I finally decided to measure the exhaust back pressure of the stock exhaust system. I believe it is the same for all 617 123s, but just for reference, this is a 300TD. I didn't have a good gauge around for this measurement but I tried my 60 psi gauge just to see what would happen. I have a pyro in the down pipe just after the turbo. I removed that and inserted a pressure tap. I measured zero pressure up to about 3000 rpm full throttle. Then at as the rpm increased, the pressure climbed and maxed out at about 4-5 psi. I don't know what RPM because I was too busy watching the gauge. Anyway, there does seem to be a significant back pressure at higher rpm. Anyone else ever make a measurement? I would like to compare my observations to others.

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For Sale: 1982 MB 300TD
1995 Chevrolet Suburban 6.5TD

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