Higher than stock 4psi boost on the 1MZ-FE?

[Alex(AUS)]

Fletch, have you checked the pressure comming out of the oil hole?

I am keen to find out what is normal. I have checked a number of cars now and they all come up with different results. Most have a lot of air coming out (some even spit oil out ). Is this normal?

Joe, thanks for the help, we are all looking forward to the BEAST that comes out of Arrieta.

Alex

[Alex(AUS)]

Ok I did my compression check today!!! I just stopped at a service center on the way between jobs and the guy did it for FREE!!!

I got approx #2:165 #4:165 and #6:165 (perhaps a little more (168) .. it was hard to tell on the guage).

The first time I measured #6 it was 150 .. but I did it for a second time and it read more than 165 (i dont understand that).

I am quite happy with the consistency and the result. My car has done 172k kms and is running 6psi, URD kit, cat back, y-pipe ....

So what do you guys think? Is 165-168 ok? I heard that 170 is about normal and ALLDATADIY says anything between 219 and 145 is fine ...

Alex

[I4 to V6 Swap]

Hmm 165 isn't terrible. How long have you been running the 6psi? I am wondering cause I have one sitting in my room, with all my mods already installed, prepared for 6psi. I didn't put the pulley on cause I read about all the problems. Thanks for the info. I may put the 6psi on.

[Alex(AUS)]

I heard that 170 was about normal for anything but a new engine. So the result isnt too bad. I might buy a compression guage and do it again ...

I have had the supercharger on for almost one year. I did blow my original knock sensors running the stock fuel system and tune (I installed the URD kit shortly after).

What is the compression supposed to be? Has anyone measured the compression on their higher mileage engine? Have you measured your compression I4 to V6 Swap?

Thanks,

Alex

[I4 to V6 Swap]

So you have had the supercharger with the 6psi on for a year? I have yet to do a compression test. I was waiting for my friend to bring their tool over. Hopefully I can get a test done. I have heard anything between 150 and 200 is supposed to be good. I have to check on what is average or on the low side. Thanks for the info. I am leaning more and more toward installing the 6psi pulley.

[Alex(AUS)]

It will be good to hear what compression you get so that we can compare ....

I should also mention that I always run 98 RON fuel (equivalent to around 94 or 95 US Spec PON fuel). Lower fuel grades may be an issue ... not sure ...

Alex

[I4 to V6 Swap]

I forgot that may be an issue. All I can get in CA is 91 at the regular pumps. That can play a big part because octane changes the point of explosion. I don't fully understand the entire details, but I remember something about that. Octane and timing and airflow. It must all be balanced. I will have to think about that. Thanks for bringing that up. I will try and get a compression test soon. I have only been running 4psi, so I hope everything should still be good.

[Alex(AUS)]

How many Ks (ahh Miles) have you done?

Alex

[Astro]

I forgot that may be an issue. All I can get in CA is 91 at the regular pumps. That can play a big part because octane changes the point of explosion. I don't fully understand the entire details, but I remember something about that. Octane and timing and airflow. It must all be balanced. I will have to think about that. Thanks for bringing that up. I will try and get a compression test soon. I have only been running 4psi, so I hope everything should still be good.

Try doing a mix of 100 and 91 octane. I do that once in a while, I wish we had higher octane (other than race fuel).

[Fletch]

I did a compression check today and the results were good. 175-180 psi in all front 3 cylinders. The plugs (OEM Denso's) looked like it was running a little rich if anything, but were not horrible for 20k miles of use.

118k miles, S/C for about 20k, 5.5psi for about 8k, Jim's fuel for 2 months.


Following not necessarily related to boost...

We did some additional diagnosis and the throttle position sensor did not seem to be functioning properly. Sometimes the % open reading did not respond at all to throttle blips, when the cable was held manually so throttle was 50% open, the diagnostic tool only read 35-40% open. With the engine off, and WOT, it was only reading 75%.

Also, the bank 1 (rear bank) O2 sensor seemed to be bad. The voltage did not fluctuate like the front bank. Front what I know about O2 sensors, at idle, they should constantly be reading, changing from rich to lean, etc.

Anyways, we checked prices and I'm gonna order both O2 sensors and a TPS. Already had CEL for TPS last week and I think/hope new o2 sensors will help.
O2 sensors: $135 each
TPS sensor: $54

[Alex(AUS)]

175-180 sounds very good (10 or so better than mine with roughly equivalent miles). I will check my O2 sensors too ... I have noticed that sometimes my car doesn’t run at stoich A/F (14.7:1) at idle (I have a wideband scanner installed).

Which procedure did you follow to test the TP and O2 sensors Fletch?

Thanks,

Alex(AUS)

[I4 to V6 Swap]

I have about 140k miles on my engine. 20k with the supercharger. I hope to test later today.

[Fletch]

All we did was hook up the OBDII tool and look at the real time voltage from the sensors at idle and through various RPM range for the TPS so see what % open the sensor was indicating. If you haven't used one before, they are very user friendly, just choose your car in the menu and scroll through the various items. Even most small repair garages should have one. It should only take 10 minutes.

[Alex(AUS)]

I have a OBD2 scanner ... I can do it myself. I thought that you physically measured the voltages from the sensors ...

Looking forward to I4 to V6s compression result ...

Alex(AUS)

[I4 to V6 Swap]

I did a compression test. It was 175, 170 and 170. The cylinder closest to the belt ws 175. Kinda weird. So after that, I decided to install the 6psi pulley. It runs like crap now. It idles quietly, but over 2k rpms, the car shakes violently. The CEL was blinking at m, and never came on. After that, I drove it home, and the CEL is on. The car feels like it is seriously retarding the timing. I guess maybe 4psi is supposedly the max. Any ideas? My guess is the knock sensors are gone, and maybe the fuel is too lean. Oh well. This is bad timing, so I might have to pay someone to fix it rather than me play around with it. It sux.