Are Duratec upgraders doing any chassis/diff bracing ?

[k80rum]

Apro-pos of nothing, I thought back the other day to the trials and tribulations Arnie went through with K2RUM's chassis around the diff hanger area, because the torque his VX was pushing out.

 

Given that Duratec installs are getting more popular and must be stumping up similar amounts of grunt, are people who are upgrading to the big torque Duratecs doing any precautionary strengthening, or are more recent chassis better braced anyway?

 

Darren E

 

K80RUM Website and Emerald maps library

 

Superlight R #54

 

 

 

Edited by - k80rum on 26 Jun 2008 14:17:01

[rgrigsby]

I've had the braces added to the diff carrier at the back but other than that I didn't have anything done. I''ve been running with around 260bhp and just over 200lbft for the last 3 years including track days, sprinting and fast road use and not had any problems.

 

The torquiest(?) Duratec I've heard of made 225lbft but it was fairly high up the rev range so I suspect unless you are bolting on a turbo you won't have any problems with a later chassis and the basic diff bracing.

 

Rob G

www.SpeedySeven.com

[k80rum]

cheers Rob. I'd assumed a 200 lb/ft benchmark. I can't remember what Arnie's VX was producing but it must be close as it was NA.

 

I'd like to go the Duratec route at some point and hadn't thought of a chassis refresh as part of the process. Sounds like it'd be worth the trip back to Arch though for some basic bracing.

 

Darren E

 

K80RUM Website and Emerald maps library

 

Superlight R #54

 

 

[rgrigsby]

I don't think too many VX's have got past 180-185lbft, mines a 2.3 so the exact capacity makes quite a difference

 

Rob G

www.SpeedySeven.com

[I.Mupferit]

Mine is a similar engine to Robs and I have the additional strengthening gussets fitted around the diff carrier. I know EFA did his own thing (in consultation with Peter Carmichael possibly?) to his chassis which I believe was a different approach to the one Arch use.

 

Not having seen his, I couldn't comment on the comparative merits or otherwise of either approach except to say the gussets on mine don't look as though they have added a great deal of strength. Having said that, I don't keep doing doughnuts or drag starts with fat sticky tyres on mine so maybe it is sufficient.

[k80rum]

Fair point Brent. Full chat standing starts and donuts probably play a significant part. Arnie had a pretty agressive clutch too if I remember rightly.

 

That's a 100% response in favour of increased bracing so far. It seems like a sensible investment to me, given the cost of the upgrade and the hassle of sorting everything out if an under-braced chassis gives up the ghost.

 

It looks from Arnie's site that it was a combination of torsion and shock loads that caused the nickel bronze welded joints to fail. He mentions changing from 4 to 6 diff mounting points and TIG/MIG welding the extra bracing. Interestingly I notice he also took the opportunity to put some hoop/plating in the transmission tunnel. Another worthwhile upgrade if the chassis is being refreshed

 

Darren E

 

K80RUM Website and Emerald maps library

 

Superlight R #54

 

 

 

Edited by - k80rum on 26 Jun 2008 15:32:41

[Irrelevant]

IIRC, Mr Webb's problems were down to his sequential box, a race clutch, and no cush-drive/rubber coupling - i.e. undamped shock loading that caused cracking.

[k80rum]

That's what I read into it when I checked his site just now Adam. It sounds like that was the major contributing factor

 

Darren E

 

K80RUM Website and Emerald maps library

 

Superlight R #54

 

 

[peterg]

Darren, Arnie used Paul Ashwick to do the welding on his chassis and AFAIK was very impressed with the work, Paul is an occasional visitor to the WSCC Surrey Area meetings at The Parrot that I think you've attended in the past as well

 

Google for 'Steel the Scene' in East Grinstead for his contact details as that is Paul's company, I'm sure he'd be happy to help

[k80rum]

Thanks Peter Duly noted. I spotted a photo of the work that was done and it certainly looked good.

 

I must get down to The Parrot again this year. I'm getting withdrawl symptoms (especially for the burgers! ) I think I need to abandon my wider wings project for the time being, put the old ones back on to get out and make the most of the rest of the summer

 

Darren E

 

K80RUM Website and Emerald maps library

 

Superlight R #54

 

[Peter Carmichael]

Arnie's chassis is pre-'96 so has the much weaker arrangement of the diff mounting. I had a fair few conversations with Arnie in the process of him getting the reinforcement work done.

[Anthony]

Darren,

 

Suggest having a chat with Bruce at Arch. He was incredibly helpful.

 

My chassis was upgraded to cover VX torque (295 bhp and 214 lb ft), this covered comprehesive work to the diff cage with thicker tubes/flanges, and using thicker guage sheet for bulkhead and floors. There were a myriad of minor changes to the chassis which Bruce addressed brilliantly. They also used steel rivets in the construction.

 

 

 

 

[k80rum]

Thanks chaps

 

Will do Anthony. I think if(when) I start down the power-upgrade route, it'd be worth my while getting a once-over from Bruce to get the latest revisions added to the chassis along with some bracing. It's a '99 vintage so there's bound to be quite a few changes that could be incorporated.

 

Darren E

 

K80RUM Website and Emerald maps library

 

Superlight R #54

 

 

 

Edited by - k80rum on 27 Jun 2008 12:00:32

[millsn]

Speak to Bruce. He is likely to orecommned that you use thicker gauge tubing in the dif area if you're replacing that bit. Apparently the failure mode is that the tube itself, rather than bending, gets a piece torn out of it where the next member attaches to it. It's therefore the gauge rather than any lack of bracing that resolves the problem.

[Mickrick]

To answer part of your original question. Yes, the newer chassis (My 2007 Arch one)

Have extra gussets on the diff mountings.

But I did spec. it for Duratec.

Can't speak for the new new ones stuck together with bird ****e though!

 

Academics are seldom any use at engineering. One must have a mistrust of theorists. (Keith Duckworth)

[dannylt]

I think mine was the car quoted with 225lbft? Sadly not any more - that was the 2.5 engine. My standard duratec chassis car has been inspected by Fauldsport throughout with no diff carrier problems yet. We replaced the propshaft cos it was cheap and the diff was toast. I usually use 6" ACB10's and mostly clutch on upshifts, which I'm sure saves the strain on the transmission.

[dannylt]

PS Stuart wants to put the extra strengthening bar for the diff carrier as per the C400 race cars to mine over the winter anyway. Only downside seems loss of luggage space, but I already have the battery and catch tank in there.