Newbie help needed - 310 or 360 or 420

[7 wonders of the world]

Duratec sump....

The dry sump offers and addition 38mm of clearance on the vulnerable front edge, as well as offering a lubrication system that has increased oil capacity.

Many owners myself in included have cracked wet sumps on compressions despite having uprated springs and a well set up car.

DS is a no brainer.

 

[Handwheels]

Thanks for all the comments - lots of food for thought. Main things & questions that jump out to me are;

LSD - I hadn't really picked up on the concerns about the Titan diff of doom before. Just spent ages reading the 'BMW/Titan LSD viability' thread - very interesting & I'm now questioning my plan to include one in my spec. Sounds like I had the same experience as everyone else who has test driven a car at CC and questioned the painful clunking of the diff - "they all do that and you're sitting right on top of it". It seems like the sensible thing to do is to get an open diff and then get SPC to convert it.

Not sure if I would have to wait until my CC warranty run out before doing this. Would welcome any thoughts on what it would be like driving a 420 with an open diff in the meantime - although a 420S has an open diff as standard.

R or S Pack - Now beginning to think the S Pack might suit my needs better, plus a 420S would be slightly more affordable than a 420R. Also the S comes with an open diff, although I'll give CC a call to see if they would supply a 420R with an open diff & check how much they'd cut the price by. My original thinking was that if I'm finally going to get a Seven I might as well get as hardcore one as possible.

310 or 420 - Before I posted my initial post I had concluded that the choice was really between a 310 & 420, & not a 360 (due to my wet sump paranoia). Seems that this is the general consensus. ChrisC - you mentioned that you increased the ride height on your 360. How did that affect the handling? (i've been studying your excellent blog in great detail!)

I know a 310 would suit me perfectly, but I am defiantly drawn to a 'bonkers' 420 & am doing lots of man-maths in my head to justify the extra expenditure.

Hood options (Mandalman) - Even if I'm going to do some trips to wetter parts of the UK (i.e West Coast of Scotland), would it be sensible to ditch the full hood that no one seems to use, & get a half hood & shower cap instead?

Tyres/Wheels - now I've started looking at the 420S on the CC configurator I've noticed that the standard wheels are 14" with 185/60 tyres front & rear.  I don't want a car with too much grip, but surely with 210 horses I'd need to upgrade to 13" wheels with 8" on the rear? I'm surprised that 185/60 on the rear is even an option.

Finally, CTRMint - I've had to stop looking at your blog because it's causing me too much painful garage-envy.

 

Cheers, R

[ChrisC]

My 360R had a flat floor setup during Post Build Check, at the time Caterham gave three ride height options, Road, Aggressive road or Race.  I choose Road, mainly to ensure I could get my car on the drive.  

I never hit the sump in 2 years of driving on Essex roads, it handled well, mainly due to the flat floor setup, but ultimate lap time would have been compromised. Not that matters over being able to get it on the drive. 

At the moment my 420R is set high, Caterham now only perform a flat floor setup after 1000 miles.

Oh and on the diff question, loads of noise about this at the moment, but this is a problem I have been aware of since 2018, and yet I still ordered a car with the R spec/Titan LSD unit.  I was always going to monitor it, and decided my course of action when need.  After all a new kit will have a warranty meaning its not a financial problem for the first two years at least.   

I bet Caterham haven't got a demo 420 with that tyre combination.     

[7Up]

My feedback for you (2 years of 420R):

- I find it underpowered (in a straight line), so would not recommend smaller engine 

- can't control the diff potential issue, so don't worry about it. Cross that bridge if/when it comes. The car is worth it!

- my car is on the 'coke can' height limit. I have to avoid the narrow speed bumps, but the long ones are fine and not had an issue to date

- have never used the full hood, only half hood

- wish i had the shift lights

Enjoy!

 

 

 

 

 

[JonT]

I've only taken the halfhood and a showercap on my Alps trips, including coming down Stelvio in a snow storm. The biggest problem is that rain can run down the roll cage and into the boot, so everything needs to be in properly watertight bags. The roof is quite claustrophobic and the ventilation terrible, so you'll steam up worse and overheat too.

[ScottR400D]

OP, I don’t remember if you’ve said but are you building this car yourself? 

If so, it’s a no brainer to get an open diff and have an SPC LSD fitted it will cost you £3/400 more but will be right from the start. 

I doubt you would get any warranty issues, plenty of kits get built with a few non CC bits in them. 

If you’re buying ready built I’d talk to CC about them fitting the LSD with an SPC or get open and do it afterwards. 

I take the point of the car being under warranty but sooner or later you’ll be running an out of warranty car with a Titan. 

[John Vine]

Re #29:

My feedback for you (2 years of 420R):

- I find it underpowered (in a straight line), so would not recommend smaller engine 

Was that a typo or do you really regard the 420 as lacking power?  What are you comparing it with?

JV

[Handwheels]

If you can do a snowy Stelvio (sounds amazing) with a half hood then that's made my mind up - interesting to see how much cc reduce price by when i 'down grade' to a half hood. II can dust down my old walking/cycling Ortlieb bags to keep my stuff dry.

Thanks

[Handwheels]

7Up - I need to work out to delete your comment "My feedback for you (2 years of 420R):- I find it underpowered (in a straight line)" - if my son sees that he'll start sending me links to adverts for secondhand 620Rs again!!

You mentioned wishing you had shift lights. Is that for track use, or do you miss them on the road too? This could be something for my winter 2022 upgrade list :)

Cheers, Richard

[Handwheels]

ScottR400D - I'll be getting a kit so will consider the option you (strongly!) suggest.

