Tuesday, November 21, 2017

How a 2002 turbo was fixed and improved from 1973 tech, to the expectations we have in 2017 of proper acceleration


Early BMW 2002tii models had a 10:1 compression ratio, but BMW lowered the Turbo to 6.9:1 to compensate for the boost that would come on later, so it really was a total dog until 4,000rpm, and then it instantly quadrupled its torque.

Jack Frederick’s 2002 has been featured in Bimmer Magazine:

“Not only has it been perfectly restored, it’s been subtly improved with the kind of modifications BMW might have made as production went on. The car is smooth, powerful, and utterly intoxicating, it’s the best BMW 2002 Turbo I’ve ever driven, and it makes even the most preserved OEM example seem like a cantankerous old beast by comparison.”

Jack sent the 2002 Turbo to Korman, the noted BMW engine builder and race-prep shop, who rebuilt the engine, replacing in the process the irredeemable standard turbo with a Garrett T03.

But the new turbo was spooling at 2,400rpm instead of 4,000, and there wasn’t enough fuel at lower rpm. So Korman added a fifth fuel injector and consulted with Turbo specialist Corky Bell and the original engineer of the Kugelfischer fuel injection system to accommodate it.

Now the turbo gauge on the dash wakes up down low and it doesn’t feel like a modern, boring, flat torque-curve. The power keeps rising with the revs in the Turbo, it’s predictable as the power rises to an apogee at its 6,400rpm redline

The battery was relocated to the trunk, and an intercooler was stuck in the hole it left behind, lowering the charge temperatures and increasing/maintaining the power.

Jack passioned his money into what amounted to development program for the 2002 Turbo, using some of the original Motorsport engineers.


https://petrolicious.com/articles/the-2002-turbo-is-still-bmws-naughtiest-car

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