Roller barrel upgrade for a 420R

[Martin_mad]

Hello All,

I am thinking of fitting a roller barrel upgrade to my car.

The car is a 2018 420R SV model.

I understand it'll give an extra 10 BHP but can somebody help with the following queries?

i) to keep within the terms of the warranty, I assume, I have to buy the upgrade from Caterham,

ii) will it improve idle speed and acceleration from stop,

iii) being a SV, will it fit within the existing engine bay without altering bonnet and

iv) can I fit the upgrade myself (Caterham reprogramming the ECU).

Many thanks

Martin.

[John Vine]

I had RBs fitted to my R400D (S3, 2008) by Caterham Crawley in 2014,  and have no regrets at all.  The quoted power 10bhp increase may seem modest, but the upgrade brought the car alive. 

I'll try to answer your questions:

(i) Yes

(ii) Yes to both, plus you get the bonus of a lovely soundtrack.  The upgrade will require a change from MAP-based mapping to TPS-based.  My plenum-induction mapping was already TPS-based following a remap session at the Two Steves.  CC will change your map to a TPS-based one.  I'm happy with the map they provided but that's not to say a dedicated re-map wouldn't improve things further.

(iii) Not sure as my car is an S3, and I needed a bonnet cut-out.  If you do need a cut-out, CC will do it as part of the upgrade.  There's a school of thought that says RBs benefit from free access to ambient air as the under-bonnet temps get quite high.

(iv) Probably (depending on your skill level) but it could raise warranty problems.  You'd need to check with CC, who may well say it would need to be done by them.   CC offered to fit upgraded (double?) valve springs for me (which I declined).  If you planned to do that bit, you should be able to do it without removing the head (using either the string technique or compressed air).   

JV

 

 

[Martin_mad]

Many thanks JV for your full and concise reply.

My major concerns are idle and acceleration. 

Regarding item iv) I am confident I can carry out the work myself but wondered  if CC would supply the parts. I have searched through CCs online parts and cannot find a RB kit for a 420R.

Once again

thankyou

Martin.  

[Benton]

(i),(ii),(iii) yes

(iv) probably not, due to (i) you'll need to check

in addition

(v) Much improved soundtrack both intake and exhaust.

However I do suggest also fitting a cat bypass pipe as:-  a. it saves the cat from bombardment! b. gives a slightly more gruff exhaust note c. for me personally I felt gave the car more midrange grunt

[7 wonders of the world]

Whats more important to you..... keeping within CC approved upgrades or gaining more bang for your buck performance ...

10 BHP on the top end you will hardly notice - but your wallet will ! to me this is not a cost effecrtive upgarde by any stretch of the imagination.

I would look else where for upgrades, reworked head, pistons rods cams and jenveys coupled with possibly an Emerald or unlocked MBE

...and dont forget a DS kit too.

[Martin_mad]

Thanks, unfortunately the soundtrack will be lost on me (hard of hearing and tinnitus Grrrrrr!) but I'll be pleased with improved ii).

[7 wonders of the world]

Is this the kit...

https://caterhamparts.co.uk/other/3768-engine-upgrade-kit-r400-210bhp-to-220bhp.html?search_query=roller+barrels&results=27

£4k for 10BHP .....  

[Martin_mad]

Ouch!

[ScottR400D]

Luke Stevens did mine for a lot less than £4k

It’s well worth doing, 10bhp but torque is improved. The car certainly feels quicker, definitely sounds better. 

Everything fits under the hood of an SV (see below) and mine idles perfectly at about 850 and will creep away with no throttle. It never did that before!

I wouldn’t worry about warranty which must be expired now anyway? 

You could probably fit the parts yourself but the hard bit is the mapping and even CC don’t have the best rep for that.

 

 

[Martin_mad]

Looks great.

Kit delivered about a year ago so still got a year to run.

I will definitely go for your set up.

You've got the main reason behind getting this done. Idle and a smooth delivery although the extra HP and torque is most welcome.

Your advice and photo is much appreciated.

[Geoff Brown]

To late for some but on ordering a kit or factory built car one should insist on the RBTB fit before delivery. I did just that for my R400 kit & saved £££s. It did take persistence & the help from Jon at Millwood. Trouble was that the numpties at CC neglected to upgrade the ECU software so starting & running was problematical to say the least!

