Caterham space frame

[Nigel Riches]

Good evening sevenista's.

Does anyone out there know if there are different frame strengths for the various models of the 7 vehicle range. 

I have heard from a fellow 7 owner here in NZ that if the car he has, a 1992 live axle, and my 1982 version, have an engine in excess of 200 bhp they won't be certified for road use as the frame won't be strong enough for that power. How these certifying turkeys arrive at this is not disclosed.

So, do the later, Arch and Cage frames have different tube wall thickness (Colin is turning in his grave) for different frames for higher powered cars?  

Any info gratefully received, just trying to get some ammo to fire back.

Regards.

Nigel.

[Tazio]

As Arch Manfactruring made most if not all of the imperial chassis, why not Ask Bruce there?, if anyone knows he does. 01480-459661.

[rj]

The Caged (or Steel Fabrications) chassis is heavier than the Arch made. The Arch chassis came, albeit DeDion, with a 250BHP R500 Evo engine.

 

[opplock]

I'd get written official confirmation that there is such a rule before getting too excited. Also worth ascertaining how they assess engine power. If they were putting cars on a dyno every time they had a WOF (MOT) test I'd have heard about it. 

NZ used to have no end of bizarre regulations. Assuming it is genuine the people who dreamt this one up had no doubt never heard of a Caterham. I'd guess that it was aimed at locally built specials or beach buggies.

They did introduce a law banning imports of LHD cars about 15 years ago. A friend over there has an LHD 911. He is forever being pulled over and told that the car is illegal. To which his answer is always the same - car exempt as registered before they passed the law.   

[nickh7]

I thought it was the axles that weren’t up to it not the chassis . Elie Boone has a BDR in a live axle he modified a live axle to take the power . 

[elie boone]

i only have 170 bhp and a non std  (to caterham configuration ) Ford Banjo axle. if you ditch the dreaded A frame and go 5 link, baffle it and shim the bearings fit an LSD then 200 bhp would be about the limit of the axle. Beware even the Graduates used Rakeway can break a half shaft with 110 BHP as happened in Spa this year. A  modified Ford Banjo can take 300 BHP and i bet it's lighter than a DD tube.

[mjdm]

When I imported my Caterham into NZ in 2008 the low volume type approval inspection never touched on the subject of engine output power. I've never had it on a dyno so have no idea what its putting out and was never asked what it might be by the inspector.

If this is a genuine regulation then it must be post-2008. I would read up on it to see if the regs have changed. You could try here - https://www.lvvta.org.nz

Mike

[7 wonders of the world]

Live axle equipped cars have an overall lower weight than a DeDion car however the unsprung mass of the LA is higher than the DeDion set up and has no adjustment for rear geometry....

[Matthew Willoughby]

Slightly OT but just to correct Elie's post above, the Grads car that lost a wheel at Spa was due to the halfshaft nut coming loose and then falling off rather than a Rakeway halfshaft failiing. In Grads there has only been one Rakeway failure in 10 years.

[elie boone]

Matthew, i had the Rakeway hub with a piece of half shaft in my hands in the Mc Millan stand at Spa and even when the half shaft nut loosens it should not result in a breakage.  There was a old crack about 1/5th of the axe just ask Graeme Smith as it was his classic that had the failure