Coupe Weight-saving Ideas

[MikeNZ]

Someone on here (Booty?) suggested that shedding 100kg or more on a Coupe quattro was quite do-able. So I got to thinking as I am thinking of doing some weight reduction foir performance enhancement, and am intrested in any BTDTs from anyone.

Some of these ideas are more viable than others due to the cost/weight/benefit issue, but these are a few I've thought of:

Using non-height adjustable seat frames as they are definitely lighter. Not so good for tall people unless they can be lowered/cut down a bit.

Replacing seats with lightweight Recaros as factory seats are heavy.

Installing a factory fibre boot lid as used on later Ur-qs (though the weight loss might be a bit marginal, especially given the stupid prices quoted for these - anyone know what is the actual weight difference?)

Lighter exhaust when it needs replacing anyway.

perspex rear side windows

Stereo delete (incl speakers, but leaving grilles in place to cover holes)

Fibreglass bonnet (anyone know what is weight saving?). Aftermarket fibreglass panels sometimes don't fit right though.

Lighter wheels (wheel choice is limited enough even without considering weight saving!)

Using a space saver spare, or even replacing that with can of foam like new cars. Bit risky for longer trips.

Lighter radiator (aluminium?).

Anything else in engine bay that could be replaced with something lighter - brackets for alternator or ps pump??

Removing towbar if your car has one. Mine does (very corroded) and it is coming off soon.

Carbon sunroof panel (would also avoid corrosion issues between the 2 skins of the steel sunroof panel) Better to find car with no sunroof to begin with, as no drains to cause A-pillar corrosion.

Eat less, do more exercise!!!!!!!!!

These might start the ball rolling, am interested in what others think.

Along the same lines of subtle improvement, to reduce drag and smooth airflow underneath, use slightly trimmed Ur-q ducts under radiator and the matching one on the opposite (driver's) side (on non-turbo Coupes there is big hole underneath on drivers side behind bumper - smoothing this might help drag slightly). Or use a B4 plastic undertray suitably trimmed to help smooth airflow underneath.

[Alfashark]

All of the above sound quite feasable (I'm guessing this is still going to be a road-legal car)

As far as the fiber bonnet and bootlid go, there can be MASSIVE weight savings made (not sure about CQ's in particular) but I did have a friend with a Z32 300ZX, from memory the bonnet on that was comparable in weight to the one on my CGT, we took moulds of it and passed it on to a friend of a friend who made a really nice fitting fiberglass one... as long as it was balanced right, you could hold it up on the palm of one hand with ease.

The carbon sunroof idea sounds good too, if you cant find a CQ without a sunroof

Not so much as weight reduction, but weight shifting... how about moving the battery back into the boot? It wont really change how much moment-arm the mass of the battery has, as it will still be roughly the same distance from the back of the car as the existing battery is from the front (still with me?) but it does have the opportunity to move some of the weight rearwards and more importantly lower in the chassis.

Just thinking out loud there, as I have never seen inside the boot of a CQ, so I'm not sure how much less space there is compared to a CGT...

[4v6]

Aluminium flywheel will make a very noticeable difference in the lower gears and make the engine more responsive.

Loss of approx 10 pounds of flywheel weight can equate to something like losing 100 pounds off the weight of the car and although not super cheap, it will very definitely work well.

[Isimmo]

Jay (Puglife) and I have spent many a happy hour working this all out, including corner balance weights etc. Jay has quite a compehensive list of the weight of items (Ur quattro) and there are a few surprises.

Firstly, the Audi Fibre bootlid is close to the weight of the steel one, so no major gain there. And an after market fibreglass bonnet will also be similar in weight (might even be heavier) than a steel. Kevlar/Carbon will clearly be lighter, as so will your wallet.

Seats wise, there is some serious weight in them, replace with lightweight Cobra or similar.

Ditch the rear seat, spare wheel and as much trim as possible, rear cards, parcel shelf covers, speakers, seatbelts, the lot.

Fit harnesses.

Alloy wheels are pretty important too, expensive, normally = light alloys . So if it's running aftermarket alloys they may weight several kilos more each. And that is unsprung weight.

Then there is, for the seriously intent, the carpet and insulation... This is bloody hard work, and makes the car pretty hardcore, but will save quite a bit.

Then it's on to the doors, these can be replaced with carbon, so can the roofskin. GT wings in carbon will have to be specially made.

Finally... (or should that be initially) you'll save weight going for a 4 pot, and it can be made to make similar power to the 5 pot...

[Emjay]

Originally Posted by Isimmo

Finally... (or should that be initially) you'll save weight going for a 4 pot, and it can be made to make similar power to the 5 pot...

Ian that last sentance is sacrilidge. May save weight but you won't get that noise

I should know having just blasted around the business park at work this morning. Boy have I missesd the sound of that engine revving it's nuts off and making sweet music like nothing else....now take that back young man and repent!

[Puglife]

Not yet complete and taken from a 1986 UR but gives a very good idea of area weights, i am doing a wieght location diagram to show weights in particular sectors of the car as well.

http://www.t85q.com/jay/weightlist.html

[moonwatcher]

Originally Posted by MikeNZ

Someone on here (Booty?) suggested that shedding 100kg or more on a Coupe quattro was quite do-able. So I got to thinking as I am thinking of doing some weight reduction foir performance enhancement, and am intrested in any BTDTs from anyone.

Eat less, do more exercise!!!!!!!!!

These might start the ball rolling, am interested in what others think.

Along the same lines of subtle improvement, to reduce drag and smooth airflow underneath, use slightly trimmed Ur-q ducts under radiator and the matching one on the opposite (driver's) side (on non-turbo Coupes there is big hole underneath on drivers side behind bumper - smoothing this might help drag slightly). Or use a B4 plastic undertray suitably trimmed to help smooth airflow underneath.

With regards to Eat less, do more exercise!!!!!!! you could go to the loo, that could save a bit of weight (not coupe specific)

[20vcqdriver]

Originally Posted by MikeNZ

Replacing seats with lightweight Recaros as factory seats are heavy.

Installing a factory fibre boot lid as used on later Ur-qs (though the weight loss might be a bit marginal, especially given the stupid prices quoted for these - anyone know what is the actual weight difference?)

Lighter exhaust when it needs replacing anyway.

perspex rear side windows

Stereo delete (incl speakers, but leaving grilles in place to cover holes)

Fibreglass bonnet (anyone know what is weight saving?). Aftermarket fibreglass panels sometimes don't fit right though.

By modern standards the seats are lightweights, but fitting proper rally jobs would save a few Kg.

Lightweight exhaust could end up a false economy in the long run for the sake of a mere 5kg.

As mentioned there is little difference in weights between steel and fibreglass boot lid and bonnet.

The series 2 is already over 100kg lighter than a series 3, so be thankful you are not in one of those barges ....though even they are lightweights compared to a modern A4.

[4v6]

Liking that weight "map" of yours Jay, i can fill in some of the blanks if you wish as ive got a block bare, crank, valves, head etc etc.

[Puglife]

Originally Posted by 4v6

Liking that weight "map" of yours Jay, i can fill in some of the blanks if you wish as ive got a block bare, crank, valves, head etc etc.

Good stuff tony, I lost the data for those and have since sold on the components. I must say i'm putting alot of effort into all of this but its mostly down to me attempting to build a very well balanced UR quattro around what audi initially designed.

Mr simmonds is assisting me with alot of research, I think he gets just as excited as me