[BMWApp]

I was wondering if anyone could tell me the differences between Stage 1 and Stage 2 tunes. I currently am running the Carbahn Autoworks Stage 1 tune and love it but am curious about the differences between Stage 1 and Stage 2 tunes. I just had the Active Autowerke high flow catted downpipe installed and am thinking about going to a Stage 2 tune (BM3 or MHD). Other than an increase of 1-2 psi in boost, what other changes are made to the tune when going to Stage 2?

[johnung]

Originally Posted by BMWApp

I was wondering if anyone could tell me the differences between Stage 1 and Stage 2 tunes. I currently am running the Carbahn Autoworks Stage 1 tune and love it but am curious about the differences between Stage 1 and Stage 2 tunes. I just had the Active Autowerke high flow catted downpipe installed and am thinking about going to a Stage 2 tune (BM3 or MHD). Other than an increase of 1-2 psi in boost, what other changes are made to the tune when going to Stage 2?

Stage1 to Stage2 is NOT just another 1-2psi of boost.

By definition, a Stage 1 tune is designed to safely increase the performance of the engine without any hardware modifications.

A Stage2 (or higher) tune requires prerequisite hardware modifications. There are two common mods needed.

COOLING:
Note: Cooling is an issue with F3x cars with engines that have FMICs. The newer modular engines such as the B58/B48 use high capacity water-to-air cooling. So they do not have an FMIC and they wouldn't need a cooling upgrade unless it was a very high power track car.

Often if a car has a Front Mounted air-to-air Intercooler (FMIC), the additional boost of a Stage2 tune will overwhelm the stock intercooler with a volume of air that is coming through it at a rate that is too fast for it to cool effectively.

The result is that the engine's Intake Air Temperature (IAT) rises too high. The engine's failsafe systems activate and protect the engine by modifying engine timing and throttle position. This is called Heat Soak. To the driver the engine begins to feel sluggish. Eventually the engine could go into limp mode.

Now many things can cause an engine to feel sluggish. If an engine feels sluggish when driving around on a hot day, driving in traffic or driving at 90mph on an interstate highway, NONE of those are due to Heat Soak. The engine is running at low/med revs in those situations.

Heat Soak only happens when an engine is at high revs forcing an unusually large amount of air through an intercooler. The obvious high rev situation is running lap after lap on a racetrack.

Note: that a Wide Open Throttle (WOT) run down a 1/4 mile dragstrip is unlikely to induce Heat Soak simply because it would be difficult to raise the intake air temperature outside the safety limit in only 11-13 seconds.

Heat Soak can be induced on the street by making repeated WOT runs in succession so that the FMIC does not have enough time to recover. The Intake Air Temperature continues to climb until it's at an unsafe level and Heat Soak is induced.

There is a highway near me where the red lights are spaced just right. When traffic is light I can make WOT runs in succession. With my tuned engine and stock FMIC, after 5-6-7 WOT runs in a row, I could feel my engine get sluggish. Heat Soak!!!

Now if you start with a much higher ambient temperature like if it's 90-100 degrees outside, Heat Soak can be induced sooner like after 3-4-5 WOT runs in succession.

You'll hear the IAT's of various aftermarket FMIC's compared. That's fine if you are literally choosing one for a track car. But don't make the mistake of using IAT numbers to choose an FMIC for a street car. Why? Because driving on the track and driving on the street are very different.

The track is a high revving environment where a big volume of hot air is being pushed through the FMIC constantly. Big cooling capacity is important.

But street driving is very different. They is a lot of stopping and starting, standing starts, and acceleration from very low revs. An intercooler that is too big or is too slow pushing air through it causes the dreaded Turbo Lag!

Turbo Lag is when the Intake Air Pressure is low so it takes time for the turbo to spoil up to increase the boost pressure. That delay or lag is what the driver feels when it takes time before the power comes on. If an engine has Turbo Lag, the driver will typically step on the gas and feel the delay from a standing start like when a light turns green, or when trying to pass a car or when trying to accelerate onto a freeway on-ramp.

So bigger is NOT always better when choosing an FMIC. And cheaper is NOT always better. Lots of FMICs are cheap because they are heavy slow-flow units with bar & plate internals that are more likely to cause Turbo Lag.

The stock BMW FMIC is actually a high tech quick flow unit with more expensive tube & fin internals. It is sized perfectly for say 300hp. It's right in that sweet spot to provide power without heat soak and without turbo lag.

Note: The only FMICs that I know to have quick-flow tube & fin internals like the BMW stock FMIC are the Wagner Competition Series EVO1, EVO2, and the huge track model EVO3. My own Wagner Competition EVO1 is sized to about 400hp. If I was tracking or upgrading my stock turbo to produce 450+ horsepower then I would get the Wagner Competition EVO2.

But tuning the engine to say 375hp now can over run the stock intercooler with more air than it can cool fast enough to prevent heat soak. But now it's important to choose an aftermarket FMIC upgrade that will prevent heat soak without being too big or too slow so that it also increases turbo lag.

