darren f Posted April 20, 2003 Share Posted April 20, 2003 I’ve done about 900 miles in my R300 and on the whole am delighted with it. But………….. It doesn’t seem particularly happy below 3000rpm, nor does it like ‘snap’ opening of the throttle . Planting the loud pedal below 3k normally results in a worrying hesitance / misfire. Going down a gear (or two) and getting the revs up results in it pulling like a train. Obviously, I’ve found myself driving round the problem- driving through 30 zones in anything other than 2nd is not fun and ‘booting it’ from low revs has to be carefully planned to avoid any embarrassing ‘cough / splutter / cough’ scenarios. Also, there are only 2 standing start options- either the ‘granny on a Sunday drive’ method or the less-than-discrete ‘lots or revs / extremely rapid progress’ method *biggrin* . So for fear of embarrassing myself further, I’m throwing myself at the mercy of the Blatchat experts. Opinions please on what we are talking about here. Is it an inherent characteristic of running roller-barrel throttle bodies (or even of the R300 model….. ‘they all do that sir')? Or is more related to a less than ideal engine map? Other Blatchatters run Emerald engine management systems- is that the ultimate answer? I know the obvious replies will be ‘it’s a performance engine set-up- rev the nuts off the thing and don’t worry’ and I'm sure that given track conditions it would be absolutely awesome. However I can't help wondering if I shouldn’t be expecting slightly better road-manners than I’m currently getting. darren f The Building of R300SEV is Here Edited by - darren f on 20 Apr 2003 23:53:59 Link to comment Share on other sites More sharing options...
Peter Carmichael Posted April 20, 2003 Share Posted April 20, 2003 This isn't right. caterham haven't had convincing track reconrd on getting their maps right for the ecus, but this is the first I've heard about the R300. Is it as god intended or do you have the airbox or a rear exhaust. either of these could throw out the mapping. if not then something else could be causing problems - either the map or abnormally low fuel pressure. Sounds like a lean misfire. Uncorrected this could result in holes burned through the pistons, so make sure caterham fix it to your satisfaction. Link to comment Share on other sites More sharing options...
Jan T Posted April 20, 2003 Share Posted April 20, 2003 Having just ordered an R300 and living in London (where despite Ken Livingstone's 'best' efforts we still have traffic) I am a little disturbed by this posting so let's hope someone out there can post some positive news/update on this issue. Jan And along came Peter right on cue! Edited by - Jan T on 20 Apr 2003 21:53:11 Link to comment Share on other sites More sharing options...
darren f Posted April 20, 2003 Author Share Posted April 20, 2003 Peter- no airbox or rear exhaust. Exactly as came out of the factory (albeit self-built). Even still has the cat in place (but hopefully not for long for track use ). Any other R300 owners had any similar experiences? I did speak to one owner at the March Snetterton track day who also said that his 300 wasn''t happy below 4k revs and had to resort to 1st and 2nd gear in town (Orange, factory built- sorry can't remember the chap's name). This was whilst I was still running mine in, so I hadn't had the same experience. Jan T- don't let me put you off- the R300 is an awesome car- but mine definitely prefers 3k+ rpm and the open road. darren f The Building of R300SEV is Here Link to comment Share on other sites More sharing options...
tezza Posted April 20, 2003 Share Posted April 20, 2003 Well I do remember seeing this crop up in earlier post about R300 and the R400 (had heard that R400 ecu's were looked at by Caterham). I have a R300 plus a friend of mine does and they both do it, did ring Caterham but was told of no know issue with the map, GREAT!. As you can guess not too happy with Caterham's view, I wish they would just say we will look at the map to check it out. Would be nice to know just how many are getting this problem (if it is one). Perhaps everyone with R300 would like to tell us how they are getting on. PS both cars have decat as recommended by Caterham so I would hope that they test the affect on the map with this in place. May put cat back to run a test. terry Link to comment Share on other sites More sharing options...
darren f Posted April 20, 2003 Author Share Posted April 20, 2003 Terry, Thanks for that, I'm a bit more reassured now. So that's four 300s with low revs running problems. If we can get some evidence together perhaps CC will take some interest. I also recall the postings on the problems with the R400. Can't recall if it was a similar problem though 🤔. Did the 'fix' solve the problem? (I was hoping getting rid of the cat might help the problem, from you experience obviously not. Oh well, c'est la vie ☹️) darren f The Building of R300SEV is Here Link to comment Share on other sites More sharing options...
