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#256
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![]() ![]() ![]() Here we go again… Thanks for the response Spanner.I was going to base the g50 install on what Ricola has done around the frame horn area. He has raised the box and moved it forward at the same time and built a cradle/engine mount and new frame horns.However he uses a combo of torsion bars and coil overs.I was wondering wether to get rid of the torsion tube completely as I will be using the uniball set up and just coilovers with no torsion bars.What do you think ??
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gee dub |
#257
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Hi mate, Walter has retained his o.e and runs a G 50, many others have too including Russ Fellows, so it can be done, and it's no mean feat to remove the t/ tube, it's the king pin for the rear chassis stiffness and alignment, the frame bracing needs to be in place before the tube is cut out to avoid distortion, also you can't use uniball with no t/tube, so a new control arm points or wishbone pivots need ploting, I did this on my rally cross 4x4 1303 with a Mac strut rear a arm set up, no T/tube but modified horns and coil springs, the prop shaft was where the t/ tube used to live, ,after all that work, I can say catagoricaly a complex car is no fun and a mare to work on, it needs a team of mechanos to look after it, at least for eventing, my mantra now has changed, a bit harsh, but I've been round the block, and unless you do the work yourself, KEEP IT SIMPLE, As much as you can, the original kit can work really well as I'm now proving with my b/j car, it has no problem with keeping double wishbone cars behind, in Rich's case, he had to go super stiff working with a cab' to avoid chassis flex and he knew what he wanted and was able to do the work himself, I think on balance I would keep the t'tube to use the uni balls, but possibly cut the centre section out to move the 'box forward enough and use coil springs on Existing a arms, or you could shorten the b/housing as Walter did successfully and leave the tube intact, this saves a mass of work and would be my way, indeed it may be on the cards soon when my 'box brakes which it will eventually with 200hp twisting it.
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#258
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Hi Spanner,I really appreciate your input here so thanks for all your comments.
I have had another look at Ricola's build and I think I will more or less go with how he has done his.I am considering an additional upper top mount for the rear shocks tied into the cage/gearbox cradle.I know Wally has machined his gearbox to fit without cutting the torsion tube but I am going Subi so this is not an option.( Wally persuaded me to fit a Subaru engine as I know he adores them…lol ) Anyway back on topic. Aerodynamics….. Ricolas car sits level as far as I can remember @100 mm but his is a vert.I was wondering what would be the ideal ride height for a road car (1303 ).. I like a car to sit slightly lower at the front so I am thinking something with a 20 mm difference,say 90 mm at the front 110 at the rear ??? surely this stance would aid the aerodynamics of the car???? Wally What is the front and rear ride height of your car…Thanks again fellas..
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gee dub |
#259
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#260
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really you should be balancing the corner weights than tyring to get a raked ride height.
I'm like spanners in that i i try and keep things stock if i can, or tweeked stock. its all to easy to change everthing and have a car that handles worse than a worn out stocker. just because it can be done dont mean you need to.
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my race car build galleryhttp://www.flickr.com/photos/1406263...7602662665607/ my web site www.rnjmotorsport.co.uk |
#261
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Yeah, I sure must have twisted your arm for picking that engine hey Graham?
![]() The rakes stance may look cool for some, but its not good for starightline performance at all. Reasons are mostly aerodynamically and castor related. Level is the best compromise imo. Never really measured ride height, but this pic gives an idea maybe? ![]() |
#262
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Aerodynamics of a bug
Thanks for the replies fellas its all good information.
Something else I have been pondering about is running boards.I got wider than standard on my car as my wings/fenders have been widened.I will be taking them off soon to give them a tweak. I was wondering about putting fibreglass flat bottoms on them with just access for the fixing bolts.Not sure if this is worth the effort though ? would the added weight of the fibreglass out weigh any aerodynamic gain, any thoughts ??? Looking forward to getting some serious time on the car soon so i'm gearing up for what I want to do.
