535is Turbo (ex 633 Callaway)- 2020 Update

Discussion pertaining to positive pressure E28s.
tschultz
Posts: 3911
Joined: Mar 01, 2009 8:58 PM
Location: Denver, Colorado
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Re: 535is Turbo (ex 633 Callaway)- 2020 Update

Post by tschultz »

Thanks Charlie!
Ken, it was great to see yo' momma out on the mountain. :moon: :rofl:

I didn't get any driving videos unfortunately but maybe can come up with some later this year. My brother got a bit of me running down the mountain pulling away from the E39 M5 which was no surprise with the weight difference. But boost in those cool temps sure felt great!


I did forget to mention the week before the trip the car stalled out on me in front of my house and would not restart. It turned out that the coil went bad and had failed. It was also the source of the slight misfire I described above. I had checked the plugs and they looked good so I had been thinking of Wasted Spark. For my low boost setting, no need so far. The (used) replacement did just fine as I understand they rarely fail. Surprising that it failed, but otherwise smooth sailing. Deciding if I want to buy new or just a cheaper used unit that will work just fine.

A couple more photos.
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Last edited by tschultz on Nov 03, 2020 11:21 AM, edited 1 time in total.
tschultz
Posts: 3911
Joined: Mar 01, 2009 8:58 PM
Location: Denver, Colorado
Contact:

Re: 535is Turbo (ex 633 Callaway)- 2020 Update

Post by tschultz »

I have been letting you all down with my lack of updates and photos, I know!

The cooler temperatures mean I haven't yet swapped out the radiator but plan to do away with the south African unit--harder driving and the temps just creep up and up if the ambient temperature is above 70F. I have been driving the car for the last 4+ weeks and made some small adjustments in the tune.
This means I have driven the car about 2750 miles this year, a lot of which has been trying to tune is for consistency in the tune and drivability like stock. I am averaging about 20.5mpg and running up to 150/160kpa boost (8-10psi).

I did advance some timing in the boost region (Thanks to Nosis for sharing his tune) which helped improve performance and has made the car fun to drive although it doesn't loose traction when going straight due to the way boost arrives. Makes for a fun setup and definitely faster than the old M5... I might look into a boost controller solenoid to reduce the spool time some more by holding the wastegate shut, it seems my board might have the provision for it, so I just need to verify it has the output signal I expect.

I adjusted my EGO control to PID instead of Simple and noticed it was quicker and better at holding my target AFR in normal driving. It seems that there is some error built into the fueling equations where sometimes at idle the computer wants to add/remove fuel, but otherwise with VEAL running, the map I have is good for the load range otherwise, regardless of temperature. I also set the control interval for the idle valve at 100ms which helped almost eliminate my hot idle oscillation although there is a little bit of oscillation during warmup.

I also found that CLT based table is best for idle valve initial values, rather than MAT based-- this results in a more consistent tune.

I do get some strange startup behavior at about 40F and below where it takes a few cranks to keep the car running by itself. Otherwise though, I have been able to hop in the car and drive it. Smoothing out the advance in the low load range reduced some bucking that was occurring at light throttle.

Last week, I noticed boost was building way higher than expected and acceleration was lazy. I hit 178kpa (13.5psi) which is just below my boost cut limit, although I didn't fully rev it up, we were close. It felt slow since the pressure was bleeding out and the wastegate was partially open. That limit is also at 90% duty cycle of my injectors, so a good ceiling it turns out for my current setup. It turned out the wastegate line and blow off valves had popped off and boost was leaking as the wastegate wasn't opening fully (spring pressure only, no pressure assist).

I hope to share some more photos and details soon here.

In the mean time, here is the 318i project I have been working on here and there with my brothers. I designed and had the center console 3d printed. Hoping to do something similar for the cluster surround.

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tschultz
Posts: 3911
Joined: Mar 01, 2009 8:58 PM
Location: Denver, Colorado
Contact:

Re: 535is Turbo (ex 633 Callaway)- 2020 Update

Post by tschultz »

Just to follow up, here are some recent settings from my tune, good with B34 and 91octane:

current MAT correction, about as close as I am going to get for consistency based on temp:
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Current barometric correction by altitude. Not intuitive but these setting work for me... good about 85-60kpa:
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Current throttle accel enrichments:
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The improved ego closed loop control settings that have been working 30F-85F:
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Closed loop idle settings. Sometimes has a small hunt warm and still have more of a hunt when warming up:
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Driving last week with the wastegate not fully opening and the boost leak--see how slowly boost builds. Hit max duty cycle of my injectors at 170+kpa. My target has been 150-160kpa for max boost.
Good to know my spark advance was good.
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Fixed, that acceleration and steady boost is more like it! Mixtures right at 12:1AFR. Duty cycle at about 80%
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Here ire the corresponding ignition table, advanced slightly in boost from 2018. Reduced advance near low rpm low load to eliminate most of the slight bucking that was occurring.
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Also I found some slip on Coilovers from Ireland engineering for a good price. I decided to see if they were worth the risk in getting a stiffer rear spring and possibly changing to camber plates that will allow me to dial in a bit more negative from camber and maybe some caster and height adjustment. This was me mocking them up with some spares I have on the shelf just for comparison purposes and mounting. 280# front springs, 440# rear, both fixed rate springs.
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Here's how the PO had them on his car:
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A great thread here talking about handling: viewtopic.php?f=3&t=11423

I have found that I have a bit too much understeer, but going up close to stock ride height has helped reduce understeer. That is to say, I want to keep some rake and keep the camber in the rear close to 0 so that I don't add too much grip and cause even more understeer.

If I do go lower, I will be looking to keep the correct geometries. My 25/18 bars are good and I may play around with their settings a bit more.
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