5 Speed Gearbox Conversions
Posted: Sat Oct 02, 2010 9:35 am
Hi
A much flogged topic I know so apologies to all.
Followers of this subject (many), if they're like myself, might be somewhat confused by the seemingly endless permutations/arguments/technical intricacies/real and imagined problems that have been discussed over the years so I thought I'd do a "condensation" exercise and see if the waters can be made less muddy.
The reason- well I have a converted car which works pretty well using a Type 9. Homemade I know but I am a cheapskate!
A friend however who is building a bitsa car based on a ratty S3 keeps asking me if I'd run up a conversion like my own (presumably just after breakfast whilst I have the odd hour or so). Having learned the hard way that it's not worth reinventing the wheel I was weighing up the pros and cons of the various ways of converting his car. His options are more than mine were since he has the body removed.
So- assuming my info is correct the available options are-
Alan Voights- don't know if they still offer their package and if so what the waiting time is.
Advantages- ready made/all in one/no searching around for odd bits.
Disadvantages- possibly availability issues/cost.
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"Home made" Type 9-
Advantages- cheap(ish)/has been done so proven to work/lots of Type 9 boxes out there/doesn't require a sandwich plate/no chassis mods
Disadvantages-need some technical expertise/the correct bellhousing is pricey (?360 new)/no patterns to work to so a bit hit and miss as a process/need to source other necessay items (propshaft, gearbox bracket, clutch disc,speedo cable)/problems fitting it to a Spyder spaceframe.
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Fit an electric overdrive to the 4 speed box.
Advantages- the best of both worlds/retain the stronger simpler box/ease of use/no other alterations required
Disadvantages- probably pretty expensive since new mainshaft needs to be made/requires substantial alteration to chassis and body/pricey overall
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Fit a box from a rear drive Alfa Romeo
Advantages- has been done and it works/lever pretty much in the original 4 speed position as standard so no linkage alterations required
Disadvantages- getting hold of a good box/2nd gear synchro sometimes a problem/requires a sandwich plate/modification to gearbox to link it to a prop with a sliding joint/requires quite a bit of detail work regarding the starter and clutch operating systems
-------------------------------------------------------------------------------------
Fit a Borg Warner T5
Advantages- gear linkage doesn't really need alteration- lever position is very close to 4 speed unit and if necessary it can be altered without too much work/very strong box so well within elan power output limits/wide choice of ratios/fits a std chassis with only very minor mods to chassis/trim/proven conversion/probably doesn't rtequire a sandwich plate (see below).
Disadvantages- the one with the nearly ideal lever position is ex TVR so not exactly lots of them (in the UK anyway)/pricey even secondhand/fitted to big V8 motors so might have been battered/won't fit a spaceframe (apparently)/conflicting reports about the gearchange quality/problems sourcing a bellhousing (apparently the most suitable ones were fitted only to certain american Fords, in the UK RWD sell one to match a T5 to a Ford block including the twin cam but it needs quite a bit of modification as there are two starter positions and no provision for hydraulic clutch release
-------------------------------------------------------------------------------------Mazda MX5
Not clear on this one since it seems to have sank below the radar but a major issue seems to be the ratios and the price and the requirement to rework the gear linkage (although I don't know how much of a problem the last point is compared to a Type 9). Seem to be quite a few boxes available however and has a good reputation for the change quality.
-------------------------------------------------------------------------------------
So- would a fair summary be
Type 9- feasible/ has been done/readily available/minimal changes necessary.
Borg Warner T5- feasible/has been done/even fewer changes necessary/limited availability of boxes
Overdrive- feasible/has been done/requires considerable chassis/body alterations/only suitable if you're prepared for a huge amount of work
Alfa Romeo/Other 5 speed boxes- have been done but might be problems with matching to engine/clutch operation/starter position.
Additionally, all conversions might require changes to spigot bushes, input shafts.
I'm only raising the topic yet again because-
A)- I'm looking for up to date info (it might help others also weighing the options).
B)- I'm hoping somebody can update me on T5 conversions since these seem to involve
the least amount of work/hassle.
Regards and your views awaited.
