Joined: Aug 2017 Posts: 124 Threads: 15
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Location: East Sussex
I have just started driving my EA Sports replica after 4 years of building.
I'm only planning to use it on the road i.e. not in competition. The engine has a high comp head, 3 branch exhaust and 1 1/4 SU.
It has a standard, 2 SYN 4 speed box and 4.9 diff. and 19" wheels.
The step between 3rd and 4th gears is really noticeable and spoils the driving experience. I'm thinking that I have several options available to me:
1) Fit a numerically higher diff e.g. 5.25
2) Fit close ratio gears e.g. Super Accessories ratios
3) Do both 1) and 2)
I would welcome any advice please.
Thanks Alan
Joined: Aug 2017 Posts: 606 Threads: 24
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Does it feel like its overgeared in top.Try fitting a pair of 17's on the back to see how it drives.
I would fit a close ratio box.
I have a 4.9 and 400x 18's on one car and it feels good.Another has 350x19's on a 5.25 and I think it's undergeared.
Joined: Aug 2017 Posts: 605 Threads: 18
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Location: Sheffield South Yorks
Car type: 1932 RN saloon
I have a sports with 5.25 diff,19” wheels and Super Accessories close ratio gearbox. 3rd gear is too close to 4th for where I live (hilly Sheffield/Peak District). Car has Speedex head, 30mm inlets, Ulster 3 branch exhaust and Nippy type downdraught carb, standard camshaft and larger rad tappets.
Cheers,
Dave.
Joined: Aug 2017 Posts: 1,397 Threads: 25
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Location: North Yorkshire
Are you sure you want to stick with 4 speeds? When I built my Ulster I started with a Vince Leak C/R 4 speed with a 5.25:1 CWP, 19" wheels. Whilst it all worked well I always felt that something was 'wrong'. In the end I changed to a 3 speed box with fake Ulster ratios. Not only was the car transformed but the fun was transformed too. I'd never go back to 4 speeds. I do use the car for speed events so that, obviously, was a factor in the change but it's a road car I use on the track rather than a track car I use on the road and it works so well in both environments. The long second is, particularly, good; 55+ mph and a change up to top is brilliant at the Traffic Light Grand Prix! OK, for next season the new axle is 5.67:1 to give some more punch out of the slower corners but I'm still sure it'll remain a great road car.
Steve
Joined: Aug 2017 Posts: 3,210 Threads: 100
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Location: Darkest Bedfordshire
Alan,
My Ulster rep currently has 4.9 axle ratio and for a long time ran with 4-syn. I can't disagree with you but for me hill (mountain) climbing is important and I didn't want 3rd any higher. I have in fact just fitted a 4 speed crash box which is the opposite of the way you want to go, but it now has a splendid 'supercharger' shriek in second!
Your thinking is good, in my humble opinion. Drop to 5.25 to lower top and go CR to bring the other gears up. Or do as Steve suggests. It's very much a question of how you want to use the car though.
I'm not quite convinced about 17" wheels, theoretically yes but you might well find the rolling radius of a 17" tyre is as big as a 19", at least check before investing. I ran on 15's for a while but didn't care for them myself, too low (to the road) and very bouncy on the tyres they had.
Joined: Aug 2017 Posts: 701 Threads: 12
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I use a pair of 17" wheels for non VSCC hill climbs on the type 65 fitted with 3.25 section tyres.
Up Wiscombe it is faster with the 17" on the back.
Sports ratio box and back axle.
I do have an engine that will rev a bit though which helps.
Joined: Aug 2017 Posts: 1,666 Threads: 46
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Location: Auckland NZ
Car type: 36 Nippy, 31 RM, 38 Special, 24 Works Rep
I concur with the others, fitting a CR box either 3 or 4 speed will be the single best tuning mod you can do in a special. On the road a 5.25 rear end with 19" would be my choice however a friend prefers 4.9 in his car as it keeps the revs lower when crusing, he does however admit he prefers the 5.25 for speed work. I have use a variety of wheel and tyre combinations for hill climbing, it is a quick and easy way to alter the final drive ratio, however aesthetically some sizes just look better and in competition some combinations are not acceptable, particularly with UK regulations.
Black Art Enthusiast
Joined: Mar 2015 Posts: 5,188 Threads: 223
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Location: Scotchland
I don’t run a 4 speed box in any of my SWB cars but I have changed all of them to from 4.9 to 5.25 ratio which I find to be an excellent mod. if you want to stay in top gear for longer.
