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-   -   COBB AccessPort Question (http://legacygt.com/forums/showthread.php?t=194953)

rob-2 10-18-2012 05:53 PM

COBB AccessPort Question
 
I'm about to pull the trigger on the COBB AccessPort. I want to go stage 1 with one alteration. I'd like to ensure when cruising at 80mph, 3k rpm in the 5EAT I'm not in boost.

Does the COBB system allow you to program the system like this?

I realize, I'm going to get flack for 'wanting performance, while wanting MPG'. I want the balance of both. While in cruise control I dont feel the need to burn anything more. Thoughts?

Does the forum have a sponsor I should send my business to? In Nevada would love it by next week.

Thanks for the input.

Rob

Haight 05LGT 10-18-2012 08:52 PM

If you are looking for a custom tune then you should consider a pro tune or etune from forum tuners/vendors such as Infamous1 or Cryotune. Both of them would be able to answer your questions promptly. Both of them are also able to tune using the AP

Max Capacity 10-19-2012 04:57 AM

There is a Vendor forum on here, just look up top.

I don't believe AP can do what your asking. I tuner may be able to make some adjustments...?

I have found that my cars get better mpg on a tune rather than staying stock.

lee07 10-19-2012 09:18 AM

Sell the AP and use that $ to get a tune/stg2 parts

iNVAR 10-19-2012 09:21 AM

I'm not 100% sure but at 80MPH, your car is going up against a fair amount of wind resistance. The amount of power required to accelerate or even maintain speed goes up exponentially as you go faster.

Even with 0% WGDC dialed in, your car will still develop wastegate boost at that speed due to wind resistance and other things related to physics. It is impossible, without physical modification of the car, to make the turbo generate 0% boost under throttle at that speed because the load on the engine is high enough to cause the turbo to generate boost. And because it's a feedback system, it's not possible to open the wastegate to bypass the turbine until you're generating the required wastegate boost. Get it?

COBB does have an economy map that does kill off the boost as much as possible, but you'll hate yourself for running that map because it'll be slow as hell.

Control your foot, ease off the gas, you should be fine.

Rester5350 10-19-2012 09:33 AM

Quote:

Originally Posted by Haight 05LGT (Post 4121190)
If you are looking for a custom tune then you should consider a pro tune or etune from forum tuners/vendors such as Infamous1 or Cryotune. Both of them would be able to answer your questions promptly. Both of them are also able to tune using the AP


Do not forget Tuning Alliance! :p

rob-2 10-19-2012 10:34 AM

Quote:

Originally Posted by iNVAR (Post 4121695)
I'm not 100% sure but at 80MPH, your car is going up against a fair amount of wind resistance. The amount of power required to accelerate or even maintain speed goes up exponentially as you go faster.

Even with 0% WGDC dialed in, your car will still develop wastegate boost at that speed due to wind resistance and other things related to physics. It is impossible, without physical modification of the car, to make the turbo generate 0% boost under throttle at that speed because the load on the engine is high enough to cause the turbo to generate boost. And because it's a feedback system, it's not possible to open the wastegate to bypass the turbine until you're generating the required wastegate boost. Get it?

COBB does have an economy map that does kill off the boost as much as possible, but you'll hate yourself for running that map because it'll be slow as hell.

Control your foot, ease off the gas, you should be fine.

This is great info. I really want the extra power for fun.

I saw last night they have the eco mode which could be great for the long trips I take.

I realize I am asking for a lot :)

Berzerklo 10-19-2012 10:42 AM

Quote:

Originally Posted by iNVAR (Post 4121695)
I

It is impossible, without physical modification of the car, to make the turbo generate 0% boost under throttle at that speed because the load on the engine is high enough to cause the turbo to generate boost. And because it's a feedback system, it's not possible to open the wastegate to bypass the turbine until you're generating the required wastegate boost. Get it?

