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TECH LETTERS

Quattro Non-Turbo Quest

I am interested in buying a non-turbo Audi Quattro, preferably a 4000CS/90, but have been a bit underwhelmed by the power of the standard 5-cylinder motor.

My first question is whether there are any significant differences in horsepower or torque for this motor over time from its introduction in the 1984 sedan through about 1990, or by model (4000/90 vs 5000/100).

My second question is what CARB-approved modifications are available to improve specifically mid range performance (Chips/cams/intake/exhaust) and where such aftermarket parts or services are available.

I greatly enjoy the technical focus of your magazine, and appreciate any help or referrals your can offer.                              L. Kozimor

In order to better answer your questions, we placed a call to Ned Ritchie at Intended Acceleration in Olympia, Washington (360 / 754-1411). Ned has many years of experience with the German car with four rings.

In regard to your first question, the normally aspirated two-valve Audis such as the 4000 and the 90 have more or less the same horsepower.- The 4000s are based on a K-jetronic injection system while the 90s are Motronic.  As with every car, there is a trend to increase horsepower as development continues, but the differences aren't startling.  Both injection systems work well and provide reasonable reliability.

As to your second question, we came up with a blank. In the USA, Audis have long been treated like a stepchild by automotive enthusiasts as compared to other European cars.  With the large costs and amount of time associated with having a product CARB certified, it is not surprising that there really aren't any bolt on parts that are smog legal for normally aspirated Audi cars.  While owners of VWs, BMWs, and Porsche cars get to play with exhaust systems, throttle bodies, mild cams and other fun parts, owners of Audis are generally relegated to sit on the sidelines. In choosing a 4000 quattro, you will find that there isn't much available from Europe either, certainly not like the amount of tuning parts available for other cars. There are non-smog legal parts that can be used on your car if you happen to live somewhere that is not subject to emissions testing.  Schrick makes a couple of nice cams that will increase high rpm horsepower to the detriment of the low end. If you feel like tearing into your engine, high compression pistons can be fitted and the head reworked to improve performance. A tip that Ned suggested was advancing the timing on the K Jetronic cars to 12 degrees at idle.  This gives about 10 hp on a stock engine.  If the engine pings under load, you will have to back it off.  For Motronic cars, you'll have to change the chip to advance the timing.  High octane fuel should be used when doing this.  An adjustable cam gear with a Modified ignition system will nicely complement the package.

By far the best method of increasing the horsepower and performance of an Audi 4000 quattro is to put a turbocharged engine in. This is not  exactly in accordance with your desire  to have a non-turbo car, but the concept is appealing.  Since you would be using a factory set-up, you can take the car to a referee and have the whole conversion approved.  The donor engine and injection system to use is from an 86-89 Audi 5000 quattro.  You will have to fit the engine and all of the accompanying injection parts. The battery will have to be relocated underneath the rear seat.  For proper clearance, the steering control arm on the right side has to be replaced with one from a turbo Quattro coupe. Ned has done this conversion before and he highly recommends this method.  It seems to be a lot of work and expense, but when you start adding up the cost of buying cams, pistons, and other tuning parts, it is probably a cheaper way to go in the end.

Doing this conversion will net 162 hp compared to about 115 hp stock. Intended Acceleration has a modified ECU for turbo engines such as these that has been CARB approved. According to Ned, this adds about 60+ horsepower.  For the most adventuresome, Intended Acceleration has a replacement turbo and modified ECU that can put out a claimed 260+ horsepower depending on what other modifications you undertake. The replacement turbo has not been deemed smog legal.  All in all, the equation looks like this. 4000 quattro + factory turbo engine and injection = more smog legal horsepower for the dollar than you can get by any other method.

INTENDED ACCELERATION

© Copyright 1997-2000 Ned Ritchie