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gee dub |
#263
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Hi Graham, quick answer, in general, the more floor area, at the right rake angle and ride height, the better as regards good low drag aero dynamic performance, the big decision for a road car is how low you can run it, given that it's a lot of work to run a bug low enough for racing at the ideal 40mm, which is out of the question for a road car, my running boards tie into the pan to widen the flat floor area, but it's not practical for a road car as the jack points have to go in the bin, and the cost of making GRP stuff these days is a joke, don't ask,,,, I would just use something that looked neat with the wide wings, it's the 100mm road car ride height that offers no realistic gains from teasing out small aero detail, but modern cars do exploit lower ride height for Aero advantage, you only have to look at the world championship rally cars going ever lower,,,,,
The best way to lower any car, especially a Stone Age design like ours is smaller wheels and tyres, mine would be on 13" spun alloy wheels and lightweight hot rod tyres tomorrow if,,,,,, well, cash in short. But You have enough power anyway to relax a bit on drag factor, but my aim is to go as quick as possible as near stock as possible,,,,, there is tho a plan B if the opposition start going quicker than in the past. |
#264
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Aerodynamics of a bug
Thanks for the reply Spannermananger…
I was wondering if it was worth the effort with the running boards but probably not, I didn't think about the jacking points. Also thanks Judgie on the heads up on balancing the corner weights. Another area of the car that I do want to play with is the rear bumper.As I have a front bumper spoiler I want to build/modify a rear bumper from an old beetle/porsche body kit I have.One reason for this is to give the car a balanced look when viewed from the side.A standard rear bumper with my front end would look odd.The standard beetle bumper on an 03 is in my mind a kind of box shaped parachute.Just the shape seems to me to be totally wrong and the drag and turbulence it must create surely would add to rear end instability ? Or do you think that the air is mainly detached by the time it reaches the bumper ? [IMG] ![]()
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gee dub |
#265
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I had the same thoughts about the rear bumper and filled the box up with construction foam and rounded it off a little.
It also stiffened up my GRP bumper a bot. You have no idea how many people asked me at shows why I had my bumper filled with yellow foam LOL! |
#266
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![]() go so deep into the turns, i would concentrate on the front, then get it road tested to see whets needed, a sleeper is preferable to any heavily reworked looker, they are lighter for a start, so can turn and brake quicker, i cant get photos up just now to show where im at with no more than a flat bottom, lots of work, and already ive run into more understeer, meaning the rear is working harder than without the underpanels, it will morph and turn into a diffusor proper eventualy, but a, it dont need it yet, and b, it can be ripped off or damaged after hours of work and cash,, and all these add ons make the car a bitch to work on, i have stuff to do at the front and that includes a splitter unfortunately, as i want to keep all stock looking as much as possible, but the rod is gridding up near the front row now days, so really needs add ons at the front, and possibly wider front tyres.. all good fun. ![]() |
#267
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I have been looking at the front splitter idea for some time now. Here's my progress on a splitter / bumper setup. The donor bumper came off a BMW e46 m3 circuit car. I do have a lot of data of the car without it, so will be able to see on the logger if it make any difference.
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Beetle Circuit Racer #71 2176cc Turbo Beetle Circuit Racer #170 1914cc Beetle Project T4 2666cc Twin turbo Methanol " ![]() |
#268
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hi 4agedub, hows that turbo coming along? well done on the front panel with splitter, Graham has a Rover version adapted to his 1303 which looks great, these take more air to the underside at the front than a b/j car, but both benefit from a proper air dam with splitter, i have some ideas i will cobble together soon to balance up my b/j car, at the moment i run various fairings and air channeling ducts at the front both to vent my rad' and oil coolers out into low pressure areas and also stopping lift, the rear is flat paneled right through just to help reduce drag by intention, but no doubt the spin off with an increase in under steer points to more rear load being generated. the mystery's of photo bucket on tablet remain unsolved, but ill try the pc to post up a few shots. success, here you can see the floor area extended both out to the sides and also into the wheel arches, ive left enough room to work on the car and support it, all mods have some trade off i guess, under the trans is paneled out with a duct for air to the diff, i will temp strip it to monitor things but have allowed for airflow into the clutch etc. the second one shows the ride height at 55mm before the under panels went on, its come down to about 50mm now, still 10mm above the minimum, but getting there, the exhaust needs yet more work to clear the ground and get the primarys up out the way, but i fancy oiking the motor up yet another inch will be the best way forward, i really should be buying a logger also, but for now i fancy using a small bullet cam to measure suspension compression on the fly, that should prove out things..
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#269
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I'm about a month away from starting the turbo engine and taking it to the dyno for some tuning. Still got plenty to do.
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Beetle Circuit Racer #71 2176cc Turbo Beetle Circuit Racer #170 1914cc Beetle Project T4 2666cc Twin turbo Methanol " ![]() |
#270
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