Changing the final drive ratio... | Page 2 | FerrariChat

Changing the final drive ratio...

Discussion in '456/550/575' started by F456M, Dec 8, 2018.

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  1. gsfent

    gsfent Formula 3

    Nov 16, 2009
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    Jerry
    I have done this on 3 other non-Ferrari cars (BMW, Mercedes and Mini). I use about a 12-15% reduction, but my goal is to make old 6th gear about the same as new 5th gear. 6th then is a true overdrive, assuming you still have enough torque to "pull" the higher gearing in 6th (can't imagine it would be an issue with a 456M). Other than a computer program adjustment for the Mercedes (all wheel drive), it has worked flawlessly, using off the shelf parts to mix and match.

    Remember, you are giving up the same percentage of TQ in the lower gears, so I typically offset with some power adjustments (headers being the easiest) to recapture some of that.

    Feel free to PM me for any additional info that I might have which may be useful to you.

    Regards,
    Jerry
     
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  2. F456M

    F456M F1 Rookie

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    Thank you for the very interesting replay. I have actually never heared about anyone doing it with a normal car. Can you decribe it more in detail what you did and the results? Also, what are the downsides? And what was the cost invoved and why did you do it? Thanks alot!!
     
  3. G. Pepper

    G. Pepper Three Time F1 World Champ
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    I had a very underpowered RAM 1500 QuadCab 4x4 pickup with the non-Hemi 4.7L V8. It came with 20" wheels and 33" tires, so when I got a 4" Rancho lift for it, I put 35's on it. It was a real chore to go up hills at freeway speeds, so the answer was to gear it deeper, not taller. No problem at all for that vehicle. So you want taller final ratios for lower RPM's at cruising speeds. If the final is an easy swap, it shouldn't be a problem, but they appear to be mounted on the opposite side from each other. If that's just a technicality due to packaging, and the swap will work, then this should be a straight ahead proposition.

    I hope you do this, as I would be interested to know the results.

    The number one culprit of road noise is wheels and tires, usually, BTW. I used P-Zeros on the 456 with the stock rims and they were immeasurably better than the P-Zeros on the Barchetta wheels, or the Nittos on those wheels.
     
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  4. gsfent

    gsfent Formula 3

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    Not sure the board is interested in non Ferrari stuff, so I sent a PM. Feel free to post or PM back.

    As to cost, it is generally NOT cost effective. But we do a lot of things to our cars that are not cost effective to make them the way we want them! :)

    Regards,
    Jerry
     
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  5. F456M

    F456M F1 Rookie

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    #30 F456M, Dec 14, 2018
    Last edited: Dec 14, 2018
    Hey Pepper. I have a Chevy 1500 Avalanche aswell, and these 1500 chassis pickups have low rpms and pulls trailers not very well, but they cruise so good!! Mine has the 5,3 l 275 hp. Vortech engine and I think it has something like 1.600 rom when doing 100 kph / 65 mph. A V8 like that is not the same kind of high revving engine as a V12 Ferrari, but the thing is tall and wide and weighs in at around 6300 pounds and when driving a steady 100 kph. it will zip about 11,5 liters every 100 kms. which I think is really good for that big vehicle. The 550 weight is one ton less, has tires with less friction, half the drag and has a ton of torque at all rpms. 270 NM at idle to be exact... And it is more thirsty. I am not going to reduce the rpms. to 1600 at 100 kph, because that is very low for this engine and not the relevant speed, but let’s say you get 2.200 at 130-140 kph. etc. That would make the car really great for cruising. Also at 180 kph. which is te ideal cruising speed for me, something like 3500 would be really nice.

    One more thing that came to mind... If the spline and good diameter in the gear pair for each gear are the same, then maybe 3rd gear would work if the the toothed wheels would exhange position....? So buying these and install as replacements for 5/6th would do the trick?

    To be honest, the idea of changing the final drive ratio is probably the best thing because then the ratio of each gear would be the same relative to each other. But of course,it is a matter of cost to if a custom machined final drive gear is super expencive. I feel that 1st is also very low. If you floor it, it is like abuse and the wheels get immense wheel spin. Maybe to raise the ratio would make it faster even from take off? Not that I do it alot but still...

    About the opposite direction on the 456 picture. To me that would mean the drive shafts would spin in the wrong direction? So probably it is not possible?
     
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  6. F456M

    F456M F1 Rookie

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    Gsfent / Jerry from Florida have sent me a very interesting personal message and said I could post it here if I wanted to. I am sure it is interesting to all others who have read this far on this thread even if the cars he changed the ratios of are not Ferraris. The principle is the same.

