some cars do not have a wideband o2 sensor and only have a narrowband. i would assume ours does have a wideband. i would still get a dedicated setup with a new sensor for tuning. sensors get fouled up especially during the tuning process and the lambda reading can we way off. ran into this tuning a friends SR20DET g20, sensor didn't seem to show changes we were giving it in the ecu.......we finally figured out it was just so fouled up from the car running like crap that it was useless.

 

Three main reasons:

1.) Stock O2 sensors are not wideband.
2.) Sampling rates from dataloggers are nowhere near sufficient to get useful data from the stock O2 sensors.
3.) AFR ratio measurements are more accurate the closer they are to the combustion chamber.

 

I'm using a PLX setup to log 4 channels + a wideband. Usually I'll look at AFR+IAT/Timing/MAP/RPM.

Yes, you get about 1 sample per second from the ecu and i wish I could log more, but it's verified my guesses with iat:timing.

 

I spoke with the guy from Dashdaq and he claims that the newer cars are much faster. Can anyone confirm if 09's are any different, I'm just curious if this is true.

I also learned that this unit has some type of 3rd party unit that will allow for more options. I would really be interested in putting a temperature sensor in the rear reservoir for *****s and giggles. Wouldn't that be interesting, looking at the IAT's and water temperature during a 1/4 mile run.

 

Thanks guys, much appreciated.

 

The limiting factor has always been reading this information through the OBDII port. The only way to truly get data 'per second' is to install devices to monitor the individual sensors, like the Innovate MTS.

 

Another way would be to tap into the CANBUS or MOST systems that our cars rely on, and read the data through there. Unfortunately, that kind of system does not exist currently.

-m

 

Ok so I datalogged my E55 a couple of weeks ago, and I'm getting some insane IATs. I don't know why. I have a CM30 and a huge heat exchanger. I suppose I could have air in my system but it's very unlikely. Would like some feedback. Going to take it by CPT hopefully next week when I have some time.

To give some background on the log. 85F ambient with fairly high humidity. Runs done around midnight.

There are 6 clean highway jaunts. Four going one way on the highway, the last two occurring after I turned around. The times before and after the runs were me going to and from the highway.

-m

 

Holy crap Marcus! Could air in the system really cause IAT's as high as yours? Could high IAT's be tune related? Sorry if that question seems lame but I've been curious for a while.

Has anyone had a CM30 gone bad?

 

I've had a CO90 go bad... twice. But the way the IAT's drop in those plots I would not think the pump is bad.

 

Spot on Ahmad. Boost looks good, and recovery on the IATs isn't bad either. Coolant looks perfect. We are going to re-bleed the system when I take it in, but I am not convinced it's the magic bullet solution.

Might be the sensor... might be something else. Not sure at this point.

-m

 

Hi Marcus, thanks for sharing. I'm only starting to get familiar with this platform, however I have a quite a few years experience with eaton s/c cars. One thing that bothered me from the start was the lack of a factory reservoir for the intercooler. I have seen eaton s/c cars boil the intercooler fluid while dynoing (using clear hose connected to the intercooler core, you could actually see the green coolant mix turn white from all the tiny air bubbles created by the boiling fluid). When air bubbles get in the intercooler fluid circuit, the heat transfer efficency drops off dramatically. Which would cause higher IAT spikes in our platform.
Mb did address the boiling point by tying the intercooler to the coolant circuit, thereby pressurizing the system. That however doesn't help once you some air bubbles caught in the system.
While bleeding, it seems pretty much impossible not to let some air back in the system when swapping the black nipple on. A possible work around would be to leave a small section hose attached to the bleed point and plugging that instead. Like a 6" section of reinforced black hose that rose above the height of the intercooler core. Connect that to a piece of clear hose for bleeding purposes and cap it when finished.

**For those just getting aquainted with these cars (like me :o), keep in mind you need to pinch the return hose (just below the bleed point) in order to force the fluid through the bleed hose.

Getting back to your graph. The IAT were pretty high to start (130*), how many runs did you make before logging?

 

just my 2 cents. when i used to log my VW - i always found it much easier to graph some things separately to make the graph easier to read and then going to additional stored data for detail...

Marcus - Does your logger allow you to use RPM or Speed in the X-Axis?

