R400K to Supersport R??????
Discussion
I've got a 2003 K Series R400 which I build and had from new, so I've had it 11 years now.
I'm wondering about updating to a new car, partly to take advantage of the updates in the last 10 years (if there are any??) and partly as I think it'd be a great project for me and my lad.
I'm mainly road use with maybe 3 or 4 track days a year, so I was thinking Supersport R may be the best option?
Anyone got any experience of going from an R300/400 k series to a newer Duratec car like a Supersport R or R400 duratec?
Any views on how they compare??
I have a SSR on order having sold my 210 bhp k last year. I tried a Cerb and Exige after selling the Caterham but neither fit the bill.
I have included in my SSR order the 220 bhp upgrade. I drove the standard car and it did not have the urgency or more importantly the responsive fizz of the K on TB's hence the upgrade. I have not driven a Duratec with this configuration but everything I have read has reassured me that I have made the correct choice. I am saving a few £k over the R400
I have included in my SSR order the 220 bhp upgrade. I drove the standard car and it did not have the urgency or more importantly the responsive fizz of the K on TB's hence the upgrade. I have not driven a Duratec with this configuration but everything I have read has reassured me that I have made the correct choice. I am saving a few £k over the R400
Edited by LawrenceR on Tuesday 11th November 18:49
The Duratec is a little heavier upfront and it is probably that that will be most noticeable. In standard form it is also a little flat on throttle response, but the Roller Barrel conversion transforms it. Overall, the Duratec Caterhams are good and any shortcomings will soon be forgotten.
LawrenceR said:
I have a SSR on order having sold my 210 bhp k last year. I tried a Cerb and Exige after selling the Caterham but neither fit the bill.
I have included in my SSR order the 220 bhp upgrade. I drove the standard car and it did not have the urgency or more importantly the responsive fizz of the K on TB's hence the upgrade. I have not driven a Duratec with this configuration but everything I have read has reassured me that I have made the correct choice. I am saving a few £k over the R400
I have included in my SSR order the 220 bhp upgrade. I drove the standard car and it did not have the urgency or more importantly the responsive fizz of the K on TB's hence the upgrade. I have not driven a Duratec with this configuration but everything I have read has reassured me that I have made the correct choice. I am saving a few £k over the R400
Coincidentally I too have an 11 year old K series (originally 140 bhp now 230) and I also built a Sigma academy car for 2013 season. Based on that experience I wouldn't swap my imperial car for a metric one. I also love the revvy nature of the K so I doubt I'd want a duratec either. If I wanted to do anything project-wise I'd strip and rebuild my current car - getting the chassis refurb'd and re-skinned by Arch along the way and replacing the bits that look a bit tired to end up with something akin to a new K series imperial car 
I think you need to get a go in a Duratec ASAP to see if it gives you the buzz you want it to.
Some of my thoughts on the Sigma build are in the build diary section of sevenracing.co.uk
I think you need to get a go in a Duratec ASAP to see if it gives you the buzz you want it to.
Some of my thoughts on the Sigma build are in the build diary section of sevenracing.co.uk
My R400 kit is due to be put together at the end of this month and with me before Xmas.
I tried both the SSR and the R400D and preferred the R400. 6 speed box felt a lot better, I think the dry sump is better, especially on track. By the time I'd put the things I wanted on a SSR there was only a couple of grand between it and the R400.
I tried both the SSR and the R400D and preferred the R400. 6 speed box felt a lot better, I think the dry sump is better, especially on track. By the time I'd put the things I wanted on a SSR there was only a couple of grand between it and the R400.
Strip, refurbish and rebuild your current R400 would be a far more enjoyable, fulfilling and educational experience than a flat-pack new buuld.
You have the heritage feel of contributing/adding to a projwct you started years ago.
A totally rebuilt 7 as the outcome having spent less money.
And maybe the clincher, you get to keep the joyous K series on throttle bodies character you clearly. enjoy!
You have the heritage feel of contributing/adding to a projwct you started years ago.
