Lightened rear subframe
Discussion
Hi
Been following the beam v subframe thread as I'm looking to make my car lighter to improve performance.
I'm still undecided if it's the right way to go, but while I'm trying to make my mind up I thought about making the rear subframe lighter.
Does anyone have any info on or pictures of a miglia rear subframe? I understand they drill them to make them lighter and I'm after an idea of sizes, positions and number of holes so I don't affect the structural strength of the frame.
Thanks
Neil
Been following the beam v subframe thread as I'm looking to make my car lighter to improve performance.
I'm still undecided if it's the right way to go, but while I'm trying to make my mind up I thought about making the rear subframe lighter.
Does anyone have any info on or pictures of a miglia rear subframe? I understand they drill them to make them lighter and I'm after an idea of sizes, positions and number of holes so I don't affect the structural strength of the frame.
Thanks
Neil
It's the front sub-frame which is over-engineered. The rear is relatively light to start with.
I am always a bit suspicious about lightening the rear sub-frame on a Mini for the road, as if you get rear-ended and don't have a full strength sub-frame you will probably end up needing a new shell. Also, the weight you could be saving will be low down relative to the C of G, so you could be reducing the stability a little.
I don't like beam axles for the same reason.
It's OK on a racing Mini which is only used on the track as new body-shells are the norm and you have a big 6-point cage to protect you.
I am always a bit suspicious about lightening the rear sub-frame on a Mini for the road, as if you get rear-ended and don't have a full strength sub-frame you will probably end up needing a new shell. Also, the weight you could be saving will be low down relative to the C of G, so you could be reducing the stability a little.
I don't like beam axles for the same reason.
It's OK on a racing Mini which is only used on the track as new body-shells are the norm and you have a big 6-point cage to protect you.
Fair point, and whilst the car is road legal it is only used for track days.
The subframe on the car is probably lighter than is should be as it's seen better days. I'm swapping it for a good used one and thought this would be a good opportunity to experiment.
I can see where the front and rear sections of the subframe could be drilled, but I'm not sure about the side sections surrounding the suspension cones/trumpets.
Neil
>> Edited by Neil8p on Monday 8th December 21:31
The subframe on the car is probably lighter than is should be as it's seen better days. I'm swapping it for a good used one and thought this would be a good opportunity to experiment.
I can see where the front and rear sections of the subframe could be drilled, but I'm not sure about the side sections surrounding the suspension cones/trumpets.
Neil
>> Edited by Neil8p on Monday 8th December 21:31
Neil, you could probably lighten the rear sub-frame by cutting lightening holes in the transverse beam sections. However, the longitudinal, i.e. fore and aft sections are, I would guess, stressed to take mainly compressive loads in the event of a rear end impact which would make any form of lightening a bit suspect.
On my rally cars I always weld and strengthen the sub-frames, front and back, so lightness is less of an issue. I get weight reduction by using perspex windows, no sound deadening, etc, my car weighs around 715 kg with 5.5 gallons of fuel (i.e. half-full).
On my rally cars I always weld and strengthen the sub-frames, front and back, so lightness is less of an issue. I get weight reduction by using perspex windows, no sound deadening, etc, my car weighs around 715 kg with 5.5 gallons of fuel (i.e. half-full).
Neil,
When you are fitting your perspex windows try taking all the glass out first from all the windows, then make a pile and try lifting it. Then lift all the replacement perspex. It's amazing! You realise what you are saving with perspex. Also, it is lowering the C of G as well, which is a good thing to do.
Now, the question I am pondering at present is how to get some weight out of my 1991 Cooper which i'm preparing to the new Formula 1400 Enduro rally spec. You are not allowed to replace glass with perspex, the shell must be standard and carpets must be fitted in the front. I shall remove all the radio/stereo system as that really does weigh quite a bit, but where to go from there. Of course, I'll take out all the sound proofing material, but I guess it won't save much and I've got to fit the full cage and the sump guard, spot lights, etc.
Any ideas anyone?
When you are fitting your perspex windows try taking all the glass out first from all the windows, then make a pile and try lifting it. Then lift all the replacement perspex. It's amazing! You realise what you are saving with perspex. Also, it is lowering the C of G as well, which is a good thing to do.
Now, the question I am pondering at present is how to get some weight out of my 1991 Cooper which i'm preparing to the new Formula 1400 Enduro rally spec. You are not allowed to replace glass with perspex, the shell must be standard and carpets must be fitted in the front. I shall remove all the radio/stereo system as that really does weigh quite a bit, but where to go from there. Of course, I'll take out all the sound proofing material, but I guess it won't save much and I've got to fit the full cage and the sump guard, spot lights, etc.
Any ideas anyone?
You have to run full interior trim, but can rip out the sound proofing behind the trim.
I think I'll go for SPARCO seats as they do FIA Approved ones which weigh 5.7 kg each, so that's a bit of a saving.
The doors, bonnet and boot all count as body, but maybe the inner door panels would take a bit of metal removal - you wouldn't save much there though.
I don't like the idea of a shell that's been lightened by the well known rust process. I might crash it and don't like the thought of sitting there with great big bits of rusty steel stuck where the sun don't shine!
The trouble with all rally cars is that as fast as you save a bit of weight, you put it back on again with strengthening and/or underbody protection (and I don't mean deodorant!).
It's not going to be easy to save much.I think a diet is the answer here, that's what my son (navigator) says as well!
I think I'll go for SPARCO seats as they do FIA Approved ones which weigh 5.7 kg each, so that's a bit of a saving.
The doors, bonnet and boot all count as body, but maybe the inner door panels would take a bit of metal removal - you wouldn't save much there though.
I don't like the idea of a shell that's been lightened by the well known rust process. I might crash it and don't like the thought of sitting there with great big bits of rusty steel stuck where the sun don't shine!
The trouble with all rally cars is that as fast as you save a bit of weight, you put it back on again with strengthening and/or underbody protection (and I don't mean deodorant!).
It's not going to be easy to save much.I think a diet is the answer here, that's what my son (navigator) says as well!
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