Looking for thoughts on caterham integrated dash

[TurboWood]

This is my first post so let me start with hi. I don't have a lot of experience with 7's, but have been a car guy for all of my life. I've owned various sports cars over the years, but after reflecting back on the joy I got from each it became clear that less weight and fewer driver aids = good.

 

Now down to business-ish , I've just placed a deposit on my first 7 kit. I've decided on a Caterham, but haven't made up my mind on the interior. This will be a 90%+ street car with the occasional trip to the track.

 

I intend to use the quick-release steering wheel either way, but I can't decide between the integrated dash and standard. Instead of trying to do this blindly I would like to get some opinions on each.

 

Is there anyone that has the integrated dash and regretted it (for whatever reason)? How annoying is it to manually turn the signals off with the standard dash when using the car regularly around town? Are the lowered floors with the integrated dash annoying for any reason?

 

Thanks,

Daniel

[twobone]

I find the basic dash great. The turn signal switch falls right at hand when driving. Also its so retro basic that it fits the character of the car. It also gives passengers the giggles.

[Croc]

First a point of clarification. By integrated dash I assume you mean the curvy/swoopy design as pictured half way down this linked page?

 

http://usa7s.com/vb/showthread.php?t=6281

 

Assuming that I understand you correctly then I have one of these in my CSR. It was not actually my choice as I jumped on a kit that had it spec'ed where the owner had to sell it before construction.

 

The good

- Easy to use, easy to see dials

- Turn signals are wonderful after multiple sevens with the original dash

- looks pretty :cooldude:

 

The bad

- Insanely hot bare metal chassis tubes running down the tunnel length - I get a burned right elbow. The regular dash covers up these tubes in pleather/vinyl capping.

- steering wheel too low in my lap to be ideal

- does not allow removable steering wheel

- the curved opening for the legs limits my knee room for pedal work. I am a fairly chunky character so this may not be an issue for you.

 

 

On balance, I would not do an integrated dash again. I would go standard dash, regular dials and removable wheel. I have zero regrets with the rest of the car and would spec it the same way again.

 

Some other clarifications:

- This integrated dash option is CSR only. It is not available on the S3 or S5 (SV) chassis

- The integrated dash uses a Rover Metro steering column to get a indicator/wiper binnacle. For this reason it will not allow a removable wheel.

- If you go standard dash then construct it with a delay module on the indicators where they cancel after some time period 20 seconds or so. There is a thread on Blatchat to this effect.

- The lowered floors are an independent choice from the dash choice. I am 5'11 and think the lowered floors are brilliant. I have tried them in Caterhams of both dash designs and think they work well. If you are a midget then I would not suggest the lowered floor option but everyone over 6 feet should consider them as standard.

 

If you are around the NYC/Philly area I would be happy to show you my car for you to make an informed decision after seeing it in person.

[TurboWood]

Thanks guys, that's very helpful. I do like the idea of a passenger giggling and then quickly shutting up as the car rockets to 80mph at 1g.

 

Mike, I had found your thread a week or so ago and have been staring at the pictures ever since trying to decide. Your comments about the wheel not being removable are a surprise though. The US sales rep and the order form clearly depict the integrated dash coming with lowered floors and a removable momo steering wheel as standard. I wonder if they have made some changes since your kit was made??

 

Your feedback on the lowered floors are great though. I'm also 5'11", but was not sure they were a good idea. I hate the feeling of being too low in a car, but it sounds like that may not be an issue. The worst example from my experience are corvettes. You can't see where the front of the car is. Do you know how much lower the lowered floors are? If I wear a helmet with the standard floors will I risk being taller than the rollover bar?

 

The hot tubing definitely isn't attractive. I had not given that any thought at all.

 

Thanks,

Daniel

[Croc]

I have the track day roll bar which gives my head 2 inches of clearance with helmet. The lowered floors add 1.5 inches (roughly) and so without them my roll bar head clearance would be marginal.

 

Even though I am lower I can still see the tops of the front wings which is my front extremity. A corvette nose slopes away so you are not sure where the front corners are. I think lowered floors will be a good addition - a Caterham with lowered floors and aeroscreen is still a very airy position on track and you will appreciate the lessened wind buffeting on road when touring. Best way to check head clearance is to try a Caterham on and ask an observer to check your head clearance. If you are concerned then spec the tall track roll bar. I know they say the integrated dash comes with lowered floors but Caterham UK factory told me they can special order without when I visited in November 2010 - hypothetical for me as I wanted the lower floors. Caterham USA were not aware of this until I discussed what the UK told me.

 

If it helps I am back with my car on June 13 and can take an eye level photo looking forward to help you gauge?

 

If they can do integrated dash with removable wheel then this is a change since the 2011 model CSRs - a very welcome change - as it is a challenge getting into a CSR with the fixed wheel.

