Manifold Vacuum

[Ozstyle]

Hi,

does anyone out there know what the base line inlet manifold vacuum reading should be for a standard TVR 5 litre engine at idle?
I've checked mine and think the reading is to low (13 in Hg), according to my research a healthy engine should be between 15-20 in Hg.
Any feed back is appreciated.

thanks

ozstyle

[chris52]

Can't answer your question but I am interested to know why your testing the vacuum in the plenum? Are you experiencing some problems or just doing a health check.

Chris

[ladygooddriver]

19 is about bang on. 17 to 21 is the margin. Have you checked your ignition timing? If slightly out this could be the source of your low reading if no other problems exists.


Lady

[Ozstyle]

Thought I would give it a basic health check after doing some reading up on engine diagnostics. The car goes well but I have felt it seams to lack a bit of fiz.
All vac checks looks good apart from the low reading at idle. I would have expected a lower reading than a stock rover V8 due to the performance cam but 13 in Hg would appear too low.

Looks like I have an issue, could be due to a few things, retarded ignition timing, retarded valve timing or a minor vac leak.