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KOH / Dual Sport / Endurance Racing Light Weights - A thread for smaller buggies

27K views 95 replies 41 participants last post by  JF 
#1 · (Edited)
The large majority of the KOH style rigs I have seen posted are LS powered and typically sporting a Dana 60 front or a 609 or something even more exspensive. Many are growing in size as well, moving closer to a TT design.

They are awesome for sure, but I know there are some 4 & 6 cylinder rigs in the mix. I would like to see more about those buggies, like powertrain info, total weight, tire size, and what lighter weight axles are surviving the abuse.

There was a 4banger thread here -> http://www.pirate4x4.com/forum/showthread.php?t=852022&highlight=banger+koh&page=5 but it focused mainly on total investment.
 
#6 ·
Suzuki 1.6 8 Valve, ported/polished head, junkyard rotating assembly, GSXR 750 Fuel injection, Megasquirt ecm. (By FAR the smallest in the field)

Suzuki 5spd

Suzuki t-case with Trail Tough 4:1 gears

FJ80 axles (low pinion front), ARB's, 5.29's, Longfield and Poly shafts

37" KRT-b's

FOA 2.0 resevoir coilovers

No spare tire, 8/10 psi

We were 1 hour over time at KOH (replaced a brake line, had alternator issues, welded the trans crossmember on Jack North, spent about an hour on spooners wedged in some rocks), so officially a DNF.

Since then, we have finished EVERY mile of EVERY race, and seem to have more and more time left over at the end.

At SMORR, the alternator braket broke causing the waterpump to not pump, subsequent overheating blew head gasket on lap 1. Had to pit all but 1 lap to add water and try to cool her off while running about 70%. We spent about an hour in the pits combined and finished 12th. Getting that hour back would of bumped us up a bit (7th/8th).

It now has 2.5" C/O on the front and 2.5" triple by-passes on the rear. The 8valve is coming out and a 16 valve is going in. Turbo may be an option, but I need to be sure my t-case can handle it.


This move to El Paso in January has kinda fawked up all my big plans!!

I know I am kinda the JV 4cyl team, but Matt Messers turbo Ecotec is a mean little beotch. He was in the top 20.

Rob
 
#8 ·
No need to keep it a huge secret. I'll let a little cat out of the bag.


350hp (with plenty more available) '87 Ford 2.3L Turbo out of a Merkur XR4Ti with an HX35 slapped on it.
Built C4 with low first and a bunch of other uh, goodies.
Atlas 5:1
Toyota 8" front with FJ80 outers, Ruffstuff housing
LP 9" out back, all spidertrax with a Ruffstuff housing
2.0"x14" short body Bilsteins, 2.0x2.0" airbumps up front
2.0"x17" short body Bilsteins, 2.0x2.0" airbumps out back
37" treps mounted on racelines
16 gallon cell

Overall weight somewhere around 3k race ready.

As it sits in this picture, it's ~1850lbs with 90% of the parts on it. Spares and fluids are going to be quite hefty.

I'd also like to clarify that this is absolutely not a KOH racer. It's an RCrocs Class 3 comp buggy with the ability to race our east coast woods races. Tight chassis, short wheelbase, and a little bit of pep under the hood seem to be king. We'll see how it does. At times I wish I didn't conform to Class 3 rules since I could shave more weight by ditching the stock YJ frame and tub, but such is life.



 
#10 ·
Tons. It's cryo treated for good measure. If it doesn't hold up i'll likely end up building a 9". This project has taken so many different directions and it shows with some of the parts selection.
 
#11 ·
I will be racing the the ultra 4 Stampede with an ultra light single seater. Hoping to qualify for KOH. In a couple of weeks I'll let you know how it went! :)
 
#16 · (Edited)
Check out the dirtbuilt 1.5. 4 banger making good hp if needed.
 
#18 ·
We haven't raced at KOH, but have been running local races in PA at Line Mountain(tight woods racing) and the ultra4 type race series at Rausch Creek.

the rig was originally built for class 3 in rcrocs at rausch, based off a geo tracker frame :laughing:

drivetrain - 2002 suzuki 2.7 V6, all aluminum 4cam, 185hp, 4spd auto, dual toy cases(stock gears)

axles - toyota 8", front is a widened/modified stock housing, fj80 hp diff/5.29/detroit, longs. rear is a ruffstuff housing, front range full float kit welded on, 5.29/ARB in a V6 diff. gears are not cryo'd, and haven't given any issues.

suspension is 3link/4link, bilstein 2.0 14" shortbody coilovers, tires are 37" treps on old school campbell ent. beadlocks :smokin:

overall the rig is kind of overbuilt, probably weighs #3,4-500 lbs race ready with a spare tire and a 16 gallon fuel cell, it's been working well other than a few bugs here and there, and my longs are clicking all the time now :laughing:

plenty more pics and details in the build thread, link in my sig.

 
#23 ·
For the turbo 4cyl guys are you running air to water intercoolers? How about meth/alc/water injection?

I have a turbo B series honda that probably makes ~300hp in an Integra I built several years ago. I am kind of burnt out on the import car thing and have often considered running the motor in a transaxle buggy. The FMIC would work when moving but when stuck or spinning all 4 on a climb the lack of air flow would cause IAT/EGTs to climb and lead to knock....
 
