stock vanos or cobb ap vanos?

**sharptech** · 10-05-2012, 12:59 AM

So been messing some more with e30 maps and notice without changing anything but vanos tables I loose boost. About 2psi especially midrange. What makes Cobb vanos tables better/different?

**GermanBoost Ads** · 10-05-2012, 12:59 AM

**Sticky** · 10-05-2012, 01:53 PM

I wouldn't mess with the Vanos unless I really knew what I was doing.

**dzenno@ProTUNING Freaks** · 10-05-2012, 02:13 PM

The difference between stock and OTS Vanos maps is in the valve overlap between the intake and exhaust valves/cam timing. Stock vanos has more overlap than OTS and this is why you see that boost difference which in tern also affects power obviously.

**sharptech** · 10-05-2012, 04:56 PM

Wouldn't you want a little more overlap? Maybe I'm confused.

**dzenno@ProTUNING Freaks** · 10-05-2012, 05:17 PM

No. Usually with higher backpressure setups due to smaller more restrictive turbos you want less overlap. Overlap in this case represents the time during which both intake and exhaust valves are open. Picture it as a hole straight through the engine to the exhaust side..at higher rpms especially reducing overlap helps minimize exhaust gas reversion due to increased backpressure and also helps pressure differential in the intake manifold as the time during which the exhaust valve is open together with the intake valve is minimized so more boost is allowed to build due to what you can consider technically reducing an induced boost leak

**rader1** · 10-05-2012, 06:05 PM

Cam timing/phasing(and it's effects on reversion and cylinder scavenging) is a VERY interesting subject if you ever get he chance to sit down and do some reading.

**Itsbrokeagain** · 10-05-2012, 06:21 PM

Originally Posted by rader1

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Cam timing/phasing(and it's effects on reversion and cylinder scavenging) is a VERY interesting subject if you ever get he chance to sit down and do some reading.

This.

**sharptech** · 10-05-2012, 09:19 PM

Ok thanks guys! Might just have to go do some reading

**BrenM3** · 10-05-2012, 09:33 PM

Many of us have found by using different vanos profiles the car can go up and down 30-40 ft lbs in the midrange!

**marv85** · 10-08-2012, 04:24 PM

Originally Posted by BrenM3

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Many of us have found by using different vanos profiles the car can go up and down 30-40 ft lbs in the midrange!

up from what COBB has already setup?

**vasillalov** · 10-08-2012, 05:18 PM

dzenno is correct as usual.

As an interesting side effect: a certain amount of overlap can be beneficial for cooling off the exhaust valves and lowering the EGTs as it allows cooler air to enter the exhaust side of the engine for a bit longer. As a consequence of that, it will improve emissions.