Edited June 2, 2013 by Croc

[Kitcat]

Croc:

 

Does the 2" taller roll-over bar come with a top that still works? Or does getting the taller bar eliminate the top?

 

And, can you achieve the same "lowering" result by going with Tilet seats and a non-lowered floor? I know you chose the more comfortable standard CSR seats, but did that have the effect of positioning you higher?

 

Turbowood:

 

Are you building the car yourself, or is Cat USA or someone else doing it? What will the paint color and scheme be? When are you hoping to be on the road?

Edited June 2, 2013 by Kitcat

[Croc]

Croc:

 

Does the 2" taller roll-over bar come with a top that still works? Or does getting the taller bar eliminate the top?

 

And, can you achieve the same "lowering" result by going with Tilet seats and a non-lowered floor? I know you chose the more comfortable standard CSR seats, but did that have the effect of positioning you higher?

 

 

With standard (non-lowered) floors and standard roll bar/standard track day roll bar was marginal clearance for my head - maybe an inch.

 

Adding lowered floors creates about 1.5 inches extra clearance.

 

Adding the tall track day roll bar creates another 1.5 inches clearance (over the standard track day roll bar).

 

Going from regular leather seats to Tillets gives you an extra 0.5 inches and if you take out the seat track for fore/aft movement you gain a further 0.5 inches.

 

All of the above are incremental changes.

 

The hood is put together for your roll bar type - so you do not go without.

[scannon]

Mike,

 

Have you considered Lizardskin coating on those hot tubes on the console?

[rnr]

If I wear a helmet with the standard floors will I risk being taller than the rollover bar?

 

Dont forget that the windshield on a Seven is non-structural. To truly pass broomstick you should measure from the rollbar to the engine block which is quite a downward slope.

[TurboWood]

Kitcat,

I am intending to build it myself, but it will be a while. The kit is supposed to arrive in Denver in September, but I don't return (permanently) until January. I've been on a work assignment in China for what will be three years. I've also not decided on the engine. The Duratec is a nice (but expensive) option. I'm a turbo guy and really want the ability to get 300hp. A turbo K20 or the Volvo T5 are at the top of my list at the moment, but we'll see. One of my close friends is pushing an N/A K24, but I'm not sure it will fit (too tall). I ordered one of the 40th Anniversary versions so the color was fixed, but I like red.

 

Croc,

Thanks for the additional information. When I look at pictures of you driving (http://www.usa7s.net/vb/showthread.php?t=6594&highlight=lowered+floors&page=3) I agree it looks like you have 2" of clearance assuming the roll bars are 2". The top of your head is close to the bottom of the cross bar. I would definitely welcome pictures, but I think you have already sold me on a lowered floor.

 

rnr,

You make a good point. Do any of the Caterhams actually meet this? Looking at pictures of cars it seems unlikely that even lowered floors would protect the driver per this rule. I also see that the real racing Caterham's have full halos which suggests it's needed or is that just a mandate by the rules?

 

Thanks,

Daniel

[rnr]

rnr,

You make a good point. Do any of the Caterhams actually meet this? Looking at pictures of cars it seems unlikely that even lowered floors would protect the driver per this rule. I also see that the real racing Caterham's have full halos which suggests it's needed or is that just a mandate by the rules?

 

Broomstick rules are typically for track days but most clubs in the west coast dont measure it themselves. Full on racing mandates a cage which creates a new hard point over the windshield and allows you to pass broomstick.

 

In the end its all up to the driver and the their risk tolerance - my car(below) does not pass broomstick to the engine either. I do plan on adding a removable secondary hoop at the front for track days but felt that the side impacts were a greater risk than a rollover which is why I had those added first.

 

http://farm5.staticflickr.com/4030/4678659725_4936566f86_z.jpg

[Croc]

Dont forget that the windshield on a Seven is non-structural. To truly pass broomstick you should measure from the rollbar to the engine block which is quite a downward slope.

 

For one track day I was actually tested with a stick from top of roll bar to the front of the engine block. For the record I pass although it is close. In the NE if a Caterham has a low engine block then the broomstick rule has been applied to go from the roll bar to the chassis tube under the nose cone in front of the engine.

[TurboWood]

It's difficult for me to see why Croc's car is ok and rnr's car is not, but the point is taken. Lowered floors sound like a good move for somebody my height. If I end up racing it more frequently than I anticipate then I'll have to consider a track-day bar.

 

Does anyone have any comments on engine? I've seen photos of a K20 in a 7, but never a K24. How much "spare" room is there in front of the duratec (in the event I tried to squeeze a 5cyl in)?

 

What about transmission? I'm tempted by the S2k box as they can be found much cheaper than the caterham unit and are robust to 300+hp.

 

Croc,

In your original thread you had mentioned that the caterham 6-spd was a bit notchy. Has it smoothed out now that you have given it a good beating?

[Croc]

It's difficult for me to see why Croc's car is ok and rnr's car is not, but the point is taken.

