Subframe prep - Bill Sollis Book?
Discussion
How do gents. As some of you racers know, Im researching other minis prepped for racing. My mind has turned to subframe prep (stengthening, lightening etc) and I was wondering if there are any guides as to where to make them lighter etc?
Does anyone have this book and does it show you in there?
http://www.amazon.co.uk/Building-Preparing-Racing-...
Help much appreciated
Does anyone have this book and does it show you in there?
http://www.amazon.co.uk/Building-Preparing-Racing-...
Help much appreciated
tom
that bill solis book is crap. it mainly consists of him telling the world how good he is, with a few photos of cars and very little technical details.
i think frame streghening and lightening depends very much on your choosen application. rally will need diffent need to race for example.
my frame has reinforcers at the front where the tie bars mount as a lot of stress from hard braking passes through the welded brackets. it also has plates welded under the bottom arm mounts for the same reason & to stop it bending up when jacking it up.
ive also welded plates where the bump stops press against. this is due to the car running fairly low. the frame bends easy here, once it bends it affects how the car handles as the arms go higher up than they should.
unless your doing rallying i wouldnt bother seam welding it.
that bill solis book is crap. it mainly consists of him telling the world how good he is, with a few photos of cars and very little technical details.
i think frame streghening and lightening depends very much on your choosen application. rally will need diffent need to race for example.
my frame has reinforcers at the front where the tie bars mount as a lot of stress from hard braking passes through the welded brackets. it also has plates welded under the bottom arm mounts for the same reason & to stop it bending up when jacking it up.
ive also welded plates where the bump stops press against. this is due to the car running fairly low. the frame bends easy here, once it bends it affects how the car handles as the arms go higher up than they should.
unless your doing rallying i wouldnt bother seam welding it.
Agree with guru here.
Basically the front sub-frame is over-engineered in most respects, except for the tie bar mounting 'ears' which do need triangulating.
For rallying I do some seam welding, but even that is not really necessary unless really rough forestry events are contemplated.
I've often thought about lightening the front sub-frame as the webs at each side would take a lot of metal removal without much reduction of strength. You could cut some large holes, maybe 2" diameter. There are other places where weight saving could be appropriate too, although I need a sub-frame in front of me to explain further.
The rear frame is, IMHO, about right in strength/weight terms. For rallying, it's a good idea to weld some additional metal along the bottom faces fore and aft for forest events, but for pure tarmac that's not necessary. For sprints, racing and hill-climbing, a beam rear axle set-up is fine, so long as the regs allow. I would never do that for rallying as I would hate to go off backwards into a bloody great tree and not have the longitudinal sub-frame structure there.
One really good way to save weight is to form a sheet of aluminium into the same shape as the roof panel, cut out the entire leaving about 2" around the edge and bond/rivet the aluminium panel in place. A very old friend of mine called Mo Mendham (anyone heard of him?) did just that in the 60's and his Mini was the lightest around. The scrutineers never spotted it either! He trained in the aircraft industry with me and I could tell all sorts of stories about him and Minis, like when he got beaten by a well-known Mini team. He couldn't believe they weren't cheating, so he broke into their workhop one night, stripped one of their engines down and measured everything. Then he did the same 'tweak' to his car and beat them. They knew and he knew that they knew, etc., but no-one ever said anything.
Basically the front sub-frame is over-engineered in most respects, except for the tie bar mounting 'ears' which do need triangulating.
For rallying I do some seam welding, but even that is not really necessary unless really rough forestry events are contemplated.
I've often thought about lightening the front sub-frame as the webs at each side would take a lot of metal removal without much reduction of strength. You could cut some large holes, maybe 2" diameter. There are other places where weight saving could be appropriate too, although I need a sub-frame in front of me to explain further.
The rear frame is, IMHO, about right in strength/weight terms. For rallying, it's a good idea to weld some additional metal along the bottom faces fore and aft for forest events, but for pure tarmac that's not necessary. For sprints, racing and hill-climbing, a beam rear axle set-up is fine, so long as the regs allow. I would never do that for rallying as I would hate to go off backwards into a bloody great tree and not have the longitudinal sub-frame structure there.
One really good way to save weight is to form a sheet of aluminium into the same shape as the roof panel, cut out the entire leaving about 2" around the edge and bond/rivet the aluminium panel in place. A very old friend of mine called Mo Mendham (anyone heard of him?) did just that in the 60's and his Mini was the lightest around. The scrutineers never spotted it either! He trained in the aircraft industry with me and I could tell all sorts of stories about him and Minis, like when he got beaten by a well-known Mini team. He couldn't believe they weren't cheating, so he broke into their workhop one night, stripped one of their engines down and measured everything. Then he did the same 'tweak' to his car and beat them. They knew and he knew that they knew, etc., but no-one ever said anything.
For track use we lighten the rear frame in the following way. Rear web is lightened with 1" holes drilled equidistant. The front (in car) cross section is lightened in the same manner in the box section. Makes getting gravel out easier afetr visiting the traps. We seam weld the frame at the corners for strength. All the surplus material in the webs of the subframe (single metals thickness) are removed.
Front subframe has the tie rod mounts reinfroced with triangular plates and also has 1.5" holes drilled in the webs (where engine mounts attach). This allows the frame to fold in frontal impact and stops energy being transfered back into the shell and cage via rear subframe mounts.
Front subframe has the tie rod mounts reinfroced with triangular plates and also has 1.5" holes drilled in the webs (where engine mounts attach). This allows the frame to fold in frontal impact and stops energy being transfered back into the shell and cage via rear subframe mounts.
