986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post - IMS

Smallblock454 · 07-30-2017, 09:43 AM

This sample calculation was done by using 1 litre as the inner volume of the tube and a max. temperature of 200 degrees Celsius. As said, the volume will be higher. So measure an IMS tube and recalculate. I suspect the pressure will be much higher than 14,4 PSI, because i think the inner volume of the IMS tube higher.

Besides that in a crankcase you have a negative pressure, but in an closed IMS tube you have positive pressure – as said before.

So the freeze plug handles negative pressure, not positive pressure. So to say it isn't pressed to the outside, it is sucked in.

And if you have 14 psi negative pressure in a crankcase and you have 14 psi positive pressure in the IMS tube, the pressure difference is 28 PSI.

Casper Labs IMS: just do a google search.

Regards, Markus

07-30-2017, 09:43 AM	#29
Smallblock454 Registered User Join Date: Jun 2014 Location: LB, Germany Posts: 1,515	This sample calculation was done by using 1 litre as the inner volume of the tube and a max. temperature of 200 degrees Celsius. As said, the volume will be higher. So measure an IMS tube and recalculate. I suspect the pressure will be much higher than 14,4 PSI, because i think the inner volume of the IMS tube higher. Besides that in a crankcase you have a negative pressure, but in an closed IMS tube you have positive pressure – as said before. So the freeze plug handles negative pressure, not positive pressure. So to say it isn't pressed to the outside, it is sucked in. And if you have 14 psi negative pressure in a crankcase and you have 14 psi positive pressure in the IMS tube, the pressure difference is 28 PSI. Casper Labs IMS: just do a google search. Regards, Markus Last edited by Smallblock454; 07-30-2017 at 10:35 AM.