turbo: blow thru vs. draw thru

I built & delivered hundreds of draw through V8 systems before 1980.

Don't spread BS about turbocharger bearings. A Draw through system will NOT damage a turbocharger bearing. We only had to warranty one turbocharger, and that turned out to be a blocked oil drain from a bad customer install.

The turbocharger can be located in any location on a draw through system. Any type of system needs to locate the turbo above the liquid level in the oil pan for gravity drain back of the oiling system. Some people have used scavenge pumps, but this is usually not necessary with a little planning.

A "BOV" is not necessary on draw through systems. When you close the throttle the compressor runs into vacuum & keeps spinning with very little load. No need for the stupid duck call dumping turbine energy.

True, you can't run an intercooler on a draw through system. We never found it necessary for street systems with 1.8:1 pressure ratios & pump gas.


I never had a blow through system I was happy with. All of them had metering issues, especially in transition. Slobbering rich, bowls overfilling when the pressure regulator could not reduce pressure, leaking fuel like a lawn sprinkler, etc. I had an AK Miller install that was a turd on the street - his response was that it was "great at WOT". Yeah, ok. I hear people say they have a blow through that runs great. I have yet to see one you could drive in traffic.

B.