Calling Superlight R owners - past and present...

[Nick Bassett]

As a current SL-R owner, I'm keen to hear from other SL-R owners past & present in relation to how smooth a drive I can expect from a VHPD engined Caterham... let me explain...

My SL-R is completely standard apart from Piper verniers and an Emerald K6... the cam timing was checked this weekend and is set up correctly. Compression test & cam follower clearances also as they should be and all sensors appeared to be working on the Emerald software (- TPS changed) - so far, so good!

But... I have two main issues with my car:

1. Cold starting

2. Horrible shunting between 2 & 3000rpm  on light throttle settings that makes the car horrible to drive in traffic/going around roundabouts etc and quite honestly dangerous

Let's start with the latter... this really is as bad as it sounds - in fact it seriously impacts my enjoyment of driving the thing - on throttle accelerating, the car pulls like a dream, but the moment I get caught in traffic or am going around a roundabout, this horrible drive-train shunting starts and it's not nice. I find myself cringing each time it happens and am constantly changing down to a lower gear in traffic in a bid to keep the revs up and out of the 'shunting zone'.

I & others suspect is is down to a dodgy map on the Emerald, but even if I take the car to a reputable rolling road mapping session, how good can I expect the drivability to be on this car, when properly mapped? 

The cold starting issue I think can be sorted.

I've heard that Northampton Motorsports to be pretty good at Emerald mapping - anyone else in a position to comment or make other recommendations?

Ideally I would take it to Emerald, but they are too far, especially in a shunty Caterham! I did wonder if I could post them my Emerald for them to upload a standard SL-R map on to it and post back - anyone else done this?

Thanks in advance,

Nick 

[TomB]

Have you a laptop with the Emeral software on?  the first thing Id do is look at the map in the software when the engine is running to make sure all the sensors are working as they should.  Id replace the plugs, leads, coil. oil and get it remapped or at least looked at.  All you know, it could have been mapped with the verniers and now be sub-optimum.  

Cold start is easily sorted at the RR but might have to stay overnight so its properly cold.  Ive heard Northhampton are good, youll find lots of folk have used them. 

Edit - mapped without the Verviers!

[ste]

OP, for reference mine starts and idles, even from stone cold like a normal family hatchback. No histrionics or fuss; turn the key and it fires up and idles very evenly. It also pulls at all revs with no flat-spots or stuttering.

Mine has verniers and an Emerald but also has Jenvey DTH ITBs fitted. I wouldn't have thought the jenveys make all of the difference though and your issues sound more mapping or sensor related.

[ste]

Id follow TomB's advice above but would also be suspecting TPS or temp sensor.

[Piers300]

Check to see if you have a spark when cranking. If so, then your ECU May have a bad earth.

Taking all precautions, take the air filter off and spray a small amount of fuel in each throttle body. If it fires immediately on cranking, then you have a bad earth. The injectors draw a fair bit of current and a bad earth prevented mine from operating/injecting when cranking. I had this problem on an R300 and if was very difficult and time consuming plus expensive to find the fault. Also check the multi pin connector under the throttle bodies for corrosion. - mine was green. It’s not easy to get undone but persistence is needed.

Piers

[Graham King]

NIck, you have a Private Message.

Graham

[Nick Bassett]

Thanks all - & Graham have pm'd you back!

TPS was replaced with a known serviceable one, so that can be eliminated.

I suspect the majority of this is down to a poor mapped car - just need some reassurance that a decent map will make the car much more enjoyable to drive...

[TomB]

'Horrible shunting between 2 & 3000rpm  on light throttle settings'' and 'throttle accelerating, the car pulls like a dream' sounds a good candidate for a poor mapping in the that area of the throttle/fuelling/load settings.  The previous owner might have asked the mapper to concentrate on top end power as he was using it for track, with less concern about the lower end.  Although a few hundred quid and a day off work, its probably what Id be looking at doing.  

An alternatively could be to drive it with a mate and laptop and have a play with the settings on the fly while driving to see if you can temporarily improve it - which will reinforce that its the map that the issue.  Or you could fit one of those self mapping / wide band lambda probe things (that I've forgotten the name of - was it an 'Innovate wideband lambda?) - to refine the map in this area as you drive.   

 

  

[SLR No.77]

Get it mapped, but before doing so make sure the throttle cable is functioning cleanly with no excess slack, any holes in the map will be exaggerated by a dodgy cable.

[ste]

Mine has an Innovate wideband Lambda on it. Good kit IME and I'm sure will be in no small part why mine is so tractable. Obviously it needs someone who knows what they're doing with the software too, but it makes things much easier.

[Nick Bassett]

Thanks ste... I know DVA has told me that Jenveys are much better than the KV6s having a much shorter tract into the head etc...

My old Supersport had Jenvey's fitted and was an absolute peach at starting, idling and general road manners.

[TomB]

I've got the SLRs on my Supersport, and they seem perfectly useable, obviously not the same head & cams as as VHPD, but Id think with a remap it should be much improved.  If your after originality, you should keep the SLR/ KV6 TB - that what early SLR came with before the PTP and roller barrels TB. 

[Nick Bassett]

That is a good point you make about slack in the throttle cable - we removed some at the weekend which has made a difference - previously from idle it was a bit like an on/off switch once the slack had been taken up!

[Nick Bassett]

Yes I do want to retain the originality of the SL-R Tom, so the KV6s and all their associated weight & gubbins will remain!

[SLR No.77]

The KV6 throttle bodies are not as bad as some people might want you to believe. It's worth however checking that the plastic sections on the butterfly valves are secured properly (they might not be at the age of the car) and if not, remove them and solder up the two holes in each butterfly valve where they're mounted.

Stu.

[ste]

I still have my KV6 ITBS. They're safely in a box in the garage should I ever want to restore the originality! I'd have probably kept them on but a previous owner had already made the swap.