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High power CEC owners
alistairolsen - 9/9/08 at 10:55 AM

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

Mr Whippy - 9/9/08 at 10:58 AM

not asking for much are you...

alistairolsen - 9/9/08 at 11:07 AM

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.

Surrey Dave - 9/9/08 at 11:18 AM

It would be alright if we knew what intrinsically meant!!!!

alistairolsen - 9/9/08 at 11:25 AM

Of or relating to the essential nature of a thing; inherent.

Mr Whippy - 9/9/08 at 11:30 AM

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

UncleFista - 9/9/08 at 11:35 AM

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

alistairolsen - 9/9/08 at 11:35 AM

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!

Mr Whippy - 9/9/08 at 11:41 AM

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

JoelP - 9/9/08 at 11:52 AM

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!

smart51 - 9/9/08 at 11:57 AM

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.

alistairolsen - 9/9/08 at 12:02 PM

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

Mr Whippy - 9/9/08 at 12:38 PM

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

turboben - 9/9/08 at 01:01 PM

Dont use 1st (only parking!)
2nd 50mph
3rd 80
4th 100
5th 125 on the limiter at 7k

hope that helps
Ben

JimSpencer - 9/9/08 at 03:06 PM

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]

alistairolsen - 9/9/08 at 03:19 PM

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....

mr henderson - 9/9/08 at 03:38 PM

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

JimSpencer - 9/9/08 at 03:41 PM

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.

Chippy - 9/9/08 at 03:51 PM

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

Paul (Notts) - 9/9/08 at 03:55 PM

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)]

alistairolsen - 9/9/08 at 04:15 PM

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

Paul (Notts) - 9/9/08 at 04:41 PM

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.

tcr - 9/9/08 at 05:07 PM

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

kenton - 9/9/08 at 05:45 PM

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

turboben - 9/9/08 at 07:05 PM

Alistair, just out of interest what are you building and what engine are you going to use?
Ben

MikeR - 9/9/08 at 07:16 PM

I disagree with what you're saying based on a conversation with NS Dev last night in his garage. He spanners for a caterham race team at weekends. The data logger on that showed the car doing around 135 - 140 on 200ish bhp.

Not sure what you call winding up to speed, but i'd have thought if you can get there on a track thats fast enough.

(nb i may have miss quoted / miss understood what was said last night but i'm pretty sure of the conversation)

quote:
Originally posted by JimSpencer
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]

Volvorsport - 9/9/08 at 07:22 PM

youll need the highest possible gear ratio in first that you can pull away with , light cars with high power dont need as much torque multiplication .

so 2.2:1 is used in some close ratio 4 speeds , and it also depends onyour rear diff , so that means starting in second if as mentioned before your using std gearing from the donor or thereabouts .

my volvo gearing is about 29mph in first !!

TOO BADD - 9/9/08 at 07:36 PM

Assuming gear change at 6800.....
Ist 46
2nd 70
3rd 98
4th 112
5th 138
225 50 15 Toyo R888

My redline is set at 8000 so my figures are
54
83
115
132
163 !!!???

200bhp with unknown torque and will spin from start to 7500 ( 50 ish )in first without dropping the clutch and with a little more in second and sometime a waggle in third.
All controllable.....

BGH close ratio and 3.92 LSD

[Edited on 9/9/08 by TOO BADD]

[Edited on 9/9/08 by TOO BADD]

the_fbi - 9/9/08 at 08:09 PM

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.


Presuming this was an 20XE with an F18w or F28 its possible.

Take a while to get up there, but it would get there.

JimSpencer - 9/9/08 at 08:58 PM

quote:
Originally posted by MikeR
I disagree with what you're saying based on a conversation with NS Dev last night in his garage. He spanners for a caterham race team at weekends. The data logger on that showed the car doing around 135 - 140 on 200ish bhp.

Not sure what you call winding up to speed, but i'd have thought if you can get there on a track thats fast enough.


Hi

I was using the speed trap on Aintree back straight, i.e. - it's the quickest place we go.. around 1/3 mile last corner (a fast one too) to speed trap - good bench mark for a reasonable track day car.
So thought it would make a good example.

Somewhere a bit bigger would see more - as would holding the foot planted and let it wind up, as would different tyres - wind direction and teams knowing what they're doing etc etc
- but either way what a Seven is about - it's the abilty to hurtle out of a corner up to a good speed quickly... and then stop before the next bend..
so we're mot a million miles away either way..

Aintree on Saturday was:-

175bhp = 114
240 = 125
300+ = 135

Known cars (striker, Westfield, Dax - in that order) & recorded via MST timing.

[Edited on 9/9/08 by JimSpencer]

[Edited on 9/9/08 by JimSpencer]

alistairolsen - 10/9/08 at 07:04 AM

Paul (notts) cheers fella! sounds promising.