 

My car is ok for HPDE/track days because it can pass a broomstick test. My car will never be acceptable for racing. For the east coast, SCCA/NASA want a full cage for racing. There are posts on here by Blubarisax on his quest to develop an acceptable cage on Caterham that satisfies the bureaucratic SCCA flunkeys. RNR's car would not be acceptable for racing on the east coast because it is not a full cage but he would be welcomed for HPDE/track days where things are more flexible.

 

 

In your original thread you had mentioned that the caterham 6-spd was a bit notchy. Has it smoothed out now that you have given it a good beating?

 

It has got better with age plus I am more used to the tight gate spacing on the gear box.

 

If I was doing a lot of touring like you are thinking I would suggest you explore getting a custom BGH gearbox from the UK with a usable first gear and an overdrive 5th combined with a 3.41 (or possibly even 3.3) diff ratio. This would reduce revs nicely for 5th gear cruising. Mine sounds busy at 70mph.

[Kitcat]

FWIW-I have owened a 5 sp Cat and 6 sp, and driven a member's Ultralight w/Honda gear shift. I liked the Honda best (short, precise shifts), the 5 sp Cat next, similar just not quite as slick, and 6 sp least (very hard to tell what gear you are in or to find the next, exp after all that "muscle memory" associated w/5 sp tells you you are in the wrong gear). As I am learning it, tho, it is growing on me. It is nice to have 2 more usable gears than the 5 sp , in wh/both 1st and 5th are irrelvant at most tracks. But all these trannys are excellent.

 

Skip Cannon (see scannon post above) has a 300 hp Miata turbo in his Caterham. Its cheap, relaible and tons of parts are available. That wld be on my short list of engine options.The Miata 5sp seems to be robust and they make a 6 sp as well. I owned a Miata 5 sp and wld rank its transmission equal to or better than the 5 sp T9 transmission. I suspect Skip had a build diary that shows how he put his car together.

Edited June 4, 2013 by Kitcat

[TurboWood]

Attached are a couple example vehicle accel curves based on a dyno plot I pulled from the internet for the 260hp Duratec (random, but hopefully close). You can see it in the top right of the plot.

 

Assumptions:

10% drivetrain loss (optimistic?)

Drag, 0.7cd

Area, 15ft^2

Rear end, 3.38:1 (std for CSR)

First plot: Caterham 6spd

Second plot: Honda AP2 6spd

 

My conclusion from this exercise are:

1) Cat gearing is good, but 70mph cruise engine speed is high >3000rpm

2) Honda 1st gear is too short, but 2-6 are quite good (70mph cruise at ~2700rpm)

3) Cat gearing allows for 60mph at 8000rpm which would be perfect for a Honda K20 (maybe K24), but is pushing it for most other engines (Duratec probably ok)

 

Comments?

 

Daniel

[Kitcat]

It hurts to see that cd in writing:).

Drive train loss is optimistic. Hard to get a handle on since hp estimates are always so optimistic. I think 15-20%+ are more typical in these cars.

3000 rpms at 70 doesnt seem too bad. With all the wind noise, vibration, flapping, you likely wont notice. And for most motors that is near their sweet spot, so not overstressing the engine.

My X-flow powered Cat turned around 3500 rpms in 5th @70 mph and I pilled up a lot of miles at that speed with no adverse effect on engine/driver.

Edited June 4, 2013 by Kitcat

[Croc]

Rear end, 3.38:1 (std for CSR)

 

Standard spec for a diff ratio on a CSR here in the US has been 3.62:1 which is what I have. 3.38.1 is rare but personally I think it would be a good ratio to have.

 

This means at 70mph I am not far off 4000rpm in 6th. My theoretical top speed with my gearing and tires is 150mph at 7800rpm which is the redline for my spec duratec engine. Not that I have ever seen that speed - I keep it to 7000rpm which equates to about 135-137 area. With the billet crank you can up the duratec to 8500rpm and it loves to rev.

 

I think you run into the problem that the standard T-9, the Honda Ap2, etc are all designed for large heavy cars which need a low first to get things off rolling from rest. The Miata gearbox is designed for a small light car and so should give a better match up. The Caterham 6speed works well but is intended more as a circuit box (and the ratios are perfect for that) and so limited cruising abilities.

[TurboWood]

The miata boxes actually aren't any better.

 

1st gear ratios:

Miata 5: 3.163

Miata 6: 3.815

S2k Ap2: 3.133

Cat6: 2.69

 

The Caterham6 definitely has the best first gear, but it's such a close ratio 6. I wonder if there are customer gears for the S2k box?

[Croc]

The puzzle you are looking at is why I have always thought getting a custom ratio BGH 5 speed box provides the best solution long run. Ok so it is not 6 speed but you can have 5 well designed and spaced ratios for a decent price (at least compared to the Caterham 6 speed).