    Message from Jerry:

    ”Hi. Not sure the rest of the board is interested in non Ferrari info, but glad to share.

    1. BMW E39 M5. I always thought it was geared a little too stiff from the factory. While it helps 0-60 times slightly for marketing, it wasn't really necessary. The predecessor 540i with 282 hp had a 2.81 diff with the 6 speed manual tranny. The M5, same gearbox, with 394 hp had a deeper 3.15. Made no sense.

    So after much searching, I found the 850CSI 6 speed had a 2.65. Just about perfect. Put in a 2.65 diff, added headers (40 hp at the crank) and the car was quicker and more economical on the highway turning about 500 rpm less. Car was rated 19 mpg highway, I could get 27 mpg at 70 mph if I drove gently (no fun in that). Then I added a supercharger and gentle driving went out the window! :) But I can still pull low 20's on the highway, over 600 crank hp.

    2. Next was the Mercedes. 2002 ML500. Great car. Again, factory gearing was strange. Older, less powerful 430 came with 3.46. New 500 came with a 3.70. Again, after much research I picked up a pair of 3.09's from a diesel in Germany. Install was a breeze but because of the reduction, the car went into limp mode. Had Renntech (well known Mercedes tuner) reprogram the computer and all is good. Car rated about 16 mpg highway, I get around 19 on trips (running 75-80 mph). If you can keep it around 70, you can get close to 20.

    3. Mini Cooper (1st gen) was harder. It has the diff as part of the transmission and because it is twin layshaft, it effectively has 2 diffs!! Once again, lots of research. I picked up a used transmission from a diesel Mini in the U.K, reasoning a diesel has a lower redline and would have taller gears. This one was a little trickier, and we ended up using the diesel gearsets but put them back into the original tranny casing. Once again, I get about a 500 rpm reduction. Mileage hasn't changed as much because I added a cam, bigger injectors and headers with a low restriction cat.

    Benefits primarily a more relaxed cruise and some better mpg's translating into a longer fuel range on the highway. If you need more power, simply downshift a gear. Math shows about a 15% reduction, Mini a little trickier with the twin layshafts, but similar. The key is to gear it so old 6th is roughly new 5th. Then everything seems to work fine.

    There is a great online calculator which you can swap gears or rear ends and get speeds in gear to see the effect of various changes. It is smokemup. I think dot com. There is a small annual fee, well worth it as you can calculate a bunch of things besides gearing.

    Hope that helps. You can post any of this if you like, just didn't think the Ferrari crowd would care about this.”
     
  7. tazandjan

    tazandjan Three Time F1 World Champ
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    Erik- Remember, too that Ferrari speedometers read about 10% fast at top speed. An unmodified 550 is not going to go 340 km/hr on anything but the speedometer. That is 211 mph and Type F140 engines kind of top speed.

    The big problem with a higher speed rear end is not 1st gear, but reverse.
     
  8. F456M

    F456M F1 Rookie

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    Let’s see the positive side of it!! I will have the world’s fastest Maranello in reverse gear.
     
  9. tazandjan

    tazandjan Three Time F1 World Champ
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    Erik- Affirmative, and the most clutch wear in reverse, too.
     
  10. F456M

    F456M F1 Rookie

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    Yes, and wirh F1 gearshift it becmes even worse. I had to reverse up a steep hill at night with my 2003 Maserati 4200 Cambiocorsa. It was a nightmare. The 550 is garage parked 99% of the time in a flat garage, and it will not be much of an issue I think. But ideally, a very short reverse could be great to have. No real use for high speed reversing anyway...
     
  11. contadino

    contadino Karting

    Oct 18, 2016
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    F456M
    probably you need another car not a F550 ....
     
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  12. F456M

    F456M F1 Rookie

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    #37 F456M, Dec 20, 2018
    Last edited: Dec 20, 2018
    So if you know best, what is the proper way to use the 550? I have driven the car exactly 50.000 kms. and burned about 10.000 liters of gasoline and enjoyed it alot! Still a car that is on top of my wish list. What car have you got?
     
  13. contadino

    contadino Karting

    Oct 18, 2016
    82
    ITALY
    F456M sorry, mine was just a thought ....
    I read your posts and you're looking all the ways to change the 550 to get another car, it's not a bad thing, my it was just an observation.
    F 550 have the shorter final ration because it is a much sport and a fast car in respect at 456, with shorter ratio the acceleration is fast ....
    I agree with you that in the normal driving don't use all the acceleration but this is the car ...
    Of course you can make as you want in your car :)
    At the end if you will found a gearbox of 456, can remove your and install the other, in this way you will save your orginal gearbox in the garage and have new long ration for have more comfort and less consumption in the cruise driving ....
    I have not 550, times ago i was on a 575 of a friend ....

