problems with caterham CSR not running right

[Guest]

I have recently purchased a CSR. I have had some problems with it. Any help suggestions welcome. When in traffic at low speed when touching the accelerator lightly the car jig/jogs judders backwards and forwards, sometimes really badly. I then have to jump back on the clutch or accelerate hard to stop the judder. I have road humps and this is a real problem. The car has been twice on the rolling road to be mapped and it is still not right. The car has been tuned by Cosworth to 280. The guys that mapped it have suggested the exhaust may not be right (previous owner put £2500 worth of BTB exhaust on it, non cat)?? The guys at mapping have suggested that the caterham roller bodies for race may not be right and is it worth changing to Jenvey throttle bodies! Any help grateful before I start spending £1000's more to get it right.

[tbird]

when you say judders backwards and forwards, do you mean what is often refered to as Kangaroo hopping , that is a known problem with CSRs, not sure if the problem still applies at your level of modification, there was a Caterham recall/fix, which I will look up for you

 

OK pdf is http://uk.caterhamcars.com/sites/default/files/content/uk/documents/csr260_tech_update1.pdf, you may need to create an account with Caterham to download and it does specify CSRs with original equipment, so not yours but may give you a starting point

 

Tim

 

Edited by - tbird on 4 Oct 2013 22:16:40

[Martin J]

Didn't they fit a stronger throttle return spring(s) to stop your right foot bouncing on the loud pedal?

[tbird]

yep new throttle spring, but I think as important was a new map.

 

some more reading here

here

and here

 

haven't read all the ay though all of them but lots of ideas to get you thinking, they are fantastic when running nicely so keep going 😬

 

Tim

 

Edited by - tbird on 4 Oct 2013 22:56:30

[jimh]

Mine suffers a bit with this.

I checked that mine had the recall stronger throttle springs fitted and it had. I then tried all three CC maps on it but none of them really cured the problem. I also fitted an extra spring in the pedal box but this really didn't help either so I have now removed it. I finally got mine remapped by the Two Steves and this has made things a lot better. It still does it occasionally but I have learned to drive round the problem mostly. I tend to press the side of my right foot against the footwell.

Lots of information from the Two Steves (the one that talks) about this problem when I was having the mapping done.

[Alan Reeves]

I cant quite understand the backwards ( as well as forwards) bit of this post but if the mapping is not up to spec then they are a Class Kangaroo...The two steves fixed mine and I can pull away on tick over, where did you get yours done?

 

I also did not bother with the spring mod as it works so well .

 

alan

 

[David aka Blue7]

It is the nature of "the beast" It doesn't like town driving, doesn't like slow and in particular it doesn't like bumpy roads at slow speeds, which can cause exponential kangarooing Tuning to 280 bhp has probably exacerbated the problem but you soon learn how to cope with it. Great fun though 😬

 

Edited by - Blue7 on 7 Oct 2013 19:07:37

[Mick Day]

Quoting Blue7: 

It is the nature of "the beast" It doesn't like town driving, doesn't like slow and in particular it doesn't like bumpy roads at slow speeds, which can cause exponential kangarooing Tuning to 280 bhp has probably exacerbated the problem but you soon learn how to cope with it. Great fun though 😬

Er........... NO! Just because the max BHP is 280 doesn't mean it should kangaroo & be undriveable at low speed. Ever seen a 911 doing this?

 

Have a chat with the 2 Steve's & get it mapped properly.

[Guest]

Thanks for your replies everyone. The car has actually been mapped twice by the 2 steve's! The car is better but it is still far from right as still kangoroo'ing badly at low speeds. Hence my post for suggestions. Didn't want to say it's the 2 steve's as I know they are fantastic and they did a super job on my last caterham, but this one is just not right. Going to go down the Jenvey route after speaking to Caterham and Steve and Steve and a few others.

[Guest]

This has got nothing to do with the 2 steve's not being able to do their job, they have been great and have spent hours and hours on this car. Steve has driven the car himself and said there is a hesitation problem. But both have been extremely helpful with other suggestions.

[Harry No Sheds Flatters]

I am not sure I would go to the expense of fitting Jenveys before I was satisfied that evrything else had been checked. For example do you have the additional throttle spring fitted, has the cam timing been checked, have you checked for air leaks? I had a highly tuned K on roller barrels and the two Steve's mapped it and it would pull in 6th from 30 mph without hesitation.

[MartinH]

I have recently fitted the same Cosworth roller barrels to my R300 as are fitted to the CSR and the kangarooing is getting on my nerves now. When blatting hard or on track its fine but 'normal' driving through town it kangaroos all over the place at low revs. You learn to be very careful on the throttle and anticipate the jumping by slipping the clutch or changing down a gear but I would really like it solved. Guess a rolling road session is needed but interested in the factory fix for the CSR, it says the solution is not suitable for DIY installation but I don't buy that. Has anyone else made mods to their roller barrels or throttle that have helped with this?

Cheers,

Martin

[David aka Blue7]

Er........... NO! Just because the max BHP is 280 doesn't mean it should kangaroo & be undriveable at low speed. Ever seen a 911 doing this?

 

I didn't say it was undriveable 🤔 There are some big differences between German engineered Porka 911's and Caterham to mention a few wings don't fly off, they have decent lights that you don't have to upgrade, the dials all work and don't steam up, no leaks in the footwell, new diffs not reconditioned, windscreen washer bottles don't fall off, engine mountings that don't crack ... etc etc. 😬 😬

 

This is my second CSR both bought new and it is no different to the first one and to quote CC "it is the nature of the animal". If you have owned and driven them for a long time you don't notice it but it is the new owners who get a bit of a surprise (maybe Porka 911 owners ), and think there is a problem.

 

Back in the 70's you could achieve a similar "sensitivity" in SU carbs by fitting different needles and springs.

 

Have a chat with the 2 Steve's & get it mapped properly

 

I ain't in Deepest Darkest West Sussex Mick, I am a wee bit further north in North East Scotland so a bit of a long journey to consult the two Steves and in any case I quite like my CSR as it is including it's Ozzy roodementary tenancies 😶‍🌫️

 

I don't wish to get into a tedious argument about it so this is my final contribution to the topic. Good luck and enjoy p1collectables

[Paul Deslandes]

I would first look at the throttle linkage and check that there's no 'stiction' i.e. stickiness in the linkage. Then consider changing the linkage mechanical advantage to reduce the amount of throttle opening, just off idle, per pedal movement. Basically you have a mechanism with too much gain making it oscillatory. With the mass of your foot, when you touch the throttle at very light openings, the car jerks forward, your foot comes off the throttle, car slows down suddenly, foot goes down etc. Heavier spring will help but reducing the initial throttle opening by increasing the throttle lever arm length should cure it. For more detail of what I'm talking about, see here.