So if you are choosing between several intercoolers, it is often a mistake to think that the one with the best IAT rating is the best choice. They could all have IATs within the range that won't induce heat soak in your Stage2 horsepower engine. So that would mean that in this example IAT is actually meaningless. The one with the best IAT might have the worst Intake Pressure Drop, the indicator of Turbo Lag!

Be careful about listening to recommendations for this or that intercooler, along with their statement that there isn't any turbo lag with it. It's very common to just get used to driving a car with lag and not being conscious of it until you drive another car with less lag.

An FMIC is only a "recommended" hardware upgrade for a Stage2 tune because if you don't have it, your engine will protect itself.

A HIGHER FLOW DOWNPIPE
For a Stage2 tune, a higher flow either catted or catless downpipe is a "required" upgrade. The boost level settings of a Stage2 tune are too high for the back pressure generated by the resistance of the stock downpipe. The Stage2 tune tells the turbo to spin faster to a point where that stock back pressure can damage the turbo.

A catless downpipe has emissions issues depending on your state's requirements. It also has a gasoline smell.

A catted downpipe can eliminate the gasoline smell but the ability to handle emissions varies by the quality of the catalytic converter, which can vary widely. Also a catted downpipe, since it has more resistance can have less performance. I suspect that this may vary widely too since few catted downpipe manufacturers quote performance numbers.

My Fabspeed catted downpipe uses an HJS catalytic converters which are considered the best in the world and are used on many exotic cars. Fabspeed quotes dyno numbers that their catted has 93% of the performance of their catless downpipe.

Hope this helps!
Some links below...

Wagner Competition EVO1
https://www.kiesmotorsports.com/coll...428-435?aff=22

Wagner Competition EVO2
https://www.kiesmotorsports.com/coll...rcooler?aff=22

[Asvplee]

This is directly from protuning freaks. I don’t have the specs for stg 1 but you can compare to stage 2 and 2+ below.


Below are gains for for Stage 2 and stage 2+ for different octanes.

Stage 2 91 octane: up to 24% HP / 32% TQ
Stage 2 93 octane: up to 26% HP / 32% TQ
Stage 2 E30 octane: up to 30% HP / 35% TQ

Stage 2+ 91 octane: up to 37% HP / 62% TQ
Stage 2+ 93 octane: up to 43%HP / 68% TQ
Stage 2+ E30 octane: up to 47%HP / 73% TQ

[340iGUY]

I am looking to get Bootmod3 and have read that the stage 2 only needs a high flow downpipe.
Those are great Stage 2 gains for just a downpipe.

[eluded]

Originally Posted by johnung

My Fabspeed catted downpipe uses an HJS catalytic converters which are considered the best in the world and are used on many exotic cars. Fabspeed quotes dyno numbers that their catted has 93% of the performance of their catless downpipe.

How much for the b58 dp

Do u have a link to this. That was such a long post to have to go to bed now.

[johnung]

Originally Posted by eluded

How much for the b58 dp

Do u have a link to this. That was such a long post to have to go to bed now.

See Fabspeed website for HJS B58 downpipe. They regularly run 15% off sales

[luca10]

Originally Posted by eluded

How much for the b58 dp

Do u have a link to this. That was such a long post to have to go to bed now.

https://www.vr-speed.com/vrsf-4-5-ca...0i-xdrive.html

That's the downpipe I use, as many others do on here. Great quality and great price, can't go wrong.

[gippy]

if i wanted to make a stage1 tune the most safe it could possibly be, would it be worth putting in a performance cat, air intake, (anything else?).
Or is that just overkill and it wouldn't make any difference to reliability? (just on stage1)

[johnung]

Originally Posted by gippy

if i wanted to make a stage1 tune the most safe it could possibly be, would it be worth putting in a performance cat, air intake, (anything else?).
Or is that just overkill and it wouldn't make any difference to reliability? (just on stage1)

Performance cat or intake won't make a difference. But if the car (N55, not B58) has a stock Front Mounted Intercooler then an upgrade to this model FMIC would provide more reliability to a Stage1 tune.

https://www.kiesmotorsports.com/coll...428-435?aff=22

[G.Newt]

If you want a downpipe that won't throw a CEL, get a CG DS-1 and call it a day.

[kern417]

Geez dude. That post was ridiculously long and over half of it isn't even related to the B58.

The only difference with stage 2 is dialing in fueling for your downpipe and sometimes more boost (depends on the tuner). It gives you a little more peak power and a wider powerband. I posted the details here.
https://f30.bimmerpost.com/forums/sh...63&postcount=2

[BMWApp]

Originally Posted by kern417

Geez dude. That post was ridiculously long and over half of it isn't even related to the B58.

The only difference with stage 2 is dialing in fueling for your downpipe and sometimes more boost (depends on the tuner). It gives you a little more peak power and a wider powerband. I posted the details here.
https://f30.bimmerpost.com/forums/sh...38;postcount=2

Thanks. This is very helpful and what I was looking for.

[mike@x-ph.com]

keep in mind tuners decide their own stages. Just because they are both stage 2 does not mean they are comparable in any way. Most tuners refer to stage 2 as a car with FBO (including downpipes) on a stock turbo.

