Working out a BEC project, several questions so far.
Discussion
Interesting video here of the famous Hayabusa Turbo Bug :
https://youtu.be/mltCdPF9MGI
This was undoubtedly built at great expense what with the engine built by Holeshot racing (around 350 HP) and the chassis being a one off all aluminium piece designed and made by Zcars...
you can however see one big issue here : the steering (as well as, secondly the sierra diff that is waaaaay too short)
I dont know what they used (maybe the original steering box which is super nice in the standard car because it is like 1 3/4 turns from one end to the other), but here with such output it does look like it needs addressing somewhat.
Paddle shift maybe, but surely steering damper DEFINITELY ?
https://youtu.be/mltCdPF9MGI
This was undoubtedly built at great expense what with the engine built by Holeshot racing (around 350 HP) and the chassis being a one off all aluminium piece designed and made by Zcars...
you can however see one big issue here : the steering (as well as, secondly the sierra diff that is waaaaay too short)
I dont know what they used (maybe the original steering box which is super nice in the standard car because it is like 1 3/4 turns from one end to the other), but here with such output it does look like it needs addressing somewhat.
Paddle shift maybe, but surely steering damper DEFINITELY ?
Edited by Reliant on Sunday 19th August 17:42
Quick shot of the bug steering set up :
I'm thinking that welding a bracket to the pitman arm and to the chassis kick up rail i will be able to host a damper that would indeed only be reachable by going under the car but at least would avoid the car snaking around when shifting at speed ?
I'm thinking that welding a bracket to the pitman arm and to the chassis kick up rail i will be able to host a damper that would indeed only be reachable by going under the car but at least would avoid the car snaking around when shifting at speed ?
Edited by Reliant on Monday 20th August 06:58
Chris-S said:
Doesn't it have some pretty serious bump-steer built in as it stands? Anything you can do about the basic geometry to improve it at all?
Random thought, convert to forks, or perhaps wishbones, with a suitable rack??
I'm not sure it's bump steer thats occuring here. It looks like he's taking his hand off the wheel to shift the gears and that makes the car snake around when the clutch goes back in (plus the HP obviously can't be helping)Random thought, convert to forks, or perhaps wishbones, with a suitable rack??
The car is moving so fast and if he's using the OE box, the steering is so direct, i have the impression that it could do with some work to get it straight.
I would really rather keep the OE box if possible
hi
thanks for all your input.
I'm not under the impression that a stock Reliant has bump steer, but I do know you can flip it around quite well thanks to its super direct steering.
that said,what technique do you use to test the stock setup for any bumpsteer ?
A guy who built a GSXR1000 bug used a rack from a Vauxhall Astra (I think). I have a couple of photos of the setup but cant really make out how he went around setting the links up etc it looks weird. But he said he did that to have a less direct steering action to avoid zigzagging up the road when driving fast
thanks for all your input.
I'm not under the impression that a stock Reliant has bump steer, but I do know you can flip it around quite well thanks to its super direct steering.
that said,what technique do you use to test the stock setup for any bumpsteer ?
A guy who built a GSXR1000 bug used a rack from a Vauxhall Astra (I think). I have a couple of photos of the setup but cant really make out how he went around setting the links up etc it looks weird. But he said he did that to have a less direct steering action to avoid zigzagging up the road when driving fast
Its progressing slowly
I had to redesign the laser cut parts to tweak the chassis set up a bit so thats taken a bit longer due to the backdoor laser cutting supplier I have, that plus life in general.
I also needed to fix my car since i need to trailer the chassis to the welders 😅
As soon as anything substantial is done I will put it here.
Thanks for the interest and advice
I had to redesign the laser cut parts to tweak the chassis set up a bit so thats taken a bit longer due to the backdoor laser cutting supplier I have, that plus life in general.
I also needed to fix my car since i need to trailer the chassis to the welders 😅
As soon as anything substantial is done I will put it here.
Thanks for the interest and advice
Hi
I do have a generic chassis question however.
Before finalising the plans I have struck something I'm not certain about.
Is there a way to get an idea of suspension travel needs ?
Basically i have approx 2 inch of wheel hub movement up and 2 inch down before encountering any major clearance issues between the half axles and chassis rail.
I have no idea whether that is ample enough (just in case) for a light coilover fitted track car or if I need to anticipate more.
