Gear ratio advise please

70_charger · Post by **70_charger** » Fri Oct 30, 15 8:01 pm

Hi any advise would be helpful
600hp motor, a833 4 speed with 26-27" high tyres
What would be a good ratio for street , strip
My choices are 3.54:1 , 3.73:1 or 4.10:1
Thanks Shaun

68Runner · Post by **68Runner** » Fri Oct 30, 15 9:41 pm

All depends what your after

There are plenty of gear ratio calculators online. Put in your details and it'll give you your desired ratio

Cannonball · Post by **Cannonball** » Fri Oct 30, 15 9:54 pm

you need the 4,10 get you out the hole rev the conkers of it and drop the hammer, if you are on the factory clutch linkage affair you need to strengthen them all to Bananarama!, reinforce the firewall pivot are, and tie the mtr down real hard or you will have missed shifts regular, go round beefing it all up before you make any attempt to power shift it,

70_charger · Post by **70_charger** » Sat Oct 31, 15 7:27 am

I'm after best gear to give not bad drive ability on the street but more importantly best gear without affecting street too much for the strip. I tow the caravan to the track with the charger. I'm not running a tall tyre but may change to a 28" from the 26.5"
Dunc 4.10 on 26.5" wouldn't that make it a it to high revs on the motorway? Thou yeah prob best for out n out strip use
Thanks for your help

Blue · Post by **Blue** » Sat Oct 31, 15 8:05 am

Gearing for the track is dictated by the RPM your engine makes maximum power at, if you don't have a reasonable idea of where that is then you'll just be guessing at what the right ratio might be. At that power level with a 4 speed I'd want to be using a 29" x10.5" slick to stand a reasonable chance of it hooking up with some sort of consistancy.

68Runner · Post by **68Runner** » Sat Oct 31, 15 11:54 am

On the F100 I built it had 460ci +C6. Axle was a 3.73 with 31" tyres. Did about 60mph at about 2500rpm.
I was going to go to a 3.08 and it would have done about 70mph at same revs.
Reckon you'll get a decent launch and cruise with a 3.73 and your tyres

Dutchrunner · Post by **Dutchrunner** » Sat Oct 31, 15 5:15 pm

How about best of both worlds?
4.10 and gearvendor behind 4-speed?

Mick70RR · Post by **Mick70RR** » Sat Oct 31, 15 6:19 pm

I use 3.91 gears and a Gear Vendors overdrive. I fitted them a week before the overdrive arrived and there's no way I could have lived with them on their own. I'd use 3.54 gears if I didn't have the overdrive.

Pete · Post by **Pete** » Sat Oct 31, 15 7:00 pm

Some great advice there.

Especially the beefing up points.

One other point but I am probably stating the obvious: it is essential to have a reliable rev limiter there as one missed shift / false neutral and you will over-rev and lose the motor without one if you are at peak revs on the track.

70_charger · Post by **70_charger** » Sun Nov 01, 15 11:05 am

Thanks for all the advise fellas I can't afford gear vendors so I'm torn between 3.54 and 3.73 I will see if I can find out what rpm the motor builds peak power and see what you all think then.
Rev limiter is in msd 6 digital unit, clutch release bearing may be being swapped to hydraulic

Pete · Post by **Pete** » Sun Nov 01, 15 12:27 pm

I think you will have great fun but you better buy a broom!

I would be really interested to hear how you get on with a Hydraulic release bearing - I toyed with the idea of one many years ago but bottled it....

GJUK · Post by **GJUK** » Sun Nov 01, 15 1:08 pm

I went from 4.1 to 3.55 gears for road use.
Much better and still quite nippy.

No point in doing 0-60 then screaming its tits off at 70mph on the motorway trying to keep up with a yaris.

Cannonball · Post by **Cannonball** » Sun Nov 01, 15 1:29 pm

oK

I THOUGHT SHAUN HAD BECOME A RACER ATTENDING THE DRAGS ETC, HENCE IT NEEDING 4,10 BUT IF THIS IS NOT THE GOAL THEN YES FOR SURE A 3,55 GEAR IS THE WAY, BUT CRIKEY YOU MAY AS WELL DROP IT TO 3,23 GEARS NOT A LOT OF DIFFERENCE IN THE ACCELERATION AND BETTER RPM,S FOR TAKIN YOUR MOMA OUT,

AS THEY SAY THE CHOICE IS YOURS,

70_charger · Post by **70_charger** » Sun Nov 01, 15 5:21 pm

Lol Dunc yeah I know it's one or the other but trying to get happy medium between the two but on the side of strip use as I can live with discomfort on the street but think the 4.10's will make it unusable for motorway use as I drive to Santa pod etc. Don't want all out race car just a quick street strip car. What's best taller tyre and lower gear or lower tyre and higher gear ??? Tyre height at 26" with 3.54 is near to a 31" tyre with 4.10 ??
Shift at 6500rpm so Peak Hp around that rpm

Cannonball · Post by **Cannonball** » Sun Nov 01, 15 6:09 pm

70_charger wrote:Lol Dunc yeah I know it's one or the other but trying to get happy medium between the two but on the side of strip use as I can live with discomfort on the street but think the 4.10's will make it unusable for motorway use as I drive to Santa pod etc. Don't want all out race car just a quick street strip car. What's best taller tyre and lower gear or lower tyre and higher gear ??? Tyre height at 26" with 3.54 is near to a 31" tyre with 4.10 ??
Shift at 6500rpm so Peak Hp around that rpm

now i am being serious, is it a 83/4 or dana ???
ii 83/4 get yourself a 2.92 or 2.76 for road use, also get yourself a 4,30 or 4,56 and swap it at the track, an hour tops then swap back to come home thats what i used to do with my charger,.
if its a dana go somewhere around 3,90 and use a tall tyre for street driving a 28 tall slick,