daves4

I'd like to see how the readings of mine compare with another (i.e. how much bouncing around the needle does).

hyperionguy

You mean under constant throttle input, or do you mean it fluctuates quickly and wildly when going on and off throttle in traffic?

daves4

For example, go up to like 18-19 PSI, then drop to like 14ish, and then back to 16-17, and then between like 14.5 and 15.5.

Maybe this is fine, but I don't know of another to compare to. Also, in stock mode (APR Stage I), it goes to around 8.5-9, and holds solid. I don't see this 'holding solid' in chipped mode.

Mark P

what does yours do? Are you talking about how your car spikes boost, or just about how much jitter the needle gives at any point in time?

My needle is very stable and I can basically hold it at any value (with the corresponding foot pressure) and it stays there without much of any jitter.

My gauge is almost 5 years old and still working great, Electro-Luminescent backlighting and all.

Mark P

it took me a while to compose that post (multitasking) and now I see the posts below

daves4

I don't see what you say: "very stable...at any value". It seems like the WOT values tend to bounce around.

Maybe this is normal, but I don't any anything else to compare to.

Mark P

"very stable and I can basically hold it at any value (with the corresponding foot pressure)"

What I meant was that if I want to put my needle at 10psi and hold it there, I can easily do that by applying the needed pressure on the gas pedal. The needle being steady is a result of both smooth programming and a needle/gauge that is stable.

When you talk about WOT (in chipped mode only), that the gauge is fluctuating, that is not an issue with your gauge, but rather in the car/engine/programming. It sounds like the gauge is likely accuratelly repoting what it is sensing. While it might not be ideal, it's likely not unusual. It could be due to a stickying mechanism, such as the N75 valve, N249 valve, wastegate, or even bypass valve. You might also find that it's more erratic when you are in lower gears at powerful/torqy parts of the RPM band. That is, in 2nd/3rd gear at 3000 RPMs if you go WOT, your boost will likely be more erratic (spike, drop, recover, etc) than it would if you were in 6th gear and also went WOT. Or even if you were in 3rd but eased into WOT (Slowly apply pressure to throttle while you watch the boost slowly raise to the max value, then continue to put your foot to the floor. That will likely be smoother as well.

Here's APR/Abt/GIAC K03 chips on a single car in 3rd car, so you can see what they're like. Note the GIAC was spiking in this version causing throttle cut, and likely not fully representative of updated versions...

<img src="http://ctny.audiworld.com/mark/s4/misc_data/k03_chip_comparo/boost_psi_act_all.gif">

daves4

That's pretty much what I see. !!!THANX!!! for the detailed info!

Mark P

no problem )