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Throttle

R

ras62

Member
I have removed the throttle return spring and bracket from my C2, I think it is only needed if the car has cruise control, the difference in accelerator feel is very marked. I noticed this when comparing the C2 to an RS last week and was surprised how much lighter the accelerator was to press. Items 11 & 36 on this diag.

http://dcauto.gotdns.com/images/full/964_USA_89_94_KATALOG/pg_0058.jpg
 
Its only a spring but it makes a big difference to how the car drives daft as that may sound, the cars feels more urgent and heel & toe changes are easier. With a lightweight flywheel even better of course but that is a mod for another day. I recommend trying it, if you don't like the feel / response then its a 2 second job to revert back.
 
I'll try it out this weekend Rob. However, I would be interested to hear if other RS owners have it present i.e. is not there on all RSs or was the one you saw a one off mod?
 
The RS does not use this spring / bracket, I have checked numerous pictures of the RS engine bay. The spring is only used on the C2/C4 as it is there for cruise control throttle return, a safety feature I think. T'was Dan explaining this to me when I asked why the throttle on the two cars felt so different.
 
I did a bit of searching on Rennlist and found that some 964s have the helper spring and some don't. If I'm right, it's not on the later cars unless cruise is fitted.

So, I gave it a go this morning and removed the bracket and spring. As you say Rob the the pedal feels extremely light as a result. Very weird in fact. However, everything works properly without the helper spring.

In comparison to before, throttle response is immediate. It's so quick that I got wheel spin when I pulled out of junctions the first few times. Red line comes up very quickly in first and second gears so had to keep an eye on that. Heel and toe changes are much easier and much more immediate. When I drove Oldtimer's new orange C2 I was amazed at how much quicker his throttle responded than mine. I'd put that down to it having more power and being mapped by Wayne. Mine now feels similar to that so you might have just saved me about 500 quid to have it mapped! [:D]

The other side effect is that today was the first time that the car didn't stall when cold (it's always done this since having the LWF fitted). Whether that's because the revs don't drop as quick as I come off the throttle I'm not sure. It'll be interesting to see what happens after a few more goes.

Here's a few pics for those wondering what the mod is.

Original set up with bracket and helper spring (mine has always had a kink in the spring):

IMG_00602.jpg


The removed bracket and spring:

IMG_0065.jpg


Assembly now without the bracket and spring:

IMG_0064.jpg
 
Hi Steve, your comments sum up the feel quite nicely. It does take a few miles to get used to the new setup but it makes modulation of the throttle much easier. I have run with it for a week or so now and prefer it.
I had a look at John's car last week but his still has the helper spring attached, maybe the response was due in part to the m/sport clutch?
 
That bit was a little tongue in cheek Rob [:D] The greater response of John's engine is down to a few tastey bits like different cams and Wayne's magic mapping. But I'm very happy with the free upgrade ta! [:)]
 
mines a 91 with plasic inlets and does not have the spring or bracket bugger was looking forword to a softer pedel
 
The plot thickens Ray, I wonder why they are different. Nice drive back on Sunday, even the traffic was kind.
 

ORIGINAL: ras62

The plot thickens Ray, I wonder why they are different. Nice drive back on Sunday, even the traffic was kind.
Click to expand...

Even bigger discussion now going on, on Rennlist. Seems like plastic manifolds don't have it. It would be interesting to test the lightness of Ray's pedal seeing as his car never had the spring set up in the first place.
 
I can only assume it feels like the RS I tried when I noticed / remarked on the difference. I am not sure if my car now feels the same or lighter tbh, but it is better to drive. Perhaps a very light helper spring would be even better, I will see what is available and report back. What have I started here lol..
 
The helper spring is there to help with getting through trackday noise testing , where an unintentional blip on the throttle caused by a nervous twitch can cause an extra db or two...which can be crucial for 964s with modified exhausts ...[;)] ...... of course this does not apply to 964RSs which is why they have no helper spring fitted...[:D]
 
Like all great ideas: brilliantly simple and effective. Thanks for this excellent tip. You are absolutely right about throttle response and heel-and-toeing- transformed! This goes some way to compensating the £200++ I'm about to spend on a new spoiler transmission...

James
 
I'm not sure how long I'm going to keep it this way because I find the very light feel of the throttle to be a bit weird! I'll keep it at least until the track day at Castle Combe on Friday to see what difference it makes on track. A big plus at the moment is that the car hasn't stalled (when cold) since doing the mod.
 
I removed the helper spring on my car at the weekend after reading this thread, I genuinely think it is one of the best modifications I have made since getting the car. I feel I can modulate the throttle much more accurately now without the extra resistance of the helper spring, although I am used to a light throttle pedal having had Elises and Caterhams previously. Thanks for the tip!
 

ORIGINAL: RLambert

I'd like to try this but have cruise, what does the spring do ?
Click to expand...
Good question, I think it is a belt & braces type approach to not having the throttle stick open. If the car is fitted with cruise then I think this spring is strong enough to overcome the cruise servo motor but feedback on exactly when it is fitted seems to confuse this view. If you have cruise I would not remove the spring tbh.
 
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