A year ago I started racing my Ralliart Colt at a local hillclimb in the Barossa valley (www.collingrovehillclimb.com.au).  At the time my car was still running the stock exhaust and as a result delivered its power in a rather torquey, all or nothing kind of powerband low in the rev range.  It was very hard to control wheelspin on this narrow winding tarmac and it was very frustrating seeing my car perform well in the first two sections of the hillclimb, only to be a second slower in the last third of the course relative to other competitors.  It felt like the car had the heaviest flywheel ever, so heavy, that it was impossible to control wheelspin once boost set in.  No amount of throttle control seemed to help – it was either on and spinning wheels, or off and bogging down.

Rewind a little, to when I first started tuning and adjusting my Ralliart Colt.  One thing I quickly learnt was that if you floored it in 1st, and did a fast high revving change into 2nd, there was a very real risk of over-rev, that then often resulted in a missed shift – grinding synchros etc.  After a while you get used to it and drive to get around it, but it never stopped being annoying and the risk never truly went away. Those that have blown a synchro know exactly what I mean.

How to make this throttle move faster? The traditional approach to a faster throttle with the Ralliart Colts or Colt Version R’s is to modify the throttle map.  However, I never found this made any significant difference to the speed the electronic throttle was being opened or closed.  Different but still not fast enough- if only we had a cable throttle!

Fast forward to the next Collingrove Hillclimb event. I was determined to have better control of boost and throttle.  I changed the throttle map, and also modified the Wastegate Duty Cycle (WGDC) maps to try and get more linear, controllable boost.  I was faster, but frustratingly, the car still really struggled in the tight twisty corners of the hillclimb.

Around this time, another rcolt.com forum member, AST, was experiencing a similar problem with his JDM import Colt Version R on E85 at the race track.

The following radical suggestion was made by member Rcus – try disconnecting the top clutch sensor and see if the problem persists.  So we both did..

It made an amazing difference to the speed of the throttle response.  At first, it felt too fast, if such a thing is possible. The over-rev on 1st to 2nd gear changes was completely gone.  Wheelspin was now easier to control with the right foot.  Amazing! It was like one of the biggest negatives of the rcolt was removed, and so easily.

So why’s it work? Imagine doing a hill start. You need the revs to rise as quickly as possible whilst you let go of the hand brake and slip the clutch.  The fastest throttle possible is needed in this situation.  OK – what about when driving in motion? Imagine driving in 1st or 2nd and hitting a bump. Your foot lurches forward and if it wasn’t for a slower throttle, your driving experience would be rather jerky and uncontrolled.  It’s this effect that I suspect had Mitsubishi apply a smoothing effect on any throttle movements.  Lets face it the average driver doesn’t need or want lightning throttle.  But for that hill start, all drivers need fast throttle!

So try it – disconnect the top clutch sensor and see what you think.  I’d advise logging the car after doing this though – as your car is more likely to find itself into throttle/load situations it didn’t find itself before. Also if you have a throttle controller already – don’t do this without removing the throttle controller first.

Note there are two sensors connected to the clutch pedal.  The side one detects whether the clutch is completely pressed in, and is used for the clutch in to start requirement (also frustrating).  The other sensor is at the top, and is easily disconnected.

Thanks to Rcus for suggesting this mod on rcolt.com, and if you try the Ralliart Colt Fast Throttle Mod, let me know how it goes!  If you’d like to see footage of my Collingrove Hillclimb runs, my fastest (to date) footage is here Youtube – Collingrove Hillclimb Ralliart Colt

The original thread on rcolt.com is located here