alistairolsen
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| posted on 9/9/08 at 10:55 AM |
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High power CEC owners
could you please post up your max speeds in each gear (assuming 6800 limiter) given your current gearbox, diff and tyre size?
Also comment on your power and torque and how you find it on road, track, how controllable wheelspin is etc.
Cheers
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Mr Whippy
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| posted on 9/9/08 at 10:58 AM |
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not asking for much are you...
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alistairolsen
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| posted on 9/9/08 at 11:07 AM |
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surely anyone who actually drives their car will know this intrinsically! for instance my old corsa:
@6800
1st - 35
2nd - 60
3rd - 90
4th - 125
5th - 150 ish (never revved it out, was a bit over 3k at 70.)
car had 150bhp and 150ftlbs of torque thru the front wheels.
wheelspin was possible int he dry, but very controllable and easy to avoid even int he wet.
Ratios were very well placed for road use, never had the car on track.
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Surrey Dave
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| posted on 9/9/08 at 11:18 AM |
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Eh!
It would be alright if we knew what intrinsically meant!!!!
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alistairolsen
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| posted on 9/9/08 at 11:25 AM |
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Of or relating to the essential nature of a thing; inherent.
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Mr Whippy
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| posted on 9/9/08 at 11:30 AM |
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quote:
Originally posted by alistairolsen
surely anyone who actually drives their car will know this intrinsically! for instance my old corsa:
@6800
1st - 35
2nd - 60
3rd - 90
4th - 125
5th - 150 ish (never revved it out, was a bit over 3k at 70.)
car had 150bhp and 150ftlbs of torque thru the front wheels.
wheelspin was possible int he dry, but very controllable and easy to avoid even int he wet.
Ratios were very well placed for road use, never had the car on track.
oh right sure 150mph in a corsa and with only a measly 150bhp, you should have worked for Ferrari and shown them where they were going wrong...sigh
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UncleFista
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| posted on 9/9/08 at 11:35 AM |
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quote:
Originally posted by Mr Whippyoh right sure 150mph in a corsa and with only a measly 150bhp, you should have worked for Ferrari and
shown them where they were going wrong...sigh
From a quick glance it seems to me that 150mph is what the car was geared to do, the fact that it didn't have enough power to do 150 would be
borne out by the "never revved it out, was a bit over 3k at 70" comment 
Tony Bond / UncleFista
Love is like a snowmobile, speeding across the frozen tundra.
Which suddenly flips, pinning you underneath.
At night the ice-weasels come...
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alistairolsen
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| posted on 9/9/08 at 11:35 AM |
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max speed in gear at 6800 limiter, not terminal velocity, of course I know it wont do 150, as i said in my post, Im judging that one from revs @
70.
c'mon guys, its really not that hard a question to answer, but if you dont know, or dont want to tell me then stop trolling!
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Mr Whippy
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| posted on 9/9/08 at 11:41 AM |
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quote:
Originally posted by alistairolsen
max speed in gear at 6800 limiter, not terminal velocity, of course I know it wont do 150, as i said in my post, Im judging that one from revs @
70.
c'mon guys, its really not that hard a question to answer, but if you dont know, or dont want to tell me then stop trolling!
sorry I was to busy driving to write it down
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JoelP
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| posted on 9/9/08 at 11:52 AM |
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whippy if you're bored in the office, you can choose to only post on threads where you can help people...
if he wanted to hear assholes he'd've asked everyone to fart!
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smart51
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| posted on 9/9/08 at 11:57 AM |
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I'm fairly sure from watching top gear that the more powerful jags can do 50 odd in 1st. In which case, 1st in the jag is probably the same
gear ratio as 2nd in a corsa. Then, with 4 litres of engine and V8 low down torque, it probably pulls away nicely in "2nd" and would just
wheelspin like it was doing burnouts in "proper 1st"
I remember making the rolling road for the dodge viper factory. The second generation viper would do 50 MPH per 1000 RPM in 6th. Tick over was at
500 RPM but it would drive very comfortably at 500 RPM in 6th at 25 MPH. If you put your foot down, the engine would not bog down or grumble but
would accelerate quite nicely. The V10 was probably making about 20 BHP even at that speed. It had a lockout function on 2nd and 3rd gear (to save
fuel ) such that if you didn't floor it off the line, you could only go from 1st to 4th. 4th was pretty much the only gear you needed at any
speed.
