So, I started doing some datalogging on my mini today and I noticed a couple of things that seamed a little off, but I wanted a second opinion. First, the maximum amount of throttle position when floored is 91% just wondering if this is normal. It consistently logged the floored position a 91.37%. Next the tmap sensor maxed at 22psi. Is this normal? I read somewhere that it should read around 27psi for a stock mini cooper s. keep in mind the tmap includes atmospheric so that puts me around 7.4psi of boost @ ~6000 rpm under 91% throttle. Just wasn't sure what to expect and wanted some input. I have the excel sheet if it would help anyone.

 

Yes, the throttle position is right. Cars seem to vary from high 80's to low 90 percent range. As for the boost we would need to know more about the car, miles, SC pulley(if any) etc.

 

It's an '02 with 60k miles and stock pulley size. Thanks for letting me know about the throttle, never datalogged a car before and wasn't sure what numbers to expect.

 

Well, I should clarify, I know the first gen MINI's throttle run in that range, I'm not sure about all fly by wire throttle cars. The boost reading sounds odd. What are you logging with? I know some of the off the self units have multiple "readings" you can log. There is absolute pressure, which you appear to be reading, and then boost, or gauge pressure, which will show vacuum and boost. You will need to calibrate the zero reading on your unit for varying atmospheric pressure before you log boost if you logger can't take a differential between the two MAP sensors.

If the reading is correct there are a number of different mechanical items you can look into.

 

I'm am reading from the TMAP sensor using laplogger wired odb interface. The max reading I got from a few runs was 45.7 in hg. Todays barometric pressure reading for where I am is 29.97 in hg. This puts it at around 15.7 in hg in boost which equates to 7.7psi of boost. This was the absolute maximum reading I got though. Most 6k readings where around 44.5 in hg. Around what boost levels should I be seeing? I've noticed a few times where i will have momentarily loss of boost (will drop to around 35in hg can both feal it and see it in the log only lasts a split second though). Could this be the bypassvalve going out? I know I'm in need of replacing my intercooler couplings. No visible leaks, but are getting pretty old.

 

Bypass Valve
SC Belt
Couplings
Worn SC

Various things to check. Check the BP valve and look at the belt tensioner.

 

Check all the usuals: belt, bypass valve, IC couplings. That said, if you're running a bone stock engine you should only see 10psig max anyway, especially on a high-mile engine.

WOT almost never needs to equal 100%. Anything over 90% TPS is usually considered WOT.

 

About 10psi is the money spot for boost, so you may be a bit leaky or slippy.

As far as TPS concerned not reading 100% is not unusual, my MINI does it and my friends B15 Sentra is like that.

 

Ok, I'm pretty sure it's not the belt as I just replaced that about a month ago, could be the tensioner though. Anyone got any hints/tricks for checking for boost leak? Figure that's the next easiest thing to do. If that ain't it anyone know of any instruction on getting to the bypass valve? presumably I'd have to take off the inlet manifold which means I have depressurize and take off the fuel rail.... just trying to get an idea how much work it would be to get to the bpv. I have a feeling that since it is an '02 with the original bpv it may be that, if not it's probably gonna break anyways so might as well update it.

 

The throttle position you're getting is a bigger spread than I get in the R56s. I only see 18-78. I never thought of it as a problem, I just accepted that's the way things are.

 

I was under the impression that the TPS reports degrees, not percentage... so 90 is wide open throttle, etc. but I'm not sure where I got this impression -

 

Here's the spreadsheet of my log bout 11minutes of data:

http://download.hagerupsite.com/log_...09-1328_58.xls

Thanks for all the comments so far! Anyone got any hints for checking for boost leaks?

 

What are you using to capture the data? I use an iPhone ap and an OBD dongle.

This is what I do with the data: http://homepage.mac.com/barryt/.Movi...AprilBesti.mov

 

pretty neat! I would love to take a lap around Luaguna Seca some day.... I used a laplogger usb interface (just a seriel/usb obd converter) and for right now the software they provided, but I'm working on finding/making a C# library for elm327 commands so I can make my own app. I can take the raw data right now that it is throwing me and use that for about anything though. You weren't kidding bout your tps either looks around 17-78. Think mine was around 4-91

 

The BPV comes off after the intake horn. It's easier to get the horn off of you pull the TB. Other than that it's pretty easy.

For leaks, you can go ghetto carb cleaner in every joint and look at RPM, or go to a shop with a smoker, they can plug the TB and the exhaust tips and pressurize everything with smoke and you will find every leak tip to tip.

 

It’s a seven-year-old MCS; I wouldn’t bother with troubleshooting right now, just go straight to the maintenance items. Get a new bypass valve, adjust the butterfly to center and “almost” closed (just enough to barely see light in the bore). New intercooler output duct gasket, new supercharger intake gasket, new bellows, and a hose clamp to replace the single use band on the BPV hose-to-supercharger-intake-duct. Flush the intercooler with acetone or non-chlorinated brake cleaner; clean the bellow contact edges on the supercharger output duct and IC output ducts, plus the intake lip on the supercharger. Assemble all and after applying correct torque to the bellows clamps, try to push the ends with your thumbs, if the bellows scoot one way or the other, unbolt and exchange clamp halves between the two clamps and/or swap ends. A mismatch of casting and clamp shape is common; I have a few spares I use to swap to find the best occlusion on whatever MCS I’m working on when I see that happening.

With the vehicle on stands or ramps, remove tension on the tensioner and lock in place, remove the lower splash shield, pull the belt off the crankshaft pulley, grab the pulley at the edge with thumb and forefinger knuckle and try to wiggle, also push upwards on the pulley with the heal of the hand, if it wiggles and clinks, or can be moved the slightest amount by hand, replace the crankshaft vibration damper.

If it were my MCS, I would pull the SC and change fluid on both ends also, but that’s me, you can probably get away with waiting another 20k miles before doing that.