I do have a generic chassis question however.
Before finalising the plans I have struck something I'm not certain about.
Is there a way to get an idea of suspension travel needs ?
Basically i have approx 2 inch of wheel hub movement up and 2 inch down before encountering any major clearance issues between the half axles and chassis rail.
I have no idea whether that is ample enough (just in case) for a light coilover fitted track car or if I need to anticipate more.
Riiight.
I've had a bit of spare time so I've spent it on working out some more on this project. It needs to be well on its way by the end of the year because i would like it fully functional by 2020.
Current headscratching is regarding the brakes.
The OE system has two 18mm piston brake cylinders upfront, and one 17mm piston brake cylinder on each side at the back.
So basically Reliant balanced out the bias almost equally.
I tried to keep that in mind while searching for caliper alternatives.
Here is what i have come up with :
Front :
A mix and match :
Ford Fiesta mk3 caliper (49 mm piston)
Renault Twingo mk1 disc (240 mm)
All hosted by a morris minor rim (excellent as it is 4x101.6 PCD and big 14 inch diameter) it will need widening however because stock it is 3 inches wide and to preserve closest possible to stock tyre diameter i need to use a 155 tyre so i think i need around 4.5 meaning i need to slot the center into a modern rim hoop)
The disc just needs to be machined (overbore to fit snugly on the Reliant hub so it will be naturally centered).
Back :
I tried to find the smallest diameter piston calipers possible (within reason) and after hours of search and realising that most car use the same parts regardless of year brand or model, heres what i came up with :
Fiat Uno turbo calipers (30mm piston)
Fiat rear discs (227 mm diameter)
I havent quite got 50/50 in piston diameter total front/rear so i might need a bias knob but the fact that the rear discs are smaller in diameter means less leverage so in theory less power at the back ?
The BMW hubs are getting redrilled (to 4x98, like the Renault 5 turbo rims I am using for the car) and turned so they fit into the discs that are also 4x98 being Fiat items.
I also received all the steel for the chassis, I figured it would be better to build it new and not have to faff around welding a chassis that originally is galvanised...
I've had a bit of spare time so I've spent it on working out some more on this project. It needs to be well on its way by the end of the year because i would like it fully functional by 2020.
Current headscratching is regarding the brakes.
The OE system has two 18mm piston brake cylinders upfront, and one 17mm piston brake cylinder on each side at the back.
So basically Reliant balanced out the bias almost equally.
I tried to keep that in mind while searching for caliper alternatives.
Here is what i have come up with :
Front :
A mix and match :
Ford Fiesta mk3 caliper (49 mm piston)
Renault Twingo mk1 disc (240 mm)
All hosted by a morris minor rim (excellent as it is 4x101.6 PCD and big 14 inch diameter) it will need widening however because stock it is 3 inches wide and to preserve closest possible to stock tyre diameter i need to use a 155 tyre so i think i need around 4.5 meaning i need to slot the center into a modern rim hoop)
The disc just needs to be machined (overbore to fit snugly on the Reliant hub so it will be naturally centered).
Back :
I tried to find the smallest diameter piston calipers possible (within reason) and after hours of search and realising that most car use the same parts regardless of year brand or model, heres what i came up with :
Fiat Uno turbo calipers (30mm piston)
Fiat rear discs (227 mm diameter)
I havent quite got 50/50 in piston diameter total front/rear so i might need a bias knob but the fact that the rear discs are smaller in diameter means less leverage so in theory less power at the back ?
The BMW hubs are getting redrilled (to 4x98, like the Renault 5 turbo rims I am using for the car) and turned so they fit into the discs that are also 4x98 being Fiat items.
I also received all the steel for the chassis, I figured it would be better to build it new and not have to faff around welding a chassis that originally is galvanised...
Edited by Reliant on Saturday 18th May 14:31
Looking desperately at £500 and up CNC flat oil sumps, i was lucky to score this modified rewelded one on ebay for 170 
Engine height level therefore set, i figured out all the tabs and spacers needed to fit the engine.
Just waiting for the parts and all the chassis will be tacked and sent to the welder
Engine height level therefore set, i figured out all the tabs and spacers needed to fit the engine.
Just waiting for the parts and all the chassis will be tacked and sent to the welder
Edited by Reliant on Thursday 17th October 16:35
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