuers sometimes weld heims directly to the shock shaft to reduce overall length.
Rear Shock Length: The Length of shock is typically unrestricted, however at least a 14" shock is a good idea with.
Should I run a 2.5" Bypass or a 3" smooth body?
This is one of those questions that have people on both sides.
2.5" Pros:
- Bypass shocks are externally adjustable. This means that shock valving can be dialed in quicker and does not require shock disassembly.
- Bypass shocks are position sensitive. A bypass shock has multiple compression and rebound zones. This allows for soft valving to soak up little bumps and stiffer compression for harder hits. If valved right, the top area of the shock past the last compression tube becomes a hydraulic zone similar to a hydraulic bumpstop. Rebound similarly has multiple zones that allows you to control how fast the suspension will "drop" out.
2.5 Cons:
- With long races, limited travel, rough courses and rough drivers, some have experienced shock fade during a race. To compensate for this, some have found creative ways to increas oil capacity by using the longest shock possible etc.
- Rebuild Costs. Some are finding their shocks "cooked" after a race and rebuild their 2.5" shocks after every race , repacing mainly the seals and oil.
3" Pros:
- Large oil capacity and surface area resists shock fade for longer races.
- Shocks may not need to be rebuilt for several races to the entire season.
- For the front shocks which take the most abuse, It is debatable whether bypasses really help with limited travel.
3" Cons:
- Dialing in shock valving requires diassembly and can take longer to get right.
- Shock has only one compression and rebound valving when compared to bypasses.
- Inital cost more expensive than smooth bodied 2.5", however comparable to 2.5" bypasses.
Drivetrain
Transmission / Transfer Case
Front End
Rearend
Rearends currently in use: Dana 35, Dana 44, Chr 8.25, Ford 9", Ford 8.8"
The gear ratios for JeepSpeed usually run into 5-6 ratio which tends to rule out stock axles. The most common axles used are the Ford 9 inch and the XJ Dana 44. Both have a large number of ratios available and have a larger ring gear.
* Here is a idea of what a basic (Currie) JS rear is going to run a team.
Housing and Axles Retail JS team
* EXTRA HEAVY DUTY HOUSING - MIG WELDED TO YOUR SPECS... 399.9500 379.95
* CURRIE PERFORMANCE 35 SPLINE AXLE PACKAGE...................... 459.9500 436.95
* SPRING PADS - 3.00 INCH X 2.25 INCH - PAIR ......................... 19.9500 18.95
3rd member
* 9 Inch Ford (9IN) 5.14S Ratio - 35 Spline - Spool (SP) Diff. - 9+ Nod Race [R] Case - Currie Alloy [C] Pin Sup - 1310-Short 9+ (A) Yoke .................................................. ..1257.65 1194.77
[NRT_Chris]
Steering
Unibody Frame / Cage
Cage
Material: Recommended 1 3/4" .120 DOM Tubing.
*Jeep Cherokee XJ 8 Point Cage - Weld-in Kit - starter cage
*Jeep Cherokee XJ Stage I Chassis Stiffeners
Engine
*62mm Throttle Body - you can buy from NRT_Chris or myself (support our sponsors)
*1987-2001 Jeep Cherokee XJ Motor Mount Brackets
*ATK crate engine or Jeeptricks engine (another sponsor)
Electrical
Lighting
Fuel System
Fuel Cell
*Current Manufacturers Jaz, Fuel Safe
*Current Types: Under the Floor in Stock Location or In Cab Mounted
-Fuel Pump
Body
Body Style
2 Door or 4 Door Cherokee?
No real competitive advantage with either. One opinion is that the extra door pillar of a 4 door may help with body stiffness. Choice is really up to personal preference e.g. driver accesibility, driver vision, looks, accesibility to rear etc.
Front Fiberglass
*Current Manufacturers: Hanneman, Trailer Products...
*Rear Fiberglass: Hannman makes rear fiberglass for the MJ that can be addapted to the Cherokee. Most others are using flares rather than fiberglass.
*Fiberglass is not really needed to stuff 33" tires. More for weight savings in the hood area or just for looks.
Safety
Seats
Current Manufacturers
- Mastercraft
- Beard
- PRP
- Sparco
- Twisted Stitch
There is an on going debate regarding over the safety of Suspension seats over Shell type seats. Some say suspension seats contribute to back injuries and advocate Sparco type shell seats. A majority of racers are currently using suspension style seats for now.
Wheels / Tires
*The most common tire size is either 33x10.5R15 or 33x12.5R15
*American Racing or stock only
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