Hello All,

This is my first post and wanted to start off thanking everyone on this forum for the excellent information.

I've done several searches about EGR and ARV valve disabling but I can't seem to find a consensus on the ARV valve. I have a 1985 300SD federal and I currently have BB's in the EGR and ARV vacuum hoses for "testing". I noticed a huge boost in low RPM performance and less of a turbo lag. I saw a mention in some ARV thread that the 85's don't have overboost protection for the turbo so the ARV is necessary. Am I risking damage with the ARV plugged? Thanks for your time.

The ARV is only an emissions control device. Its 100% useless without the EGR. Well, its useless from the start, but you get my point.

assuming that the SD is the same as the D in this regard, you do indeed have OVP. A disabled ARV does not cause dangerous boost pressure

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1985 300D cali 190K

http://mercedes.thatchermathias.com/mw300d.jpg

Thank for the responses. What are the benefits/costs of running with a blocked EGR but unblocked ARV? Is the ARV hurting performance with the EGR blocked? Does it make sense that I should see such a dramatic increase in performance (shifts better also) or do I potentially have something else wrong? If folks are absolutely sure no harm can come to pass from a blocked ARV I just assume keep it plugged. I haven't tried to unblock it with the EGR blocked to see if there is any difference in performance.

None.

The downside is slightly increased NOx emissions. The upside is no plugging of your intake or ALDA lines, and perhaps a slight increase in power and economy.

-J

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
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