My Kart Cross design

**bigblock** · 05-28-2011 11:23 AM

Hi guys,

I went through many of the building threads of this forum during last weeks and they challenged and motivated me to design and build my own buggy

So, I would share with you my experience.

My initial idea was to build something just for fun, but I found out that actually also many racing opportunities there are for such kind of vehicles.

Where I live (Italy) there is a class named “Kart Cross”, very affordable both in terms of costs as well as building and racing rules.

There are a lot of races open to this class, that is very popular also in other EU country (France, Spain, UK..). I think the class was born in France.

Basically, the main rules are quite simple:

Max length: 2600mm (102’)
Max width: 1600mm (63’)
Max height: 1400mm (55’)
Engine: bike derived. Max 600cc. Limited modifications allowed
Transmission: free but without differential.

I don’t know if an English rules book exists, but here there is the Italian version: http://www.autocrossitalia.it/REGOLAMENTO%20KK.pdf

And here the French: http://www.ufolep.org/modules/telech...art%202011.pdf

After spent a couple of nights on the 3D Cad, I’ve now a good mock-up of the chassis and suspensions layout. A lot of design still need to be done (upright, steering, pedal box, body supports….).
This is the status of my project as it stands now:

Width = 1551mm (61’)
Length = 2600mm (102’)
Height = 1260mm (49’)
Ground clearance = 135mm (5’)
Front track = 1326mm (52’)
Rear track = 1385mm (54’)
Wheelbase = 2050mm (80’)
Chassis weight = 60,7 kg (132 lb)
Front Wheels: 165/70-10 (18,5x6x10)
Rear Wheels: 225/40-10 (18x10x10)

Any feedback and suggestion will be very appreciated.

More to follow in the next weeks.

**Gene** · 05-28-2011 11:36 AM

Welcome to MBN!

Looks good. Front end is similar in shape to Protodie's cars. Seat appears to not have enough head room. Should nerf bars be removable?

We don't have this type racing in the US but I think it would have fans and participants.

**KrunchWorkz** · 05-28-2011 05:37 PM

Looks good, but I do agree with Gene, you don't have enough head room. You want some head room so if you end up on your lid, and your cage makes a nice imprint in the dirt and sinks some, you want a buffer to keep your melon from making contact with the ground.

**bigblock** · 05-28-2011 06:35 PM

your point is well taken. I got the same conclusion as soon as I added the virtual "myself" (6 foot tall). I have increased a little bit the roll bar height and now the head seems to have enaugh room. What do you think ?

it also seems that I will be able to bolt the pedal box at the line between the two rear mounting point of the front whishbone. That should be ok.

**BigRed350x** · 05-28-2011 08:31 PM

I would try and find a little more room for your engine. It looks a little smushed in there behind your seat.

**Tappet Head** · 05-29-2011 05:07 AM

Looks good man, A little tip for on the track, make the front wider than the rear, makes the buggy more stable in corners and allows for better turning, something to do with the way the outside wheel is driving with in the track of the front wheel. And yeah a little more head room may be nice. Can you get the motor any lower in the chassis? The Lower your CG, the faster you can corner.

**bigblock** · 05-30-2011 08:42 AM

Originally Posted by BigRed350x

I would try and find a little more room for your engine. It looks a little smushed in there behind your seat.

I would like to know if someone out there that has a 600cc Suzuki or Yamaha engine can share the distance between the seat bulkehead and the rearmost point of the engine bolted in place

thanks.

**TutTech** · 05-30-2011 09:14 AM

From my 2005 GSXR 600cc engine the front of the air box to the back of the case is 21 inches.
(no headers on just the part your measuring.)

looks good and the points everyone else said I agree with also.
Keep us posted and good luck.

**TALON** · 05-31-2011 08:35 AM

Hello BB
I have recently measured a few jap inline fours for comparison the results are in the engines part of the forum in Tuts thread . If you rotate the engine in you r sketch forward about say 20 degrees you will have a better idea of how they will sit in a frame

**Gene** · 05-31-2011 11:43 AM

I agree wioth Talon on rotating the engine forward to the point where the oil pan flange is paralell to the ground.

With the ending rotated back the oil pump won't operate properly or won't operate at all.

Consequence is you will realize how close the cylinder and more importantly exhaust header are to the back of your seat or firewall.