engine/gearbox/diff - puzzled question
Discussion
Ok, here's my question I'm hoping you, the masses can help me with.
If I pair a 2ltr engine and a six speed box to a diff off a 5 speed 1.8ltr, what am I going to lose and gain.
My head says more ummph in the lower gears, but lose in the higher gears. Am I right ?
Help/guidance/advice greatly appreciated.
If I pair a 2ltr engine and a six speed box to a diff off a 5 speed 1.8ltr, what am I going to lose and gain.
My head says more ummph in the lower gears, but lose in the higher gears. Am I right ?
Help/guidance/advice greatly appreciated.
Details like what engine, gearboxes and diffs. And what you are meaning by diff, do you mean the crown wheel and pinion ratio (I'm guessing you do).
If you know the diff ratio's and gearbox ratios you can work out terminal speeds in gear (tyre size also needed). Which will probably tell you what you are wanting.
If you know the diff ratio's and gearbox ratios you can work out terminal speeds in gear (tyre size also needed). Which will probably tell you what you are wanting.
hmmm, ok I need to do some googling then, but....
It's a Mazda 2.0 ltr engine mounted to a Mazda 6 speed box (both from a 2007 MX5 Mk3). Then linked to a diff (I don't know what I mean here if that makes sense) from a 1.8ltr 5speed box, both from Mazda MX5 Mk3 (2006).
So I guess my question remains am I losing out all round or gaining somewhere ? If it;s a dead technical answer I apologise in advance for my ignorance and stupidity.
Cheers
It's a Mazda 2.0 ltr engine mounted to a Mazda 6 speed box (both from a 2007 MX5 Mk3). Then linked to a diff (I don't know what I mean here if that makes sense) from a 1.8ltr 5speed box, both from Mazda MX5 Mk3 (2006).
So I guess my question remains am I losing out all round or gaining somewhere ? If it;s a dead technical answer I apologise in advance for my ignorance and stupidity.
Cheers
This is one of those threads that could see people get banned again, and that some admin on here seem to love vs genuine technical threads...
LOL
But that side.
You do seem very confused, what exactly are you trying to do, change, fit, whatever ?
http://www.cargister.com/calculator-gear-ratio
http://calc.teammfactory.com/
LOL
But that side.
You do seem very confused, what exactly are you trying to do, change, fit, whatever ?
http://www.cargister.com/calculator-gear-ratio
http://calc.teammfactory.com/
Edited by stevieturbo on Thursday 19th May 12:02
There's a mobile game called Drag Racing Classic, in which the aim of the game is to race the computer/other players to a 1/4 or 1/2 mile finish. You use the "money" generated by winning to upgrade your engine, tyres and performance related parts, but one of the key parts of the game is the ability to adjust your gearbox and final drive ratios, so you can change the way the car accelerates.
To put it as simply as possible, gearing gives you a tradeoff between acceleration and terminal speed, the speed at which the car will not go any faster. This could be limited by max engine RPMs or it could be limited by aerodynamics. In the game, you want to make sure you do not reach maximum speed before the end of the track, but at the same time you need to maximise acceleration. To throw a spanner in the works, you also get to use Nitrous, which gives you a massive but short-lived hike in power, and then you need to pit all this against available grip.
If you have a compatible phone or tablet, download the game and it will highlight exactly how changing gear ratios affects performance. You can make a change and then race against yourself in pre-modification state to see instantly how your gearing changes affect overall performance. Sounds complicated but the game is gloriously simple.
To put it as simply as possible, gearing gives you a tradeoff between acceleration and terminal speed, the speed at which the car will not go any faster. This could be limited by max engine RPMs or it could be limited by aerodynamics. In the game, you want to make sure you do not reach maximum speed before the end of the track, but at the same time you need to maximise acceleration. To throw a spanner in the works, you also get to use Nitrous, which gives you a massive but short-lived hike in power, and then you need to pit all this against available grip.
If you have a compatible phone or tablet, download the game and it will highlight exactly how changing gear ratios affects performance. You can make a change and then race against yourself in pre-modification state to see instantly how your gearing changes affect overall performance. Sounds complicated but the game is gloriously simple.
I'll see if I can dig out a shareable link for my gearbox calculator for you to play with as well.
Download this and have a play.
https://drive.google.com/open?id=0B3MNxd-B85sjVXpP...
Download this and have a play.
https://drive.google.com/open?id=0B3MNxd-B85sjVXpP...
Edited by weeboot on Wednesday 18th May 10:41
This is something us kitcar boys play with a lot
From your little bit of info front engine rear wheel drive using MX5 components that only differ from standard configuration with the diff ratio and possibly the wheel/tyre size.
At this point we would have all the numbers and use a gear speed calculator which is easily found on the web. The only other parameter I would use is maximum revs, from all this you get max speed in each gear.
Bowling & Grippo have a number of open source calculators that can give estimated acceleration figures if you know bhp and weight.
A very simple and crude estimation is that if the Diff ratio on the standard car is higher ratio (i.e. 3.6 - 1) than the one you are fitting (say 3.9 - 1) your car will accelerate more quickly but will hit the rev limiter in each gear more quickly and have a lower top speed.
PLEASE NOTE, LOWER BIG NUMBER = HIGHER RATIO, HIGHER BIG NUMBER = LOWER RATIO.
The same applies for bigger or smaller tyres, bigger being higher ratio smaller being lower
BUT BEWARE OF THE ASPECT RATIO
A 205-40-17 will have the same rolling radius as a 205-60-15 CAVEAT this was a pure guess you should use a readily available tyre size calculator
From your little bit of info front engine rear wheel drive using MX5 components that only differ from standard configuration with the diff ratio and possibly the wheel/tyre size.
At this point we would have all the numbers and use a gear speed calculator which is easily found on the web. The only other parameter I would use is maximum revs, from all this you get max speed in each gear.
Bowling & Grippo have a number of open source calculators that can give estimated acceleration figures if you know bhp and weight.
A very simple and crude estimation is that if the Diff ratio on the standard car is higher ratio (i.e. 3.6 - 1) than the one you are fitting (say 3.9 - 1) your car will accelerate more quickly but will hit the rev limiter in each gear more quickly and have a lower top speed.
PLEASE NOTE, LOWER BIG NUMBER = HIGHER RATIO, HIGHER BIG NUMBER = LOWER RATIO.
The same applies for bigger or smaller tyres, bigger being higher ratio smaller being lower
BUT BEWARE OF THE ASPECT RATIO
A 205-40-17 will have the same rolling radius as a 205-60-15 CAVEAT this was a pure guess you should use a readily available tyre size calculator
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