Turbo ben - mx5 based locost with a volvo T5 engine.

The FBI, it was an r reg corsa 1.2 complete with the LS badging and everything on a late dispak xe, F20, equal length shafts, 288mm brakes, decent tyres and no extra weight. Cost me £600 to build with new bearrings, clutch, cambelt etc and made an entertaining commuter for a year. Did 15k in it and sold it on for 1300 quid

quote:
Originally posted by TOO BADD
Assuming gear change at 6800.....
Ist 46
2nd 70
3rd 98
4th 112
5th 138
225 50 15 Toyo R888

My redline is set at 8000 so my figures are
54
83
115
132
163 !!!???

200bhp with unknown torque and will spin from start to 7500 ( 50 ish )in first without dropping the clutch and with a little more in second and sometime a waggle in third.
All controllable.....

BGH close ratio and 3.92 LSD

[Edited on 9/9/08 by TOO BADD]

[Edited on 9/9/08 by TOO BADD]


Thank you! Kinda what i expected.

NS Dev - 10/9/08 at 12:02 PM

Ok,

Vauxhall XE 2.0 16v

Normally Aspirated

204 hp @6400 rpm

168 lbft torque (can''t remember what revs at)

Yokohama A048R tyres, medium compound, 195 x 60 R14

Std type 9 gearbox from 1.6 4 cyl sierra

3.62:1 LSD diff from sierra XR4x4

Car weight = 540kg

My limiter is 7500revs so not sure on speeds but ballpark 40mph 1st, 70mph 2nd, 90mph 3rd, never looked in 4th and 5th, certainly over 110 in both.

In terms of traction...

here's my shouty bit!!!

THERE MUST BE SOME REALLY CRAPPLIY SET UP CARS ON THIS FORUM!!!!

IN DRY CONDITIONS I have NOOO problems with wheelspin in ANY gear other than first. It will take full throttle in any gear, and just grips and goes, with a touch of slither in first and second gears, but not what you would call "wheelspin", just wheelslip and a bit of squirm.

That's using 140 lb/inch rear springs, which i know are much softer than most on here run, and probably explains the increased grip.

Wheelspin is not a problem, and another 30hp would be sensibly useable.

0-60 is currently around 4 secs, (3.8 best)

1/4 mile on datron gear is 11.9 secs, but that wasn't on a dragstrip so may or may not be dead accurate.

[Edited on 10/9/08 by NS Dev]

alistairolsen - 10/9/08 at 12:53 PM

cheers for taking the time to type that

sounds pretty promising!

jeffw - 10/9/08 at 05:28 PM

[Edited on 10/9/08 by jeffw]

smart51 - 10/9/08 at 08:10 PM

quote:
Originally posted by JimSpencer

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

[Edited on 9/9/08 by JimSpencer]


No, this is way off. I've had 120 out of my car at 11,750 RPM (the red line in top). A dyno plot of my engine shows 152 BHP at 10,000 but only 100 BHP at the red line. 100 BHP is good for an indicated 120 MPH. I don't have a windscreen screen BTW.

NS Dev - 10/9/08 at 08:27 PM

The caterham C400 superlight racer that I spanner on pulls 144 mph at snetterton.

That has 220hp and 8000 rpm

MikeR - 10/9/08 at 08:51 PM

damn, i thought it was 140 to 145 but thought i should err on the side of caution.

And i was 20bhp out well i was tired.

JimSpencer - 10/9/08 at 09:12 PM

quote:
Originally posted by smart51
quote:
Originally posted by JimSpencer

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

[Edited on 9/9/08 by JimSpencer]


No, this is way off. I've had 120 out of my car at 11,750 RPM (the red line in top). A dyno plot of my engine shows 152 BHP at 10,000 but only 100 BHP at the red line. 100 BHP is good for an indicated 120 MPH. I don't have a windscreen screen BTW.


No its spot on - as its actual speeds by actual cars properly recorded.. see the posts above clarifying, what was just an example, > but folks can't seem to accept an example they want specifics..

It was just used to a set context - which was 1/3rd mile after beachers bend at Aintree -
Which is all incidenal to the point anyway

But the removal of the screen makes a big difference as it would too for the Caterham - thing is we Have to run screens in sprints..

JimSpencer - 10/9/08 at 09:53 PM

quote:
Originally posted by NS Dev
IN DRY CONDITIONS I have NOOO problems with wheelspin in ANY gear other than first. It will take full throttle in any gear, and just grips and goes, with a touch of slither in first and second gears, but not what you would call "wheelspin", just wheelslip and a bit of squirm.

That's using 140 lb/inch rear springs, which i know are much softer than most on here run, and probably explains the increased grip.

Wheelspin is not a problem, and another 30hp would be sensibly useable.