Appreciate that other feedback is go with the standard Titan, and then when it needs a rebuild after 2 years I swap it out for a SPC. Based on the 15 pages of comments in the recent Titan thread I'd be working on the assumption that the lifespan of my one (in a mainly road used Seven) would be low end of 'not very long', especially if I do go for a 420. Yet more food for thought...

[JonT]

Here's Stelvio. Note the altitude and the snow on the windscreen.

 

I was back the following year - this time the pass was shut due to the depth of snow. Still only a half hood!

[DougBaker]

Tonneau covers are more useful than any form of hood in my view.

With only a driver in the car the passenger side tonneau keeps half of the cockpit warm and reduces the amount of wind chill. You can put the unused driver tonneau over your legs in a real downpour to keep your legs dry. Goretex sorts out the rest.

I have used the full hood in the past though not very often, it makes for a more relaxing and less tiring environment when driving long distances in poor weather. Back from a track day in Anglesea to Surrey as an example. While we have taken the roof with us on our European trips I am not sure we ever used it abroad despite rain and snow, far less water than you would expect gets to the passengers once you are moving at a reasonable speed.

Just after taking this photo a passing German offered my wife a lift down the mountain in his Merc, she declined 

As to power and engine choice if there are limits to what you can spend then £1000 spent on driver training will do far more good than that same money spent on a extra bhp/torque. 

[7Up]

no typo! there are plenty of modern cars which are quicker and i often find it needs more. I really stress here in a straight line!

[7Up]

no typo! there are plenty of modern cars which are quicker and i often find it needs more. I really stress here in a straight line!

[7Up]

Regards shift lights, I would say mainly track, but occasionally road too. When concentrating ahead, its impossible to look at the rev counter (for me anyway).

 

[JonT]

Are these straight line issues at higher speed? ie where the caterham aerodynamics are really costly and the low weight no longer offers as much advantage? I'm really wondering what cars are faster than a 420 at country road speeds.

 

[ScottR400D]

#35, Handwheels. 

If I was buying a kit, knowing what I know now, I’d definitely spec the open diff and have it SPC’d before I installed it.

Other than the extra £3-400 cost I can’t think of any reason at all not to.

[Handwheels]

Thought it was time for an update as two months later I've finally made a decision and signed on the dotted line this morning.

Eventually settled on a S3 420R with lowered floors as its bonkers Jekyll & Hyde character was just too seductive, but mainly to prevent the 'what if...' question popping up in the future.

Options I've decided to go for are 13" Apollo wheels (8" at rear), interchangeable windscreen/aero screen (last minute addition), battery cut-off switch, track-day roll bar, leather seats, removable Momo wheel & heater. I had already decided on the colour (vintage green with yellow stripes) about 30 years ago - so that was the one simple choice.

Really appreciate all the amazing and invaluable advice I got from my original posting - ChrisC your offline comments and offers of support deserve a special thanks.

Now just need to convert my carport into a garage and then build it...

[Nigel B]

Good choice! I am a little biased though, I've had my 420R for eighteen months now & I'm still loving every minute.

Mine also has all the options you mentioned, although I went for blue! I know what you mean about the Jekyll & Hyde character. They're incredibly docile & tractable & will quietly burble through town with no complaints, but as soon as you squeeze the throttle, all hell breaks loose!  
 

Are you building it yourself? When do you expect to take delivery? 

[Handwheels]

I'll be building it with assistance from one of my sons. He's recently started an apprenticeship with Ford so will be doing an additional Caterham module next year!

Delivery is due sometime in May, although wonder if Brexit &/or Covid will slow things down a bit if components get held up.

[Nigel B]

That doesn’t sound like TOO much of a wait, by Caterham standards, although I’ve no doubt it will still be agonising!

It’s great that you have a willing & competent helper! I bought my 420R second hand, although I did build my first Caterham. That was a live axle, Vauxhall engined car, back in 2002. It went together pretty smoothly, once I’d worked out what parts I had & what was missing (the rear axle, for example!). It might be a good plan to perform a thorough parts check before you start, so you can chase up any missing parts immediately. 

Having a good peruse of the assembly guides in advance is a good idea too, as well as looking at people’s build blogs, though I’ve no doubt you’ve probably already had a look at some of those. You mentioned Chris Collins above. His build blog is fantastic & he’s a very helpful chap, both here & on the Facebook groups. He’s helped me out on a number of occasions. 

Anyway, enjoy the anticipation! 

[Billy.Whizz]

Great choice, sounds exactly the same as mine except for the yellow stripes. I take delivery april/May (factory build tho). I'm also in the Essex group, so look forward to seeing you sometime soon.

Bill.

[ChrisC]

Hope we can meet soon at the club night (restrictions permitting).  

Building a car is a journey, not always one that follows the expected path.  I am sure you and your son will have a fantastic experience and the sense of pride a joy you get when your car passes IVA is fantastic.          

Oh and nice car choices, can't wait to see it :-)

[Handwheels]

I'm looking forward to when we are allowed to meet up at Gt Baddow, and eventually joining my first Essex blat in my completed Seven is definitely one of my major targets.

Sure you'll be hearing lots from May onwards!

[Purplemeanie]

Handwheels, Can't go wrong with a 420R! But I am also biased!

ChrisC's website is a fantastic resource now... and goes way further than anyone else, my Purplemeanie site included. But if you want something to put you to sleep then my site is reputedly a great option! :-)

At the risk of another bit of self promotion, I'll point you at my build video too. It's a bit bonkers how many people have watched it now, but I suspect its more entertainment than education, but you might get a kick from it if that's your thing.

Also, if you haven't seen it already, Caterham Cave is doing a good series on building from kit, though he's not finished editing and uploading the full series yet...

And finally, you can find a list of many of the build blogs here if you haven't found it already...

https://www.lotus7.club/guides/getting-started-guides/build-blogs

Good luck with the build!

John