Hi all !

I actually (surprisingly) never seen a thread on this before ..

How do you read the damn thing ?!?

All i see is the needle go up to 100 (?) when WOT .. actually it goes up to 132 ish ..

Anybody else ever wondered what it meant?

 

It means there's 100 kilopascals of pressure being built up. To get PSI divide by ~7 if you're reading quickly (or 6.7 if you have the time) which yields you ~14/15 PSI.

Basically think of 0 as atmospheric pressure, anything above 0 (boost) is the turbo building more pressure in the manifold by forcing air into it allowing more fuel to be used and therefore more HP being available. When you're in the negatives (vaccuum) it simply means you're at or below atmospheric pressure so therefore are burning less fuel and is how a naturally aspirated vehicle runs (because it's not forcing air in, only sucking in what is available from the snorkel).

This is kinda simplified but thought it might be a better idea than going into crazy details.

 

wow great stuff .. thanks

 

Or swap the damn thing like everyone else. Lol.
Kept it for 2 years before I got sick of converting in my head. Who thinks in kpa. Seriously!

 

Ya I read about that .. but I have a sedan and in Qc the option wasn't even available on any model !

What can I do to change it? .. I've seen a few posts go around about an interceptor thing ..

 

You can order the PSI gauge from Crate Engine Depot (cheapest you're going to find) and it's a direct replacement. I've kept the kPa gauge because tbh I don't "read it"..I see where the needle is and know whether I'm boosting where I should be or if it's too low start questioning if something is wrong.

The kPa system is more exact than PSI by a mile unless you have a meter that reads off a fraction of a pound. Think of tire pressures for example. 33PSI can be anywhere from 225kPa to 230kPa or so whereas most gauges read 33, 33.5 or 34, there's no in between. GM recommends 225kPa for tire pressure (33PSI) so with minute changes you can get exactly to 225 whereas using PSI is one of the three above.

Long story short GM has to provide a kPa gauge with the vehicle due to Canadian law, that's the only reason they do .

 

I have a 09 SS/TC sedan stock boost gauge for sale if u want

Reads up to 30PSI

 

Where do you see this? I checked couldn't find it

 

Send a PM to Tom (CrateEngineDepot on here) and ask him about it. A number of people have ordered it for their TCs in my general area and I'm 99% sure they said they ordered it from CED.

 

I don't think it's law. Only the speedo has to be in metric by law but the boost guage doesn't have to be they chose to do so.

Case and point the Canadian Dodge Caliber SRT-4 boost guage reads in PSi.

 

It's "supposed" to be in metric, every aspect of the vehicle is "supposed" to be in metric in Canada. I think you're right it doesn't "have" to be but it's strongly recommended and is as near a law as you can get without being told "you can't sell this car here because".

 

I Have just adjusted to Kpa... + it's easier to follow since our tires are given the same unit

 

http://www.crateenginedepot.com/store/Gauges-C506.aspx

 

definately not illegal since you could just remove it and not have one. its not a required part on a vehicle... just suggested part with any kind of boost application.

 

Well, anyone who deals in absolute units or vacuum on a regular basis, generally likes the metric system better.
ie; many tuners and designers will do their work in kilopascals.

With that said, I think in dual units. I do all my testing, and tuning in kpa... but have a psi gauge in the car.

 

You could just buy a normal autometer boost gauge from a performance parts store too. That's what the stock one is anyway.

 

Most of those gauges are mechanical and require a vacuum source somewhere on the manifold. The stock boost gauge is electrical and gets it's reading from the ECU so you can't just swap them out. Just get the factory PSI gauge from CED.

 

Yeah... that's not a hard job to do.

- Run vacuum line though firewall
- T into boost reference line
- Install gauge

Easy 10 min job.

 

^^ True and a bit more accurate too.