Hey guys, before i write anything i would just want to say i did search the forum and google to find no spot on answer to what im looking for. I recently got a 60mm prosport boost gauge off Alta's website, did the install to 100% making sure there were no kinks in the vacuum hose etc. Upon startup (opening ceremony ) i noticed the gauge doesnt zero out but sits at -1.5 psi. At redline im getting a peak of 8.5 psi. My questions are, can this electric gauge be calibrated to zero upon startup? If not, do i have a boost leak and where are commen areas to look at if i do? To me honestly i think its the gauge seeing as that -1.5 of boost will bring me to 10 psi. Im running an 06 with alta CAI. Any help is greatly appreciated guys and if anyone has questions on the install or needs help send me a pm.

 

you should being seeing atleast -15PSI at idle (if your gauge reads vacuum) and depending on S/C pulley any where from 10-20psi at the top end of RPMs. sounds like your line going to your gauge might have a leak somwhere. Happened to me the line slipped off my t connector and got a super small hole in it. couldnt for the life of me figure it out till i replaced the whole run, with higher quailty line have not had a problem since.

 

Im reading -15 vacuum and peak positive pressure of 8.5 psi...the hoses that came with the kit where pretty thick rubber, i cant see them being defective any time soon and my t fitting setup was snug as well. I noticed that one of the boots on my intercooler where a little worn, could that be the issue maybe?

 

Im running a stock pully also.

 

Intercooler boot problems have plagued the mini for a long time, so yes you could be leaking from there. And 8.5 psi at top end rpm is about right for when I had a stock pulley.

 

you sound right on man, -20 to -15 psi while driving, and stock pulley, ya, 8 or so sounds good. you have to go to 15% or 17% to see double digits with your boost.

if you had a real leak, youdk now it.

as for the IC boots, clean the metal really well on the IC itself, then spray some soapy water on the boots, then have someone goose the throttle! check for bubbles. Otherwise, i believe it should be fairly easy to tell if you have a leak, your car just wont have power... also, you notice a leak with your gauge when you goose it, bc your boost should (if your leaking) go way up, then back down for no reason (i think

 

Well then, i would def notice it cause im always goosin it . As far as the boots go i already got them on order from Alta. I noticed last night that i actually peaked 9psi, it was about 6deg cooler outside so it throws my calibration theory out the door. I guess outside temp makes all the difference even by a couple degrees.

 

those alta ones are supposed to be a PITA to put on. Various methods have been used, i think the "best" one is to heat them in water. However, IMO, your best bet, to avoid stabbing a hole in the things, would be to do it the "proper" way, by actually removing the driver side supercharger horn completely. This gives you complete lateral freedom to remove old boots and install (with less pain) then new boots.

again, ive heard horror stories of people busting big or little holes in those alta boots just by putting them on... (i almost busted a hole in my Regular boots putting them back on!)

 

After u heated them up in water did you apply oil to the inside of the boot for easier insertion?

 

Switch to a quality gauge. Prosport gauges aren't known for their accuracy. My Defi boost gauge reads 15-18 inHg at idle and 14-15 PSI near 6300 RPM. I'm using a 15% pulley.

I had a vacuum leak a few weeks ago, ended up being a small tear in the vacuum line. With the leak I was reading 8-10 inHg at idle and 7-8 PSI boost. You'll hear a hissing sound with engine running if there's a leak.

Other quality gauges are Autometer or VDO. These gauges are expensive but if you're going to have gauges in your car, don't you want them to be accurate?

Good luck with your troubleshooting.

 

Stock boost at top end should be 10.5 PSI for '02-'04 and 11.5 PSI for '05-'06 (due to tighter clearance of the teflon-coated rotors). If you can retrace all wiring and boost lines, and you can verify the intercooler boots are properly installed (as I have crimped them the wrong way once or twice myself), then I would suspect the gauge is the issue. Agreed Autometer is good. Mine is GReddy (was the only company that matched factory gauges back when I had my old '02 MCS).

The intercooler boots appear to start cracking a little depending on how often you take off the IC combined with age. When I bought my GP intercooler last year, I opted to buy new boots. And don't buy the silicone aftermarket ones; they don't seal as well.

 

The gauge will stay for now, i know mechanical gauges are way more accurate but some time later ill get a quality electric gauge, when $ permits lol. The troubleshooting is still at a standstill, im starting to think it just might be the BPV not sealing correctly. Boost peak is still 9 psi, this was on a colder night. No signs of hissing either.

 

Didnt install the Alta boots yet, should i just send them back and get stockers?

 

Anything silicone... I would say yes. OEM is best for the stock and GP intercoolers. The OEMs cost more, but it's worth it to stick with them. If memory serves, I always have better luck getting the driver's side (larger) OEM boot seated first, then work in the smaller one on the passenger side. Once both are in place, you should be able to wiggle the IC left-to-right a small bit without the boots coming off.

 

Remember to subtract (1) PSI or Inches HG per thousand feet of altitude. Vegas is at least 2k feet above sea level.

 

So my reading of 9psi at sea level should be about 11?

Edit* Vegas is 2030ft above sea level, so we can say at sea level im running 11psi which is about normal for an 06 cooper? Ive also read these boost gauges are all set to sea level calibration so its looks like 11psi is accurate.

Edit* Oops, didnt see the subtract in there lol. So im reading 7 psi sea level?

 

Thanks for the tip, im gonna be sending these back tomorrow asap, when i reassembled my intercooler i did it just how you described, larger boot first then smaller, slid in like a champ.

 

Rejeme is correct. I forgot about a change of boost at higher altitudes.

 

The altitude shouldn't affect the zero point of a mechanical gage, a boost gage is reading in psig or "pounds per square inch gage". That is the atmospheric pressure plus the pressure in the manifold.

It could affect the maximum boost shown. With thinner air, there is less air to compress.

Dave

Edit: Doh! I forgot about the vacuum part of the boost/vacuum gage, it would indeed cause the gage to register lower pressure at higher altitudes!

D.

 

Ok, so the higher up you go, the boost gauge will show a lower psi rating because it cant compress Oxygen as well as a car at sea level. So the vehicle at sea level will register a higher psi rating on the gauge?

 

Correct, respectively, the some occurs with the vacuum reading. It will display a lower number/reading at altitude vs. sea level. A car that makes 20 psi boost at sea level will only make 15 psi at 5,000 above, say Albuquerque. That same car would show 15 in/hg vacuum at idle, where it would show 20 in/hg at sea level.

 

At sea level or there about, it should be at zero psi, and zero inches of mercury, with the motor stopped. Drive up into the mountains a couple of thousand feet and it will show less than zero psi. If you went to Death Valley, it may go to the plus side of zero psi. Imagine a barometer on the vacuum side of the gage, though not nearly as sensitive.

Dave

 

+1

 

That makes complete sense. So my reading is pretty normal, i actually peaked it at 9psi sometime last weekend, didnt know when it happened but it was recorded lol.

 

Call WMW, ask to talk to Way. Suggest your thinkings of the BPV failure and the model/year you have.