hi all, just a quick one, ive got a boost gauge plumbed directly to the manifold on my 300tdi converted 90, and im noticing shes boosting at roughly 3/4 bar when cruising at 65 ish on the bypass.
to those who have gauges fitted, can you have a look at yours when doing the same sort of driving and report back what readings your getting? i would of thought i should be cruising along pretty much off boost, given the fact im using disco 300 axles and transfer box, and only registering boost pressure when climbing a bank? all in all the 90 flies along nicely around country lanes and up to about 50/55, but just seems to be working hard to maintain a steady cruise of 60/65 (holding throttle constantly 2/3 way down)
My setup is all standard disco gearing, standard suspension, but im running 265/75/16 greeway machos on steel modulars if that makes much difference.
Thanks in advance
James.

Mine pulls about .5 bar at 60 as I recall. It's a 1990 200Tdi on standard wheels and transfer box though - it only pulls 1 bar if I floor it.

To get it pulling that much I had to cut a bit off the wastegate bar, wind it right in and put a spring over it to increase the preload!

What is the point of a boost gauge

i put it in because upped the boost a little bit when i rebuilt the engine, and the only sensible way of knowing whats what when its been adjusted is by means of a gauge.

So by what your saying Daz, the tyre size and disco box may well be loading the engine that bit more hence the boost levels at 60 compared to yours.

My Defender will be lower geared so the engine will need to rev more but use less power to maintain a speed so I'd say so.

If I win the wheels and tyres I'm bidding on this weekend I'll let you know the difference with just a wheel swap (31" - 33") I'll look again when I put the disco transfer box on too but that will be a project for another month!

Boost gauge should really be taken off at the wastegate as its there to mainly protect the turbo, mine runs at about 8-10 PSI in the same sort of driving mine is a 90 with the same set up but has winches roll cage etc so a bit heavier. If its nice and level the boost will drop to 5-6 PSI I have tweeked the pump a bit.

James1966 said:

Boost gauge should really be taken off at the wastegate as its there to mainly protect the turbo, mine runs at about 8-10 PSI in the same sort of driving mine is a 90 with the same set up but has winches roll cage etc so a bit heavier. If its nice and level the boost will drop to 5-6 PSI I have tweeked the pump a bit.

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Why should it be taken off at the wastegate, and how does this protect the turbo?

Forgot to say, I've taken my feed for the gauge just after the turbo before the intercooler so the pressure will be slightly higher than manifold pressure.

Taking it strait off the manifold would be the most accurate thing to do as you know what's getting into the engine rather than the boost being created - the important thing when messing with boost is to protect the engine