Shorter diff ratio for Renault 395 gearbox? Possible collective order

[Mecky]

Hi guys,

I'm racing a Europa S2 with 395 gearbox in Europe. This gearbox has a freaking long ratio. The top speed of my car is 236 km/h at 7500 RPM. That is much too long for circuit racing. Unfortunately, Renault did not build other diff ratios for that gearbox. At least not near the place where I live. I found a company in Germany, which is able to manufacture the bevel- and ring gear after they measured my original parts. I will go from 9/34 to 8/33 ratio. That reduces the top speed around 20 km/h.

Now, i received the price for bevel- and ring gear. 5195 € for one set and 3320 € for two sets. More sets would be even cheaper.

That leads to my question: Is there anybody out there, who wishes a shorter gearing for their Renault 395 gearbox? We could do a collective purchase order.

If yes, please answer to this topic in the next week. Thank you in advance!

Best regards
Stefan

[Lotuswins]

Hi Stephan,

So the gearing is too tall for the track then?  What fifth gears are you running? (there are two stock ratios).  Which 395 are you running?  From the pictures it appears that it is an early 395 box since it doesn't have the CV axles, and it appears that the bell housing doesn't have a bearing, just a seal for the input shaft?

If you are running the taller fifth gear, moving down to the 0.91 ratio fifth may be a cheaper alternative to lower your top speed.  In my TCS with a 365 box but 395 fifth gear I tach about 4k at 70mph and on the track it is usable at least, whereas the Lotus 365 fifth gear was too tall and no acceleration was apparent on the straights in fifth.  But it is a bit high of a rpm for the freeway.

Also, if you are wanting a closer spaced gearset and it is an early 395, the 365 gearset will fit and with the shorter 395 fifth the rpm changes are really nice.

Jerry Rude
4005R

[Mecky]

Hi Stephan,

So the gearing is too tall for the track then?  What fifth gears are you running? (there are two stock ratios).  Which 395 are you running?  From the pictures it appears that it is an early 395 box since it doesn't have the CV axles, and it appears that the bell housing doesn't have a bearing, just a seal for the input shaft?

If you are running the taller fifth gear, moving down to the 0.91 ratio fifth may be a cheaper alternative to lower your top speed.  In my TCS with a 365 box but 395 fifth gear I tach about 4k at 70mph and on the track it is usable at least, whereas the Lotus 365 fifth gear was too tall and no acceleration was apparent on the straights in fifth.  But it is a bit high of a rpm for the freeway.

Also, if you are wanting a closer spaced gearset and it is an early 395, the 365 gearset will fit and with the shorter 395 fifth the rpm changes are really nice.

Jerry Rude
4005R

Hi Jerry,

thanks for your input. My overall gearing is too long, while the steps between gears are actually quite nice. For example, on the Circuit Zolder in Belgium, I don't need 5th at all, because the longest straight is only around 800 metres and my top speed did not exceed 180 kph there. My 5th gear has the ratio 0.861. I already calculated the difference with a 0.91 5th gear, but it would not really help for my problem. That's why I'm now going to order the newly manufactured bevel- and ring gear as a one-off. It's very expensive, but still less than a Trans Concept gearbox, which would cost between 8 und 10 k in my required spec. That would be the high-end solution, but I have to also look at the budget.

Of course, my gear box has output bearings on the diff. It wouldn't work without them. You can see the rollers still on the diff and the outer ring still in the housing on the photo.

It's a nice idea to blend a 365 and 395 gearbox. But I don't really know where to source a 365 gearbox and I read that they are quite expensive (ballpark 3 - 5 k $), because Alpine guys can use them, too. That's why I will prefer to let a new set of gears be manufactured for me. The cost is similar and I don't have to buy used parts, which could end up in an unpleasant surprise. Good to know that it's possible, thus. I once tried to blend a 395 and NG3 and I was very lucky that the part I needed from the NG3 was one of the very few parts that the gearboxes share. Most of the parts were completely different.

Regards
Stefan