310R vs 420R

[SKC]

Hi

The weight difference between the standard Sigma and standard Duratec from Caterham is 15kgs. This is with the Duratec being fitted with a lightweight flywheel and the Sigma being fitted with a standard flywheel.  Fit Caterhams lightweight flywheel to the Sigma and this will reduce the weight by about 2.5kgs.  Fit our ultra light flywheel and clutch and this will reduce the weight by a further 2.5kgs, not only reducing overall engine weight but also reciprocating weight meaning a dramatic improvement in throttle response.  In fact fitting one of these to a 125 Sigma makes the car a nicer car to drive than a 140 Sigma.  Fit our lightweight alternator installation and this will bring the total weight difference down to a total 23kgs lighter than the Duratec.

On the subject of dry sumps, we also offer our own very neat installation for the Sigma.  This is a double scavenge system which is very efficient and which means a smaller capacity oil tank can be used, again saving more weight over a Duratec dry sump installation. For those interested in seeing this, please look at our Facebook page, Premier Power Race & Performance Engines.  The car shown here is a 310R which is also fitted with an ultralight flywheel and clutch.  Having driven alot of different Caterhams, I have to say that this as a standard spec car (no horse power increase) is a great car.  It's not all about horse power, it's about the driving experience, the excitement and the throttle response, all we expect from a light weight sports car.  Driving this and then driving a standard Duratec car, the Duratec just feels lazy, it doesn't have the response.

I'm not adverse to Duratecs.  If you want 200bhp + then that's the way to go but a 200bhp Sigma, being light weight is as good a match for a 220bhp Duratec in my opinion.  200bhp in a Caterham is a quick car, the thing owners need to think about is what are you using it for...and do you need 200bhp or 200bhp +?.

Ok these are the views of someone that sells these products and upgrades for both Sigma and Duratec engines but also someone that is a proud Lotus 7 Club member, a Caterham owner and that's constantly aiming to improve the driving experience we all enjoy.

Regards

SKC*byebye*

   

[Golf Juliet Tango]

And 25kg weight penalty if you choose an SV (probably more once you have filled the bigger tank - but you can go further between fills).

[7 wonders of the world]

Dont forget the BMW cast iron final drive and associated ironmongery adds circa 7kg, the Mazda 5 speed box another 10kg too.......

....and the Metric chassis is heavier than the imperial to by around 5kg.....

Colin would not be happy.....

[Geoff Brown]

erm.....420 "smooth & progressive & not responsive" ?  

2013 R400 Superlight with RBTBs (220bhp ish) : VERY responsive, mad/bonkers, noisy/raucous, stump pulling torque in most gears &  enough induction/exhaust noise (with blue flame) at full chat to frighten small children & animals.  

Have CC changed the nature of the 2.0L 210bhp Duratec?

[mike150]

My ideal car might well be a perfect R500d or a perfect R400/420R with a 6 speed box but I never found such a car and before anyone says 'millwood have an R500', I know but it looks crap in solid green imo and its over priced imo, I've spoken to John.

 

So do what I did and buy a 620s, 5 speed issues irrelevant as you have lots of power!

[Geoff Brown]

I personally know the previous owner of the solid green R500 at Millwood. For all its dowdy looks it is a nice car & one of the first produced. Very carefully hand built to replace a previously purchased R500 that was a complete pile of carp. 

Built during Ansars time on pain of death as the original owner had CC over a barrel with the imminent launch of litigation & the threat of exposure due to the fact that his daughter was a producer with the BBC programme News Night.

I would suppose some stripes would brighten it up? 

I have a 'perfect' R400 - RBTBs, 6 speed, LSD, carbon............not for sale!

[ScottR400D]

“So do what I did and buy a 620s.....”

The OP’s changing his current car because he wants, understandably, to build his own.

Unfortunately, as CC won’t sell 620 kits he’s limited to a 420, which to be fair is more than enough for the road and the occasional track day. 

[mike150]

Geoff Brown.........................I know all about it, I spoke to the owner and he told me the story....................... unfortunately after he sold it to Millwood, as I said though the solid green is my personal least liked colour on a car and the price made me pass on it. I did even consider Carbon wings and strips to lift it a bit.

[mike150]

ScottR400D.............I know, I was just putting the idea out there!

[Garth]

Hi James

Just read through this thread with interest - it is a tricky decision to make and it is difficult to compare. It seems that all Caterhams have their own unique attributes with no two being the same! Also so many variables with respect to gearboxes, diff ratios etc which change the way it feels/drives! I have a Sigma SV with just under 200bhp with a longer 1st and 2nd in my type 9 box and love it. It revs freely and sounds great! I have not driven a Duratec and mine back to back to really appreciate the differences, but largely agree with the comments expressed! 

Sounds like it will be great to build it with your dad and you will obviously enjoy it irrespective of which car you build. For me I would think hard about what you want from your car and then look for the best fit. If you go Sigma you must speak to Stuart at Premier Power. If you want brutal torque, then consider the Ecoboost for Duratec money or go for the Duratec for less torque but with different characteristics to the Ecoboost!

Wanted to say more but family matters drag me away! Drop me a line if you want to talk further!

Cheers

Garth

[heptagon]

Hi all

i was trawling the archives actually looking for LSD comments when I found this interesting thread from a couple of years ago.  
I'm looking to come back to the fold and see loads of 420R's on the market but am thinking it's a bit too fast for road use for me and I'm looking for something that will be fun like my old K series VVC was. 

It's now got me thinking about the Sigma 310R again and going for one of PP packs, I think I could end up spending 420 money but would have a really individual and special car.  The comments earlier about the Sigma engine characteristics really appeal.

Anyway once I can drive a few cars I think I'll get it clearer in my mind what would suit me best.  I'm sure it will all fall in place eventually..  I may need to have a word with PP to understand what I'd be committing to first 

[Toughie]

Stuart at PP is very helpful.

As for "a bit too fast for road use", I keep saying we're a club full of megalomaniacs, all wanting more power.  If you go for a 310, what power do you want PP to bring it up to? 

How does that compare with a 420, if you're thinking it'll come to 420 money anyway?

[heptagon]

Good question, certainly not trying to get 420 power.  I was thinking more of the driving involvement through great throttle response and the sound those things make.  Have fun getting to speed on the road rather than be teleported there if that makes sense

[ScottR400D]

I think you’re underestimating the throttle response of the 420 but overestimating how fast they are. 

I can’t say I’ve ever found my 220 R400D ‘too powerful’ and never had a moment’s difficulty in controlling the power it has. Well, the odd time when the Titan had packed up maybe.......

I just don’t get that view at all. 

[Geoff Brown]

To repeat my comments in #29:

2013 R400 Superlight with RBTBs (220bhp ish) : VERY responsive, mad/bonkers, noisy/raucous, stump pulling torque in most gears &  enough induction/exhaust noise (with blue flame at night) at full chat to frighten small children & animals.  

Have CC changed the nature of the 2.0L 210bhp Duratec?

I have the same opinion as ScottR400D  

[heptagon]

The 420R is certainly on my test drive list 

 

[7 wonders of the world]

Nothing is 'a bit too fast'.....

They will only go a fast as you make them....

However if you do open the taps the performance is significantly more than most tintops...

Is your driving up to it - ?

Why not get an assessment from ROSPA, or IAM, many have Police instructors in their groups, there's also a club member who's name escapes me that has a driver training business too, 

 

[Mrp]

#40 

Hi Geoff

As far as I'm concerned I have a R420 (2017) with RBTB and Cat delete so R440 in Caterham terms and I concur with your findings, also coming from a Roadsport 140 so previous C7 experience..

Mrp