Just a little explaination of whay I did this. I have the XZT with commander, and the module works well, until the weater starts getting cool out. If the temperature drops below 0 celsius, my truck has a hard time making boost.

What it is doing, is under a full throttle acceleration, the boost will reach 29-30 psi and hover there while my egts get really hot. The engine is a noticably louder, sounds like advanced timing in a gas engine. So I decided to unhook the hose running from the electrical part on the turbo to the actuator and plug it. The truck now has no issues making boost, will go up to 40 to 43 psi when I put my foot into it, and more improtantly, my EGT's stay real cool now. (Nice when i have the trailer hooked up)

Would leaving it this way possibly cause any damage?? And any ideas why it would do this in the first place. It is just strange that it only does it when it cold outside, in the summer it runs great, makes boost right away, and there are no EGT problems.

 

You will naturally make less boost in cold weather. Cold air is already denser than warm air and naturally will not compress as easily. I would not recommend leaving it this way at all. Your Commander is reading boost off of the stock MAP sensor which will not read much above 42psi especially not accurately. I would say you probably are seeing spikes in boost pressure more like 45 psi or more and you will very quickly kill your stock turbo with those pressures. You need to hook the wastegate back up and run a boost fooler as the 06 wastegate is controlled electronically. I'd stay down in the very low 40's for boost on a stock turbo unless you want to replace it soon. Boost foolers are cheap (like 70 or 80 bucks) check the DTR store for a Quadzilla fooler. Their prices are good. Surprised you didn't set any codes with it unhooked.

 

This is not correct. The air density of cold air does not prevent the compressor from making boost. Actually it is just the opposite. For a given rpm of the turbo it will move more cold air mass then it will move a warm air mass. Note that all the after market air filters promote "Cold Air Intakes".

 

I have the XZT with commander, it does boost fooling. I am not seeing any higher numbers with the wastegate unhooked than what i normally see running the XZT. My boost goes to 40-42 psi when the temps are warm outside, with the wastegate hooked up. I just can't figure out why when it gets cold outside, I can't build boost with the wastegate hooked up, but i can with it unhooked. The xzt is supposed to do boost fooling, which it does, but something is telling the wastegate to stay open. if it is the XZT or what?? I don't know. Would a bad sensor, such as the air intake temp sensor, be making the computer think it has to open the wastegate. I am at a loss as to what it could be

 

For what its worth I think Cold-air intakes are a joke... The turbo instantly heats all that 'cold' air any way but that's another issue. I'll admit I may be wrong but am only basing on what my own experiences are. Maybe I am experiencing the same problem, who knows? In hot weather I see higher boost pressures with higher EGTs, i suppose due to higher intake temps. In cold weather I see less boost, however EGT's are still higher even with the lower intake air temp. I assume the higher EGTs in this case are due to less boost (less airflow) In mild temps (55-65 degrees) I still see the higher boost levels as in warm weather however the EGTs are lowest in these temps and the truck also seems to run the strongest with the most power. To warm or to cold seem to lessen performance. I always thought this to be normal.

 

Thats a possibility. It sounds like it is definitely a temp related problem. There are some controls built into the fueling curves for temp that might cause this but I was under the impression they were taken from the MAP sensor which should be seeing warmed air anyway. Its possible at those temps the intake air is so cooled down the ECU does not realize the engine is up to temp and is tripping the WG as a safety feature.

I would call Quad and put that question to them. They have to have seen somethig like that and probably know what the trigger is.

I am runnign just the Quad boost fooler and do not remeber seeing any problems building boost in the lower temps but now ya got me wondering. Will have to test that this winter to see if there is a point at which the WG opens.

 

This is much closer to the truth but for different reasons. An ISO day is based on 59 deg F. Many designs are based on this temp and anything warmer the compressor is less efficient. When the temps are colder the computer controlled trucks we drive today can be detuned to prevent exceeding ratings. This de tuning may in some cases be too aggressive but if you were to dyno your truck you would find that the truck makes the same HP but at dramatically different boost levels as the ambient temps change (lower ambient temps and lower boost equal the same HP as higher boost at higher ambient temps). The reason for this is the mass flow is the same.

 

Ok, I will try getting ahold of quad and see if they know what is going on with this thing.

 

I had problems with my 07 building boost as well. I ended up unhooking the wastegate actuater arm so the wastegate would never open. It worked fine for me.

 

Hmmm....I wonder how well that'd work? I believe the Quad XZT already has a built in boost fooler (I think - same as I have). ECM thinks wastegate is open, but it's really not. At this point, what's the worst that can happen as the XZT is a tow module only and is not designed for huge HP gains anyway?

 

Yeah, not too sure myself, I've had it unhooked for about a week now, about 1500kms, and havent had the check engine light go on yet, so we will see. Am going to try to get ahold of quad today if I get time and see if they can help me with the original problem of no boost.

Festus , do you have any problems with yours when the weather temperature starts dropping??

 

Not that I've noticed, but I haven't really looked for it.

Btw, PM me with what you find out from Quad. Ask about unhooking the actuator arm thing too if you don't mind - save two phone calls. I haven't forgotten about the PM you sent about the hose - just have to find the info for you.

 

Festus,

Hey, would you mind pm'ing me your source for the espar heater? I was reading the thread in the AB forum about the heaters, and I need one. I would be up for a beer sometime, but it looks like I won't be making it into the city for a long time, getting busy at work........

 

I'll add that in there when I find the other info for you.

 

AB forum, do you mean an alberta forum? sorry to high jack the thread, just a tool push with lots of time on my hands lol. Just curious..