Caterham VVC - Pros and Cons

Caterham VVC - Pros and Cons

Author
Discussion

arun1uk

Original Poster:

1,045 posts

197 months

Wednesday 18th July 2018
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Hi all,
Does anyone have a Caterham K series VVC?
I've seen a nice one and thinking of buying. Before I do that, has anyone got or had one?

Pros and Cons?

I hear upgrades are limited, unless you ditch the VVC gubbins, which defeats the purpose...however, the torque delivery is very linear, quite heady power delivery (peak power at 7,800rpm), but makes a lovely noise.

Would be interested to hear thoughts!

Cheers

Trophy200

226 posts

200 months

Wednesday 18th July 2018
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Have you spoken to these people?

https://www.kmaps.co.uk/

Trophy200

arun1uk

Original Poster:

1,045 posts

197 months

Thursday 19th July 2018
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No, but thanks for the heads up. Will definitely contact them tomorrow to get some insight. I thought the MEMS ECU wasn't adjustable, but their website seems to differ in opinion!

upsidedownmark

2,120 posts

134 months

Thursday 19th July 2018
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It depends on age - I think it's MEMS3 to be mappable. Kmaps are certainly helpful and know their stuff..

As to the VVC, haven't driven, and have no idea, but have you dug around dave andrews page? kengine.dvapower.com. Lots of info there.

Anecdotally I've heard that the VVC isn't entirely reliable, no idea as to the reality of that. My question would be why bother - vvc lets you tame the emissions and low rev pootling characteristics while getting a decent power. Not convinced that is really worthwhile - 1) it's a caterham, not a bus - you don't need that much torque to shift it, 2) you presumably are buying to drive, not to sit in traffic on the way to the supermarket!

Ok, slightly tounge in cheek, but still. FWIW mine started as a base 1.6, and for all I'd heard about revvy k's and needing working (which I was up for) I can't say it lacks shove anywhere from ~1500 onwards - even if the torque figure is low, in that car it hops forward just as quickly as the TDI daily.. just that it keeps getting better as the revs build. It's now had some mild upgrades, and has more power and torque, pretty much everywhere. Possibly the VVC can't handle the wilder cams that are needed for really big power, possibly if you're going to make an engine with > 100bhp/litre you accept/don't care that it's not going to be the most well mannered thing at 1200rpm on part throttle.

The main advantage I could see (if you're looking for a base to build on) is that the VVC starts with bigger valves than the standard head. As a point in its self without development in mind, 160ish is apparently the sweet spot, and a vvc is perhaps not a bad way of getting there.

arun1uk

Original Poster:

1,045 posts

197 months

Thursday 19th July 2018
quotequote all
upsidedownmark said:
It depends on age - I think it's MEMS3 to be mappable. Kmaps are certainly helpful and know their stuff..

As to the VVC, haven't driven, and have no idea, but have you dug around dave andrews page? kengine.dvapower.com. Lots of info there.

Anecdotally I've heard that the VVC isn't entirely reliable, no idea as to the reality of that. My question would be why bother - vvc lets you tame the emissions and low rev pootling characteristics while getting a decent power. Not convinced that is really worthwhile - 1) it's a caterham, not a bus - you don't need that much torque to shift it, 2) you presumably are buying to drive, not to sit in traffic on the way to the supermarket!

Ok, slightly tounge in cheek, but still. FWIW mine started as a base 1.6, and for all I'd heard about revvy k's and needing working (which I was up for) I can't say it lacks shove anywhere from ~1500 onwards - even if the torque figure is low, in that car it hops forward just as quickly as the TDI daily.. just that it keeps getting better as the revs build. It's now had some mild upgrades, and has more power and torque, pretty much everywhere. Possibly the VVC can't handle the wilder cams that are needed for really big power, possibly if you're going to make an engine with > 100bhp/litre you accept/don't care that it's not going to be the most well mannered thing at 1200rpm on part throttle.

The main advantage I could see (if you're looking for a base to build on) is that the VVC starts with bigger valves than the standard head. As a point in its self without development in mind, 160ish is apparently the sweet spot, and a vvc is perhaps not a bad way of getting there.
Cheers for the reply, you make some good points!
I wasn't too bothered about VVC or not, it just so happens the car I've found has it - hence asking whether there are any major pitfalls. I haven't heard too many negatives about reliability, however, I guess it's different with every car. I have a diesel daily, so the thought of working a car to 8k rpm appeals to me. Might get tiring after the novelty wears off though...hence why I've heard the Sigma's torque is better.

The car is currently at 160bhp which sounds like a good starting point. I've read through the DVA website so know I can upgrade the valves and exhaust cam with little hassle. The one thing I will invest in is a decent exhaust. It has the standard one installed but would like to a 4-2-1 to promote better breathing. Or do you think it's unnecessary.

Worst thing is that it's on 16" HPC wheels with T1R tyres...need to change to 13"s and CR500s I think. Should transform the ride quality.




upsidedownmark

2,120 posts

134 months

Thursday 19th July 2018
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I'd not avoid on the basis of it being VVC for sure. IMHO the other priority is an LSD - I ignored that advice when I bought mine and it took me about 4 weeks to decide it needed one.

I also like working the car - if the K is lacking torque, the sigma must be like a diesel. If anything VVC will fill in the low end that might be missing in a similarly powered non-vvc car. In terms of laptime, I guess torque is fast, but still..

mine got cams (piper 633, similar to supersport), and a 4-2-1 powerspeed. That jumped it from 112 peak, to 133 peak, and more torque everywhere. It's a significant change. I can't tell you what came from which, but allegedly the internal 4-1 (if that's what you have) is quite restrictive, and my gut feel is that the exhaust was a pretty significant part of the improvement. It's also less annoyingly raspy at motorway speed (not subjectively quieter or louder per se, just less irritating). If you're spinning that much faster and making that much more power I'd expect the exhaust to be even more critical.

