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Discussion Starter #1
Hi. I'm preparing my F7R for drag races i did lots of things.Now i will change the Differential Ratio.You know that F7R uses jc5 gearbox same as in Laguna.
Anyone knows the Differential Ratio of the 1.9 Laguna Dti?
Or any other Renault Car that uses jc5 gearbox with short ratios?
F7R's ratio is 57\16 =3.56
I search for like 61\15=4.06 or the best one that 63\14 = 4.5 (Renault Spring,Broadway etc uses this ratio but their Gearbox is different(jb3) so i can't uses their's.)
 

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Hi and welcome to the forum this sounds great have you got any pics.Iam sure someone will help, a bit tec for me;)
 

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Very nice car indeed.

I don't know the differential ratios, but something you may wish to consider would be to fit a pair of smaller diameter wheels and tyres (to the front, naturally) - these could be carried in the rear of the car whilst travelling to/from the drag strip, and fitted for your runs.

This way, you don't compromise the everyday driveability of your car. (plus of course, you avoid wearing out your road tyres).

Hope it helps,

Paul:)
 
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Discussion Starter #6 (Edited)
Very nice car indeed.

I don't know the differential ratios, but something you may wish to consider would be to fit a pair of smaller diameter wheels and tyres (to the front, naturally) - these could be carried in the rear of the car whilst travelling to/from the drag strip, and fitted for your runs.

This way, you don't compromise the everyday driveability of your car. (plus of course, you avoid wearing out your road tyres).



Hope it helps,

Paul:)
Thanks bro but anyway I will use 13'' inch Slick Tyres and wheels at Front in Races so Tyres aren't a problem:)
 

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Fair enough, I was just trying to engineer a way around this problem - but you thought of it first!:d

Just a thought regarding lowering the final drive - there will be an optimal degree of acceleration that your car can produce - if you lower the gearing significantly, you will have more gearchanges in the 1/4 mile. Time changing gear = no acceleration. Plus, if the gearing is lowered - then the maximum speed achieveable in each gear is also lowered.

Its just something which occured to me - it may be worth considering.

All the best with your pursuits.

Paul:)
 

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Discussion Starter #8
Fair enough, I was just trying to engineer a way around this problem - but you thought of it first!:d

Just a thought regarding lowering the final drive - there will be an optimal degree of acceleration that your car can produce - if you lower the gearing significantly, you will have more gearchanges in the 1/4 mile. Time changing gear = no acceleration. Plus, if the gearing is lowered - then the maximum speed achieveable in each gear is also lowered.

Its just something which occured to me - it may be worth considering.

All the best with your pursuits.

Paul:)
Yes u are right brother but not totaly:):).oki will have more gear changes with short Differential Ratio but the clue is that the car will turn the tour (rpm)very very more quicker than the long one.
Sounds that with short ratio ;vın vın vın (rpm quickly 4000 to 6750) no waiting to come to 4000-6750 rpm at gears
but with the longer Gear ratio ; vııııııınnn vıııııınn( rpm slow. The car is fainting especially at the 1.gear change to 2. gear at 60 km/h)
 

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Discussion Starter #9
Anyone knows the Differential Ratio of the 1.9 Laguna Dti?
Or any other Renault Car that uses jc5 gearbox with short ratios?
F7R's ratio is 57\16 =3.56
I search for like 61\15=4.06 or the best one that 63\14 = 4.5 (Renault Spring,Broadway etc uses this ratio but their Gearbox is different(jb3) so i can't uses their's.)
Nobody knows???:(
 
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