FWDRacer said:
For track use we lighten the rear frame in the following way. Rear web is lightened with 1" holes drilled equidistant. The front (in car) cross section is lightened in the same manner in the box section. Makes getting gravel out easier afetr visiting the traps. We seam weld the frame at the corners for strength. All the surplus material in the webs of the subframe (single metals thickness) are removed.
Front subframe has the tie rod mounts reinfroced with triangular plates and also has 1.5" holes drilled in the webs (where engine mounts attach). This allows the frame to fold in frontal impact and stops energy being transfered back into the shell and cage via rear subframe mounts.
That's just what I had in mind for the front.Front subframe has the tie rod mounts reinfroced with triangular plates and also has 1.5" holes drilled in the webs (where engine mounts attach). This allows the frame to fold in frontal impact and stops energy being transfered back into the shell and cage via rear subframe mounts.
Of course, for a rally car one would not do the rear as you do for your racers, but it sounds an excellent mod for track use.
My 64 rally 'S' weighs 715 kg with 5 gallons of fuel, 2 spare wheels and a small tool kit. It has perspex windows, no rear seats and no soundprofing. However, it has front carpets and standard door trims plus, of course, a full navigator's panel, two large spots, a big battery, twin fuel pumps and a huge sumpguard.
Now really upset me by telling me how much (how little!) your racers weigh in at.
652kg including driver (72kg) - and with 7 litres of fuel still left in it. Class limit is 650kg 
Mine has persex all round with l'weight glass screen, twin facet fuel pumps, 25litre baffled alloy tank, grp rear boot floor, lightweight Varley redtop battery, 3-5kg of lead ballast...
Every last ounce of extranious bracket related metal has gone
Mine has persex all round with l'weight glass screen, twin facet fuel pumps, 25litre baffled alloy tank, grp rear boot floor, lightweight Varley redtop battery, 3-5kg of lead ballast...
Every last ounce of extranious bracket related metal has gone
Edited by FWDRacer on Monday 5th November 13:30
Mk1 shells are much lighter - thinner gauges used in the earlier cars so no surprises there then. Rich.. do you have class limit? 608 is pretty impressive (is it dry?), and are you running a weld in mutipoint cage?
I could go lighter with carbon front (these don't take knocks well) and lighter radiator / alternator / starter etc but as I don't need to... I save the cash for season budget.
Note.to.self.Avoid.pies.
I could go lighter with carbon front (these don't take knocks well) and lighter radiator / alternator / starter etc but as I don't need to... I save the cash for season budget.
Note.to.self.Avoid.pies.
Edited by FWDRacer on Monday 5th November 14:00
Im struggling to understand where you lighten your subframes, I found this and wondering if this is the kind of thing I should be doing, or if you guys can point out the areas you talk of on this image?
http://i70.photobucket.com/albums/i93/andrew_walle...
http://i70.photobucket.com/albums/i93/andrew_walle...
Edited by tomkidd on Monday 5th November 16:01
Edited by tomkidd on Monday 5th November 16:02
Wow, those are just so light. The acceleration with a big engine must be fantastic. I think that 0 - 60 in about 7.5 secs on a 3.9 diff is not bad for a rally car, but with race power and so little weight it is something else.
I'm glad someone else doesn't like the plastic front ends. Personally I would never have one as you never know where the loads will be resolved in a crash case. A Mini bodyshell is a complete load carrying structure. Thus if you take away the front wings, the structure loses its integrity. I've heard all the arguments about replacing the old structure with tubes, but no-one has, to my knowledge, ever done any proper analysis to confirm the integrity in a 3/4-front crash case. Apart from accessibility, I don't think there is much of a weight saving with the flip-fronts if a lot of tubing is then used to put back some strength into the bodyshell.
Now, a carbon-fibre roof panel would be worth doing and entirely safe too. Not cheap, though.
I'm glad someone else doesn't like the plastic front ends. Personally I would never have one as you never know where the loads will be resolved in a crash case. A Mini bodyshell is a complete load carrying structure. Thus if you take away the front wings, the structure loses its integrity. I've heard all the arguments about replacing the old structure with tubes, but no-one has, to my knowledge, ever done any proper analysis to confirm the integrity in a 3/4-front crash case. Apart from accessibility, I don't think there is much of a weight saving with the flip-fronts if a lot of tubing is then used to put back some strength into the bodyshell.
Now, a carbon-fibre roof panel would be worth doing and entirely safe too. Not cheap, though.
Just stumbled on this thread. Has anyone got pics of their subframes before fitting?
Also, what/where have you seam welded (both the shell and the subframes)?
I'm currently in the early stages of looking for a project car for road use and road class hill climbing, so you can see why I'm interested in this.
Also, what/where have you seam welded (both the shell and the subframes)?
I'm currently in the early stages of looking for a project car for road use and road class hill climbing, so you can see why I'm interested in this.
tomkidd said:
What is the web? (not the world wide web 
)
The 'web', in front sub-frame terms, is the flat part on each side that the engine mountings bolt on to. They are angled from the vertical and the 'depth of section' they provide is totally adequate, even with some lightening holes bored into them. )On the subject of seam welding, it's generally not needed except on rally cars for forest use. Even tarmac rally cars don't need it, although strengthening up the structure never does any harm for any sort of motorsport.
I came to work in my rally car Mini today, so now I must face the 40 mile drive back to the accompanyment of the s/c gears and drop gears. Very nice it will be too at 14.5 mph/1000 rpm in top.
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