Hey guys picked up my 1987 Audi 5000 CS Quattro. Of course, 2 window regulators were messed up so I got them fixed. It runs great, all stock. I'm considering rebuilding the engine and doing some mods. I'm looking to improve performance and gas mileage. I'm a senior in high school and am looking to do this as my senior project. Any ideas for what I should do?

well you picked up a great car but it aint going to be cheap or easy. Start off with chipped ecu and a wastegate spring. It would be a good idea at the time to invest in ARP Head studs and either a forged resurculation valve or blow off valve to protect the inter cooler from popping its caps off. Problem is that these car's fuel distributor tops out right around 2 bar so cant get much more outta the stock fuel system. you can go efi if you really wanna dump cash but doing that you wont get much more outta it without building up the lower internals. Just as for maintenance always replace the timing belt and water pump. Would be a good idea to go through the ENTIRE motor and replace all the vacuum lines. Putting a good catback exhaust on it will help it breath. Good site is www.034motorsports.com for aftermarket parts. Hope this helped

My budget is limited only to what I can raise. I can make some money but I'm also looking to some friends of mine for a little help. My plan was to at least go over the whole engine, powder coat the block and all of those parts, clean it up and see what I could do to make it a bit stronger. Basically almost everything you've said I'm considering for performance, other than EFI. I don't want to get into that. Exhaust right now is just the front cat then it runs back over my rear axle where it's cut off. The biggest issue I'm looking at now is fuel mileage. I'm trying to prove that an older car is capable of achieving better mileage than most comparable new cars today, even when the older one has performance mods. Honestly, I can sacrifice performance mods (for now) to get some fuel mileage gains.

You get this back to stock, with new water-pump/belts, head gasket and filters and clean air lines she will really honk and give you 25-30 on the highway !

Standard ... :)

well if you wanted MPG you went for the wrong 5000...my 5000s gets about 35mpg just driving to work and back half highway the other half is city/back roads. but the 5kq is faster. but stock these cars are FAST relative to many modern stock cars. 6.7 0-60 if i remember is not that bad. but you could do some weight reduction to help both. get rid of the AC set up takes a ton of load off the engine and makes it lighter.

Basically I want to do all maintenance, but not a rebuild? I heard from a guy that rebuilding actually does the opposite of what I want, because it creates greater engine friction, especially in the break-in. any other things I could do to improve performance without sacrificing fuel mileage?

weight reduction is your best friend. if your are looking to gain mpg and make the car faster, put her on a diet. some of the luxuries like AC, sound insulation, power seats, they all add unnecessary weight.

also consider using a high grade premium fuel like Shell.

you can also use a synthetic oil to reduce friction in the engine, a K&N air filter isnt a bad idea either.

KEEP YOUR TIRE PRESSURES UP

weight reduction is your best friend. shed unnecessary weight like AC, power seats, sound insulation. ...ive always wanted to fit an AC clutch to my power steering pump so i can take even that much more load off the engine, but never got around to it.

perhaps the biggest influence on fuel mileage is how you drive the car...refer to http://www.youtube.com/watch?v=dKTOyiKLARk for a good laugh and some intersting results.

the computer chip and wastegate spring are a very good basic upgrade.

use a high grade premium fuel like Shell and buy from a busy gas station so you know the fuel hasnt been sitting there for who knows how long.

you can switch to a synthetic oil to help reduce friction in the engine.

A K&N air filter isnt a bad idea either.

KEEP YOUR TIRE PRESSURES UP. the rolling resistance of a tire is a hard force for the engine to overcome and is key in keeping fuel mileage up. if its a manual, simply coast down hills in neutral, imagine goin 65 down a hill on a highway while idling?? =)

run a fuel system cleaner like Techron or Lucas Upper Cylinder Lubricant once at the beginning of every season.

i have an MSD ignition coil to help burn the fuel efficiently, a good set of NGK wires and Bosch OEM plugs.

My AC is gone already and I kinda want it back. even if i have to re-install after my project. I figure for my project I can get it to good MPG then when I'm done, I can mod it without worrying about engine condition. Where can I get a a cheap chip and spring? What coil should I get?

I get a combined city/highway of 21mpg in my bone stock 88 cs quattro with 210k miles on the original engine. Highest I get is 30-32mpg highway when cruising at 60 and flat ground. Make sure everythings up to snuff on the engine before u go pumpin up the boost, and dont worry about new studs or forged recirc valves unless youre gonna run a big turbo, youre gonna hit plenty off cost prohibitive limitations on performance before u need arp studs. Its gonna cost you plenty of money just to do the maintenance on it.