6-speed box?

6-speed box?

Author
Discussion

petepetrolhead

Original Poster:

143 posts

228 months

Thursday 1st January 2015
quotequote all
Happy TVR-ing to everyone in 2015!

Anyone know if it's possible to convert a T5 box to 6-speed (I think I saw something somewhere once about 5-speed to 6-speed gearbox conversions)? Or is there an alternative 6-speed box that's an easy swap?

phazed

21,844 posts

203 months

Thursday 1st January 2015
quotequote all
Precat has a 6 speed BMW one in his grief iirc.

Pete Mac

755 posts

136 months

Friday 2nd January 2015
quotequote all
I bought my T5 rebuild kit from the US. Paul Cangialosi was very helpful and interested. He might be able to give you some useful advice, spares, bellhousing etc, particularly for the T56 box

http://www.5speeds.com/

or

support@5speeds.com

It's only the cost of an e-mail.

Pete

petepetrolhead

Original Poster:

143 posts

228 months

Monday 5th January 2015
quotequote all
Thanks everyone for your input.

I've talked to Precat about his adaptation to use an M3 6-speed box - not trivial (start by sawing off the integral BMW bell housing...), plus it isn't compatible with TVR diff ratios so a BMW diff needs to be installed as well.

I agree that the T56 is too big and heavy - also has much greater transmission losses than a T5 and needs the exhausts to be re-routed (lower).

So, looks like I'll stick with 5-speed and see about putting a lower ratio in the diff to drop the revs in 5th. Always wanted to get to 100mph in third :-)

TA14

12,722 posts

257 months

Monday 5th January 2015
quotequote all
350Matt designed one for the Cerb. Is that the same box?

anonymous-user

53 months

Monday 5th January 2015
quotequote all
petepetrolhead said:
So, looks like I'll stick with 5-speed and see about putting a lower ratio in the diff to drop the revs in 5th. Always wanted to get to 100mph in third :-)
It won't help with 100mph in third, but for the motorway maybe leave the diff alone and swap the 0.80 5th out for 0.72 or 0.68.

K4TRV

1,819 posts

251 months

Monday 5th January 2015
quotequote all
Have a look at Graham Varley's site with the Sagaris - it has a Spreadsheet which you can see the impact of changing std ratios to close ratio or changing axel ratios and different change points (you set the RPM change point?).

See here: http://www.varleyhyd.com/FJ062.asp

Suitable for all T5 box'ed cars, not just Sagaris! Have a play and see that a close ratio box/changing gear ratios may be cheaper and easier than change a whole box?

T

gacksen

680 posts

142 months

Monday 5th January 2015
quotequote all
petepetrolhead said:
Thanks everyone for your input.

I've talked to Precat about his adaptation to use an M3 6-speed box - not trivial (start by sawing off the integral BMW bell housing...), plus it isn't compatible with TVR diff ratios so a BMW diff needs to be installed as well.

I agree that the T56 is too big and heavy - also has much greater transmission losses than a T5 and needs the exhausts to be re-routed (lower).

So, looks like I'll stick with 5-speed and see about putting a lower ratio in the diff to drop the revs in 5th. Always wanted to get to 100mph in third :-)
talk to john http://www.readmanracing.co.uk/ he put a 0.68 in the T5 of my chim. keeps revs down for motorway driving. havent used it often but of course downsize is you have to fully push 4th gear high up if you don´t want to loose the right rev band in 5th.....

after almost 2 years.... thought of 0.68 had been nice.... real world experience.... wouldnt do it again wink

SILICONEKID345HP

14,997 posts

230 months

Monday 5th January 2015
quotequote all
gacksen said:
petepetrolhead said:
Thanks everyone for your input.

I've talked to Precat about his adaptation to use an M3 6-speed box - not trivial (start by sawing off the integral BMW bell housing...), plus it isn't compatible with TVR diff ratios so a BMW diff needs to be installed as well.

I agree that the T56 is too big and heavy - also has much greater transmission losses than a T5 and needs the exhausts to be re-routed (lower).

So, looks like I'll stick with 5-speed and see about putting a lower ratio in the diff to drop the revs in 5th. Always wanted to get to 100mph in third :-)
talk to john http://www.readmanracing.co.uk/ he put a 0.68 in the T5 of my chim. keeps revs down for motorway driving. havent used it often but of course downsize is you have to fully push 4th gear high up if you don´t want to loose the right rev band in 5th.....

after almost 2 years.... thought of 0.68 had been nice.... real world experience.... wouldnt do it again wink
What RPM do you get in fifth at 70mph ? I`vw been looking for a 308 crown wheel and pinion but no had any luck .

Brummmie

5,284 posts

220 months

Monday 5th January 2015
quotequote all
I have a 3.08 and get 133mph in third across qtr mile finish.

