4.8i chiptuned to 390hp

[Markost12]

Chiptuned my 08 4.8i last month.
Old 355hp 475nm
New 390hp 515nm

Engine sounds just a little better.
0-100kmh car reacts just a little bit faster (not a big difference -maybe 0.5sec faster).

Biggest difference I feel from 100kmh-200kmh.
The car is much faster, much!
No more top speed limit - when the snow melts will try.

Consumption worse when I floor it, better when I take it easy.
Average no difference.

All in all was well worth for EUR 300.

[poleposition]

How is this even remotely possible with this motor? I just dont see it. Is there anything you've seen to verify those claims like a dyno sheet or something? It just doesnt sound right.....

[nom3rcy]

What tuning company?

[nab_04]

in order to get the accurate results, you should dyno test it.... plz share with us ur results if you do the test...

and what tuning did you do?

[Markost12]

The guy remapped my ECU and he added only 10% of power. He said that is maximum allowance.
I will seaarch for a dyno in the area these days and post the graph.

One thing is for sure, the car feels more powerful.

I think that is what they do to the X6 5.0 with the performance package. Increase the power to exactly 10% by remapping. Try to calculate. Its exactly 10%.

[nom3rcy]

That isn't really how engines work...

You can tune for power and efficiency by optimizing the fuel and ignition curves, but the factory maps are pretty close with an err on the safe side - especially with electronics nowadays that constantly revise the mapping for given variables.

Power is gained by leaning out the fuel mixture and advancing timing, but this isn't a "10% across the board" sort of thing. It has to be tuned for every RPM and throttle position under the sun, among other things. It could be 10% less fuel in one spot with 2 degrees of timing advance, 5% less with 3 degree advance in another, etc

I'm sure he was just oversimplifying things for you, but saying he only added 10% of the power is very misleading. It should be described as "optimizing the fuel and ignition mapping allowed for a 10% increase in power."

But even then, he would have no way of knowing how much power was gained unless he did before and after dyno runs...

Frankly I doubt there was anywhere near a 35hp gain. Turbocharged vehicles are the only ones that can get that sort of gain from tuning, and that is because they can increase the amount of air going through the engine by adding boost.

[x5mad]

Although 390hp seems a bit optimistic it might not be far off. Remember this engine is the same one used in say 550i and 650i but in a slightly lower state of tune. These engines are rated at 270kw which is approx 368hp. Gains for a naturally aspirated engine typically can be around 5%. Add 5% to 368hp and you're at approx 386hp. I know it's not as simple as this but due to this engine being in a detuned state to begin with there are theoretcally bigger gains to be made than the usual 2-5%.

[m5james]

My 91 M5 started out stock w/ 314HP, but the D'Sylva chip I have bumped it to 340HP, so while 35 is a decent jump, I wouldn't necessarily rule it out. A before and after dyno on the same day of installation will guarantee to show if there are any positive or negative results, as there is really no other way to prove it otherwise.

[FreddyG]

Originally Posted by nom3rcy

That isn't really how engines work...

You can tune for power and efficiency by optimizing the fuel and ignition curves, but the factory maps are pretty close with an err on the safe side - especially with electronics nowadays that constantly revise the mapping for given variables.

Power is gained by leaning out the fuel mixture and advancing timing, but this isn't a "10% across the board" sort of thing. It has to be tuned for every RPM and throttle position under the sun, among other things. It could be 10% less fuel in one spot with 2 degrees of timing advance, 5% less with 3 degree advance in another, etc

I'm sure he was just oversimplifying things for you, but saying he only added 10% of the power is very misleading. It should be described as "optimizing the fuel and ignition mapping allowed for a 10% increase in power."

But even then, he would have no way of knowing how much power was gained unless he did before and after dyno runs...

Frankly I doubt there was anywhere near a 35hp gain. Turbocharged vehicles are the only ones that can get that sort of gain from tuning, and that is because they can increase the amount of air going through the engine by adding boost.

Very Good explanation and Very true!

Boost is your friend!

I'm curious to hear what software that he used to tune it.

OP: Thanks for posting this up!

[JCL]

Originally Posted by FreddyG

Very Good explanation and Very true!

Boost is your friend!

I agree, good explanation. I would just change one word in the final paragraph; forced induction engines (turbocharged or supercharged) are the only ones that can get significant gains from tuning.