Does anyone have an idea how I could measure exhaust manifold <U>pressure</U>?

I was thinking about doing some tests between the 'small' turbos I have to get an idea just how much manifold pressure is produced, but I can't find any gauges that will deal with gasoline turbo EGT's. I've found one M-Benz post that referenced their exhaust pressure gauge, but A) its a diesil, B) its on an engine/chassis that hasn't been made since I was born.

Even researching temp diaphragms/tubes you can put in-line to help reduce the process temp the gauge sees, I can't find much for under $200, let alone anything that will go past 800F.

I have seen people say the Supra guys monitor their 'EGP', but found nothing about it on any of their forums.

 

i immagine if you can find a pressure transducer that can handle the heat you could, or get a differential pressure gauge, and measure the difference from the compressor to the hot side. or i have no idea what i am talking about he hee. it is monday and i am still tired.

 

All I need is something that can send a 0-5v signal that I can record or show on a gauge, and not break down with our EGT's.

So far I've only found 500C transducers, and a press release for a 700C transducer mentioned conventional x-ducers are limited to 500C.


So that leaves me with using a huge coil of steel tube, with a relatively high temp gauge/sensor at the far end connected via silicone. I think I'll just use a spare Freescale sensor, use the coil, and fill it with a liquid/gel that won't turn to gas before 1500F. I don't need it to be very fast-acting, as I'm just interested in the average pressure every few hundred rpm.

 

Use a 5 bar map sensor. Put a -3 male fitting on the manifold. Run about 1' of 3/16" hard line with a coil or two in between the sensor and you'll be good to go. It'll also help if you put about a .040" restrictor inline to dampen the pulsations.

 

I think at one point Jeff Evans stated he was using some very simple mechanical pressure gauge attached to the manifold via a longish metal tube similar to what Tony1 is suggesting.

 

Just look at some of the ProFWD setups... the Eggum car comes to mind I know I have seen quite a few pics with their backpressure setup -- it's pretty much just like tony and nowtype describe...