[Edited on 10/9/08 by NS Dev]


Was wondering about this - likewise for me too, can't understand how wheelspin is even an issue - and that's on 1A's, use B's and other than a brisk start wouldn't see it at all.

C10CoryM - 10/9/08 at 10:56 PM

quote:
Originally posted by JimSpencer
can't understand how wheelspin is even an issue


Any idea how much torque you have?
Torque is what gets wheelspin. NSdevs 205hp is great, but the 165ft/lbs is really not that much (although not sure you need more for a light car). Compare that to the torque of a V8 and you can see why tire spin is an issue.

My car is not complete yet but specs are:

Supercharged V6. 240bhp, 280ft/lbs torque 6000rpm redline.
3.08 LSD differential
23" tires (225/45r15) RA1 or R888

1st: 45mph
2nd: 70mph
3rd: 100mph
4th: 140mph
5th: 180mph

No idea when it will run out of power but I am willing to bet this is the first car I won't have the balls the run to top speed. I am also willing to bet I will have little to no traction below 40mph.
Cheers.

JimSpencer - 11/9/08 at 08:20 AM

Hi

Certainly you're talking a lot of torque at 280lb ft, and I do think you might have hit your own nail on the head with the'do you need more than the 165lb ft' - probably not..

But it would be rude not to have a go wouldn't it ?

You'll certainly need to get the right tyres on it, and make sure the supension is soft enough and nicely damped. Lots of folk (me included) ran or run these cars way too hard.
I ended up running the car on 275F / 200R at one point and it was just plain useless. Had the error of my ways explained to me and the rates are now roughly 2/3rds of that at the front and just over half rear - much better, much nicer to drive & quicker too.
(& MUCH quicker in the wet..)

Be interested to see how you find it when it's up and running.

alistairolsen - 11/9/08 at 09:17 AM

interesting what you say about stiffness, I was chatting to BobC about this the other day and he runs very soft springing and reckons the car handles excellently. I suppose the ideal is getting the rear of the car to hunker down as you apply power, and squat properly onlaunch, but without applying too much dynamic camber.

The point about torque is of course also true, and the tyres will have a certain torque limit they can sustain grip below given a certain surface.

obviously the higher the overall gearing, the less torque at the wheels however.....

C10CoryM - 12/9/08 at 02:31 AM

quote:
Originally posted by JimSpencer
But it would be rude not to have a go wouldn't it ?
Bingo!

The silly thing is that for $60 I can buy a smaller supercharger pulley and get about 275bhp and 300ft/lbs.

I have a live axle with an adjustable 3-link. IIRC I can dial in about 110% antisquat with it in its most agressive position. So I *should* be able to get some traction. Not sure how well it will corner that way though.

Ive already learned my soft spring lesson on my last car. I turned my camaro into a road racer when I really needed a rally car. Meaning I was too stiff, too low, and not enough wheel travel. I am waiting until I have final weight before ordering my shocks/springs.

Alistair, you may want to look into antisquat. You may squatting works different than it would seem. The IRS guys who drag race here tend to run very stiff in the rear to keep the tires square to the ground.
Cheers.

bj928 - 24/10/08 at 04:35 PM

my viento is gear for 61 in first,

rev limit 6000

axle ratio = 2.73 (stock mustang gt 8.8)

1st = 61
2nd = 92
3rd = 126
4th = 163
5th = 221
6th = 327

6th @ 1000rpm = 54 mph

rear tyres are toyo 888, 295 30 18

running a viper v10 (gen 3) with stock 6 speed manual with remapped ecu, power estimates

550 hp +
575 Ib/ft +

car should weigh in at about 800kg



a good site for gear ratio calculations is http://www.f-body.org/gears/ , i use it all the time

[Edited on 24/10/08 by bj928]

Antnicuk - 29/10/08 at 02:08 AM

my stylus weighs about 650kg-700 kg, dynoed last week with 330 ftlbs and 320 bhp. 8k red line but turbo runs out of puff at 7 at the moment.

Stock Mazda RX7 gearbox which has quite a long first gear. Atlas diff with 3.09 f/d.

not sure of individual gear speeds but at 70mph i'm doing just under 2300 rpm in 5th. 3rd takes me over 100. Stock mazda diff is 4.1 and the stock car does 160 mph with only 200 bhp and 200 ftlbs

Not sure about the comments on wheel spinning equals crap set up although i know they are linked. I spin the wheels all the way through 3rd with ACB10's on the back and lots of squat, which leads me on to my next question....

I need to reduce the amount of travel my suspension has, i am already at 250 lbs rears and it still squats too much under power. I know the squat helps me get traction but its hindering my tyre choice and ride height as i have to have it high with narrower tyres to stop the tyres rubbing the arches.

what can i do to run less suspension travel other than put rock hard springs? i'm new to this suspension business and need to tame this torque!