Hello all, I am new to tuning, and new to the forum. Thanks so much for all of the excellent advice and stories and pics and conversations.
I have a 2009 535i xDrive Touring (E61) and have a JB4. I think I'm not getting as much boost as I could be/should be using the various maps: 1, 2, and 5.
I have a VRSF 5" stepped intercooler, upgraded lower charge pipe, upper charge pipe, upgraded diverter valves, dual cone intakes. I've changed the spark plugs and coils. The car has 83k gentle miles, I bought it a few months ago with about 80k miles.
I did a couple of logs with the JB4 and think I understand some of it, but not really all of it. It looks like I'm not getting anywhere close to what target boost should be, and in fact seems like the most I can get is around 9psi. I'll try to attach the links to the logs (at datazap.me). It would be super awesome if anyone could weigh in and give me a hand trouble-shooting this.
https://datazap.me/u/gerryford/log-1559175681?log=0
Thanks!
-Chris
Any codes? Consider a smoke test or pressure test. Beware failing wastegates. There are some DIY for tightening WG by shimming. Very very challenging to access. I have an 08 E61 535xi with JB4 and am currently chasing some low boost and fuel codes.
The coils may fail under the added pressure of the JB4. S55 coils fit and are a slight upgrade. You will feel the stumbling when this happens as the pressure blows out the spark.
@pbonsalb thanks for the tips. Sometimes I get a 30FF code and then sometimes I don’t. Or if I get that code, then use the JB4 to clear it, then it doesn’t come back.
Since that’s the under-boost code, I guess I need to try chasing a leak... was hoping there was just something easy or stupid that I was missing since I’m new to this.
-Chris
I would look for a vacuum line leak — they may be cracked or brittle on a 10 year old turbo motor, a leak from the turbo to the intercooler, from the intercooler to the throttle body — probably in the rubber hose at the IC or TB, or maybe a failing bypass valve, or a bad wastegate diaphrag. Smoke test or pressure test would help.
If that is all OK, it probably wastegates that don’t seal anymore. You can buy repair kits for $75 or new turbos for $1000. On 150k mile turbos, I would lean towards replacement.
@pbonsalb thanks again for your help.
Check out the latest logs: https://datazap.me/u/gerryford/after...log=0&data=1-4
16psi on Map 5! Huge difference in how it feels, and no codes (in the brief test drive I did to see how things went).
I used this DIY smoke test to find the leak: https://www.youtube.com/watch?v=L9CDZ9lu6Rs&t=100s
Leak ended up being in one of the new hose connections from the new VRSF intercooler I put on. I fussed around with it and re-tightened it and seems that the problem went away.
Above 4000-4500rpm thing hauls like a beast now. Thanks.
-Chris
Great! When the car starts stuttering and dropping power, it’s probably the ignition coils. They will work fine with the JB4 off but not with the added cylinder pressure of more boost. Mine started having issues not long after installing the JB4.
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