T-SMEC/SBEC boost control

[cordes]

I thought I would start a thread so that we can have a better understanding of how this all works. Here are my assumptions thus far. Someone correct me if I'm off.



It's 89' 2.5 TI style boost control. Thus you need the WG to be hooked up to the line which is blocked off when the solenoid is energized. The vac source should be hooked up to either of the other two barbs, and the other is vented to atmosphere through a filter.

I know for sure that if you have an 89' TII car you'll need to hook the WG up to the bottom port of the WG solenoid and the vac source to one of the other two barbs.

The more WG DC, the more boost you get.

Your boost will be limited by the target look up table which produces the lowest value given the current time, temp, rpm, etc.

If you don't select a switch for the high boost function, your low boost value will be the maximum allowed unless one of the other boost tables has a lower value.

[zin]

For me, it is easier to visualize if the ports are labeled as Common, Normally Open and Normally Closed.

I'm unclear as to what is what with regards to top, side and bottom, but it would seem that the 89 T1 style has the Wastegate "can" connected to the "Normally Open" port, which means the path through the solenoid is open/connected when the solenoid is off. Which should limit boost to whatever the "can" is set to and act as a kind of fail-safe.

The remaining port would be connected to atmosphere and thus vent boost/vacuum whenever the solenoid is "on"... The more "on time" the more boost over baseline "can" setting is achieved due to the pressure to open the actuator/can being bled away...

Perhaps this would be an appropriate place for someone to explain to me the functionality of the colored "restrictors" seen in the factory vacuum hoses... I'll guess that they are there to limit the amount of boost bled off by the WG control solenoid? Seems like the solenoid would do pretty much the same thing, but maybe they allow too much to bleed away?

Mike

[ShelGame]

That is all correct, Cordes.

One thing to add - I added a table for the WGDC to T-SMEC that will set the DC to 100% when the boost is below target. This is to help spool the turbo by reducing the signal to the WGA as much as possible to keep it from opening until the boost is close to target.

There is also a WG DC Adjustment from RPM (stock) that was not used by Chrysler much. This table can be used to increase/decrease the DC at a specific RPM to help spool at that RPM.

[zin]

That is all correct.

One thing to add - I added a table for the WGDC to T-SMEC that will set the DC to 100% when the boost is below target. This is to help spool the turbo by reducing the signal to the WGA as much as possible to keep it from opening until the boost is close to target.

There is also a WG DC Adjustment from RPM (stock) that was not used by Chrysler much. This table can be used to increase/decrease the DC at a specific RPM to help spool at that RPM.

Correct me if I'm wrong here, but is there a down-side to your method, or an up-side to Chrysler's? I could see the factory using it to tweak a laggy rpm, but if the goal is to get the power "now", keeping the wastegate closed (100% DC) would be the way to go... Can't really think of a situation that NOT going 100% would be better... I'm assuming there is a decay rate as the delta P is approached so as to smooth the transition and not "overshoot" the target boost...

Thanks!

Mike

[ShelGame]

Correct me if I'm wrong here, but is there a down-side to your method, or an up-side to Chrysler's? I could see the factory using it to tweak a laggy rpm, but if the goal is to get the power "now", keeping the wastegate closed (100% DC) would be the way to go... Can't really think of a situation that NOT going 100% would be better... I'm assuming there is a decay rate as the delta P is approached so as to smooth the transition and not "overshoot" the target boost...

Thanks!

Mike

That's the way I set the table up, yes.

I think Chrysler was probably more concerned with overshoot and keeping the boost in control than with lag. They went to the VNT and samll Mitsu turbos to reduce lag...

[cordes]

Thanks for the feedback Rob. I'll poke around in there a bit more. This is the first time I've thought about computer controlled boost.

[ShelGame]

Thanks for the feedback Rob. I'll poke around in there a bit more. This is the first time I've thought about computer controlled boost.

Pretty much the tables that are important, are mentioned above. Everything else you see in the boost control is really related to the adaptives (they work similar to the fuel adaptives).

Except when you get into the SBEC, TIV, TIII and SBECII boost control. They added a boost error correction and some WGDC adjustments due to the boost error. Kind of does what my added table does and more, but in a much more complicated way.

Also, the SBEC and later have an additional boost target table from RPM that is only used when knocking. So, if you see a 2nd boost from RPM table that is much lower than the first, that's what it is. I think I removed that table from T-SMEC.

[Force Fed Mopar]

There is also a WG DC Adjustment from RPM (stock) that was not used by Chrysler much. This table can be used to increase/decrease the DC at a specific RPM to help spool at that RPM.

This could be used to combat boost spiking at initial spool up, correct? I've been looking at it in T-LM trying to figure out how/what it was used for, I think you just enlightened me

---------- Post added at 12:13 PM ---------- Previous post was at 12:11 PM ----------

Thanks for the feedback Rob. I'll poke around in there a bit more. This is the first time I've thought about computer controlled boost.

I love my computer boost. 10 psi in normal driving, full boost when I nail it. Much better than trying to control it w/ your right foot all the time.

[Force Fed Mopar]

So I'm working on this in the Lebaron now. Hooked up the wastegate solenoid like it says to in the diagram under the hood, set all my boost targets to 16psi. Only getting 5 psi. Is this the correct way to hook up the solenoid for the Turbonator boost control to work properly?

[ShelGame]

So I'm working on this in the Lebaron now. Hooked up the wastegate solenoid like it says to in the diagram under the hood, set all my boost targets to 16psi. Only getting 5 psi. Is this the correct way to hook up the solenoid for the Turbonator boost control to work properly?

Maybe. Which Turbonator? T/SMEC?

[Force Fed Mopar]

Maybe. Which Turbonator? T/SMEC?

Yeah T-SMEC, in my '89 Lebaron Turbo GTC. Trying to do away with my flaky g-valve.

[ShelGame]

Yeah T-SMEC, in my '89 Lebaron Turbo GTC. Trying to do away with my flaky g-valve.

I put the T2 type boost control into a test version of T/SMEC... I think that's the right plumbing for the T2 boost control. But the regular version of T/SMEC uses the T1 style boost control and that plumbing is different.

[Force Fed Mopar]

Ah yeah, I forgot GTC's were T2 from the factory. I'll look up T1 routing...

[GLHNSLHT2]

just use the T2 boost control in Tsmec

[Force Fed Mopar]

Is it in Turbonator already and working? I thought he said it was in a test cal?

[Force Fed Mopar]

Anyway, my car has the older solenoids, as shown in this '88 diagram:



'89 T1 shows the newer solenoids:



If I hook up my older solenoid like it shows in the '88 diagram, does it work the same as the newer solenoid does? I'm unsure if the path between the WGA port and bleed port on the newer solenoid is normally open or not.

Or asked another way, do both '88 and '89 use the same T1 boost control?

Another question, is the orifice really necessary? What is it's purpose?

[ShelGame]

Is it in Turbonator already and working? I thought he said it was in a test cal?

Test cal, but it's posted in the last page or 2 of the T/SMEC thread, I think. If it's not, I'll put it up later. I will (hopefully) be running my car on it on Tues at SDAC.

[Force Fed Mopar]

So I hooked it up like the '88 diagram, and it still gave me 5-8 psi. So I guess I need to hook it into the bottom port.

[Force Fed Mopar]

Well that didn't change anything either. So I switched it back to the T2 setup and went to V18.1 and checked T2 boost control. Not really getting any more boost but it does look like it's trying to work, needle bounces as it spools. I'm going to put the g-valve back on to verify I can get more, if so I'm going to mess with the WOT DC.

[bakes]

are the solenoids working/ sealing?