Smileyboy wrote: ↑Oct 03, 2020 10:13 PM
That is quite the detailed list!
Now that you've had the car for a bit..,.. What is it like driving a S54 powered e28? Whats the road behavior like? What's road noise like vs the m30?
The car has been off the road since the 2nd week of August. I took her into 425 to have the punch list punched. The biggest three items being the transmission whine, the wrong springs on the suspension, and the exhaust being too low.
Mitch re-welded the exhaust before removing the transmission, and so that's done. Fits tight now. No idea why this SuperSprint system hung so low while the same model on Vlad was fine. Oh well.
We determined transmission whine was from the input shaft bearing. Input shaft must have gotten damaged during one of the many removals/installs since it was pulled from the donor car (be careful not to let the weight of the transmission be held by the shaft). 420G transmissions are not repairable; neither BMW nor Getrag provide any parts or support. I contacted many 'experts' around the world, including those who convert 420G SMGs to 6-speeds. None could offer any help with the input shaft bearing. Just the cost of having someone TRY would end up being many thousands of doll hairs. I decided to write the old transmission off and source a new one. Yes. New. There are (were) two of them left in the world. It should be here this week.
The new H&R springs are ready to go on too.
And I couldn't say no to these.
To answer your questions:
What is it like driving a S54 powered e28?
It is silly fast. I've had to change the throttle response map to be really gradual, or it just wants to leap. But with it tuned, the car is as drivable as my other E28s. I've tuned "Sport Mode" to still have a pretty aggressive throttle response, so I can still be silly. The power is everywhere, but the S54 does come extra alive above 5000-ish. I've resisted revving it too high during break-in, and the rev-limiter is set to 8200. I could go higher (according to Steve Dinan) but have no desire to do so.
I will go through rear tires fast on this car. 225s are really not enough meat for this amount of power. But options for going any wider just don't exist. There's no shortage of throttle-induced oversteer, as you'd expect.
What's the road behavior like?
I've never driven a brand new E28 before. But I imagine they felt like this car does. That said, Vlad is a very, very solid car. Tight. Minerva is the same. The M5 steering box makes a dramatic difference in steering feel. The suspension is not quite right yet; too low and too soft in rear. The new springs will help.
What's road noise like vs the m30?
I can't really answer this yet. First, the transmission whine really dominates and annoys. Second, I still have never had the dashboard/console fully buttoned up, and there's still holes in the firewall. But the SuperSprint exhaust does an nice job of muffling the sound. I was worried the car would be too loud (I think Vlad borders on too loud) but it's fine.
Cheers!