#26 ·
I have a turbo B series honda that probably makes ~300hp in an Integra I built several years ago. I am kind of burnt out on the import car thing and have often considered running the motor in a transaxle buggy. The FMIC would work when moving but when stuck or spinning all 4 on a climb the lack of air flow would cause IAT/EGTs to climb and lead to knock....
I think you will either give up too much crawl ratio or high speed running with just using the transaxle.After 5 miles on the pavement a few weekends ago in my honda power transaxle rig......I am buzzing the hell out of it to go maybe 45mph....with 39s and 5.29 in the axles. Now if ya had a slightly looser converter(to cover the lack of crawl ratio...) and axle gears in the 4.10-ish range and the HP to pull them in top gear.......:p
 
#27 ·
I don't think you need to have a 4 or even a 6cyl to be lighter and yet stay competitive. Ours are 2 seat, LS powered rigs, are a very competitive car and pretty light in my opinion for a 4400 car.
A fully dressed LS motor is surprisingly light. But like has been said before, moderate power and a well tuned suspension can get you some top finishes.
 
#29 ·
There have been some epic threads on Race Dez about why TT's weigh nearly 6000lbs, and it all comes down to tire size. If you're committed to running 39's and you want to go fast, then it takes some seriously stong parts to take the abuse and inertial energy that those rotating parts have when you get air and touch down again. Bigger axles, bigger axles housings, bigger brakes, bigger cooling systems, bigger engines, etc., it's the truest case of one thing leads to another.

Want a lighter rig, start with 35" tires on lightweight wheels.
 
#31 ·
I would personally much rather race a 3k 300hp rig than a 4500lb 500 hp rig.

Well okay, I would race either. :flipoff2:
 
#37 ·
I have a two seater Honda buggy with FJ-40 axles, 5.29 gears, 37" Krawlers. Engine is a 2.3 out of a 98' Accord, has been modified to run OBD 1 to bypass some of the stuff that is not really needed. 150hp/150tq, that is stock. I don't think having a turbo will be much of an advantage to you. Maybe more so with an automatic, but mine maxes out each gear so fast stock, I don't see much need for more power. LONG steep/slick hillclimbs would be the only time more power might be nice, mine will bog down and I have to downshift, if I can keep the RPM's in VTEC in 3rd gear it has tons of power, but sometimes the hills might be too rough to go that fast.

I have a 5 speed in mine (out of an older Accord), crawling it does fine, I have to ride the clutch a little on really hard stuff, but not bad. Top speed is about 45 I am guessing, which is probably all my rear driveshaft could take anyways, it's at too much of an angle and shakes, not much I can think to fix it though...
 
#47 ·
Alright so while not necessarily a light weight rig Brad Lovell managed a 2nd place on 37s. But, its not like he spared alot of exspense on axles or horse power.


2- 232 Brad Lovell 6:58:21
Chassis: Lovell Racing
Motor: Ford 347 Proformance stroker
Transmission: Art Carr C-4
Transfer Case: Atlas II 3.0:1
Front Axle: Spider 9 / Hi 9 35 spline Spidertrax Axles, CTM Joints, 5.14 w/ ARB
Rear Axle: Spider 9 / Hi 9 35 spline semi float Alloy USA Shafts 5.14 w/ ARB
Front Suspension: 3 Link w/ 2.5" x 14" Fox Coilovers
Rear Suspension: 4 link w/ 2.5" x 14" Fox Coilovers and Fox triple bypass
Wheelbase - 105"
Tires - BF Goodrich 37” KRT



So if you were planning to run 37s with a mid/rear mounted 4cyl with ~250hp what are the axle options without such an investment?

You wouldn't want to dump a fortune into a D44 , especially since it would probably still break .... on the other hand a D60 seems like alot of beef/weight just for 37s... is there a middle ground? Are any of the extended travel D50 TTB set ups stronger than a D44?
 
#49 ·
Just remember that for the rocks there is such a thing as too light. You can't run water in the tires in go fast so a little weight down low is preferred, especially if you have a 700lb chassi with a 4 banger.
 
#51 ·
Here is my buggy that i switch over to go fast mode for a couple of 100 mile races up here in Montana and Wyoming. Just under 3000lbs in race mode. I run a warmed up 4.3 vortec to a built th350 with kevlar clutches and manual valve body to a dana 300 with 4:1kit. My axles are toyota rear with 5.29's and the front is a toyota dana 44 hybrid. Chassis is .120 wall 1.5 chromoly. The front is set up with 14in coilovers and the rear are 16in. This set up works for me really well. I just added bump stops to the rear and now i run 35 bfg corr take offs.
 

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#52 ·
YES! that is what I am looking for. Do you have a build thread? Or just more info on your hybrid front?

I have been studying this thread by joefab about a toy/ttb50 hybrid.
http://www.pirate4x4.com/forum/showthread.php?t=837514&highlight=ford+front+axle


I have a 9" rear I would like to try to turn into a front in similar fashion. I don't have a solid grasp on what exactly is going on as far as shafts and seals in some of these hybrids. I seem to recall a 14B front thread that said they used press in seals that circle track cars run ...
 
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