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Ggerg1186 Sun Dec 27, 2020 12:46 pm

Well, I started mocking up my 914 mid engine sandrail yesterday. Got the engine and transaxle in place, made a table so I wasn't on the floor, bolted down the seats and started figuring out where the shifter & cutting brake lever would go.

This is a massive project. I need to come up with an exhaust system, rear suspension, tube chassis, wire harness, fuel system, carburation, I will be spending some money getting this built.

Priority for the project is a wide body frame. I am 6' 375lbs and don't sit comfortably in most commercially available frames. The lower frame tubes under the seats on most rails are 38" apart from outside tube to outside tube. This spacing is established by the width of the rear beam on the VW torsion suspension housing. You'll notice most driver/passenger seats are touching in the middle of the rail. My right shoulder is typically about 8" into the passenger seat when sitting in the drivers seat. I am targeting 48" wide at the frame base where the seat bolts to the floor.

Other than that, simple 80+ hp four cylinder air cooled & street legal. Just looking for a cool five speed go kart, don't need a turbo or any other stuff much beyond stock.

This is the general design I am mimicking for the frame layout:


Platform with seats mounted so I can make engine noises :) :)



Getting the engine in place:



And the transaxle:




As of right now it looks like I will have about a 102" wheelbase.

Should have about 6" suspension travel in the front and 8" in the rear.

Wish me luck! :shock:

oprn Sun Dec 27, 2020 5:53 pm

Good luck!! :wink:

Actually, I like the idea, a lot!

cbeck Mon Dec 28, 2020 5:03 am

Do you have a bender and welder? I doubt this will just bolt together. I am 6' and 240#. Most of the rails I have been in seem to fit people under 6' and 200#. Make the frame fit you. I widened the top rail, raised the windshield tube and roll bar, and then raised the dash bar so the wheel wasn't in my lap. Don't forget to leave room for dual carbs down the line.

Vanapplebomb Mon Dec 28, 2020 5:59 am

Nice that you got the D-Jet cylinder heads with the air inlet ports for the PCV system on them. Having fresh filtered air pulled into the rocker boxes keeps things nice and clean! When used with synthetic oil, you get almost zero build up of gunk in the rocker boxes.

rayjay Mon Dec 28, 2020 6:03 am

How much dirt use versus street use is the first question to answer. Every aspect of the design flows from the answer to that quesion.

ETA, actually, the first question is can you get affordable insurance and a tag without a monumental effort ?

Ggerg1186 Mon Dec 28, 2020 8:02 am

cbeck wrote: Do you have a bender and welder? I doubt this will just bolt together. I am 6' and 240#. Most of the rails I have been in seem to fit people under 6' and 200#. Make the frame fit you. I widened the top rail, raised the windshield tube and roll bar, and then raised the dash bar so the wheel wasn't in my lap. Don't forget to leave room for dual carbs down the line.

Bender, TIG, MIG, plasma, notcher, mill, lathe, master's degree in automotive engineering, and 20 years of off highway vehicle design experience, I think I am ready, but this is definitely a big job.

Ggerg1186 Mon Dec 28, 2020 8:04 am

rayjay wrote: How much dirt use versus street use is the first question to answer. Every aspect of the design flows from the answer to that quesion.

ETA, actually, the first question is can you get affordable insurance and a tag without a monumental effort ?

Iowa registering a kit vehicle is fairly simple. If need be I can register it in Vermont as an Iowa resident. I will find something for insurance.

I would say 80% of the use will be daily commute to work, assuming COVID ends and we ever go back to the office. 15% Iowa dirt road cruising with the occasional cut corn field / backwoods two-track / autocross excursion rounding out the final 5%.

rayjay Mon Dec 28, 2020 1:11 pm

You should make a tube frame that accepts 914 front and rear suspension. forget about the offroad usage.

dustymojave Mon Dec 28, 2020 1:30 pm

Ggerg1186 wrote: This is the general design I am mimicking for the frame layout:




That is a Hi Jumper/Prowler's Sand Sprite 2 frame. It did not use a VW torsion housing (Sand Sprite 1 DID use a VW torsion in an otherwise identical frame). There is a version of that frame that San Fernando Buggy offered back in the 80s that was mid-engined. They also offered a similar frame with a VW Bay-Window Bus IRS torsion that is several inches wider than the Bug torsion. But by curving the bottom rail of the frame behind the seats you can make the cockpit as wide as you want.