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alistairolsen
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| posted on 9/9/08 at 12:02 PM |
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I suspect that Ill have plenty of power and torque even if I went 4 speed 
Id love 5 ratios with a 60mph first and then 5 spaced nicely to top out at 150 (a real 150 this time Whippy) but gearkits are expensive.
I was amazed at just how similar most manufacturers boxes are!
so i suppose you could say Im using this thread to guage diff selection, and from what Im hearing over on WSCC, anything up to a 2:1 first (same as
second ont he corsa) will do nicely.
Almost tempting to fit a short diff, start in second and only use 4 gears
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Mr Whippy
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| posted on 9/9/08 at 12:38 PM |
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quote:
Originally posted by JoelP
whippy if you're bored in the office, you can choose to only post on threads where you can help people...
if he wanted to hear assholes he'd've asked everyone to fart!
oh not bored at all, just having a few coffee breaks infact, new jobs quite interesting we're installing offshore wind turbines all round the
country, very different to the last job
that’s a nicely put phrase too
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turboben
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| posted on 9/9/08 at 01:01 PM |
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Dont use 1st (only parking!)
2nd 50mph
3rd 80
4th 100
5th 125 on the limiter at 7k
hope that helps
Ben
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JimSpencer
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| posted on 9/9/08 at 03:06 PM |
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quote:
Originally posted by alistairolsen
so i suppose you could say Im using this thread to guage diff selection,
Right that makes more sense.
A really quick seven will do 140 ish, if it's got a superb engine in it, the other side of 300bhp good..
250 will see you nudge 130
200 around 120 ish
And I'm working on getting to that speed reasonably quickly, not "winding up to them eventually" sort of speeds.
Assuming you're running a box with an 'overdrive' 5th or 4th giving you the normal 0.87 / 0.88 ratio in top, you'll want diff
ratios of:-
3.7
4.1
4.4
..ish, for the power range's above
Based on the normal 185/60/13 or 195/45/15 tyres.
If what you're doing doesn't fit into that let us know the power it's going to have and the gearbox ratio's and it's a
simple job to work out the axle ratio needed.
HTH
[Edited on 9/9/08 by JimSpencer]
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alistairolsen
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| posted on 9/9/08 at 03:19 PM |
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Im not too concerned with top speed.
I want to be able to drive on the motorway at 3-3.5k rpm which means having gearing for around 150 in top.
problem is, most 5 speed car gearboxes, if mated to a suitable diff to give this top gear result in a very short first (~30mph at limiter) which is
virtually useless.
What I need to know is whats useable and what isnt. how long a first does one need? how long is too long?
Its easy to talk gear ratios and get lost in tyres sizes and lots of other factors. My sole aim in talking in gear speeds was to ascertain overall
gearing in a non technical manner. Apparently that was too difficult....
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mr henderson
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| posted on 9/9/08 at 03:38 PM |
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quote:
Originally posted by alistairolsen
My sole aim in talking in gear speeds was to ascertain overall gearing in a non technical manner. Apparently that was too difficult....
For who?
It should be obvious to anyone that gearboxes derived from normal roadcars are going to have a low first gear in comparison with the rest of the gear
set. This is because a low first gear makes it easier for less skilled drivers to manouvre at parking speeds, and for people towing caravans to move
off from rest.
The moral of the story is if you want a taller first gear then you are going to have to source a gearbox from a performance car or modify a standard
gearbox to suit
hope that helps
John
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JimSpencer
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| posted on 9/9/08 at 03:41 PM |
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quote:
problem is, most 5 speed car gearboxes, if mated to a suitable diff to give this top gear result in a very short first (~30mph at limiter)
which is virtually useless.
Nope you've got it the wrong way round.
It's if you use a std box and a 4.4 or 4.7 then 1st becomes useless, you're wanting to do the opposite..
If you put a very low back axle ratio in it, say a 3.7 (which would give you the 3k ish @ 70) then you'll find even a std type 9 will do 40+ in
1st.