Mike Biddle Posted April 21, 2003 Share Posted April 21, 2003 Darren, I had the same problem with my VX a few weeks ago after fitting a new throttle pot sensor, and resetting the butterlies on the Jenvey throttle bodies. I know you have roller barrels, but the principal is the same. I had set the airflow through the throttle bodies from memory at 6.5 units at idle, and ended up with exactly the problem you describe, misfiring etc at small throttle openings, and hesitation on "planting" the right foot. The problem turned out to be the airflow setting, it should have been 6 units, not 6.5, which had resulted in a weak mixture at idle and small throttle openings. Adjusted to the correct figure, and, Bingo! back to normal. It may be worth checking this angle out before messing with ECU's etc. Link to comment Share on other sites More sharing options...
EFA Posted April 21, 2003 Share Posted April 21, 2003 Mikes on the likely track here. The Caterham throttle bodies and R300 map require an idle throttle pot voltage of 0.43v at the rec idle speed which from memory is 800rpm. In the case of Tonys car (for which I built an R300 spec engine) we could not achieve this without elongating the holes in the throttle pot to allow it to move to the required position. At the low end, having this set to the wrong voltage will throw out the load sites - most noticable where the load sites are crammed together - at smaller throttle openings. This would cause precisely the symptoms you are getting. IMO the R300 map works very well. Fat Arn Visit the K2 RUM website See the Lotus Seven Club 4 Counties Area Website here Link to comment Share on other sites More sharing options...
SteveP Posted April 21, 2003 Share Posted April 21, 2003 Just to throw some balance in here. I have an R300, completely standard including the catalyst still in place and have none of the issues you describe. OK, it does start to really fly above 4k revs but you would expect that, but it also pulls fine from around 2k as far as I can tell. It's certainly happy crawling through 30 zones in 3rd for example. As for planting it, no hestitation whatsoever and you just zip forward. Suggest that you get it checked over SteveP Link to comment Share on other sites More sharing options...
silver-7 Posted April 21, 2003 Share Posted April 21, 2003 Darren, When I first had my R300 it ran like a dog below 4,000 rpm and would not start from cold properly either, at the 500 mile first service the car was checked and found to be running too rich, since then its been fine. I would also try Shell optimax petrol as the car seems to run better on it than before. Regards, Alex M. Link to comment Share on other sites More sharing options...
Slipper man Posted April 21, 2003 Share Posted April 21, 2003 Darren Your car has a fault. It could be anything, but my guess is a faulty sensor somewhere. Whatever, send it back and get Caterham to set it up for you. it should pull smoothly from whatever revs you want. If you are going to start running it without the cat, get them to set it up without the cat fitted - it does make a difference. Link to comment Share on other sites More sharing options...
darren f Posted April 21, 2003 Author Share Posted April 21, 2003 Thanks for all the reponses- these have certainly got me thinking . On a quick blat today the problem didn't seem so bad, I think I'm going to have to try to do some research to try to establish the exact conditions and circumstances when the problem occurs- if its going to be an intermittant problem it could be a so-and-so to isolate and sort. Going on Alex's and Keith's answers, I think a call to Caterham will be on the cards. Clever idea to combine a check and set-up with the cat replacement . Oh BTW its been run on Optimax since its 'birth' so fuel quality shouldn't be a problem. PS: Mike and Arnie- thanks guys but you completely lost me with the technical data. Cheers though darren f The Building of R300SEV is Here Link to comment Share on other sites More sharing options...
Meldrew Posted April 22, 2003 Share Posted April 22, 2003 Just to add my four penn'orth, mine pulls perfectly well at all revs (cat still installed, run on Optimax, etc). It pops and bangs on the overrun and kangaroos a little at low speed in traffic, but it doesn't have any hesitancy, misfiring or fluffiness when you open the throttle. Link to comment Share on other sites More sharing options...
Bafty Crastard Posted April 22, 2003 Share Posted April 22, 2003 Bafty's car runs fine also R300 NUT Link to comment Share on other sites More sharing options...
