Overboost Issues with Cobb AP With Catless SBE

[Aretimus]

Hello,

I am running stage 2 +SF map with the cobb ap. I was wondering if anyone is having overboost issues running this map with a catless turbo back exhaust.

Thank you

 

[AutoEuphoria]

My experience with the AP was that if you don't have the exact mods they list in the tune name you will have issues. I had a catless dp and mp and I was having overboosting issues as well.

 

[john blutarski]

Their OTS maps call for a catted DP.

 

[Aretimus]

One thing I was wondering, Does the Cobb AP shut down the wastegate ? if it doesnt how come we are having overboost issues ? shouldnt the waste gate open before we overboost ?

 

[dread]

The tune on the ap adjusts the timing of the wastegate opening to increase boost. If the tune is made for a catted dp you may overboost because the wastegate will be maxed out. Meaning it will be open 100% and you will still build boost. In cases like this a custom tune is needed.

 

[bykeryder4life]

ya as said above the maps have requirements and they list them very specifically so if you run a map that calls for catted dp and you are cattless then you will have issues, the tune thinks exhaust will flow at one rate and certain backpressure will be present, and being cattless changes it. In general, AP maps aside, this turbo tends to overboost or even creep on some people when they run cattless. The wastegate is too small to handle the flow of air and will be maxxed out very fast. either custom tune or better WG is needed

 

[speed3driver]

If you were running a catless DP and were having issues with the AP maps.
Would you..
-Send in datalogs to cobb for a custom tune.
-Upgrade the wastegate.
-weld a Cat. into the DP

 

[MSMS3]

If you were running a catless DP and were having issues with the AP maps.
Would you..
-Send in datalogs to cobb for a custom tune.
-Upgrade the wastegate.
-weld a Cat. into the DP

I'd present the three options to Cobb and ask them which would be best. You may need to do a combo of things.

Let me know what they say, because I'm considering the AP, but have stayed out of the tuning game because I'm catless and don't have the tech savvy to safely tune with the Standback.

 

[Aretimus]

Could you recommend a good waste gate to upgrade to? Are they bolt on, or do they need to be tuned?

 

[dread]

I think you would need to upgrade your manifold to upgrade your wastegate. Our manifoldss have internal wastegates. I believe cobb would tell you to weld a cat into your dp. I am pretty sure the issue can be fixed with a tune by limiting the amount the throttle opens at WOT. It might also be addressed through fine tuning of the wastegate solenoid.

 

[Aretimus]

I could be wrong here because I know very little about the wastegates. But isnt the wastegate in the manifold? for instance if i purchased a exhaust manifold with an external wastegate flange instead of internal i shouldnt have to change my turbo right ? I am looking at this manifold in particular http://siteground207.com/~protegeg/product_info.php?cPath=160_253&products_id=1553. And if i got the biggest size wastegate it would hold like a .44 is there a downside to that? For example does a .44mm wastegate only start letting out psi at 25 instead of 18 psi or is that adjustable on all of them?

 

[speed3driver]

Does anyone have a guess as to what it would cost to get a high flow cat welded into my DP?

 

[Aretimus]

My guess is it would be cheaper to buy COBB's DP with high flow cat built into it

 

[dread]

Your correct I meant to say turbo manifold.

 

[dukebrown]

Why not just bore out the internal waste gate is has a little room.

 

[bykeryder4life]

yes you can bore out the stock WG but only to a certain point, and even still there has been people who maxxed it out and had problems overboosting or creeping still(crazy to think on a stock k04). Welding a high flow cat into your exhaust would cost very little $$$ and make the cobb map run better than it does now. That would be the best choice. Aretimus the wastegate is located on the turbo, hence the term internal wastegate. It isnt on the mani. The wastegate dumps exhaust out of the same area that the turbo pushes out exhaust into your downpipe. If you took off the DP you would see the WG flapper where it actuates/dumps. If you wanted to get serious you could upgrade your wastegate, and get an external wastegate. It would be separate from the turbo and located off of the mani. It would dump exhaust gasses through whats called a screamer pipe, which can be routed straight out from below the car or plumbed back into the DP to exit with the rest of the exhaust.

 

[Aretimus]

Is adding an external waste gate as simple as: replacing the stock exhaust manifold with http://siteground207.com/~protegeg/p...oducts_id=1553, bolting on the external waste gate, and taking the lines off of the internal waste gate and attaching them to the external waste gate? If you take the lines off of the internal waste gate and put them on the external one, wont this in effect disable the internal waste gate and then it will always be closed? How bad would this mess up the ecu and the tune to go to an external waste gate?

 

[bykeryder4life]

an external wastegate wont mess up the ecu or tune on the car, it will be better than stock at controlling boost. You just need to have the proper spring in the WG so it actuates at the correct pressure. It actually can be used like a boost controller if you just run off the spring. they are much more consistent and overall better than the little stock WG. If you get one, yes, the internal WG will always be closed( you must weld the flapper shut on the exhaust side of the turbo).

 

[Aretimus]

Well that is better news bykeryder4life. Can anyone give me some information on how the external wastegate works compared to the internal one we have now. As in what controls the wastegate, is it the ecu, is it the difference in pressure like a BOV? What would I need to parts wise besides the manifold for an external dump and the wastegate itself? Is it just bolt on and move the vacuum lines from the internal to the external, or is there more to it? Does anyone know of a good tutorial on how to install one for the mazdaspeed3?

Thank you very much.

 

[bykeryder4life]

the WG is controlled by pressure, thats what I was saying when I said you can run it off the spring if you get the right one for your desired boost level. same concept as a bov like the forge with the different color springs that hold different amounts of boost...Parts wise you need a mani with a provision for an EWG(otherwise thats more custom fab work to weld on a v-band clamp for the WG), WG with the proper v-band clamp to attach it to the mani, you need a fab shop to weld the dump pipe from the WG into your DP or out to exit from below the car(VTA). Aside from that it's vac lines and bolts getting put into the proper place. The hard part of the install will be putting on the mani and having custom fab work for the screamer pipe. You also weld the stock WG flapper shut and take off the stuff you dont need anymore from it...theres no good tutorials but plenty of guys that can help and offer advice. Search as much as possible and see pics of other guys setups..