SILICONEKID345HP

14,997 posts

230 months

Monday 5th January 2015
quotequote all
Brummmie said:
I have a 3.08 and get 133mph in third across qtr mile finish.
Can you help me to get the correct parts ?

It would work perfect with 345bhp and give me lower rpm when cruising .
Want to get it around 2200rpm at 70mph .


Dereks car is actually faster over the quarter mile with the 308 crown wheel and pinion and he gets 30mpg on a run with a modified 4.6

Is this the correct one

http://www.ebay.co.uk/itm/HOLDEN-VN-VP-VR-VS-M75-3...

Edited by SILICONEKID345HP on Monday 5th January 23:31

SteveSPG

2,120 posts

201 months

Tuesday 6th January 2015
quotequote all
SILICONEKID345HP said:
Can you help me to get the correct parts ?

It would work perfect with 345bhp and give me lower rpm when cruising .
Want to get it around 2200rpm at 70mph .


Dereks car is actually faster over the quarter mile with the 308 crown wheel and pinion and he gets 30mpg on a run with a modified 4.6

Is this the correct one

http://www.ebay.co.uk/itm/HOLDEN-VN-VP-VR-VS-M75-3...



Edited by SILICONEKID345HP on Monday 5th January 23:31
i think so, john at grantura has had some in stock

gacksen

680 posts

142 months

Tuesday 6th January 2015
quotequote all
don´t remember exactly what speed it is. haven´t the car driven since the summer holliday but rev drop compared to the 0.80 standard 5th was quite massive. normally when going on curvy roads mainly drive in 3rd, 2nd and sometimes but seldom 4th with the CR gearbox.

of course if you change diff ratio it will affect all the gears.

Brummmie

5,284 posts

220 months

Tuesday 6th January 2015
quotequote all
SILICONEKID345HP said:
Can you help me to get the correct parts ?

It would work perfect with 345bhp and give me lower rpm when cruising .
Want to get it around 2200rpm at 70mph .


Dereks car is actually faster over the quarter mile with the 308 crown wheel and pinion and he gets 30mpg on a run with a modified 4.6

Is this the correct one

http://www.ebay.co.uk/itm/HOLDEN-VN-VP-VR-VS-M75-3...

Edited by SILICONEKID345HP on Monday 5th January 23:31
Can you provide the seller with the numbers off your diff, the ones on the tag.
I did this when i bought from Aus for mine.
It looks about right though.

SILICONEKID345HP

14,997 posts

230 months

Tuesday 6th January 2015
quotequote all
SteveSPG said:
i think so, john at grantura has had some in stock
I wonder if its better to pay a bit extra and get the right parts . My BTR diff is new and only done about a thousand miles ,would the 3.45 crown wheel and pinion have a value ? i could sell it .

stesrg

1,559 posts

237 months

Tuesday 6th January 2015
quotequote all
petepetrolhead said:
Thanks everyone for your input.

I've talked to Precat about his adaptation to use an M3 6-speed box - not trivial (start by sawing off the integral BMW bell housing...), plus it isn't compatible with TVR diff ratios so a BMW diff needs to be installed as well.

I agree that the T56 is too big and heavy - also has much greater transmission losses than a T5 and needs the exhausts to be re-routed (lower).

So, looks like I'll stick with 5-speed and see about putting a lower ratio in the diff to drop the revs in 5th. Always wanted to get to 100mph in third :-)
Hi just busting into your post here , I love improvements and this would be a nice one on a griff !! If you need the alloy belhousing welded providing you do all the hard work and I can take notes have template etc I will tig weld it for no cost at all cool ps MUST BE VERY CLEAN

Ste .

Brummmie

5,284 posts

220 months

Wednesday 7th January 2015
quotequote all
SILICONEKID345HP said:
I wonder if its better to pay a bit extra and get the right parts . My BTR diff is new and only done about a thousand miles ,would the 3.45 crown wheel and pinion have a value ? i could sell it .
John is where i bought my last one, as i smashed the first one.
I am not sure if he has any left, last i heard he had 3.23?? that would probably work well with the power you guys are banding around.

SILICONEKID345HP

14,997 posts

230 months

Wednesday 7th January 2015
quotequote all
Brummmie said:
John is where i bought my last one, as i smashed the first one.
I am not sure if he has any left, last i heard he had 3.23?? that would probably work well with the power you guys are banding around.
At 70mph mine is doing over 2700 rpm ,what rpm at 70mph with the 3.23 .

I tried to buy a low mileage 3.23 from Steve Strange but his attitude was terrible .

Its going to cost quite alot of money so i need to get it right .

Where is the badge on the diff ?

domV8

1,375 posts

180 months

Thursday 15th January 2015
quotequote all
IIRC about 6% difference from yours as a quick indicator Daz...

Thought about changing from my 3.23 to a 3.45 - but when I calculated it all up, I cam to the conclusion it was going to cost lots $$$ for very little real world difference...