For your build, you can use the 914 torsion rear suspension. It will be easier in the long run to build it with the 914 rear arms and matching pivot geometry. This design also eliminates concern about cockpit width. Although cockpit width with a VW torsion housing is still not limited to the width of the torsion housing.

rayjay Mon Dec 28, 2020 1:46 pm

Here is a 914 based tube frame car

https://www.thesamba.com/vw/classifieds/detail.php?id=2077694

dustymojave Mon Dec 28, 2020 2:05 pm

Parts of that look pretty good. I don't like the weak rear trailing arm mounts or the dead-end tubes where the frame narrows at the back of the cockpit. But it has potential.

rayjay Mon Dec 28, 2020 4:10 pm

dustymojave wrote: Parts of that look pretty good. I don't like the weak rear trailing arm mounts or the dead-end tubes where the frame narrows at the back of the cockpit. But it has potential.

Spend a few moments figuring out the shock movement versus control arm movement !!! A hint - the shocks are moving the opposite of the norm.


dustymojave Tue Dec 29, 2020 12:09 am

That would make replacement shocks a tricky thing. But the parts look like 914 torsions, lower arms and spindles with custom upper arms.

Ggerg1186 Tue Dec 29, 2020 9:26 am

dustymojave wrote: Parts of that look pretty good. I don't like the weak rear trailing arm mounts or the dead-end tubes where the frame narrows at the back of the cockpit. But it has potential.

Yeah, this frame tie in leaves a bit to be desired. I am not using the VW torsion tube so I will find another way to tie it together. Will likely run the tube all the way down to the lower frame hoop next to the seats.




Ggerg1186 Fri Jan 01, 2021 11:54 am

I setup my tubing bender for 1.5" tubing today. I had only bent 1" tubing for go kart projects previously. Pretty happy that it bent 1.5" 0.120" wall tubing with ease. I was planning to build the whole, project with 0.095" wall, but the local steel supplier didn't have any in stock. So I will bend the lower frame, transmission-engine, and windshield hoops with the 0.120". Everything else will be 0.083" wall.

Got plenty of snow blown under the door in the shop. Currently 18 degrees, may not get to do much more work before March.




rayjay Fri Jan 01, 2021 3:50 pm

this guy has a custom mid engine autoX car. It's a single seater, basically a Super VEE. Not totally what you are after but a lot of good ideas. The one weird thing is the excess wheelbase. There is no need for the 'empty' space between the motor and driver.

https://www.thesamba.com/vw/forum/album_search.php?search_author=JoeE13

Ggerg1186 Sat Jan 02, 2021 5:40 pm

Was hoping to "shoot the moon" with a simple v-shaped lower transmission - engine hoop. Wanted the hoop skinny in the rear for axle clearance and wider under the engine to allow the exhaust to route inside the hoop tube. Couldn't quite make it fit with a straight line so I added some kinks to the hoop. A bit more artistic than I was intending, but should work well.




cbeck Sat Jan 02, 2021 6:39 pm

Time to take a breath and think about trailing arm mounts?

Ggerg1186 Sat Jan 02, 2021 7:32 pm

cbeck wrote: Time to take a breath and think about trailing arm mounts?

Getting there, I do not plan to use the VW Beetle rigid semi-trailing arm concept. I plan to use a trailing arm with double dogbone hybrid suspension.



This requires less precision in welding and ultimately allows me to dial in rear alignment, toe, unloaded & loaded camber independently of each other as well as independent to each side. It also allows the engine mount to go where it needs to go without impacting the trailing arm mounting point.

Ggerg1186 Mon Jan 04, 2021 11:52 am

Little line sketch of how I want to tie the lower frame rail into the upper frame hoop.




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