No sir, they are currently stock. I've been playing with these all morning and I can tell you that the TB O.D. is 3" and the Maf O.D. is 3.25". I don't see any real need to change those with boost. However, I am making some changes in this area in general.

First off, I haven't been able to spend much time on the Rotrex this week as it has been crazy busy at work! Yet, I have managed to drive it to work for most of the week.

This was a good exercise as it helped point me towards a few additional pieces of the puzzle to solve. Remember when I said this was one of the most perfect test drives for one of my projects ever? Well it was, but it was also one of those situations where the more I played with it to make it better the worse it got That is until several experiments later I finally figured out the magic formula of MAF, MAP, and Fuel. Prior to that epiphany, I had developed a stumbling on low throttle and this weird missing every 30 seconds while at idle.

As of this morning that was all settled and she was running absolutely perfect under normal driving conditions. That is until I started tuning for power again. Well, I take that back with one exception, the ONLY ongoing issue I have had to date is a CEL for the O2 heater circuit. I think I burned up the heater circuit in the front most passenger side early on and I just haven't been able to bring myself to pay for the Mercedes branded replacement .

So, like I said, I set out to make some power having solved all issues to date (minus the heater circuit) including:

• insulating and heat wrapping the IC
• installing a burp tank to get air out of the IC system
• re-installing the lower pan
• sorting out all datalogging logs and formats
• creating an import filter not only for the SPD logs, but also for the AEM logs into dataloglabs (my software of choice)

On my first power run, I made 5 psi but was running super rich. So, I went back to the house, re-calibrated the tune, and went back out for another run. I made several very strong runs to the same 5 psi at relatively low rpm. Then I started pushing her a bit more but the boost did not seem to want to go up relative to the added rpm. So, I went back to the house to double check the plumbing, etc. Everything checked out fine.

On my next trip out, I blew off the MAF sensor again! Oh well, there goes my fix!

So I limp home and decide to investigate. The first thing I did was pull off the MAF and the plastic 90 degree bend to the TB. I should have done this from the very start. In fact, I felt plain stupid for not doing so already. Oh well, everything else has gone so well and my intuition has paid off at almost every turn. I was well overdue for a bone head moment and today she came a calling.

So back to the crappy (for boost) OEM setup. From the TB to the 90 degree bend, it is a combination friction and clip fit that uses a rubber gasket as a seal. This same concept is used to connect the MAF to the 90. It is most definitely not made to hold any type of pressure therefore the multiple issues I have seen.

First, the whole rig won't seem to hold over 5 psi before it starts leaking in who knows how many places

Second, at some point, it wants to just blow apart and you have to limp home.

Third, there does not seem to be any good way to fix it to make it better with the stock components. Outside of using epoxy to glue it all together, I don't see the answer.

Fourth, if I would have pulled all of this off in the first place, I would have seen how easy it was to change.

That said, I ordered a couple of new 90 degree hoses; one coming from the TB to the bottom of the maf, and the other from the top of the maf towards the IC. Then I'll connect the 90 and the IC together with a longer section of hose then what I have in place now. Simple, easy, and definitely something I should have done in the first place...... The MAF is a well designed unit with thick walls that should hold up to boost nicely.

Oh well, lesson learned. Now with that said, I am very excited about how the tuning is coming so far. I have to say, it really isn't even all that complicated. Once you figure out what the ECU wants to see and more importantly what it doesn't like to see from the MAF and/or MAP sensor, the rest is coming along just like tuning any other car.

I have fuel cut figured out and breeze right by it as the ECU doesn't have a clue it is in boost.

I have no CELs from adding the boost signal to the fuel pump regulator and my fuel pressure does seem to be increasing with boost. The little stumble is gone, the idle glitch is gone and everything seems to be behaving just like stock. In fact, I'm quite impressed with the idle as this car idles so low, I was worried about it turning the SC and having enough IAC adjustment to hold idle and not die or throw a code!

Well, so goes the good and bad news. I can't finish ramping up the power until late in the week when my hoses get here. The great news is just how strong she runs at 5 psi! I can't wait to run her on up to full boost and see what happens!