"02996ttx50

thanks for clarifying that. that fluctuating idle thing can be annoying. it prevents me from checking oil occasionally. when i read of your results i really do think a re-flash would be a good idea. but i would have thought you'd get a bit more boost than 1.0? i suspect there may be some more available as you have more open road in front of you to find it cheers.

SSST

I've been seeing it above 5500 in 2nd and 3rd on the dash.

I think I've got a log at home that shows 1.2 in 4th. I'll have to check when I get back in town. I'll need to get to a track to redline in 5th.

Stock K16's BTW.

John McM

Can someone please point me to the definitive thread on the UMW flash? My car is in New Zealand and I'm in Jakarta with limited windows of opportunity and gear so I want to see how this is done before hassling Kevin. With close to 100,000 miles on the odometer I figure I don't need to baby my car.

wross996tt

Definitive thread? Go ahead and contact Kevin...he really enjoys discussing your options...what we did was I sent some data logs (using durametric, but he also has a data logger now) and he was aware of all of my mods and the altitude I'm in. He sends me a programmer that plugs into the ODB port and voila, new program uploaded. Mine came with several programs, valet, race (100 octane), boost and stock (he will need to have the stoic program loaded). We did some tweaking afterwards also.

If you are running stock K16's, boosting over 1.0 (maybe1.1) isn't going to improve performance.

Kevin

John McM email me kevin@ultimatemotorwerks.com I will give you options. I do NOT need to remove your ECU. Go to my datalogger thread. One can READ and WRITE directly to your ECU. If you don't want to datalogger I have my OBD2 programming module that will allow files to be emailed.

c32AMG-DTM

That's what I thought too... it's too far outside of their efficiency range, isn't it?

clorigo

I am sure with more open road I will see more than 1.0 bar. That was only second gear on a city street. Didn't want to push it beyond that.

c32AMG-DTM

Yes, but you have K24's. I've seen 1.2 on my tuned X50, stock turbos with stock WGs. I'd expect you'll see 1.1 or 1.2, with enough room and load.

Try an open highway, 5th gear, and floor it without downshifting.

1.4 bar on a stock K16 sounds incorrect to me, but I'm no expert.

SSST

I was somewhat shocked to see 1.4 myself, but that's what the boost guage said.

I'm curious as to the comment that anything above 1.1 doesn't really improve performance. Boost is boost. Is it that the ECU and or fuel system can't efficiently take advantage of it?

Also, I'm running a stock exhaust. Could exhaust back pressure cause boost to spike? I know that doesn't make total sense, but thought I would ask anyway.

wross996tt

Is this a spike or sustained?

And not enough air.

K16 boost limits

Regarding loss due to waste gates..."what many folk fail to grasp is "forget the boost readings" The primary importance is to build more torque in the lower midrange. This is done by keeping the internal "gate" inside of the turbine housing shut. It is like a barn door. The exhaust entering the turbine housing from the headers wants to and will push it open. When the ECU calls for just a little "boost correction" the gate starts to swing open. The problem is, as you have found out. KKK manufactures similar "Actuators" the "springs" inside of the actuators do not have the ability to shut the "gate" quick enough or 100%.. We want the gate to close. When it is open the turbine wheel slows down.. If we need boost, the turbocharger is working double time trying to supply the boost, and overcome the open gate with exhaust gases pouring out or bleeding off the turbine wheel energy. If you have a engineered actuator system, the ability to close the gate is NOW in effect. And all the exhaust energy is directed at the turbine wheel. Allowing it to generate boost.. Early boost will translate into early torque. A benifit of this system is higher boost readings.."

spikes can happen due to leaks, faulty DVs, stuck waste gates...

c32AMG-DTM

Boost is boost, yes - but there is no free lunch either... compressors have efficiency maps, dictating their optimal ranges. The perkiness of a K16, due to its small size, also means you need to rev the bejebus out of it to provide 1.4 bar. At a point, the heat generated more than offsets the additional boost provided, with a net result of power loss. At least, that is my understanding.

SSST

The 1.4 was sustained from about 5500 to redline. I say about 5500, because the needle is moving pretty fast at that point.

It didn't feel like a net result of loss of power

32AMG - My understanding is that the wastegates on the K16 don't have the spring setup that the K24 has so you aren't trying to overcome loss through the wastegate. The K16 issue is just the volume of air you can force through them due to their small size.

I agree that this doesn't sound normal and I certainly don't want to blow or burn something up. I'll try to get the data logger on it and get the result to Kevin. The most I've seen in 4th is 1.2 to which Kevin responded "Good for you". LOL!

Anyway the car is running brilliantly right now.

clorigo

Yes, I have k24s

Kevin

It is possible to see 1.4bars and actual recorded logged boost pressures of 1.3bars with K16's "IF"

a) Only showing/recorded between 3500 to 4500 RPM's..

b) If one has recorded these pressure levels> one has mechanical turbine housing linkage/wastegate failures. The gate is frozen mechanically thru rust or a broken/wedged actuator arm (unlikely)..

The K16's can spike without controlled wastegate intervention. However, the boost will not be sustained to Redline. It is just not possible with stock K16's.. If hybrid turbochargers are mounted on the car without knowing it>anything is possible (but "b" would be more likely).

PLEASE NOTE.. On a tuned car, when we shift we can see boost spikes. It is common to see 1.2 and 1.3 at the shift points.

SSST

I'll have the waste gate actuators checked. I wasn't getting these readings before I had the 60k service so maybe they did something that jammed an actuator.