 

Marcus
I have the same problem as you. I did bleed they system a couple of times but I could not see any significant improvement. My iats numbers are the same as yours in the same conditions, I only have a cm30 pump and a 178mm pulley no heat exchanger.
I am also lost as to what to do. How do we diagnose a failing iat sensor.

 

Hello lowprofile and welcome. I always like to have technical discussions on here with people from different backgrounds. Air bubbles are without question a pesky nuisance to any air-to-water intercooling system and ours is no different. The possibility of there being air in my system is of course, undeniable, however the shop that installed my H/E seems very surprised at my predicament and is very confident that when the H/E was installed that the system was bled and sealed properly. I would tend to agree with them and think that air in the system is possible but not likely. Unfortunately I am thinking there is something else, and shardul's post reinforced this idea.

This is going to be tricky shardul. IAT sensors can be problematic because they can become heatsoaked and show IATs that are not necessarily the truth. So while the sensor itself is ok - it may have in some way been compromised to the point where it's just reporting back incorrect IATs. In my Supra days when going from a factory ECU to a standalone like an AEM we had to use an aftermarket IAT sensor (we used one from GM) and the positioning of the IAT sensor was the difference between a car that runs and a car that doesn't. When I mean positioning, I mean you wanted to keep it away from heat sources that could heat soak the sensor from the outside and cause it to send wrong IAT readings back to the ECU, and therefore cause the car to run like ****.

I might take a look tonight at the IAT and make sure it is still securely in place and has not in some way been compromised. I have a sneaking suspicion that this may be the case, but I will need to take some time to investigate that. There are other possible causes as well, and it's really going to be a process of elimination.

-m

 

Good deal marcus. I am going to check my iat sensor tommorrow night and report back the finding. It is located at the Y before they connects to the surge tanks right.

 

Thanks for the greetings Marcus. Getting right back to it, yes heat soak is a problem with any IAT sensor that is located within the engine compartment. I did note and comment on the 130* at the start of the scan. The reason why I do not believe this is your issue is because it does drop back to 15-20 over ambient which seems correct, and throughout your scanning it behaves like a proper IAT.
Aside from intercooler system, the only other variable I have seen cause high IAT was a restriction on the intake side of the supercharger. A restriction on the intake side will cause a rise in the s/c outlet temps. That should be easy enough to check when you rule out/in the IAT sensor. HTH

 

What kind of restriction are we talking about on the intake side.

 

Shardul, anything which creates negative pressure before the s/c rotors at WOT. Dirty filters, restrictive intake tubing (in one thread I came across on this forum, the op had a retaining ring in the tubing between the filter and throttlebody come loose), or even an undersized throttle body. I don't want to send you on a wild goose chase, so take a look at the simple stuff first, like filters or anything that might have been sucked up into the intake tubes.
Last thing I can come up with, when the motor is torqued against the mounts (WOT) is it possible your engine is moving enough to pinch or restrict the intercooler hoses?
I keep coming back to lack of i/c fluid flow as the most likely culprit.

 

Good point lowprofile. The 130F at the beginning of the datalog is from my car sitting and idling in my driveway. The datalog basically covered the entire run, from when I left my driveway to when I returned to it. There were no runs made prior to logging. A restriction seems like a very possible problem, however I am unsure as to exactly how something could be restricting the intake side of the blower. Something to look into though. I will be checking this out and reporting back.

-m

 

Tonight I am going to do a shake down of the cooling system and intake tract.

 

did the following this evening
1. cleaned the k&n filters
2. removed air boxes and Y pipe to make sure the IAT sensor was not compromised in any way. it looked ok.
3. did a ic cooling system bleed to see if there were any air bubbles. no air present.
4. checked all ic cooling system hoses to make sure they were not pinched. they were fine.

 

go out and log!!! post it up when you are done.

-m

 

it is a 100 F out here. I am going to wait until it drops to 85 F
Seriously I dont think anything is going to change.

 

Maybe nothing will change Shardul.....yet. You have eliminated the simple causes and that's always the place to start. Next are more involved, we are assuming your i/c pump is sufficient in flow and that the overall volume is adequate. From the results of others on this site, it would appear adding more volume is definitely proven.
I see you both have the VRP550 package. Is that the 178mm pulley?