GM Posted April 13, 2004 Share Posted April 13, 2004 Good evening Gentlemen. I am new to all this so apologise for any lack of knowledge into established protocols. I have aquired an R400 and I must say it's rather quick.Above 4000rpm it makes the most delightful earth shattering scream as it accelerates through the gears. However below 4000rpm it sounds and indeed behaves in a most hostile and aggresive manner, which is very unhelpful on a spin to the shops!The bangs and crashes are quite alarming although paradoxically it ticks over perfectly. What needs to be done to make more it more user friendly at low speeds? Your replies will be gratefully recieved. Link to comment Share on other sites More sharing options...
R400C Posted April 13, 2004 Share Posted April 13, 2004 Alot of the low speed misbehaviour of an R400 can be driver induced .... it can actually be your foot 'bouncing' on the throttle as the car goes over imperfections in the road. Try to put the side of your right foot against the inside of the footwell in the car and the effects may be reduced quite dramatically!!! If you end up with major league 'kangarooing' (very uncool), simply slip the clutch and re-release gently as you take up the drive again. R400C Link to comment Share on other sites More sharing options...
Fred Posted April 13, 2004 Share Posted April 13, 2004 As R4HUN has purchased my R400 from me, what he is looking for is how did other members found there R400 to drive before they got used to it, R400C has given one good example I have explained it takes time to get used to the R400 at low rpm but once you get used to the car it is a dream What did you find 🤔 Link to comment Share on other sites More sharing options...
Fred Posted April 13, 2004 Share Posted April 13, 2004 ops 🙆🏻sorry Edited by - Fred on 13 Apr 2004 23:50:14 Link to comment Share on other sites More sharing options...
Jason Plato Posted April 14, 2004 Share Posted April 14, 2004 The engine mapping will have a large bearing on the cars low speed / low rev behaviour . If the engine is stuttering , stamering and generally "lumpy" at low revs / part throttle , then I would suggest you need to get your current set up calibrated . This on other R400/500's has included ballancing the throttle boddies and calibrating the throttle potentiometer . You can do the ballancing yourself with a carb ballancer , but I dont think you have access to the ECU to calibrate the throttle pot' , so you will have to contact Caterham . Lastly , people often tense up when driving and this can result in their right foot bouncing on the throttle ...... relax and go with the car You got yourself a nice car there R4HUN 😬 Link to comment Share on other sites More sharing options...
Slipper man Posted April 14, 2004 Share Posted April 14, 2004 The throttle potentiometer is checked by testing the voltage across the pins - no special tools/maps/passwords are needed. Caterham can supply the instruction sheet showing what to do. Bangs and farts at low speed are a 'characteristic' generally of the car (one that I quite like!) If it is ticking over OK, are you sure the car isn't doing what it should be doing? Link to comment Share on other sites More sharing options...
Fred Posted April 14, 2004 Share Posted April 14, 2004 R4 HUN has only driven the car a few times and it's set up 100% The throttle potentiometer is spot on ecu is also ok all done by me and minister he is use to driving a standard caterham and i feel he only needs to get used to the car, he needs reassuring this is normal till he gets used to the car 🤔 Edited by - Fred on 14 Apr 2004 09:30:16 Link to comment Share on other sites More sharing options...
GM Posted April 14, 2004 Author Share Posted April 14, 2004 With profuse apologies to Fred. Thank you all for your several helpful replys. My car is absolutely superb. I most certainly did not wish nor intend to imply that Fred had sold me anything other than a supurbly built example of an R400. I am sure you are all correct that driver inadaquacy is the most likely cause of my initial experience. Albeit that my mechanical ability/knowledge is limited to say the least my thoughts were more around the ECU and I was wondering if it was remotely appropriate to have two - one for general road use and the other set up (mapped?) for track days. Again apologies to Fred - I hope he will still speak to me - and indeed to you all, I understand I should have asked my bloody stupid question on Chit Chat and not Tech Talk. Link to comment Share on other sites More sharing options...
Fred Posted April 14, 2004 Share Posted April 14, 2004 Garry, absolutely no need to apologise, I only put my post up to let other R400 members know that the car is 100% set up correctly, allowing them to answer purely on the driving characteristics of the car which I think you will find they will agree is totally different than a standard basic Caterham and does take a few hundred miles to get used to. After a few more drives you will be wondering what all the fuss was about and looking for more power. Remember to keep in touch with your progress. Link to comment Share on other sites More sharing options...
Slipper man Posted April 14, 2004 Share Posted April 14, 2004 That is what was behind my comment. These cars are VERY direct and I always find it takes me a little while to 'tune it' to the car after I have not driven it for a while. Put some miles on it, and you will find yourself driving it much more smoothly. Link to comment Share on other sites More sharing options...