If you're building a cruiser then you'll just be wasting your money on gear cluster kits as their normal aim is to bring the ratio's
very close together.
Probably the best half way option would be to use a BGH (or similar brand) 'Long 1st' box - that would give you a first gear thta would do
about 50 odd I would think.
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Chippy
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| posted on 9/9/08 at 03:51 PM |
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Don't know how relevant this is to your enquiry, but this is what mine does
V6 Cosworth 220 bhp, 230 lb's torque.
3.62 diff, MT75 hybrid box
1st @ 6K = 32
2nd" " 56
3rd " " 85
4th " " 116
5th " " 140
All of the above are when the rev limiter cuts in, which is set at 6K, and yes it does do 140, despite it being underpowered, (according to a previous
post)
Cheers Ray
To make a car go faster, just add lightness. Colin Chapman - OR - fit a bigger engine. Chippy
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Paul (Notts)
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| posted on 9/9/08 at 03:55 PM |
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OK some figs for my Rover V8 Viento - all measured on the road by a data log system..
1st @ 6000rpm 35mph ( dont use first gear)
2nd @ 6200 rpm 62mph ( from standing start )
3rd @ 6000 rpm 83 mph ( normally change at 75mph)
4th @ 6000rpm 117 mph ( have had 100+ in 4th)
5th @ 600rpm 148 mph ( never tried this )
Have had 120 mph out of it but never pushed it beyond this...
Engine produces acording to my calculations from data - 179 bph 200 lb foot torque ( at the wheels )
3.5 RV8 with uprated cam and card, lightend flywheel - aoon to have Megajolt.
Paul
[Edited on 9/9/08 by Paul (Notts)]
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alistairolsen
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| posted on 9/9/08 at 04:15 PM |
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quote:
Originally posted by JimSpencer
quote:
problem is, most 5 speed car gearboxes, if mated to a suitable diff to give this top gear result in a very short first (~30mph at limiter)
which is virtually useless.
Nope you've got it the wrong way round.
It's if you use a std box and a 4.4 or 4.7 then 1st becomes useless, you're wanting to do the opposite..
If you put a very low back axle ratio in it, say a 3.7 (which would give you the 3k ish @ 70) then you'll find even a std type 9 will do 40+ in
1st.
If you're building a cruiser then you'll just be wasting your money on gear cluster kits as their normal aim is to bring the ratio's
very close together.
Probably the best half way option would be to use a BGH (or similar brand) 'Long 1st' box - that would give you a first gear thta would do
about 50 odd I would think.
indeed, that was the direction I meant to go with the FD. a long first box would be nice, but tbh with a spread of torque going for 4 gears and
ignoring 1st would also work!
For the last two posters, how does starting out in second work out for you? I guess first is utterly useless?
cheers
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Paul (Notts)
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| posted on 9/9/08 at 04:41 PM |
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With the torque of a V8 2nd gear feels like pulling away in first in my Tin top but with more power and the ability to go straight through to 60mph if
I want without wasting a full second changing gear.
dont do it often but the engine will rev upto 6200 before I chicken out and change.
changed from a 3.9 diff to a 3.62 so that I could get the 60mph in 2nd.
Paul
The best thing about mine is not the acceleration but the lazzy gear changes. Often I dont bother changing out of 3rd unless I come to a dead stop.
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tcr
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| posted on 9/9/08 at 05:07 PM |
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tried taking my eyes off the road long enough to check but too much traffic .our car is used for sprint and drag so long 2nd / 3rd very rarely use 4th
MK MIDI ZX10R
http://www.facebook.com/media/set/?set=a.4393256076054.2182513.1427988207&type=1&l=64c91c3c17
why isnt anything simple!!!
torquetune.co.uk
nrpexhausts.co.uk
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kenton
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| posted on 9/9/08 at 05:45 PM |
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Never bothered to check each gear but i dont use 1st. 5th at 5thou rpm i do 130, not gone faster but it has plenty left if i had the nerve!!
kenton
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turboben
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| posted on 9/9/08 at 07:05 PM |
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Alistair, just out of interest what are you building and what engine are you going to use?
Ben
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