John
A much flogged topic I know so apologies to all.
Followers of this subject (many), if they're like myself, might be somewhat confused by the seemingly endless permutations/arguments/technical intricacies/real and imagined problems that have been discussed over the years so I thought I'd do a "condensation" exercise and see if the waters can be made less muddy.
The reason- well I have a converted car which works pretty well using a Type 9. Homemade I know but I am a cheapskate!
A friend however who is building a bitsa car based on a ratty S3 keeps asking me if I'd run up a conversion like my own (presumably just after breakfast whilst I have the odd hour or so). Having learned the hard way that it's not worth reinventing the wheel I was weighing up the pros and cons of the various ways of converting his car. His options are more than mine were since he has the body removed.
So- assuming my info is correct the available options are-
Alan Voights- don't know if they still offer their package and if so what the waiting time is.
Advantages- ready made/all in one/no searching around for odd bits.
Disadvantages- possibly availability issues/cost.
------------------------------------------------------------------------------------
"Home made" Type 9-
Advantages- cheap(ish)/has been done so proven to work/lots of Type 9 boxes out there/doesn't require a sandwich plate/no chassis mods
Disadvantages-need some technical expertise/the correct bellhousing is pricey (?360 new)/no patterns to work to so a bit hit and miss as a process/need to source other necessay items (propshaft, gearbox bracket, clutch disc,speedo cable)/problems fitting it to a Spyder spaceframe.
-----------------------------------------------------------------------------------
Fit an electric overdrive to the 4 speed box.
Advantages- the best of both worlds/retain the stronger simpler box/ease of use/no other alterations required
Disadvantages- probably pretty expensive since new mainshaft needs to be made/requires substantial alteration to chassis and body/pricey overall
------------------------------------------------------------------------------------
Fit a box from a rear drive Alfa Romeo
Advantages- has been done and it works/lever pretty much in the original 4 speed position as standard so no linkage alterations required
Disadvantages- getting hold of a good box/2nd gear synchro sometimes a problem/requires a sandwich plate/modification to gearbox to link it to a prop with a sliding joint/requires quite a bit of detail work regarding the starter and clutch operating systems
-------------------------------------------------------------------------------------
Fit a Borg Warner T5
Advantages- gear linkage doesn't really need alteration- lever position is very close to 4 speed unit and if necessary it can be altered without too much work/very strong box so well within elan power output limits/wide choice of ratios/fits a std chassis with only very minor mods to chassis/trim/proven conversion/probably doesn't rtequire a sandwich plate (see below).
Disadvantages- the one with the nearly ideal lever position is ex TVR so not exactly lots of them (in the UK anyway)/pricey even secondhand/fitted to big V8 motors so might have been battered/won't fit a spaceframe (apparently)/conflicting reports about the gearchange quality/problems sourcing a bellhousing (apparently the most suitable ones were fitted only to certain american Fords, in the UK RWD sell one to match a T5 to a Ford block including the twin cam but it needs quite a bit of modification as there are two starter positions and no provision for hydraulic clutch release
-------------------------------------------------------------------------------------Mazda MX5
Not clear on this one since it seems to have sank below the radar but a major issue seems to be the ratios and the price and the requirement to rework the gear linkage (although I don't know how much of a problem the last point is compared to a Type 9). Seem to be quite a few boxes available however and has a good reputation for the change quality.
-------------------------------------------------------------------------------------
So- would a fair summary be
Type 9- feasible/ has been done/readily available/minimal changes necessary.
Borg Warner T5- feasible/has been done/even fewer changes necessary/limited availability of boxes
Overdrive- feasible/has been done/requires considerable chassis/body alterations/only suitable if you're prepared for a huge amount of work
Alfa Romeo/Other 5 speed boxes- have been done but might be problems with matching to engine/clutch operation/starter position.
Additionally, all conversions might require changes to spigot bushes, input shafts.
I'm only raising the topic yet again because-
A)- I'm looking for up to date info (it might help others also weighing the options).
B)- I'm hoping somebody can update me on T5 conversions since these seem to involve
the least amount of work/hassle.
Regards and your views awaited.
John