Had some very unfortunate family news and so on and so forth...
But back on topic, I've finally finished stage2+, fbo (full bolt on), with a custom mhd tube by wedge performance.
Very happy with the performance, the car feels very strong indeed. We are estimating 420hp@crank, 98 octane map. Dyno coming soon. Ken said we could push it harder (est. To 440-450hp/400whp), but I see little point now.
I've got a list of changes... Mainly it involves freeing up the airflow, reducing heat and removing as much plastic as possible.
- VRSF downpipes
- VRSF inlets
- VRSF intakes
- Turbosmart dual bov with z4 piping, set to 50/50
- Intercooler (BMS phoenix racing wagner rip off, but its really good value for money and works perfectly).
- alloy chargepipe with meth bung blocked off
- ngk 1 step cooler, gapped to 0.22"
- rediculously expensive motul 300V oil 5w40
- all new filters
- rb pcv valve and cap upgrade (lovely bit of kit)
- mhd custom map (based off v8 beta)
Pros and cons.
Let's start with the cons...
After a week I'm getting a little stutter/flutter on startup and I think the injectors are potentially on the way out. Feels like it's misfiring on one cylinder but no codes yet. Index 08, so fairly old (revision 12 is the latest). Could be a coil but doubt it, since it's more acting like a leaky injector than a coil breaking up. Only on cold startup.
The VRSF downpipes need heating and beating to get them to fit. Had to make a small dent. Really a massssssive pain in the arse. Took an entire day for this alone. Unfortunately it's hit the heatshield a tiny bit somewhere so it needs to go back up on the ramps.
I have realised I really don't like decats as I don't have secondary now either. It was fun for a day, but it smells like a 90's subaru and the novelty has worn off after I gas myself half to death parking in the garage. I'm looking to custom fabricate the mid cats back again, maybe upgrading to hiflow ones and putting the o2 sensors behind them, and then rewiring. I've seen that the n54 can pass mot fine with just mid cats, so as long as the o2 check passes it should be fine.
The engine bay is a mess, since the emergency brake line, airconn and dme cables foul the intakes. It's not as nice as the 335, so I may change the intake for afe one day. But for now this is fine.
The turbosmart requires maintenance, the oem diverters, doing a questionable job, do not. Every 6 months I'll have to undo the tops, take out the springs, and reoil them. Not a big deal, but it's maintenance nonetheless.
The pros...
Fast. Much faster than I expected. E90 M3's are no issue, as are 400+ Hp Jags. Its very, very fast. Same power now as an m4. I would say that now I need to tighten it up a bit with m3 bushes, arms and suspension parts. An LSD would be good but then I would probably break the ring and pinion as others have done, if it grips too hard.
No slip on the Dct, rock solid there.
The turbo spool noises are wild now. You can really hear everything and this is a fun surprise. Especially with the windows shut. Not something I expected.
Enjoying the car more than ever
Next plans are to look at the new motiv flex fuel, which allows ethanol at any %. The dme adapts and w plug and play just released. Works with a new eth sensor so no custom map needed every time you change the % ratio. One map to rule them all. The z4 has a stronger LPFP than the 335 so it can run e60 no problem, perhaps even e85. I'll have a word with Ken and see. If any of you have run ethanol before you'll know all that lovely power it can offer. Almost no knock and 102 Ron+, it's basically race gas. Realistically there's little point, it's fast enough, but it keeps my mind occupied
I'll do a little video sometime soon and upload some pics of the build.
Happy Easter all.
