New to the forum, looking to do a custom build.

mek_a_nik

Hey guys, new here. my names Mike, Im a certified motorcycle mechanic, currently I work as a SPAM equipment mechanic, so I work on anything from weedeaters, to 80hp turbo diesel mowers. I am a pretty good welder/fabricator, I'v e built a few custom bikes. currently I am looking to build a 2 seater rock crawler/buggy and i have a few engine options I am looking at, I have a 1996 zx7 115hp bike engine (well i have the whole bike) and I was thinking of dropping it into a buggy frame, I have most of what I'm going to do figured out, but what I am unfarmiliar with is suspension mounting geometry and I was wondering if someone could point me in the direction of an information source, books, website etc.

thanks in advance
mike

teamidris · Posted: Fri Oct 26, 2012 5:34 pm Post subject:

It seems to be much like racing cars, with bias to make the wieght go forward or backward under acceleration. And the usual bump steer, roll centre and the one where the tyre contact is in line with the kingpin that I can never remember the name of Embarassed

(The one people screw up by fitting huge offset rims)
[roll centre is the one that makes the front wishbone arms point inward like an X when looking from the front. Where they cross is the centre of a virtual hinge]
And as these are all well easy to cock up, the best solution is to look at loads of other builds, get a book on race car geometry and build it with spare holes either side of where you think it should be. Then you can adjust and fiddle with the geometry as you run it in Very Happy

And that's my inexpirienced view on it based on my mates midget sprint and loads of off roaders I've seen Wink

mek_a_nik · Posted: Fri Oct 26, 2012 6:11 pm Post subject:

thanks, the other idea I am throwing around is, I have a totalled cavalier.

I was thinking of using the engine and manual transaxle and turning it sideways and making a 4wd coupler for the front axle. they make posi inserts for the manual trans, and the engine/tranny package is fairly small and lightweight.

baloo · Posted: Fri Oct 26, 2012 7:24 pm Post subject:

suzukivit1 · Posted: Fri Oct 26, 2012 9:13 pm Post subject:

cant beleve you dont no what a cav is or am i just getting old?
colin

aniesigh · Posted: Fri Oct 26, 2012 9:40 pm Post subject:

i'm guessing he means which variant e.g engine type and size, also pretty sure they did a 4wd cav

mek_a_nik · Posted: Fri Oct 26, 2012 9:46 pm Post subject:

well, its a fwd cavalier, its a 2001 z24, i got t-boned in it in june, motor and trans still run perfect, still driveable, i bought it back from the insurance company for $500. it has the 2.4l twincam motor, which i think makes around 160-190hp. and I allready have all the electronics in the car so i could easily keep it FI, which is better under extreme angles anyways. as far as axle arrangements, It just depends on what will be cheaper for me in the long run. Im thinking straight axles, but if I can go independant using some gm front axles or something for cheaper I will. so I will be keeping a running total so noobs like me can get an idea what it costs to build something like this. and yes dont worry there will be pics once I get under way. In fact maybe I can find a couple of front diff/axles from an s10, they have those electric diff locks in them like my 03 had. make it nice if i just had to push a button. Confused

clbarclay · Posted: Fri Oct 26, 2012 11:51 pm Post subject:

Any idea of the size of buggy you want to make or just looking for ideas?

If you keep the tyre size about normal 4x4 size then a fwd engine and gearbox turned round to drive the axles has been done to good effect, but if you want a lot bigger tyres then you will likely need extra reduction gearing as well.

There are a few people on here that have made suzuki based buggies with fwd gearboxes turned through 90 degrees and direct driving the standard axles. However for much larger tyred buggies, portal axles have the added advantage of extra reduction gearing to get the sped right. The Spider buggies are a good example of this.
http://forum.difflock.com/viewtopic.php?t=60786...r=asc&start=0

My SJ based project uses a fwd engine and gearbox with the SJ transfer box. This will result in some silly low speeds down to 0.6mph in first low with 33" tyres, even though I'm not making it to be a typical rock crawler.

A remarkably compact 2 seater buggy.
http://www.pirate4x4.com/forum/general-4x4-disc...ed-kid-buggy.html

mek_a_nik · Posted: Sat Oct 27, 2012 3:54 am Post subject:

Well im confused, If I am running my fwd at 90° and driving 2 other straight axles aren't I getting a reduction? I mean my cavalier engine and Tranny propels a 3k lb car easily up to the 105mphforum speed limiter, and that's at a 1:1 ration out of the transaxle, if I'm using a set of axles im changing that ratio from enough power to propel a car at 1:1 to a say 3.71 to 1 why do I need additional gear reduction?

baloo · Posted: Sat Oct 27, 2012 5:10 am Post subject:

baloo · Posted: Sat Oct 27, 2012 5:15 am Post subject:

suzukivit1 · Posted: Sat Oct 27, 2012 9:13 am Post subject:

clbarclay · Posted: Sat Oct 27, 2012 10:23 am Post subject:

Eclipsed4ever · Posted: Sat Oct 27, 2012 7:25 pm Post subject:

I'm running an auto 2.2 prelude engine with a welded diff turned 90 degrees. That drives shogun diffs which are 4.3 I believe. Wearing 39.5" Iroks the gearing is still reasonably good. Being an auto you effectively have infinite gearing anyway. As long as you have enough power to spin up from 1500rpm which is what you'll be at tickling around, you should be fine.
Personally I think if you go too far with the reduction, it ends up unuseable in the lower gears. Yes you have lots of torque, but that puts a lot of strain on drive components. As long as you have a reasonable motor it should be able to pull itself along! The less shifting the less desruption of grip. Just my 2p's worth

mek_a_nik · Posted: Sat Oct 27, 2012 11:21 pm Post subject:

Well here's the info I have on my engine...