^This. OP what you are asking for is impossible to accomplish with a simple tuning re-program. To do what you want would require a physical modification of your waste gate as well as a custom tune. Even then I don't think you will realize better fuel economy trying to keep your car moving at 80 MPH with no boost.

rob-2 10-19-2012 10:56 AM

Quote:

Originally Posted by Berzerklo (Post 4121853)
^This. OP what you are asking for is impossible to accomplish with a simple tuning re-program. To do what you want would require a physical modification of your waste gate as well as a custom tune. Even then I don't think you will realize better fuel economy trying to keep your car moving at 80 MPH with no boost.

I believe you're right. I use cruise control for nearly all my freeway. Just thought the motor with low/no boost would burn leaner. I'm sure the eco map will pick a few MPG's up and that will offset my heavy footed fun :)

Max Capacity 10-19-2012 11:30 AM

I have never used the eco map, I had AP since they came out, never knew it was there. If you want mpg, don't drive these cars.


On Cobb stage 1 I would get 25+ on the highway, pretty much what I get now at 280whp, 21psi, on my Tuningalliance.com map.

My 09 Spec B got over 26mpg on the way back from NJ last Sunday.

You can contact Mike at tuningalliance from the vendor forum below.

tDoug60 10-19-2012 11:36 AM

Quote:

Originally Posted by Rester5350 (Post 4121705)
Do not forget Tuning Alliance! :p

Is that who did your tune?

iNVAR 10-19-2012 11:43 AM

Quote:

Originally Posted by rob-2 (Post 4121892)
I believe you're right. I use cruise control for nearly all my freeway. Just thought the motor with low/no boost would burn leaner. I'm sure the eco map will pick a few MPG's up and that will offset my heavy footed fun :)

Your car stays in closed loop mode up to about 50-55 g/s on the MAF reading. In closed loop, your car will always target stoich so it will burn as ideal as possible.

I looked at my datalogs for you and in 5th gear at around 2800-2900 RPM, my WGDC is at 0% (I tuned it for this) and at 17-18% throttle I'm at -3.5 PSI vacuum, still closed loop at about 40g/s.

At 22% throttle, I'm in boost at about 2PSI, still 0% WGDC and I've just dipped into open loop at 63g/s.

So really, for fuel economy reasons, the question is... are you able to maintain 80MPH with less than 22% throttle? From looking at my logs, it appears that at 22% throttle I'm actually accelerating, very, very slightly, and at 17-18% throttle, I'm maintaining RPMs so I'm cruising.

But that's just to give you an idea of how thin of a line you'll be toeing between open/closed loop even with 0% WGDC dialed in.

rob-2 10-19-2012 11:51 AM

Quote:

Originally Posted by iNVAR (Post 4121972)
Your car stays in closed loop mode up to about 50-55 g/s on the MAF reading. In closed loop, your car will always target stoich so it will burn as ideal as possible.

I looked at my datalogs for you and in 5th gear at around 2800-2900 RPM, my WGDC is at 0% (I tuned it for this) and at 17-18% throttle I'm at -3.5 PSI vacuum, still closed loop at about 40g/s.

At 22% throttle, I'm in boost at about 2PSI, still 0% WGDC and I've just dipped into open loop at 63g/s.

So really, for fuel economy reasons, the question is... are you able to maintain 80MPH with less than 22% throttle? From looking at my logs, it appears that at 22% throttle I'm actually accelerating, very, very slightly, and at 17-18% throttle, I'm maintaining RPMs so I'm cruising.

But that's just to give you an idea of how thin of a line you'll be toeing between open/closed loop even with 0% WGDC dialed in.

Really interesting data. Since I don't have this data I'm not really certain.

There's a bit of mountain climbing I do on my treks, but in general it's basically flat driving. Of course I can slow down to 75mph, but than I'm 'in the traffic' and I find that more dangerous.

The AP will be in next week along with stoptech brake lines. So it should be a little more fun for myself. I'm getting the car in a divorce so this is a treat, distraction for me, not looking to make this into a track car - I have that. In case you were all wondering where I'm going with this modification.

Max Capacity 10-19-2012 12:27 PM

Quote:

Originally Posted by tDoug60 (Post 4121952)
Is that who did your tune?

As far as both my cars, yes.

rob-2 10-19-2012 01:29 PM

Well it's been ordered. Got a great deal on it. I'll report back for all those interested :)


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