Awesome build!!!

 

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!

 

Excellent news. So, factory MAF and TB stays; horrible plumbing goes.

I like!

Plumbing is a cheaper fix

Kudos on cracking the fuel curve... that's awesome.

 

Since I'm at a stopping point until about Wednesday, I figured I would post up some pics of the MAF. It is a pretty stocky unit and I love the honeycomb grill before the sensor. This is something that is highly sought after to smooth airflow in other applications! It also looks like the I.D. of the maf is only 2.69". Still, I am running an even smaller restrictor in the rotrex to keep boost under control so it is still larger then what I need

Oh, I also got my server back up and running so now I need to spend some time on the Crossfire section. I just noticed that I bought this car with 11k on the clock and expected to have the rotrex on before 20k. Well I made it with plenty to spare as I just ticked past 15k yesterday!

 

I also forgot to note the blocked off port on the TB tube. That is where I have my pcv blocked at the TB. Don't want to put 13 - 15 psi in the crank case!!!!!!!!

 

I check this thread everyday. It has been the most fascinating read and your approach to everything is impressive to say the least. I'm hoping you have this for the next Dragon run, because I plan on going and I want to see this beauty in person. Keep up the good work, and I'm keeping you and this babe in my prayers to the car Gods

 

Ditto,

Btw, how is the tranny holding up?

 

Thanks and I am going to try and make it a better read overall. I went back and read my last big post and I learned something; don't post when I'm too excited and/or tired! Good grief, I'm surprised anyone could even understand it the way I rambled on and on Oh well, it is a little cleaner and easier to read now.

As far as the dragon goes, I'm all over that one. I should have the car well sorted by then and as long as I'm not in the middle of some crisis at work, the wife and I should be good to go. In fact, I'm going to have to look closely at that one and get serious by making reservations, etc. The one that is even closer for me but a little tight for my schedule is the meet at the Texas Motor Speedway! I'd love to make that one as relatively speaking, it is in my own back yard!

 

So far so good, but you have to remember, I've pretty much kept her at mild boost and cruise for the last 250 miles. I'll have to report back once I start making full boost and get some real miles on the road.

 

Hell yes!!

If Paul makes it down in the X55 SCed V8 and you make it with the rotrex blown limited, we are truly in for a treat....

Looking forward to meeting the guy who will most likely be SCing my baby I'll buy you a beer when we get there...

 

very nice work! I know it's hard laybor

 

Any new news?

 

I'm curious as to whether or not the stock pump is up to the task, if i remember right the stock pump is god for about 350ish crank.

Also, you dont have that extra pair of injectors still do you?

 

Been a little while now.... please update this killer thread!

 

I wish we could set the notifications to notify on each reply instead of "one notification" for a new reply since the last time you checked in. If I check the site with my phone and it isn't logged in, then I don't receive anymore notifications on future responses.

Oh well, I haven't updated in a while because I have been chasing down gremlins. Nothing major, but nothing simple either.

Basically, every time I think I have my hesitation from idle to low pedal position fixed or at least almost gone, it doesn't pan out 100%. More like 98-99% but never 100% gone to my satisfaction. It is a silly thing to get stuck on but I am a perfectionist and I don't want to settle for the little bog that I have been getting (900 rpm), then perfect everywhere else. So, for the last couple of weeks I have been dissecting logs and tunes trying to work it out.

Apparently, the ecu wants to see perfect harmony between the MAF and MAP sensors on low throttle inputs and they can diverge more as rpms increase. It is a weird combination in that the MAF controls fuel based on airflow and the MAP provides load data used in the overall load calculation as well as the look up for the spark table.

These seem to be somewhat independent in that I can adjust the MAP signal and get a more aggressive spark curve while not affecting fuel trims significantly then all of a sudden they are completely co-dependant at idle and off throttle.

I've played around with maps based on a percentage of change, commanded voltage, using the load of the sister sensor, etc. However, I think I have settled on the most involved and hardest to tune strategy; MAF -> MAP conversion. So this weekend I put hours and hours and hours into building a new MAP table to perform a MAF delete (while leaving the MAF in place for reference voltages). The added complication here is that with the SC in place it throws off the airflow under all circumstances and the ECU doesn't like some of the real values. Therefore, I have to fudge reality with what is supposed to be seen on a stock motor and make the MAF work with the MAP and Fuel tables.