Carbahn and Dinan do not use downpipes in any of their maps but they still have them separated in stages based on other modifications

For a more technical answer on what exact parameters are changed from stage 1 to stage 2, i recommend contacting the tuner direct

[340iGUY]

Originally Posted by kern417

Geez dude. That post was ridiculously long and over half of it isn't even related to the B58.

The only difference with stage 2 is dialing in fueling for your downpipe and sometimes more boost (depends on the tuner). It gives you a little more peak power and a wider powerband. I posted the details here.
https://f30.bimmerpost.com/forums/sh...63&postcount=2

How do you dial in fueling for the downpipe? What does that mean?
In your link the lower octane maps runs higher boost. Why?

[FIDDYgg]

Originally Posted by 340iGUY

How do you dial in fueling for the downpipe? What does that mean?

Better flowing exhaust allows more air in on the intake stroke due to lobe overlap on the cams (exhaust valves remain slightly open for a number of degrees of crank rotation after the exhaust stroke, at the beginning of the intake stroke)... The fast moving charge of exhaust leaving the ports has a vacuum effect drawing out exhaust gases and pulling additional air into the cylinder, so that needs to be compensated for with additional fuel.

Hope I got the explanation right, that's the gist of it anyway.

[kern417]

Originally Posted by 340iGUY

How do you dial in fueling for the downpipe? What does that mean?
In your link the lower octane maps runs higher boost. Why?

Originally Posted by FIDDYgg

Better flowing exhaust allows more air in on the intake stroke due to lobe overlap on the cams (exhaust valves remain slightly open for a number of degrees of crank rotation after the exhaust stroke, at the beginning of the intake stroke)... The fast moving charge of exhaust leaving the ports has a vacuum effect drawing out exhaust gases and pulling additional air into the cylinder, so that needs to be compensated for with additional fuel.

Hope I got the explanation right, that's the gist of it anyway.

More or less. You'll improve spool and be able to hold more power up top. The car can adjust fueling on it's own, but the tune will dial in fueling so it's closer to accurate on the base tuning. Keep in mind this is an OTS map so it needs to work for multiple conditions, downpipes, fuel qualities, etc. So it'll never be perfect. But it puts less strain on the DME to compensate for the additional exhaust flow.

Regarding boost, it can vary depending on a lot of characteristics. In general our cars respond to timing more than boost. As timing drops, boost increases. Some logs from other tuners, like MG flasher, run a lot more boost on their tunes but less timing. It just depends on the tuning strategy. But you will be timing limited on lower octane fuel, so sometimes they try to add boost to make up some gains.

[Skyhigh]

Originally Posted by kern417

Geez dude. That post was ridiculously long and over half of it isn't even related to the B58.

The only difference with stage 2 is dialing in fueling for your downpipe and sometimes more boost (depends on the tuner). It gives you a little more peak power and a wider powerband. I posted the details here.
https://f30.bimmerpost.com/forums/sh...63&postcount=2

Nice overview. Assuming the data is correct, what sticks out is the very different timing advance of MPPSK. Any theories why?

[kern417]

Originally Posted by Skyhigh

Nice overview. Assuming the data is correct, what sticks out is the very different timing advance of MPPSK. Any theories why?

All of the logs are posted in the thread. But basically boost and timing are a balance. So low timing doesn't necessarily mean low power if boost is increased to compensate. That's the strategy used by BMW for their tune, most likely to compensate for varying fuel quality and conditions.

[IMS-340C]

Timing is dependent on fuel octane and IAT/Air Temperature, the lower the octane and higher air temperature the lower the timing to prevent knock.

At higher temperatures there is less oxygen so less fuel so less power so the ECU compensates with more boost/Load which leads to less timing.

That's why you see a big range in boost and timing in the logs between summer and winter, in the winter you will see low boost high timing and in the summer higher boost and lower timing.

Originally Posted by Skyhigh

Nice overview. Assuming the data is correct, what sticks out is the very different timing advance of MPPSK. Any theories why?

[Skyhigh]

Sorry, my questions might be stupid, but I have never had any dealings with that particular matter:
- I thought timing/boost is a predefined value? If so, how could there be seasonal difference? If not - what is the point of comparing variable parameters between tunes?

[IMS-340C]

Boost (LOAD) and Timing are predefined values (MPPSK Timing table attached) but the ECU corrects those values depending on the conditions, The x and y axis are RPM and LOAD and the values in the table are the timing.

Load is how much air volume is filled in the cylinders and boost is used to fill the cylinders so Load and Boost are directly related to each other so you can look at Load as Boost.

Also you can see from the table the higher the Load (Boost) the lower the timing.

Yes it's irrelevant to compare tunes just by looking at boost you/we also have to look at IAT/Air temperature and know what fuel used in the logs.

Also more important logs are used to make sure the engine is working in a healthy way.

Originally Posted by Skyhigh

Sorry, my questions might be stupid, but I have never had any dealings with that particular matter:
- I thought timing/boost is a predefined value? If so, how could there be seasonal difference? If not - what is the point of comparing variable parameters between tunes?