Stock '02. No mods except JLP filter. Consistent SoCal weather. Auto Meter electronic boost gauge w/peak recall and warning light set at 10 PSIG.

I hit the warning light every time. Peak recall consistently records 10.5 PSIG, sometimes as high as 11.5.

Am I alone? Can anyone offer an explanation? I simply can't believe that the filter could add 2.5 PSIG. You would have to feel the HP gain, and I sure do not.

 

Tim,

That's not unusual to see.

Here is a pic of my stock gauge back in the day (you can tell by the date). All I had was a modified airbox with a K&N filter panel. My stock gauge has always been real consistant and never read over 8#'s when I was totally stock.



Don't report me for showing that much boost.

 

Man that SUCKS , I can barely get 8.5 with my airbox mod. I"m only using the stock gauge, but I'm guessing its accurate up to 10psi.

A buddy of mine put a CAI on his Cobra, and he is now pegging his boost gauge.

I guess that big filter makes the big diffrence.

Mike

 

The main thing is to notice where the gauge was before the mod and compare where it is after the mod.

 

im completely BONE STOCK...and i hit 10+ psi on my 03, everytime...but the temps have to be under 60. I then disconnected my boost bypass, and now it gets pegged at like 11 or 10.5 and is stuck there through every gear...Its badass dude...cant wait to get the k&n on there...how long do ya people normally go on stock air filters?

 

no relation to the thread:

Tim, what rims are those, and im thinking since you do the tracks, you make have picked em for a particular reason? Oh yeah, and how much?

 

You are completely correct. But I did not have the gauge in before the filter and I'm too lazy to swap the filters back out to see.

BUT, even if the filter were causing the gauge to read 2.5 lbs. high, that still would not lead me to conclude that I am actually getting 2.5 lbs. of boost.

2.5 lbs of extra boost would necessarily mean a huge gain in power because, unlike overspinning the blower, there would be no additional heat -- just good ole free boost. 2.5 lbs of real boost should be worth 30 hp or more.

You'd feel that, which is about the same wakeup as a chip.

But more significantly, I have never seen a single documented case where an air filter on a stock L gained even 1 hp on a dyno or even 1 mph in trap speed. And 2.5 lbs of boost would surely do both.

 

They are Moda F5's (Tire Rack house brand). $389 each.

No particular reason, just liked the way that they look. Answering the question "what wheels would Porsche put on a truck?," these just seemed to fit the bill the best.

Weight is about the same as stock, and they are 9.5" wide, so the 295s fit properly. I use the OEM wheels and tires at the track.

 

seems like a good way to pick em, well they look badass

 

WELL BELIEVE IT TIM
A good filter "is" good for a good 2 lbs.
That's a lot of good

and to answer your ques, YES mine showed @11lbs
when I added ONLY a filter when my truck was unmoded

 

in the picture above with the stock guage, take the needle a few degrees to the left to where half of the needle is in the black area next to the guage and that is where my needle hits every time i go wide open throttle in the cool night air with the JLP intake. also, i can feel that thing pulling so much harder when i see that much boost so i am noticing the power gain.

 

My stock guage is probably not very accurate but , I read just at 8 psi on my stock gauge with a modified stock airbox and K&N and I ran 13.6 at 101, about the same 1/4 mile time as getblown5.4 who sees over 10psi on his guage which means we have about the same H.P. which would suggest we have the same boost.

I currently have a 15" Air Force One Filter with a 2# pulley and a micro tuner and I see 9.5psi on the stock gauge.

I saw 9psi with the modded air box 2#pulley and micro tuner when I pulled 386/465 on the dyno....

I would think a modded airbox or filter is worth about a 1/2psi to a 1psi...

I'm still waiting for my 4# pulley .

 

Mine showed consistent 10 lbs (just passed the 10 lb point) with only K&N panel filter--no other mods and no modified airbox. That was on the factory gauge (although since then my factory gauge and autometer gauge have always read the same).

I don't know that the filter did it--it may just pull hard.

--Rip

 

I had an open filter kit on my 2000 L. Yes I saw the boost gauge increase about 2# just from the filter. I was excited thinking it was a beneficial thing...more boost more power. Then I ran the stock unmodded box w/K&N at the track and compared it to my new open filter setup. Same night, same weather, same 60fts...and guess what. Stock box with K&N was .15 sec faster CONSISTENTLY in the 1/4.

I am convinced that the increase in boost from the open air filter did not necessarily correspond to more power. Power in these trucks also has alot to do with quality (lower temp air) and flow characteristics across the MAF and into the intake. It's quality, not necessarily quantity of air. Many have read my original findings and AOLT of people are now using modded airboxes for that mere fact.

So whoever said an open filter gives you 2# and "more power" is just pulling your leg...or trying to sell you an airkit




But to answer your post, I saw 10 psi on my gauge stock from day 1 on my 03. Of course I bought it in Oct and had it been Aug, I may have seen less.

 

I am hoping someone will explain this increased boost thing. If an air filter could really supply 2.5 lbs of boost, don't you think that every filter dealer on the 'Net would be posting before-and-after dyno charts showing the 30+ rwHP gains for $200. Hell, RPM Outlet would be claiming 65+ HP.

And in Richard Holdener's article on installing the Kenne Bell, he looked for the presence of vacuum in the intake tract. He did not see it until the airflow was way over stock, meaning that the stock filter was not a significant source of restriction, meaning that it was not causing power loss.

Therefore, I guess I'm looking for someone to explain why an open filter causes the boost gauges to falsely read high. Alternatively, someone could produce a before-and-after dyno run or timeslip showing any real HP gain. But there is no way that we are getting the increased boost without the increased power -- it's simply not possible.