[ScottR400D]

So maybe not that good an idea, Geoff?  

I didn’t think of it when I ordered the kit but had it fitted 18 months later. It cost a lot less than CC wanted and I got upgraded injectors and sensors and carbon trumpets.  

Incidentally, it’s not really just a software upgrade, I was asked how I wanted the car to run and then it was on the RR for quite a while being set up. 

Still, not a single regret since I had it done, nor any hesitation n recommending Luke Stevens. 

 

[7 wonders of the world]

If your going to that expense it would seem a good opportunity to look at other upgrades to as you will save money on addition re mapping sessions on the rollers.....

[dave_h34]

Indeed the Caterham RBTB fit under a SV bonnet without needing to cut a hole, but if you ever want to quiet them down with a "trackday intake" you'll run into problems. I also get pretty bad heat soak or vaporisation or something - runs fine until you park it up, leave it long enough and it's fine, take the bonnet off for a bit and it's fine, otherwise it coughs, splutters and tries to die for a few hundred yards until a bit of airflow gets to it. IMO the standard map is pretty rough and I'd certainly not recommend fitting them for reasons of idle and smoothness. Nothing a remap wouldn't sort but still. I think I'd be tempted to leave it until the warranty expires and look at all available options, unless keeping it Caterham original is important to you.

[Martin_mad]

Had problems with car including erratic idle and cutting out/stalling when pulling away from standstill (I seem to have improved this by increasing idle speed to just over 1,000rpm) and speedometer and tachometer dropping off simultaneously (pretty sure this was due to condensation in gauges but I fitted earthing upgrade and after drying out appears to be working). My latest problem was a cooling fan failure which I tracked down to a poorly assembled fuse/relay holder. I'm certainly not bothered about keeping it Caterham. The car has covered just over 450 miles and my wife refuses to get in it (an unforeseen bonus). Not bothered about track days but I'd like to do the odd hill climb.

[Geoff Brown]

ScottR400D - CC were astonished that I managed to start the car. It did sound like a bag of spanners inside a tin of marbles. Shut it down within 15 seconds to avoid potential damage.

CC trailered the car at their expense, uploaded the correct software with tune up, carried out PBC/pre IVA check which I conducted.

I do not have carbon trumpets but the cover & mount for sausage filter is carbon.

Might be only a 10bhp gain from the mod but it gives the car character, instant throttle response with smooth running at part throttle in lower gears & smooth tick over. Well worth the £££s

 

[Nigel B]

Interesting discussion!

This is an upgrade I’ve been contemplating for my 420R. Mainly because I miss the sound of the weber carbs on my previous Caterham! 

It's possibly a numpty question, but do ITBs adversely affect emissions? I had to have my webers adjusted at MOT time, which was always a bit of a pain. 

I’m assuming ITBs are sophisticated enough not to require MOT fettling?

[John Vine]

Might be only a 10bhp gain from the mod but it gives the car character, instant throttle response with smooth running at part throttle in lower gears & smooth tick over.

My experience exactly.  And that's with the CC map.

...do ITBs adversely affect emissions?

I would say not, provided they're combined with a suitable map.  And the fuel consumption on my R400D is pretty much the same as with the plenum.  MOTs haven't proved to be a problem for me, provided the tester is aware of the wider lambda range (0.95-1.09) applicable.

JV

[Geoff Brown]

In my case at the first & subsequent MoT the inspector mentioned that the car 'ran a little rich' 

[ScottR400D]

Mine’s been through two MOTs and several track days since fitting. No noise or any other issues. 

[ScottR400D]

Mine’s been through two MOTs and several track days since fitting. No noise or any other issues. 

[dave_h34]

Does this link work for you?: https://youtu.be/SDcA2KvtdWU

 

[Martin_mad]

very helpful, thanks.

[Grant_7]

In my experience, and although this is a different engine (Sigma), I find this captures the Roller Barrel sound very well.

[CtrMint]

Martin,Please take my input here with caution, I'm still a bit of a newbie.  My 420R developed idle issues too.  Best thing I did was to buy the SBD diagnostic cable and use their Easymap to accurately trim the tps etc.  She runs perfect now, so much better.   If you're chasing just the idle might be a cheaper option.