I have half an idea the VVC has improved pistons over standard - worth checking/knowing as above 150ish hp (and I think about 7200rpm) the standard pistons are a concern.. for me I'll need to go forged if I want to wring a lot more out.

Finally, mines on 13's, and I swapped (worn out) cr500's for zzs. While there seems to be a lot of love for cr500's, I find the zzs great (admittedly the cr500's were properly dead), and more readily available.

arun1uk

Original Poster:

1,045 posts

197 months

Friday 20th July 2018
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Thanks for your thoughts.

Yes, it's got a 4-1 exhaust and I agree it's probably quite restrictive. It's on my upgrade list but at £2k is quite pricey...
Interesting to hear about the ZZS's. I hadn't considered them but doing a bit of research shows good availability and reviews - Cheers for that.

Looking forward to owning my first Caterham. Dream come true!

upsidedownmark

2,120 posts

134 months

Friday 20th July 2018
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Np. ZZS are the official replacement for the CR500. Some difference, but they're good.

WRT exhaust I had a similar reaction.. but I eventually talked myself round on the principle that it's pointless putting in hotter cams, bigger valves etc, when you effectively have a restrictor on the output side.. It did take about 6 months though.
The other option(s) are to find a secondhand system off a higher spec caterham. The 4-2-1 and the 4-1 with an external collector are both perfectly good, if you can find one. It's just one that comes together inside the sideskin that's a sow's ear.

And yup. Had mine about 18 months now, and love it.

emss

82 posts

147 months

Wednesday 25th July 2018
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Hi,

I've regularly driven my brother's ex VVC R300 whose engine had been upgraded by DVA (K06a IIRC)
Can't see any cons regarding this setup, the engine is a bit linear but pulls hard at any rev.
The loads of torque allow vigourous accelerations regardless of the gear ratio engaged but you still can rev it to 7500 for fun.
It was really a weapon of choice on B roads...

Éric aka Alf

BertBert

18,954 posts

210 months

Wednesday 25th July 2018
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arun1uk said:
Cheers for the reply, you make some good points!
I wasn't too bothered about VVC or not, it just so happens the car I've found has it - hence asking whether there are any major pitfalls. I haven't heard too many negatives about reliability, however, I guess it's different with every car. I have a diesel daily, so the thought of working a car to 8k rpm appeals to me. Might get tiring after the novelty wears off though...hence why I've heard the Sigma's torque is better.

The car is currently at 160bhp which sounds like a good starting point. I've read through the DVA website so know I can upgrade the valves and exhaust cam with little hassle. The one thing I will invest in is a decent exhaust. It has the standard one installed but would like to a 4-2-1 to promote better breathing. Or do you think it's unnecessary.

Worst thing is that it's on 16" HPC wheels with T1R tyres...need to change to 13"s and CR500s I think. Should transform the ride quality.
I wouldn't be too worried about getting engine upgrades just yet, as a first caterham, 160bhp is pretty decent. Not all that long ago (in terms of my age perhaps), that was just below HPC level which was considered insanely fast. And who knows, maybe like me you'll end up thinking more power doesn't equate to more fun, shock horror. You are right to lose the HPC wheels though. Ghastly ride quality!

Bert

DVandrews

1,315 posts

282 months

Thursday 26th July 2018
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Just a note about VVC engines, the risk factor is the VVC mechs themselves which have a nasty habit of shearing the drive pin which will make a mess of your engine. If the engine ‘taps’ then don’t dismiss this as a follower problem, it is much more likely to be slack in the VVC mechanism(s) which is the main progenitor for mechanism failure.

Ditching the VVC mechs can be an expensive business, cams, blanking kit , verniers and ECU as a minimum.

Dave

arun1uk

Original Poster:

1,045 posts

197 months

Tuesday 31st July 2018
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Thanks for the replies.

I've had the car a week now and love it! Really rev happy, however, spoiled by the ride quality (and a silly nose colour by the previous owner).
Hoping to get black pack upgrades, aero screen and wheels/tyres as a priority.

With regards to VVC, I will definitely keep an ear out for any tapping noises. Is it possible to "service" the head, or will it require a rebuild?
Thank you again.

coppice

8,564 posts

143 months

Tuesday 31st July 2018
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Had a VVC for 15k miles before going Duratec. Loved it - lots of torque and whilst it may be fashionable to say Sevens are about power at high revs , I came from a 1.4K SS and the difference was night and day as the VVC pulled hard low down but just kept getting better through the range . It was bloody quick too, and certainly not lacking in the trouser department .

No trouble at all- from long tours to track days it was excellent. So why Duratec ? An itch I had to scratch - no regrets , significantly quicker with another 50bhp but certainly not a quantum leap ahead

arun1uk

Original Poster:

1,045 posts

197 months

Wednesday 1st August 2018
quotequote all
coppice said:
Had a VVC for 15k miles before going Duratec. Loved it - lots of torque and whilst it may be fashionable to say Sevens are about power at high revs , I came from a 1.4K SS and the difference was night and day as the VVC pulled hard low down but just kept getting better through the range . It was bloody quick too, and certainly not lacking in the trouser department .

No trouble at all- from long tours to track days it was excellent. So why Duratec ? An itch I had to scratch - no regrets , significantly quicker with another 50bhp but certainly not a quantum leap ahead
Thanks for the thoughts, I had the same debate about the Duratec but funds and experience made the decision easy! Glad you're enjoying it - I certainly am!