[Rubix]

I want to extend the ratio on 2nd gear to get more use out of my revs when accelerating 0-60/100 - is this an easy process or is a mechanic going to take my arm and my leg?

[teamgeorge]

i had an auto once... i found if you lead footed a gear it'd rev out more (or drop back - shouldn't in 2nd though)... other then that I cant help.

I look forward to the responses.

[Rubix]

I tried to lead-foot the test-drive car (the little salesman was holding onto his seat, hilarious) but I think it only punched to about 35km/hr and then dropped into 2nd. My Charade accelerates better, so I was wondering if I could get the i30 tinkered ...

I look forward to the responses.

I also looked forward to the responses... none came.

At first I thought you meant literally changing the gear ratios and this of course is not trivial.  I think now you meant altering the gear change points.  yes?

This is more do-able but I can't help either.  Just wanted to clarify the question so that others might understand your want.

[Rubix]

Yeah, I thought that was Gear Ratios - at least, that's how it's described & responds on the computer games I've played ... maybe I'll ask my mechanic and get an answer for all of us.

Well if you meant gear ratios, forget it.

[Lakes]

Only way you can change gear ratio's is to change the Diff ratio, but this will change the ratio of every gear, auto's in cars like a petrol i30 are not realy for drivers like you. you need a manuel, but i'm not against auto's i drive both. i drove my V8 auto ute to work yesturday. was fun. only other think they do to auto's is change the torque converter stall speed but you don't want that.

[Rubix]

Some Auto's are made with good ratios, like my little Diahatsu, the gears change at the right time (speed & revs), make the most of accelleration. Some, however, like this Nissan Tiida, change way too early, and then spin for a bit before they properly kick in on accelleration because the speed is so slow. I'll see how my i30 fairs when I get it.

[Lakes]

I want to extend the ratio on 2nd gear to get more use out of my revs when accelerating 0-60/100 - is this an easy process or is a mechanic going to take my arm and my leg?

Hi Rubix, seems the i30 has fou different diff ratio's, so it is possible to get a diff ratio from a different model and put your ratio of choice into your own car. but this will not only change your second gear ratio, it will change the compleat set of gears ratio's, you could also plpay with different diamiter tyres. would be all trial and error.
here are the diff ratio's they come with.
Petrol man= 4.888 petrol auto =4.121   Diesel man=3.941 diesel auto=3.532
this means in 3rd gear with an auto being 1.00 direct to diff a petrol auto will have the motor doing 4.121 turns to 1 turn or the drive wheels, if you pt a diesel auto diff in would be 3.532 turns of motor to 1 turn of drive wheel.
one problem have to find out what they use to control speedo like this could effect how speedo works too. after looking at this us diesel boys that have tuning box's could put in the auto diff ratio and have like a 6 speed just would go a lot further in 1st gear more strain on clutch if you do lots of hill starts but i'd say better economy on long flat fast trips

If you are really keen, you can plug in the various diff and gear ratios into a program I wrote some years ago (Gearcalc) and work out your optimum gearing.

Lakes, I think you will find that the speedo will work off a pulse train that can be corrected using a unit similar to this: Speedo Corrector Mk II

[Rubix]

thanks for your help. I've found the gears on the i30 do alright, can't believe how bad that tiida was. This sort of change will have to go on the backburner a bit. I'm reading about how these gearbox-y things are built at the moment.

[LuciferDarklord]

2nd gear ratio is controlled by the planetary gear set in the tranny.  Its a huge ask to change it - not impossible but pretty impractical.  Generally the only autos that have different ratio planetary sets available are boxes used for drag racing, and they are not cheap - ie Ford C4, GM TH-400 - powerglide etc.  Some 'modular' boxes may have different planetaries - like for instance if the same box is used in another Hyundai - but the ECU would probably need to be reprogrammed so it doesnt throw error codes thinking the trans is slipping.  Sorry but unless you have thousands of dollars to throw at your car you are stuck with what you've got.

[Rubix]

they made it look so easy in Toca Touring... I forgot that about the ECU - as much as I could stuff around with the actual gears, if the ECU is trying to do something and expecting something, if it finds something ELSE, it'll crap itself.
But this is why I asked the question - I wasn't sure if it was possible. I'd prefer my first gear change a tad sooner for city driving, in Toca this was for the tracks with lots of turns and next to no straights...
If life were a computer game...   

[LuciferDarklord]

they made it look so easy in Toca Touring... I forgot that about the ECU - as much as I could stuff around with the actual gears, if the ECU is trying to do something and expecting something, if it finds something ELSE, it'll crap itself.
But this is why I asked the question - I wasn't sure if it was possible. I'd prefer my first gear change a tad sooner for city driving, in Toca this was for the tracks with lots of turns and next to no straights...
If life were a computer game...   

If its just the shift point (ie the load and RPM at which the ECU decides to change gear) is all you want to change - that is feasible.  If you could edit the ECU trans map you could probably achieve this.

[Rubix]

hmmm... but I think I want my first gear to hit 4,000rpm 10km/hr sooner, rather than having the gear change at 3,000rpm instead of 4,000rpm and changing 10km/hr sooner because of this.

[Dazzler]

hmmm... but I think I want my first gear to hit 4,000rpm 10km/hr sooner, rather than having the gear change at 3,000rpm instead of 4,000rpm and changing 10km/hr sooner because of this.

I haven't driven an Auto i30 but can you just change it manually to hold the gears a bit longer?