Audi 4000 Turbo quattro Conversion

The Intro

The Project







Total Bill

Engine Specs

Special Tools


I finally got around to recording the exhaust note of the car at idle.  You can hear it by looking in my Audi gallery.  I hope to make a recording of the engine under load soon.  I have parts on order to turn up the boost, but still have a few items I want to clear up before I do that.  I had tried to cut a corner when building the engine and did not put in new lifters.  Now I think I need to as they make a serious racket with the hood up.


December 12th
Something quite unexpected happened a few days ago.  While driving to work in 40F weather I needed to cross a road briskly.  I launched the car hard for the first time.  Even on rainy days this car has never spun tires before.  It sure did this time.  I am sure that it was due to the cold weather giving more engine power and making the tires slicker, but it was gratifying.  Strangly I don't think the front tires spun, but it felt like both rear tires spun from the way the car behaved.


October 1st
I have been driving the car for a few weeks now.  Aside from a small hot start problem it has been running extremely well.  My odometer has even decided to start working again so I can calculate some fuel economy values.  I used to get between 21 and 24 MPG with my normal driving with as good as 27 MPG on the highway.  So far with three tanks of gas I have averaged 19.8 MPG.  I would imagine that some of this is due to my slightly heavier foot now, but mostly that this motor uses more fuel.

My commute is rather short and through habitated areas so I don't get full boost very often.  The motor makes 6 psi of boost when it is warm outside, but for some reason makes 7.5 psi when it is below 60°F outside.  I still have not changed anything from the factory as far as boost settings.  I want to let the motor break in a little bit first.  I have noticed that the oil temperature comes up quicker on this motor, but stays at about 105C with normal driving.

The clutch is very different feeling.  For some reason the pedal effort is lower (which I don't like).  It has taken some getting used to.  It is a little tricky to drive smooth in a parking lot as it tries to grab.  I guess that is due to the higher coefficient of friction and the segmented design.

The part throttle torque is no comparison. The car will happily climb almost anything in 5th gear at 2000 rpm (about 45 mph) with the throttle barely cracked open.  My old motor was VERY strong for a JT and I do miss the off the line launch it had, but it got weasy by 4000 rpm.  Once on boost the new motor is far stronger everywhere.

I hope to have some firm numbers to post soon for 0-60, etc.  I have noticed that the motor is very strong at part throttle, but does not feel much stronger at full throttle.  This may be the full throttle enrichment switch or it may be as simple as throttle cable adjustment.  I have not really started trouble-shooting it yet.  I think most of it has to do with having a single throttle plate when I am used to a progressive two plate unit.

Future Plans
I plan to up the boost using pneumatic controls only.  Once I get to that, maybe later this month, I will post that on this site along with my results.  At some point along the way I will likely go to electronic fuel injection, but that is likely farther off as I have other projects (non-car related) I have to work on first.  I am also considering making an exhaust manifold at some point.