Hammerhead
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| posted on 25/5/07 at 09:54 AM |
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Close ratio or not?
I have the opportunity to get a close ratio gearbox. Can anyone explain what a close ratio gearbox does in terms of benefits?
Is there a benefit or should I just stick with a standard gearbox?
Cheers.
Steve.
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Mike Page
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| posted on 25/5/07 at 10:08 AM |
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It depends on your engine and your expected use. And the cost.
For the road I wouldn't bother. For the track I'd investigate the actual ratios and plug them all into a ratio spreadsheet like this
one...
http://www.gearboxman.co.uk/inforatios.html
...but there are others on the net too.
Work out where your engine is strongest and how wide the powerband is, what diff you're going to use, on what wheels, at what fastest speed.
Hope that helps.
MIke
[Edited on 25/5/07 by Mike Page]
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Fatgadget
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| posted on 25/5/07 at 10:08 AM |
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You get more bragging rights in the pub especially if it' straight cut with dog teeth !  Seriously I reckon its only useful if you have a
peaky engine. Stops it from going off the cam when changing up a cog.
[Edited on 25/5/07 by Fatgadget]
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Hammerhead
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| posted on 25/5/07 at 10:15 AM |
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Ok thanks for that. My car isn't yet running and will be mainly for the road, hopefully with the odd track day.
I'd also like to take it to the south of france at some stage. So I guess I would be better with a standard gearbox to help me cruise on the
motorways.
Also the close ratio box is 2 hours drive away. So would have to be amazing to bother picking it up.
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snapper
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| posted on 25/5/07 at 11:43 AM |
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I am looking for a close ratio box based on the Type 9 or easy to fit to a pinto bell housing, what price would it be?
I have fitted the V6 type 9 to get a slightly better 1st and closer 2nd and 3rd, my next move was to go T5 but its a little large for my
application.
The basic problem with the Type 9 and the MT75 was the very low first which makes it useless with the 3.9 diff, if you use the 3.6 diff you hit max
velocity in 3rd and can't get much past 4500 in fourth. So ihave geared for 3.9 diff and topspeed in fourth and now trying to get the best out
of the slightly better ratios of the V6 and tyre sizes.
I eat to survive
I drink to forget
I breath to pi55 my ex wife off (and now my ex partner)
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NS Dev
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| posted on 25/5/07 at 12:14 PM |
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I thought a close ratio box would be extremely important, but now my car is on the road I have to say that is not the case.
Whilst it would be quicker with one, with a torquey-ish engine the gears feel close enough, that's with 200hp, 165lbft for torque, std type 9
box and 3.62 diff.
Put it this way, it still accelerates through 2nd gear in much the same time as it takes to actually change into second gear, so making the ratios
closer would waste more time on changes. 3rd could maybe be a touch shorter, you do at least hang onto that for a few seconds before the next change
up.
[Edited on 25/5/07 by NS Dev]
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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NS Dev
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| posted on 25/5/07 at 12:19 PM |
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quote:
Originally posted by snapper
, if you use the 3.6 diff you hit max velocity in 3rd and can't get much past 4500 in fourth.
eh?
Are you sure?????
What is "max velocity" ?
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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britishtrident
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| posted on 25/5/07 at 02:22 PM |
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Close ratio box won't make much difference to long distance crusing normally 4 and 5th are as normal.
Higher 1st and second gears make a real difference to to a small sports car, even the semi-close ratio 2000e ratios are wonderful compared to the
standard Ford issue.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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rusty nuts
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| posted on 25/5/07 at 05:27 PM |
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BGH do a modified gear ratio set up that makes ist a fair bit higher ratio, but you would be looking at best part of £500 for a rebuilt box with mod.
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NS Dev
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| posted on 25/5/07 at 05:54 PM |
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A higher first would be nice, but then with a paddle clutch and doing mainly road miles, it would be a pain at lights etc.
Second gear on the std type 9 is fine, certainly good for 75mph on my locost (speedo calibrated to 0 error up to 90mph)
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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Volvorsport
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| posted on 25/5/07 at 06:40 PM |
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i think the main advantage is the high 1st which if your std gearing is crap ie 28 mph or something - its over in a flash , and more prone to
wheelspin due to extra torque at the wheels .
and of course if youve got a peaky engine it can help with that also
www.dbsmotorsport.co.uk
getting dirty under a bus
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