Thread: 300tdi's with boost gauge fitted

Where did you connect the pressure line to?
Usual spot is to the plenum. Connecting it to the compressor outlet will tell you what the turbo itself is doing, but not actually what is in your manifold plenum which is more accurate of what is being fed into the intakes.

at this stage its at the turbo

from what i have read on here, fueling is controlled by the turbo pressure and pressure drop over the intercooler can be measured at the manifold

i figure so long as i know what the pressure drop is its probably best to have it connect att he turbo most of the time so that i get an indication of fuel

happy to listen and learn as i know bugger all about boost/fuel/connection points

Hi Kelvin,

At the manifold is better, as it is a true indication of the ACTUAL pressure available. Even better again is blocking off the fitting completely at the turbo, and using actual manifold pressure to control fuelling and wastegate operation by connecting it all up to the manifold itself. There is a handy plug already in the manifold that you can unscrew and either substitute for a designated hose fitting, or just drill and Gas tap the plug.
10psi at cruise on the highway is good, 15 to 16 under load is good, this is why these engines are so fuel efficient also, plenty of air forced into them.



JC

Originally Posted by justinc

Hi Kelvin,

At the manifold is better, as it is a true indication of the ACTUAL pressure available. Even better again is blocking off the fitting completely at the turbo, and using actual manifold pressure to control fuelling and wastegate operation by connecting it all up to the manifold itself. There is a handy plug already in the manifold that you can unscrew and either substitute for a designated hose fitting, or just drill and Gas tap the plug.
10psi at cruise on the highway is good, 15 to 16 under load is good, this is why these engines are so fuel efficient also, plenty of air forced into them.



JC

while driving to work this morning i was thinking about what would happen if i changed the plumbing so that the fuel pump receives its boost pressure from the manifold

you have just answered my question, reckon i will give it a go

I don't think it matters where you read it from, at least at the T piece on the turbo you are seeing what the boost compensator and wastegate see. It's all relative.

BTW, has anyone actually measured the pressure drop through the IC ?
I'm curious to know what it is.

FWIW I usually see around 12 psi cruising at 100km/h. Can drop to 10, but depends on road surface, head or tail wind, slight incline or decline, etc.

Thanks Rick ;

I also didn't think it really mattered where you read the Boost pressure from , at the T-piece or the manifold , as long as the Compressor is doing it's job putting out a healthy 15-16psi of boost ,as long as all plumbing was intact .

Would be handy to have both to measure pressure drop accross the intercooler.

Edit :

Kelvin 10psi crusing around 100km seems about right , and you're right about not giving it a bootfull for Boost to get up to 15psi , 300 tdi engine is brilliant engine IMO.

wont finding the pressure drop across the cooler just be an arguement for a better cooler???

Originally Posted by Pedro_The_Swift

wont finding the pressure drop across the cooler just be an arguement for a better cooler???

good point......don't think the account will release the funds though