Jason Plato Posted April 14, 2004 Share Posted April 14, 2004 Footwear is critical when driving these cars .......... isnt it Keith 😬 Link to comment Share on other sites More sharing options...
R400C Posted April 14, 2004 Share Posted April 14, 2004 R4 HUN, hope that you're getting the hang of it .... mine is now unfortunately running like a complete dog!!! See http://blatchat.com/t.asp?Id=52100 R400C Link to comment Share on other sites More sharing options...
R400C Posted April 14, 2004 Share Posted April 14, 2004 Hmmmm, didn't do a very good job of inserting a 'link' to another thread.... anyone know how to? R400C Link to comment Share on other sites More sharing options...
jimmyslr Posted April 14, 2004 Share Posted April 14, 2004 I drive a Superlight R, the pre-cursor to the R400. It does take a bit of getting used to and one needs to get the hang of gentleness with throttle and clutch to make smooth progress. With the best set-up in the world the car is still optimised for "blasting", it's not a Honda auto designed to cope with your everyday driver on their way to the shops. Top tips are footwear and smoothness. You did pick a racy beast as your first Caterham, but you'll get the hang of it. Link to comment Share on other sites More sharing options...
Gridgway Posted April 14, 2004 Share Posted April 14, 2004 interestingly in my R500, I had a problem (well a few actually, but back to the point...) with low revs drivability that developed over the life of the car. I changed to Minister's spare MBE ECU with the same map and the problems went away. I never got to the bottom of the problem as monister let me keep their ecu! Might be worth a swap with a(nother) friendly R400 owner to see what happens. Graham Link to comment Share on other sites More sharing options...
Mark Piper Posted April 15, 2004 Share Posted April 15, 2004 ....or go the Emerald route - the part throttle/from cold running in my current car (SLR spec but with more power and same characteristics) was awful on its MBE - much worse than my old SLR. A trip to Emerald for an ECU and mapping on Dave's rolling road sorted it and still gives me big flames on overrun 😬, but a smooth torque curve and absolutely no hesitancy in running when cold or under part throttle. Incidentally, I found that running the SLR exclusively on Optimax inproved the cold running characteristics enormously - try this for a while and see how you get on. Link to comment Share on other sites More sharing options...
frankyknuckles Posted April 15, 2004 Share Posted April 15, 2004 I get similar things happening with my R300, lots of kangarooing at low revs. As has been stated above and confirmed to me by Simon Lambert (ECU fuel map is ON or OFF, not analogue so this will happen), it is your foot bouncing on the throttle. I have covered about 800 miles now (from new) and I am slowly learning not to leave my foot on the throttle when going slowly over bumps, if you lift off completely, the car will behave as normal. It's probably the only gripe I have about the car. (but the price you pay for razor sharp throttle response) Link to comment Share on other sites More sharing options...
Gridgway Posted April 15, 2004 Share Posted April 15, 2004 well I think this is complete bo**ocks from my good mate Simon. I would tell him so and send it back. The (my) R500 which must be harder to map than an R300 was horrible when there was something wrong and superb when all was working well. It had several cycles of working well/broken so it was no coincidence. And yes when it was working badly, foot-bounce made it worse, but it is a symptom not a cause. I don't think it's the price of razor sharp response and I have no idea why Caterham can't be bothered to get it sorted, but I think it's very, very poor. Ahh, I feel better now and I don't even have an Rxxx to get up tight about! Graham Link to comment Share on other sites More sharing options...
Peter Carmichael Posted April 15, 2004 Share Posted April 15, 2004 It is because of lean mapping in the on/off throttle area. I managed to introduce this effect on my Emerald equipped car from a single change to the acceleration fuelling parameters - I keep all the maps under version control so I can look up and find out what the change was exactly... Just checked it out. My accel fuelling went from: 16% enrich, clamped for 30 injector events, decaying over 19 injector events to 20% enrich, clamped for 30 injector events, decaying over 19 injector events That sorted the hesitancy. Link to comment Share on other sites More sharing options...
mav Posted April 16, 2004 Share Posted April 16, 2004 R500 which must be harder to map than an R300 Why Link to comment Share on other sites More sharing options...
Gridgway Posted April 16, 2004 Share Posted April 16, 2004 less bhp/tonne less wild cams And I can't think of a reason that an R500 would work well where an R300 wouldn't. But it could be that the R500 was a long time in development compared with the R300. And another thing, if a rather sad amateur (PC) can map a 150-160ish bhp engine on an emerald and Jenvey's with nothing but sealing wax, string and interpolation, surely Caterham can get it right. Graham Link to comment Share on other sites More sharing options...
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