    By by :) :)
     
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  14. F456M

    F456M F1 Rookie

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    Ok Conradino. We all have different perspectives to look at the world. My observations of how the car is working is from real life experience. I do mean in my honest opinion that the car will not be any worse. Just better. I really dislike making changes to something as beautiful as a Ferrari. But times change and now suddenly all cars have these long ratios from the factory... Why? Because it makes the cars better. Like the first post from me described in detail, there is not much logic in having a car so low geared that in normal traffic you jump over one or two gears... I am not into hillclimbing either. I bought the car because I have always been addicted to drive fast with race boats and cars and I like to feel the effortless controlled high speed experience that these cars give. I just find it very irritating that I can’t cruise at high speed (like 200 kph.) without refueling all the time. And the noise is quite high too. When a modern Audi A3 TDi keep the same or higher average speed, it becomes a bit hillarious.

    I got a reply today from Mr. Colotti in Italy. The price for a new 6th gear is 2.500 euro and a new crown wheel and pinion gear is 4.500 euro. If more orders could be placed, the price would go down. What do you thing Maranello Skunk Works....? Would this be your new offering? The top speed would be exactly the same as 5th will be the same as 6th gear is originally. I am quite tempted!
     
  15. F456M

    F456M F1 Rookie

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    Just a comparison. A Huracan have no more than 1.500 rpm. at 100 kph. That will say it will cruise at 3.000 rpm. at 200 kph. While the 550 and 575M have 4.600! That is an increase of more than 50%!

    The Huracan have eight gears, but the ratio in «overdrive» is what determine the cruise comfort anyway. I think it pretty much proove that I am on the right track when changing the final ratio to reduce the rpms. while going fast. I am SURE it will make the car better and still be just as fast.
    Image Unavailable, Please Login
     
  16. JimEakin

    JimEakin Formula Junior

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    This is all true. But I'm wondering if it's worth the cost of changing the R&P in the 550 transaxle.
     
  17. tazandjan

    tazandjan Three Time F1 World Champ
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    Plus, will make it really hard to resell.
     
  18. Rifledriver

    Rifledriver Three Time F1 World Champ

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    No it just proves the benefit of an 8 speed over a 6 speed.
     
  19. Bas

    Bas Four Time F1 World Champ

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    Interesting thread. I'm on the other end of the scale...I'd like a slighter higher final drive ratio to make the car a little less ''lazy'' (take the term loosely) for the project I'm planning
     
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  20. tazandjan

    tazandjan Three Time F1 World Champ
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    Bas- You sound like a real hot rodder. We always went higher ratio (lower speed) on our Corvettes in the olden days.
     
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  21. someguy

    someguy Rookie

    Nov 3, 2012
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    That's a Urus. The Huracan has 7 gears. Ideally an extra gear would be your solution. however, from what is viable I'd recommend a longer 6th, as changing the final drive would really affect performance negatively in the lower gears.
     
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  22. Bas

    Bas Four Time F1 World Champ

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    Thanks...project will be very much inspired by 360 Trev's 6 speed ''challenge stradale'' and the 599 GTO...Building the car Ferrari forgot to build! A ''Challenge Stradale'' for the Maranello's...
     
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  23. F456M

    F456M F1 Rookie

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    So you want to make the 550 quicker with more rpm. along all gears? I have had several friends test driving my 550 and every one of them asked for a 7th. gear as they feel the 6th gives unneccesary high revs.

    I never really push this car like I did with cars when I was 20 years old. I enjoy it and I want to keep it. Can’t see any real reason to sell it now when many cars look more and more weird... It just feels like it could do just fine with more speed per 1000 revs. Have anyone here driven a Diablo with five speed which would equal the «new» transaxle with the new crown wheel ratio, through the first five gears? Weight, displacement, horsepower etc. is surprisingly similar on the two cars. If it works great in the Diablo, why should it not work in a 550? The first five gears would be quite like the Diablo. A friend of mine have one and I told him about this and he said there is plenty of torque so it was great to drive.
     
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  24. Bas

    Bas Four Time F1 World Champ

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    I may go with a ~6% final drive. 6-1 manifolds, individual throttle bodies, different cams etc. and loads lighter. Much like 360Trev's 360, a manual Challenge Stradale which became much more than that. But still as if the factory did it...so it won't look like some shoddy stripped out track rat.
     
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  25. F456M

    F456M F1 Rookie

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    Will be interesting to see it when you are finish. One thing that I loved with my Maserati was the intake sound. But the 550 has next to nothing of that wooop intake sound. With separate intake throttle butterflies inside a plastic or carbon box, it should get plenty of that!
     
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