This is the only way for me to command under all circumstances exactly what the MAF is relaying to the ECU as well as the MAP sensor. The early results so far are a good idle, conquered the hesitation problem, but now when I let off the gas it hunts all over the place and wants to die

So I shifted my problem from one area to another and it is just so darn hot outside that sitting out in it is bad for me and the car. I'm going to have to change the oil just from all of the idling I've done in the driveway tweaking the air and fuel curves So, I've been trying to hit it early in the morning and late at night which further limits my actual time in the driver's seat.

Oh well. The good news still, is that she runs great everywhere else and I don't foresee any issues power tuning. Everything seems to behave once I get her past 1,000 rpm. It is just the low end stuff right now that is a bit bonkers. Part of the problem is that the Rotrex flows more air than necessary. A little bit of pressure builds up pre TB and when you first touch the throttle, there is a voltage spike on the map sensor, the aem map sensor, and the maf. The stock ecu doesn't like to see a). a voltage beyond x and b). too large of a differential between maf and map in this area of the map, so it cuts fuel to pull it back down. This causes all kinds of funk in all the wrong places

I'm kind of past that and now have the other side of the sword to play with. The bouncing around after low throttle input is caused primarily by my MAP conversion tune, the fuel not agreeing 100% with the voltage I've supplied, and O2 correction. I have to get each cell in 100% agreement and there is going to be quite a bit of trial and error with this issue. The curves in this area are notoriously delicate and .1v here or there throws fuel off and if it is more than x% the engine stumbles.

Oh well, at least I am headed in the right direction and the actual hold up is quite small in the scheme of things.

 

 

Good update! Glad to see your working things out!

 

Wow, 2 whole weeks since my last update! Oh well, it has been hot and I have been either sick or dealing with family stuff so not too much to report. I have an 18 year old son that decided he is in love with a girl 1,200 miles away (over the Internet) and spends every waking minute thinking of how to leave home. Despite the fact that we signed him up for a 100k education!!!!!!

Good grief!

Well, the last two weeks have been pretty frustrating. I've had a small amount of time to fight with the "Tip-in" issue and have been through pretty much every conceivable tuning strategy. It ends up that I had a few things going on all at the same time. First off, the AEM is very finicky and didn't like the way I had the crank sensor wired. I ripped that out and started over, then in the wake of everything listed above ended up not following my own strategy and wired it wrong a second time. All while thinking I just made it better

This caused me grief as I then ran into a new strange behavior at idle and while cranking. Anyway, days later and in between hazes, i discovered my problem and corrected it promptly. Even then, with (2) perfect twisted pairs sheathed in shrink tubing I still wasn't 100% happy. I ended up having to perform the "resistor mod" to clean up the signal to my liking. I also ended up moving some grounds as the AEM didn't like the sensor ground I was using.

R-compart made a really spectacular wiring diagram but I am going to have a few edits with things I've found along the way.

Then when these changes didn't address the tip-in issue 100% nor did converting to a MAP based tune and disabling the 02 sensors, I noticed a weird behavior with the fuel trims. I kept seeing the STFT's read for a few minutes then stop and go to zero. The previous o2 sensor heater code I was throwing went away with the ground change and better wiring. Therefore I had not noticed this earlier as there was nothing to investigate down O2 alley at the time. However, that proved wrong when I connected both o2 inputs to the one good sensor and the trims started functioning normally as long as the car was running.

So what I'm left with at this point is a MAF based tune (just plain easier to deal with short and long term), O2 inputs to the AEM disconnected, and (1) bad O2 sensor. I ordered a new one that should be here Friday so I can resume.

Next on the agenda is installing the new O2 sensor and re-connecting the O2 interception of the AEM so I can change the A/F in between closed and open loop. Then I should be good to go.

I can tell you this much, I've dissected the tune on this thing about a 100 different ways! In the end, no amount of time is wasted going down these rabbit holes because in the end I learn something with each dive

 

Did you by chance get my last pm?

 

Thanks for the updates, Web. Projects can be slow sometimes, and setbacks will happen, but your perseverence will see you with one very cool crossfire and I have no doubt many others will benefit from your knowledge in one way or another.