Measuring boost on a P38 DSE - what pressure & what guage to get?

Hi All,

I'll be having a day or two off next week sometime and one of the things I wanted to do was measure the boost pressure on the dse to see what it's delivering, spurred on by oil in the intercooler (which i'll also be flushing out (with parrafin/degreaser solution?))

I'd like to measure the boost pressure that is being delivered and also what should be delivered? where do I take this measurement from?

Any thoughts on what gauge to buy? (it'll be coming off of ebay as i have some money in paypal!)

cheers and thanks in advance
jt

hi, you will use a "t" piece and put in on the tube exiting from the turbo to the waste gate. in should read 1.2 BAR -oem-

To clean, i personally prefer gas , much easier and dries faster...remember to also clean the inlet manifold. if you got a MY99 model, try to disconnect the EGR also.

hi, you will use a "t" piece and put in on the tube exiting from the turbo to the waste gate. in should read 1.2 BAR -oem-

To clean, i personally prefer gas , much easier and dries faster...remember to also clean the inlet manifold. if you got a MY99 model, try to disconnect the EGR also.

jtonthebike said:

Hi All,

I'll be having a day or two off next week sometime and one of the things I wanted to do was measure the boost pressure on the dse to see what it's delivering, spurred on by oil in the intercooler (which i'll also be flushing out (with parrafin/degreaser solution?))

I'd like to measure the boost pressure that is being delivered and also what should be delivered? where do I take this measurement from?

Any thoughts on what gauge to buy? (it'll be coming off of ebay as i have some money in paypal!)

cheers and thanks in advance
jt

Click to expand...

Oil in the intercooler and induction system is normal. This system should be flushed every 48,000 miles. Boost pressure should be measured whilst the vehicle is being driven, and not just static. Extend pressure tube into car and drive up a long hill under differing loads. 1.2 bar around 18 psi is the maximum you should see. Fit a T piece into pipe going to maximum pressure diaphragm on side of turbo. Problem is you may well be getting plenty of pressure from turbo but because the intercooler is partially blocked by crap the air flow is restricted. Proper cleaning of the intercooler can have a dramatic effect on performance. Best solvent for this is Acetone it eats the carbon deposits if filled, sealed off, and left to soak a while. Put about litre in and seal ends then give it a good shake to get the main **** out. Empty then fill and seal off and leave for an hour or so. giving it a shake now and again. Then rinse a couple more times agitating as you go. Until Acetone is clean. Around a tenner for a gallon which is more than enough. Failing the availability of Acetone use some brush wash or spray gun cleaner available from automotive paint distributors. 25 litres for little money.

I judge mine off the readings I'm getting from the Map sensor using faultmate. I presume this is the ultimate test as this is manifold pressure after all losses form leaks etc.

Nitromors original cleans all the carbon and gunk from intercoolers etc, but is probably more expensive than acetone.

Thanks chaps! Very much appreciated! I didn't realise the turbo should run at that high a pressure!

I'm away from home and won't be back for a while, so if there are any photo's of location of pipe etc, unless it's on RAVE? I'll get some pipe, t piece and gauge sorted then!

Any suggestions as to where I could buy some acetone from in a large quantity? (as i'm away i'd like to order it online) I have this at home: Meguiars Super Degreser do you know whether that could be used if I don't get around to sorting some acetone?

cheers and thanks again
jt

jtonthebike said:

Thanks chaps! Very much appreciated! I didn't realise the turbo should run at that high a pressure!

I'm away from home and won't be back for a while, so if there are any photo's of location of pipe etc, unless it's on RAVE? I'll get some pipe, t piece and gauge sorted then!

Any suggestions as to where I could buy some acetone from in a large quantity? (as i'm away i'd like to order it online) I have this at home: Meguiars Super Degreser do you know whether that could be used if I don't get around to sorting some acetone?

cheers and thanks again
jt

Click to expand...

Glasplies of Southport will send to you about £9.00 per gallon + delivery.

hi there i was wondering if anybody could tell me where this pipe is,as i am trying to do the same and for the life of me i cant locate it ... paul

Pipe runs under inlet pipe at front of turbo, from compressor body to waste gate actuator.

thanks wammers i ll have another look ,paul

i cannot for the life of me find this small hose having removed the heat shield and engine cover please someone tell me where i am going wrong

rajansrover said:

i cannot for the life of me find this small hose having removed the heat shield and engine cover please someone tell me where i am going wrong

Click to expand...

Of course, we're assuming you do own a diesel...

its def a diesel ... 94 with a bmw lump

just a thought what about connecting the t piece in the pipe from inlet manifold to map sensor to see what boost is actually getting through to the engine?

would that work nathan

do i need to take the turbo hoses off to access the smaller wastegate hose ?