Pedal weight on throttle bodies?

[SLR No.77]

Just fitted SLR throttle bodies (KV6 type) and I've found the accelerator pedal weight to be uncomfortably heavy - such that it's unpleasant trying to drive smoothly - when compared to my old plenum setup. I feel that the throttle return springs should be a tad lighter. Has anybody any experience of this?

 

I can have lighter springs made up, but would be better to do a few if other people have the same problem?

 

Stu.

[F355GTS]

Stu

 

Mine seem fine and from memory of my Supersport was very similar

 

Mark

[c21vhpd]

does that mean you're on the road now? What did you have to do to the head?

 

I didn't find any noticable change between the KV6s and the Jenveys, but I drive in normal shoes, not Pixie boots. The throttle sometimes was a bit sticky, but it was intermittent, and not at the expensive end. I put it down to the dodgy angle that the cable leaves the 21's pedal box.

 

I assume your cable routing is OK - have you tried using a new one?

 

Honda Passion Orange, 640kg , and proud of it

[SLR No.77]

Hi Craig,

 

TBs cleaned up beautifully, replaced a few of the bolts with stainless items, but other than that they're as they were. They're fitted combined with an Emerald which so far is working superbly. Cold starting doesn't yet appear to have been a problem, the idle air control valve is still fitted, but locked in the closed position - my Emerald map is not using it.

 

Only critiscism of the setup has been the pedal weight - I'm considering removing one of the 4 throttle return springs to reduce it slightly - don't now how this measures with the MSA blue book re track days etc? Using my original throttle cable at the present, but I may change to yours - a lot longer!

 

Head's cleaned and stripped - no obvious problems visible so far - could be either a good sign, or a bad one!!!! I'm taking it down to Dave Andrews - he's going to look it over. and if reasonably happy we'll do some work on it - reducing valve pockets etc.

 

I'll let you know how I get on.

 

Stu.

 

[Chelspeed]

No rules for track days. For sprinting you need a throttle return spring for each throttle spindle, so for KV6 bodies that's 2 isn't it?

 

Disconnect all throttle springs and move the throttle over the full range and check there's no resistance caused by a bent spindle, sticky bearing etc. Provided that's OK then as you suspect it must be that the springs are too heavy.

 

My Vx has 4 separate Jenvey throttle bodies, each with a return spring, plus another spring on the throttle cable quadrant mechanism. I too thought the throttle pedal was too heavy. I ended up taking the spring off the cable bit plus removed the two springs off no 2 and no 3 throttle bodies, just leaving a spring at each end of the assembly, one on body no 1 and the other on body no 4.

 

As the throttle cable attaches to between body no 2 and no 3 that means a single failure anywhere in the pedal - cable - throttle spindles assembly cannot cause any throttle to stay open. On a theoretical basis of course this doesn't comply with the words of the blue book as I have four throttle spindles and two springs but I think in view of the above it satisfies the spirit of what they were trying to achieve. Never had scrutineering problems either.

 

So long as you satisfy this type of check then I would say you'd be fine.

[SLR No.77]

Now removed one of the springs. Each pair is made up of an internal and external coil - I took one internal out. It's made a vast improvement, and I'm going to live with it for a while before deciding whether to take out the other internal one. The other pair of springs will require removal of one of the TBs to do any mods, so definately leaving alone for now.

 

Stu.