Engine Type: Inline 4 Cylinder
Displacement: 2.4 Liter (146 CID) Liter (VIN): T RPO: LD9
Bore: 90 mm / 3.54 in
Stroke: 94 mm / 3.70 in
Compression Ratio: 9.5 to 1 from 96-98-----/-----9.7 to 1 from 99-02
Firing Order: 1-3-4-2
Horse Power: 150 @ 5600 rpm
Torque Rating: 155 @ 4400 rpm
Lubrication System Oil Capacity without Filter Change: 3.75 Liters / 4 Quarts Oil Capacity with Filter Change: 4.25 Liters / 4.5 Quarts...Almost EVERYWHERE this reads 4 Quarts...Including the GM Service Manuals
Engine Oil Type: SAE 5w30
Engine Cooling System: 10.7 quarts
Brake Fluid: Delco Supreme 11 or DOT-3 Equivalent
Cluch Fluid: Delco Supreme 11 or DOT-3 Equivalent
Refrigerant: R-134a Power Steering Fluid: GM p/n 1050017
Manual Transmission Fluid: Synchromesh, GM 12345349
Automatic Trans. Fluid: Dexron 3 ATF
Oil Pressure @ 3000 RPM: 207 kPa / 30 psi min
. Oil Pressure @ 900 RPM: 69 kPa / 10 psi min.
Recommended octane: 87
Fuel Tank Capacity: 14.3 gal.
EPA Mileage Estimates: (City/Highway) Manual: 23 mpg / 33 mpg Automatic: 22 mpg / 30 mpg
Fuel Delivery: Sequential fuel injection (SFI) Thermostat opening temperature: 180 degrees F Emissions: Low emissions vehicle equipped with single Catalyst

mek_a_nik · Posted: Sun Oct 28, 2012 12:19 am Post subject:

Im sure it will run a little better once I change the exhaust, intake, and remove some things like the ac compressor.

mek_a_nik · Posted: Sun Oct 28, 2012 1:16 am Post subject:

Well... let me tell you my intentions and then tell me what you think would be best. I am not interested in competitive crawling. I have a family now and I want something I could pile them in and go trail riding. I live 30 minutes from the Rubicon and many other trail areas. I just want something with enough articulation to handle most normal trail obsticals, but still fast enough to cruise around in open areas and still be fun. I would probably run 36-40" tires to try and keep it more affordable. I would like to keep it compact and lightweight. But be able to seat 4. I am thinking rear engine in front of axle.

baloo · Posted: Sun Oct 28, 2012 2:36 pm Post subject:

"I would like to keep it compact and lightweight. But be able to seat 4. I am thinking rear engine in front of axle."

that sounds a tall order but l guess lightweight is relative, l would call lightweight well under a ton so an sj dosent really qualify even before all the roll cages bumpers made of girders, winches etc are added in, but if the norm is 5000 lbs then 2500lb might be considered lightweight,
anyway have you decided on solid axles or independent yet ? as this will affect the layout greatly, if you have 2 rows of seats with foot room plus an engine and box behind the seats plus some propshaft length to allow the rear axle to move up and down then we are getting up towards 120" wheelbase not compact as you require, maybe solidly mounted diffs might be the way to go despite the fact they will limit the wheel travel, at least if the diffs dont move then you could mount the engine above them and cut the length of the rear prop down to next to nothing as it has no need to move up and down,
it might be an option to use your engine and box mounted over the front diff with the one out put feeding back into a centrally mounted remote transfer box that splits the drive to the front and back, you get the option of another gear reduction that way as 40" tyres are eating into the reduction you have in the fwd gearbox, you would need to weld the diff in that and then you could use the front output to drive a little capstan winch on the front end

anyway keep us posted of how it goes

Andy

mek_a_nik · Posted: Sun Oct 28, 2012 6:39 pm Post subject:

Well... I was considering a cab space roughly the size of a clubcab mini truck, nothing too big. Back seat is just for kids. The weight of the cavalier is 2670 @150hp so if I can stay under that I will be happy, but as far as top speed im o my looking for may e 50-60.

rockwatt · Posted: Tue Oct 30, 2012 3:05 am Post subject:

clbarclay · Posted: Tue Oct 30, 2012 2:04 pm Post subject:

What sort of cruising speed are you after?

You may find gearbox won't give a wide enough range of gears on its own to allow both controlled engine braking down steep slopes and cruising on road without revving the nuts off the engine. I would look for a suitable divorced transfer box with a 1:1 high range ratio, which with the normal 3.71:1 axles (or similar ratio) should give a decent top speed, while the low range will allow it to crawl.

If you go for live axles there have been some useful suspension calculators posted on Pirate 4x4 to help with link geometry and spring rates.

For example
http://www.pirate4x4.com/forum/general-4x4-disc...request-help.html
http://www.pirate4x4.com/forum/ballistic-zone/9...ocks-hybrids.html