Evo X MR - 20.2psi peak, 11.5psi taper, is this right?

ksattic · Jan 25, 2009, 05:31 PM

I have just installed a Zeitronix ZT-2 with 3.5bar MAP (boost/vacuum sensor), and when doing a 3rd or 4th gear pull from 3 to 7k RPMs, I see the following results:

Peak: 20.2psi
Tapers to: 11.5psi

Does this sound right? From what I have read, I was expecting the taper to be 13.5psi, but that could be because of my altitude. I am at 5000ft and the temp was about 25F. My VIII would taper to 17-18psi at the same altitude according to my Defi BF.

I have tee'd into what I believe is the vacuum line for the fuel pressure regulator, but I would like confirmation. Pic on this thread:

Evo X Boost Gauge Install ,No splicing, No firewall drilling,Pics+Vid= Clean As Hell

I also have the ZChip and Forge UNOS MBC, but they are not installed yet. Will be able to give before/after results when that is installed.

JoeyM3 · Jan 25, 2009, 08:26 PM

what mode was the tranny in? i remember reading that different modes limit the boost level

JDW1479 · Jan 25, 2009, 08:37 PM

^ That might be true. I have noticed the OP senerio just yeaterday. Man this is weird. I did a short burst of speed the other day (in normal mode, letting the car do the shifting) and I notice the boost gauge peaked at 21psi and then tapered down to 12psi. I was like WTF. I checked for boost and vacum leaks and couldn't find anything. Did some more high speed runs and the samething happened. So tonight on the highway I got the urge to use the paddle shifters. Going about 40 in 3rd gear I floored it. Peaked @24psi and tapered to 19psi. So I believe the tranny mode does play apart in the boost levels. But hey, I could be totally wrong.

ksattic · Jan 25, 2009, 09:27 PM

I can take a look at this tomorrow. I was in normal mode but using the paddle shifters to stay in gear. I didn't realise the car would behave any differently based on the mode if not in D!

Yup, there's definitely something fishy going on. Looking at my logs, the car accelerated significantly faster from 5-7k rpms in 4th gear than it did 3rd! (~3.2 seconds to ~5.5 seconds).

JDW1479 · Jan 25, 2009, 09:56 PM

I didn't know there was a "boost" difference depending on what mode your in either. But I'm sure its there to protect the tranny. Who knows, just another hurdle in the SST world!

ksattic · Jan 26, 2009, 01:47 PM

I also have a pretty loud noise which to me sounds like the stock DV fluttering, although I am not sure. The DV is fairly loud, very easy to hear in the cabin. If I floor it in 6th (manual mode) at 2500rpms and then take my foot off at 3k when boost is starting to build, I'll get a fairly loud fluttering noise and the car will shake lightly. Also, the car will occasionally suddenly lose boost pressure at around 3k rpms when doing this test, causing the car to jolt (decelerate) when the pressure is lost. The boost pressure is lost in a sharp burst as if the DV is suddenly giving up.

I'll do some runs tonight (if it stops snowing) to see if I can log this.

ksattic · Jan 26, 2009, 11:23 PM

I didn't realise I needed to calibrate the MAP for altitude. After doing this, the boost values seem fine.

Here's a thread I started for my boost dump issue I mentioned:

X MR suddenly dumping boost during acceleration (logs, pics!)

stokEd · Jan 27, 2009, 03:11 AM

Quote:

Originally Posted by ksattic

I have just installed a Zeitronix ZT-2 with 3.5bar MAP...

Why did you swap out your MAP sensor? The Evo X comes from the factory with a 3 bar MAP sensor.

mad_VIII · Jan 27, 2009, 03:56 AM

Quote:

Originally Posted by Manboy

Why did you swap out your MAP sensor? The Evo X comes from the factory with a 3 bar MAP sensor.

He didn't the ZT-2 is a wideband controller made by Ztronics that accepts other sensors as well, like boost and egt.

stokEd · Jan 27, 2009, 04:42 AM

Quote:

Originally Posted by mad_VIII

He didn't the ZT-2 is a wideband controller made by Ztronics that accepts other sensors as well, like boost and egt.

Ahh, okay. Thanks for clearing that up.