Discussion
modifying the 4.2 is expensive .. the caliper only takes discs to 304mm.
easiest route is to get the whole lot off a 4.5 cerbera with the separate discs and bells on, then get a big ap disc conversion. you should be able to do the fronts bigger to 330mm with better pads front and rear, with fluid change etc for about 1500 pounds including buying the secondhand parts.
330mm fits in a 17inch wheel but not a 16inch wheel though.
easiest route is to get the whole lot off a 4.5 cerbera with the separate discs and bells on, then get a big ap disc conversion. you should be able to do the fronts bigger to 330mm with better pads front and rear, with fluid change etc for about 1500 pounds including buying the secondhand parts.
330mm fits in a 17inch wheel but not a 16inch wheel though.
plasticman said:
Are you sure about that Joolz , the o/d of the 4.5 bell is about 215 mm , doesn`t leave much swept height ( is that the right term ? ) Dave
it's the method I use to do 4.2 conversions .. tvr dealers throw the discs and bells away off the 4.5s and fit the one piece tuscan versions .. a ready cheap supply of alloy bells with std AP bolt circle so you have access to the AP catalogue for discs, though in truth there's only really one that you should use*
this is because for some reason tvr have an OE Ap disc of 29 point something mm thickness hence the caliper centre offset is calculated on that .. meaning you can only use the 28mm aftermarket Ap discs in the std caliper with the std TVR hub adaptors. You *can* use the 32mm AP versions if you have bespoke caliper adaptors made. I fit the 304mm / 32mm grooved discs on the 4.2 conversion and the 330mm/28mm version on the 4.5 conversion which is a direct replacement fit, all you need is some 4mm caliper to hub adaptor spacers.
targarama said:
Joolz.
Could you offer a similar upgrade on my T350 from std to something a bit meatier Sagaris/Red Rose sized?
Ta.
I've not seen the difference between the std caliper and the red rose caliper on later TVRs.. it all depends on the disc path as to what sized disc you can go up to without having to change the calipers..
in essence the answer is yes, it all depends how much has to be changed to accomodate the larger discs ... TVR changed the calipers around 2003 but I don't know if they used a one-size-fits-all approach or if they had two separate calipers for small discs and large discs ..
any particular reason why you want to change though? The T350 shoudn't suffer the same problems a cerbera does as it's considerably lighter. Big discs do however look damn sexy, most of my big disc conversions are sold for cosmetic reasons, most never go anywhere near the track
trackcar said:
Joolz.
Could you offer a similar upgrade on my T350 from std to something a bit meatier Sagaris/Red Rose sized?
Ta.
I've not seen the difference between the std caliper and the red rose caliper on later TVRs.. it all depends on the disc path as to what sized disc you can go up to without having to change the calipers..
in essence the answer is yes, it all depends how much has to be changed to accomodate the larger discs ... TVR changed the calipers around 2003 but I don't know if they used a one-size-fits-all approach or if they had two separate calipers for small discs and large discs ..
any particular reason why you want to change though? The T350 shoudn't suffer the same problems a cerbera does as it's considerably lighter. Big discs do however look damn sexy, most of my big disc conversions are sold for cosmetic reasons, most never go anywhere near the track
Thanks. Daftlad (PHer) tells me they used the same calipers with adapters to allow bigger discs. I'm pretty sure the std brakes are the same as a std Tuscan.
After 6 or so quick (for me) laps of Outlton Park in the summer my brakes faded badly. Not happened on any other track. I also got a bit of fade towards the bottom of the Stelvio Pass last year (wasn't pushing that hard - 2 up and full of luggage and as you know it gets quite tiring on those roads after a while).
I have 1144s on the front, std rears. I've since changed the fluid for some better stuff at the 12k service, but I don't want it to happen again when I'm in the middle of enjoying myself. Might have been crappy fluid, but the fluid was only a year old and the brakes hadn't been touched since new ... ah, theres the answer - TVR put vinegar in the lines instead...
I'll probably try DS2500s all round this year.
trackcar said:
did the braking effect deteriorate but the pedal stay firm, or did the pedal go soggy and still brake the car ok, or did the pedal go soggy and braking perforamnce drop off? .. each scenario has a diferent cause.
First one - less braking effect, but the pedal felt OK-ish.
plasticman said:
I just tried different sizes of discs in the T350 calipers and they will take upto 340mm .Still cannot see how you have enough space for the pad on a 305mm disc (4.2), just set it up myself and could not do it , Dave
are you using the t350 caliper on the 4.2 disc? the later pad area is much greater than on the earlier calipers which could explain teh difference.
targarama said:
did the braking effect deteriorate but the pedal stay firm, or did the pedal go soggy and still brake the car ok, or did the pedal go soggy and braking perforamnce drop off? .. each scenario has a diferent cause.
First one - less braking effect, but the pedal felt OK-ish.
if the pedal felt firm then it's not a boiling fluid issue, it's a pad being worked out of it's operating range issue. A change to a more track-orientated pad would sort that out, or fit some ducting to get more cool air over the disc/pad combo.
Road pads that are running too hot can start to generate gas before the friction drops off in a big way. One way to extend the range of a road pad without impairing the cold performance is to fit grooved discs to remove the gas. Don't go overboard though, 4-6 grooves per side is plenty.
Newer TVRs have drilled discs and the pads have gas slots in them aswell so tends to not be such a big issue, however they only work if they're cleaned out at service time, and knowing how little time some places spend on servicing I doubt they run an airline through the drillings or a file down the pad slots ...
trackcar said:
drilled discs
drilled discs are *bad*, m'kay? 
It seems very common for pads to have a slot down the middle, but I thought this was just to prevent the pad from cracking as the back plate flexed under heavy braking. Even very mundane pads have this feature. Do the TVR pads have more than this?
Gassing Station | Cerbera | Top of Page | What's New | My Stuff