Solo Posted April 22, 2003 Share Posted April 22, 2003 Darren My R300 doesn't have these problems either - pulls smoothly at low speeds regardless what gear it's in with no hesitation. It is a bit tricky to start from cold though - Hyperion will look at that when they do the 500 mile service next Monday. As an aside, I took the Cat off yesterday and it now seems to pop and crackle a bit more - lovely! Steve Link to comment Share on other sites More sharing options...
darren f Posted April 22, 2003 Author Share Posted April 22, 2003 Sorry to continue this thread going but this is now worrying me. Anyway here goes, the results of my research….. The problem looks to be between 2000 and 2500rpm, lower down than I thought. This equates to about 30mph in 5th (6-speed box)- the car just will not pull from there, lots of hesitance / misfiring / distressing behaviour . It’s the same in 4th (and obviously 6th at the same or lower revs). Keep it burbling along above 2.5k and it seems to pull ok. Every other injected car I have driven could cope with lower revs in top gear- even my company Mundane-o will pull (albeit slowly) without complaint from less than 2k revs. Flame me if you wish but being new to Caterham ownership, am I asking too much here? Is it really such an inflexible unit that it should require 4th gear when leaving built-up areas? Even when only pulling 500kg? Opinons / experiences please darren f The Building of R300SEV is Here Link to comment Share on other sites More sharing options...
Graham Perry Posted April 23, 2003 Share Posted April 23, 2003 I am no expert on Roller TB's but can they not get out of balance like carbs ? If they can, then surely this is a simple thing to check Link to comment Share on other sites More sharing options...
singlespeeder Posted April 23, 2003 Share Posted April 23, 2003 Mine was a pig to drive through town,went back to Caterham who said they balanced RBTB ok since then,problems were between 1.5-2.5k revs. Link to comment Share on other sites More sharing options...
SteveP Posted April 23, 2003 Share Posted April 23, 2003 Darren, After reading your first post, I tried this experiment in my R300 - stuck it in 6th running at 2000 revs and pressed the loud pedal - car pulled smoothly right through the revs, no hesitation, misfire or anything. Not astonishing performance but smooth nonetheless. As others have suggested maybe it's just a simple case of balancing (but have no idea what this involves, how to go about it, etc) but suggest you just ask Caterham to check it over - it is under warranty after all. SteveP Link to comment Share on other sites More sharing options...
Colin Grundy Posted April 23, 2003 Share Posted April 23, 2003 Darren From memory, ISTR Simon Scott had a similar problem on his and it went back to CC. for a re-map. If you look at his build diary all will be revealed. Apologies if Ive got my wires crossed. Link to comment Share on other sites More sharing options...
Slipper man Posted April 24, 2003 Share Posted April 24, 2003 Many of these cars have a flat spot at around 2,500 RPM which is caused by emission rules, which test the car at that speed. However, if your car is running properly, it will be as untempermental as a Mundaneo at low speeds. My R500 will pull cleanly from as low as 1,200 RPM in top, and your car should be better. The throttle bodies need to be balanced in the same way as twin carbs, and there is other fettling that can be done. This is a new car still in warrenty - take it back to the manufacturer (or a main agent) and get them to sort it out - without a laptop plugged in it is very difficult to see where the fault is. Link to comment Share on other sites More sharing options...
darren f Posted April 24, 2003 Author Share Posted April 24, 2003 Thanks again to all who have responded- especially Steve P for even doing the road-test for me *thumbup* . Currently in discussions (via mail) with Simon at CC about getting it looked at (and getting the bloody cat off *smile* ). I will report on the findings. darren f The Building of R300SEV is Here Link to comment Share on other sites More sharing options...
Red SLR Posted May 1, 2003 Share Posted May 1, 2003 Did you get it sorted? Where is you lambda sensor? 4th primary or before the cat? (should be b4 the cat) See X777CAT here Link to comment Share on other sites More sharing options...
darren f Posted May 1, 2003 Author Share Posted May 1, 2003 Simon, No progress at present because Caterham cannot look at it until late May (they are "very busy" just now). The lambda sensor is in just before the cat- I got that checked out after reading your cat problems on your build site . When it goes back to CC in May I will have the cat taken off, when I suppose the sensor will go in the 4th primary 🤔. Caterham tell me that the ignition map will stay the same as they only have one for both catt-ed and non-cat cars . ..............Waiting with anticipation to see what occurs (particularly now I've probably upset all and sundry by posting it all on here ) darren f The Building of R300SEV is Here Edited by - darren f on 1 May 2003 18:12:17 Link to comment Share on other sites More sharing options...
Bafty Crastard Posted May 2, 2003 Share Posted May 2, 2003 When I build my R300 I fitted the lambda sensor in No4 pipe on the advice of Caterham Technical, said its neater, works as well ! At post build Caterham Midlands move it to before the cat, the cable was streched to point That I thought 🙆🏻 to this and put it back into No4 pipe, seams to run ok will see at 500 service R300 NUT Link to comment Share on other sites More sharing options...
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