Unichip - does tire size matter?
Thinking of putting a unichip in my car... would it be a problem if I tune the unichip when I've got 195/45/15s but switch to 195/50/15s in the future? Will I need to retune the chip?
Could be that the car feels "slow" on the 195/50/R15's.
(My brother has a corsa with a cav 2000 16V engine and he says he can feel the difference between 195/50 and 195/55 on acceleration?)
Engine mods will matter, tyres and other mechanical mods wont.
Change in wheel / tyre size will affect the gearing but not that drastically.
Changes in wheel size will not affect the gearing. The gearing is fixed by the gearbox.
It will affect forward speed but the Unichip doesn't touch forward speed, it only manages the engine.
Changes in tyre size will affect the overall gearing, ie: the ratio between road speed and rpm in a particular gear.
Unless you change the wheel size and the tyre profile to keep the rolling radius constant.
The unichip will be unaffected though.
in supporting what I said
I remember Fast Ford (sorry I swore) doing an excellent article on changing wheel size.
Apparantly, a better more accurate measure is going my what is called "wheel turns per mile" rather than rolling radius.
ie. a 185/70 tyre on a 13" rim had 879 turns per mile comapred to a 185/60 on a 14" rim having 939 turns per mile.
Last edited by trebor; 22-02-2002 at 12:05.
I guess it depends on what way you interpret the post
Re: Thanks Tomstickland
Am I missing something here. Surely the larger wheel and tyre combination i.e. the 185/70 on A 14" rim would complete less revolutions over a mile distance rather than a smaller combination that would have to turn more times to complete the same distance.
Originally posted by trebor .... a 185/70 tyre on a 13" rim had 879 turns per mile comapred to a 185/70 on a 14" rim having 939 turns per mile.
Sorry, meant to say 185/60 on a 14"
Yes, typing these messages before I go to work or during lunchtime, perhaps I don't make myself clear or make mistakes
Though gearing does include engine rpm, gearbox, differential, wheels and tyres, thus changing any or all of the above effects the overall gearing.
It's cool, I picked it up wrongly
Anyway, none of the above is going to effect the Unichip. Only fitting a "Kenwood" or "Max Power" sticker would require a chip adjustment.
Would that be removing it from the ECU and placing it firmly on the shoulder? lmao lmao
Originally posted by tomstickland Anyway, none of the above is going to effect the Unichip. Only fitting a "Kenwood" or "Max Power" sticker would require a chip adjustment.
You set 'em up, I'll knock 'em down.