hey all

now, looking @ getting a tickford ECU... i have just been informed that i may have issues with the diff ratios being out - by car currently only has the stock 3.08, compared to the tickford 3.45's...

will this cause issues? i'd rather not waste my money if all i'm going to have is problems!

cheers

I'm pretty sure the diff wont make a difference because its based on a speedo cog thats matched to your diff. If you switch to a 3.45 diff you have to get the cog that matches it for the speedo sender unit.
I'm pretty sure I'm right Fraser.

hmmm that was my thinking too pete - but just wanted to make sure...

lol good to see you're so confident!

yeah, thats rite

it mite be an issue with speed limit but meh, who cares

well knowing me johno, that'll really be an issue!

If your car is Auto then the shift pattern won't be quite right - but I knew a guy who put an EDXR6 ECU into a Futura with 3.08 diff and he reckoned that the change in shifting was noticeable but not a hassle.

In short the auto control part of the ECU works to a table of rpm / tps / vss values to determine shift points - if you use an ECU programmed for 3.45 diff in a car with 3.08 then it'll see a higher roadspeed for any given rpm and tps to what it's expecting - to the ECU the car will seem to be going downhill slightly - the real world consequence should be that downshifting might be somewhat more reluctant and upshifts will happen very soon (you may find yourself using Power mode more than you do now to offset the situation).

As I said tho - that fellow with the EDXR6 ECU and 3.08 diff reckoned it was actually barely noticeable and not a problem.

When you go the other way I know from experience that the driveability is IMO too much adversely affected - ie. std ECU programmed for 3.08 diff with 3.45 actual diff ratio makes Economy mode act almost like Power mode, and Power mode becomes pretty much unuseable ( the ECU thinks the car is going slightly uphill so downshifts are easy to provoke and upshifting becomes quite reluctant).