Speed3 and outside temps

[Moonpie.Express]

I live in VA and we have those 30 deg to 60/70 deg temp changes alot this year.
The one big thing I noticed is that mid to upper 60's this thing WANTS to GO!!! Not so much in the lower temps.
Last Monday (18 Feb) I drove from VA to RI. I was seeing upper 60's in NJ & NY. Hit the gas (75 -100% throttle) and the damn thing would spike to 19 and settle around 17.5-18psi. Only mods: Cobb SRI and Dogbone.
I did this a couple of times just to verify what I was seeing. I could not do it too many times, because we all know that at 70mph that much throttle for 5-10 sec will put you in the 100+ range.

Coming back the Thu after, the outside temps hovered around mid 30's. Noticed that the car did not pull and never saw as much boost. As a matter of fact, I had several instances where boost went to around 10psi and started stuttering (fuel cut?). In one instance, I heard the turbo spool, saw the initial boost and got the stuttering. I kept my foot in the throttle a bit and noticed the spool sound (Cobb SRI) yet my gauge dropped to 15-20 in of vacuum.

This being my first turbo car, I am still learning whats normal and what the warning signs are. My concerns are the upcoming summer and what the car will do then (monitor, monitor, monitor!). I just know that she has a lust for those 65-75 degree temps and at those times desire to sate them for her.


If anything here has been answered before, I apologize. I just think that the mods we do during the winter (for us that have some good temp variances) need to be closely monitored when the weather gets better.

 

[Mid_Life_Crisis]

I live in VA and we have those 30 deg to 60/70 deg temp changes alot this year.
The one big thing I noticed is that mid to upper 60's this thing WANTS to GO!!! Not so much in the lower temps.

It has been observed by those in really cold climates that when the temp gets into the 30s the performance goes to hell. If the temps get low enough, the performance comes back.
There seems to be a range in which the maps are totally screwed up, or perhaps there is a part that does not work properly in a certain temp range (I find the likelihood of screwed up maps more believable, personally).

 

[Moonpie.Express]

So does the map itself have several bands of operation or is it just the parameters of the one?

 

[Mid_Life_Crisis]

So does the map itself have several bands of operation or is it just the parameters of the one?

The maps for these cars are hugely multi-dimensional (lots of tables). The system checks things like temp, throttle position, current boost, etc and uses all that to decide which table to reference to set injector duty cycle, spark advance, wastegate opening, etc. All it takes is for one table to be screwed up and you get bizarre results like what we are seeing. This multi-layered table complexity is one of the main reasons Cobb gives for it taking so long for the AP to come out for our car.

 

[dparm1984]

It has been observed by those in really cold climates that when the temp gets into the 30s the performance goes to hell. If the temps get low enough, the performance comes back.
There seems to be a range in which the maps are totally screwed up, or perhaps there is a part that does not work properly in a certain temp range (I find the likelihood of screwed up maps more believable, personally).

If that's the case, this car will be frighteningly fast come April, lol.

 

[dparm1984]

The maps for these cars are hugely multi-dimensional (lots of tables). The system checks things like temp, throttle position, current boost, etc and uses all that to decide which table to reference to set injector duty cycle, spark advance, wastegate opening, etc. All it takes is for one table to be screwed up and you get bizarre results like what we are seeing. This multi-layered table complexity is one of the main reasons Cobb gives for it taking so long for the AP to come out for our car.

Coming from the Honda world, most of us who were serious with engine builds and custom tunes used to swap for OBD1 (pre-1996) engine computers and run conversion harnesses. The OBD1 stuff is a lot simpler to tune and has very little in the way of pollution controls compared to OBD2.

Unfortunately that isn't an option for the Speed3 since it is too new of a vehicle.

 

[Texaco]

Agree. I live at 8600 feet in Colorado and expected better performance at temps below 30. Cooler air over the TMIC right? No hard data, but it does seem to have less power in the cold temps. Strange.

What I want to know is how it would feel if I ever get it near sea level! I am probably 15%+ down on power at this altitude and have never had it below 5000 feet...lol..

So warm temps and sea level...maybe time for a road trip to the Pacific Coast Highway...(headbang)

 

[07speed3]

I noticed in my car the other day i was cruising about 50 in 5th gear and was goin past were cars merge onto the road and i wanted to get in front of this guy i saw coming out of the corner of my eye so like i have done befor i pushed the throttle down and boost started to build and started to pull then it was just like nothing there...i kept my foot on the gas and it slowly built boost back up and it hasnt happened since also did it on hard acceleration in third one too, is that fuel cut?
O and also its been about 30 to 34 degrees here.

 

[dparm1984]

^ Might help to use complete sentences rather than huge run-on ones. That post is really hard to understand.

 

[ovillems3]

Has anyone checked their fuel trims with the Cobb SRI?
my trims are all over the place, short fuel trim up to 50 when I floor it, and it takes awhile to settle when at idle.
I also changed my spark plugs to the 1 step colder ngk's.
Im going to try the MS intake again to see if there is a difference.

Hopefully its not the plugs or anything else.

I tried the MS intake, samething....now for the plugs(another day).