A totally rebuilt 7 as the outcome having spent less money.
And maybe the clincher, you get to keep the joyous K series on throttle bodies character you clearly. enjoy!
bertie said:
There's thr rub, and a big motivation for the change....
The R400 k on roller barrels is frankly a pain in the arse on low throttle.
The thought of a more torquey and well behaved engine is a major appeal.
bertie, it's just not set up right if it's a pain on low throttle, mine is completely smooth and tractable all the way from 750 to 8000 rpm.The R400 k on roller barrels is frankly a pain in the arse on low throttle.
The thought of a more torquey and well behaved engine is a major appeal.
IMO the duratec is too 'grown up' .. the 'k' is a brilliant hooligan engine beautifully matched to the car, the R400 6-speed just perfect .. of course I'm biased, but, like grubbster, if I'd wanted a duratec I'd have swapped it for one by now!
johnvthe2nd said:
bertie, it's just not set up right if it's a pain on low throttle, mine is completely smooth and tractable all the way from 750 to 8000 rpm.
IMO the duratec is too 'grown up' .. the 'k' is a brilliant hooligan engine beautifully matched to the car, the R400 6-speed just perfect .. of course I'm biased, but, like grubbster, if I'd wanted a duratec I'd have swapped it for one by now!
I've had verniers fitted and timed in, I've had the throttle bodies set up...IMO the duratec is too 'grown up' .. the 'k' is a brilliant hooligan engine beautifully matched to the car, the R400 6-speed just perfect .. of course I'm biased, but, like grubbster, if I'd wanted a duratec I'd have swapped it for one by now!
It's tractable, it's just that the throttle is so hyper sentative, and coupled with the backlash in the drivetrain, it makes it almost imposible to drive along at say 30mph without it clanking back and forth like a kangeroo. I put it down to the roller barrels over sensitivity / lack of progression.
By contrast, my previous car was a 1.6K Supersport 6 speed and that was lovely, but that was the normal single throttle and plenum setup, I was hoping a new Duratec might be similar??
johnvthe2nd said:
It just shouldn't be like that .. take it to track and road in Rainham and you won't be allowed to leave until they've got it running smoothly
As I say, it runs smoothly, the engine doesn't miss, cough or fart.I put it down to the combo of hyper sensative roller barrels and the backlash in the gearbox & Diff.
Also, regards weight, in the Chris Harris R400 video at Cadwell with Ali Ansar, they mention the Duratch is even lighter than the K series?
Edited by bertie on Wednesday 12th November 10:47
Dunkield said:
Without wishing to derail, there are several references to metric over imperial chassis or vice versa, apart from the obvious what are the differences?
The metric chassis has metric sizes threads (hence the name) and is mostly welded (not all joints), whereas the imperial is brazed. The triangulation in places has been changed to better accommodate the Ford engines too. Caterham say it is stiffer (and my experience is that it is). The quality of finish is not as nice as the imperial as, visually, the welding has spatter etc and brazing is smooth. Some say they are harder to repair, but my understanding is the process is identical i.e. any new section is usually brazed in. bertie said:
As I say, it runs smoothly, the engine doesn't miss, cough or fart.
I put it down to the combo of hyper sensative roller barrels and the backlash in the gearbox & Diff.
Also, regards weight, in the Chris Harris R400 video at Cadwell with Ali Ansar, they mention the Duratch is even lighter than the K series?
at the risk of going round in circles, I still don't think it's set up right .. the roller barrels are the same as on the duratechs afaik, and they shouldn't be that hyper sensitive .. mine aren't, and if they're not balanced they will give the symptoms you describe .. anyway, just saying, you could quite easily get the same problems with an R400 duratech.I put it down to the combo of hyper sensative roller barrels and the backlash in the gearbox & Diff.
Also, regards weight, in the Chris Harris R400 video at Cadwell with Ali Ansar, they mention the Duratch is even lighter than the K series?
Edited by bertie on Wednesday 12th November 10:47
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