Homemade peak hold digital boost gauge

[Spooled]

I just thought I'd report for anyone else that ever thought of trying this. I decided to try a digital tire gauge out for checking peak boost today. I had a very good feeling that it wouldn't be accurate enough, but I at least thought it would be within a PSI or two. Low boost registered at 7.0, and I started to think it might actually work! I switched to high boost and it registered 19.5 PSI, then 21 PSI on the second try. I know I'm not even close to that pressure or I'd have free A/C in the side of my block, not to mention I'd expect a lot more power. My mechanical boost gauge reads 5 PSI low and 8.5 high (although even that isn't totally accurate I'm sure).

I am thinking I will stop by Frys' Electronics and look for a gage pressure sensor made for 0-15 psi then make a peak hold circuit. It's sort of a cheap DIY project to play with. Anyone else try something like this?

 

[slo03.5msp]

It is possible you could have a 19.5 lb spike which is why it registered that high.

 

[Spooled]

I thought about that, but watching my standard boost gauge it only peaks at 8.5-9 psi. I can't imagine a spike like that would sneak by. Anyway, I used the gauge on my tires afterwards and got a spike to 42 PSI (another 10 PSI over reading) the first time I used it, then it registered the correct 32 PSI. I think it's probably jsut a little wacky. Might try it again.