6
Diverter valve options for the TSI peaking 25 psi
- Thread starter allset
- Start date
Bender1
Banned
Right - but if the DV isn't holding (not talking about flutter, just in general), you would see a drop in boost, correct?
grambles423
Automotive Engineer
Correct....but look at all of the boost logs. The flutter happens only when the peak happens and you've overshot your requested means.
THUS being a normal controlled response.
grambles423
Automotive Engineer
Actually, if I remember correctly, the flutter only happens 2500-4000 PSI, exactly the time that the overboost is being controlled. I dont hear it the rest of the RPM band to redline.
A_Bowers
Moderator
I can see and feel this on my K03.
Im sure most other folks running stage 2 will agree. About 2500-2700 rpms if you go WOT at that point the wastegate will like grambles said regulate boost pressure to keep from overcompressing. I can see boost spikes on my gauge right before the wastegate cuts in and releases.
Exhaust note changes slightly too..
grambles423
Automotive Engineer
This is the common "hesitation" that almost everyone feels and starts freaking out about. You can feel it VERY much so on an aftermarket intake because there is less restriction, thus allowing for the boost to peak sooner and harder so the wastegate has to dial back harder. This often gives you weird MAF spikes as well.
The stock intake's restriction actually helps the linearity of the boost profile and acts like an integral portion of a PID controller. It creates enough restriction to allow the boost to reach its peak linearly.......but requires more time.
The stock intake's restriction actually helps the linearity of the boost profile and acts like an integral portion of a PID controller. It creates enough restriction to allow the boost to reach its peak linearly.......but requires more time.
jorgeecolina
Banned
Another reason to NOT BUY a POS intake!
A_Bowers
Moderator
I know exactly what you are saying with your PID loop. It has that requested value, and the time it takes for the output (in this case boost) to equalize to the requested value is the hesitation. its like it overshoots in both directions trying to compensate for the values requested vs the produced results.
You would think over time the ECU would learn the "mods" and adapt..
grambles423
Automotive Engineer
Well......you still need some up top power with the stock box. It'll restrict your flow too much in the higher rpms.
jorgeecolina
Banned
Good point!!!
grambles423
Automotive Engineer
The ECU can only do so much for the onset and the lag of reaching maximum boost. Those are all mechanically limiting factors that the ECU would never see.
This is me just assuming, I dont know a lot about the MED17, but the ECU code seems to be written to allow for maximum spool characterisitcs intially, then control the overshoot and match the specified value through the rev band. However, the IHI/K03 cannot actually DO this physically thus the boost dies so quickly at higher RPMs.
Plus, the ECU doesnt have enough space on it to have an entire algorithm to adjust itself to new modifcations since it's only designed for stock tuning.
grambles423
Automotive Engineer
I would love to design a variable intake that would "open up" at higher RPMS
A_Bowers
Moderator
In my realm of work, its why we are switching over to the solid state relays vs old electromechanical relays. There is delay in the operation of devices plus the accuracy.
the way my brain is looking at is compares it to a micrometer to a yard stick..one is super precise and demands thousandths, vs the yard stick which is in 1/8 of inches...
Thats what im calling the requested vs actual values in my head...
if that makes sense
A_Bowers
Moderator
That wouldnt be to difficult i would imagine.
Very similar to the "active" exhaust that so many high performance vehicles are running. They have that butterfly valve on a vacuum actuated device.
IT CAN BE DONE!!!
Time to put Honda's resources to work!