how accurate can this be?? have seen it mentioned here before and allready have a manometer and a decent vacuum (henry industrial cleaner) so gonna give it a try but has anyone any experience with this or know if it is any good for accurately tuning ports and manifols?

Cheers,


Russ.

David Vizard did an excellent article in PPC recenty. Well worth a read (DIY flow bench and comparison to commercial bench). He got very good results iirc.

yup, works very well as long as you have a powerful vacuum and an accurate manometer. I am trying to get hold of a digital one for this job at the mo.

nora batty, i have that mag but overlooked the article. says he spent hundreds a quids on it tho! mine cost nowt cos ive already got the stuff!

cheers,

Russ.

let us know how you get on and how you do it.

Vizard also did an article decades back in CCC.

I have done some flow testing (but on gas turbine compressor blading) and a large part of getting anything like meaningful results from that that job was correcting for ambient pressure and temperature.

first impressions-
i just hooked up the hoover to a board of wood with a hole in it to sit the manifold on to test each port, and then put a vacuum tube through the side of the hoover tube (i had a spare so a i just drilled a hole in it) was all a bit heath robinson but should be all ok but it seems my water filled manometer isnt accurate enough.
on some of the ports it reads the same as if the manifold isnt covering the hole, and on others it reads about a quarter of a milbar above that. i dont think the hoover is the problem cos if i stick my finger over the hole and move it about (ooooeeer missus ) the reading changes quite drastically.
i gave up after a put me hand over the tube and all the water got sucked out of the manometer so now im gonna put a pizza in the oven and watch tv till i stop pissing meself!

Useful book - How to Build, Modify and Power Tune Cylinder Heads