{"id":976,"date":"2019-04-24T09:02:27","date_gmt":"2019-04-24T09:02:27","guid":{"rendered":"http:\/\/mcnab-racing.co.uk\/?p=976"},"modified":"2021-12-08T08:21:11","modified_gmt":"2021-12-08T08:21:11","slug":"a-tale-of-2-turbos","status":"publish","type":"post","link":"https:\/\/mcnab-racing.co.uk\/?p=976","title":{"rendered":"A tale of 2 turbos…"},"content":{"rendered":"

Been an interesting month and a half, 430d was awaiting EGR recall parts, so Eastern BMW loaned me an LCI 435d for the first month of the wait. Very similar spec on both cars, but a surprisingly different driving experience.<\/p>\n

So what difference does 1 extra turbo and 2 extra diffs\/driveshafts make? Well, the engine and torque delivery really is quite remarkable, the internet folklore isn\u2019t without justification. My god it likes to rev! Same core 6 cylinder lump but the 35d\u2019s extra low down torque is very noticeable, it also revs way quicker and carries a very different engine note.<\/p>\n

Never actually got round to sticking my vbox in to see what the acceleration figures were like to compare against my 30d. Equally, I can\u2019t comment off the line, I\u2019m not in to traffic light grand-prix and have never really believed in roasting the nuts off a car someone has been kind enough to loan you. From on the roll to legal speeds on motorways & dual carriageways however, the buttdyno confirms it\u2019s definitely quicker, despite some internet theories of the 30d having nearly the same power to weight ratio.<\/p>\n

Ride is not such a favourable review, however. The extra couple of diffs, well actually the transfer case, require additional ride height for ground clearance and that\u2019s why I didn\u2019t consider a 35d when shopping for my 4 series. From an aesthetics point of view as much as dynamics. You don\u2019t have to push the car down a twisty road to feel the suspension is a bit more ponderous, the higher ride and more roll just don\u2019t give the same feel even through fairly mundane corners. Also, on the motorway in cross winds, it\u2019s amazing how much more it wanders with the additional airflow getting under the car.<\/p>\n

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An interesting comparison was pre-LCI vs LCI. Most interesting, to me, was the different feel of the gearbox. It\u2019s the same ZF 8hp unit, but the LCI version seemed to engage \u201ccoast\u201d mode far more readily. Now that I have my car back, I\u2019ve noticed it operates very differently. In both the 435d and subsequent 420i I was loaned [more about that at some other point], at anything over 30mph in EcoPro, lifting would have the car go in to coast mode. The revs would drop to idle and the car was coasting with clutches presumably disengaged to enable this. When asking for some engine braking via the paddles, say slowing slightly for traffic on the motorway, the first pull on the paddle would actually bring the car back in to 8th<\/sup> <\/span>gear, then you would start going down the box. On my 430d, the first downshift pull on the paddle, immediately pulls the box down a gear. I like this feature quite a lot and may well see if there\u2019s a gearbox software flash update available for my car to put the LCI map on it.<\/p>\n

Other notable differences and my feelings on them:<\/p>\n