MyE28.com

Greetings from England

I've noticed that TCD are having a lot of success in turbo charging a standard M30 engine. However, Alpina with their E28 B9/B10 and E34 B10 offered a modified M30 engine giving a bit more power (218bhp -> 245/260bhp). What impact would these changes have with respect to their suitability to be turbo charged? Would they be more/less robust? Would they have more/less potential for power gains?

i am guessing they have a much different cam profile (suited for NA applications) and a higher compression, neither of which are ideal for turbocharging.

Engine

6 cylinder in line, capacity 3430 cc, bore/stroke 92/86 mm, compression ratio 9,8 : 1, max. power 191 KW/260 bhp (DIN) at 6000 rpm, max. torque 325 Nm (240 lb ft) at 4000 rpm

Crankshaft running in 7 bearings, light alloy cylinder head with hemisperical combustion chambers, long connecting rods with extra light short MAHLE pistons to reduce friction loss, piston head cooling, forced lubrication with oil filter in main stream, engine oil cooler, water cooling with thermal-controlled viscous fan, electronic grid-controlled ignition and fuel injection with fuel supply cut-off, BOSCH motronic M1.3

EDIT : This is E34 B10 (E28 B9/B10 have higher 10.2:1 & 10.6:1)

You only limitation will be the compression ratio. 9.8:1 will limit your boost to ~5psi with M1.3.

Obviously the engine is configured for a higher rpm power band, that will be the same whether turbo's or not.

RussC

MXH_RHD wrote:Greetings from England

I've noticed that TCD are having a lot of success in turbo charging a standard M30 engine. However, Alpina with their E28 B9/B10 and E34 B10 offered a modified M30 engine giving a bit more power (218bhp -> 245/260bhp). What impact would these changes have with respect to their suitability to be turbo charged? Would they be more/less robust? Would they have more/less potential for power gains?

A .120 MLS HG and studs will cure the high CR. The cam isn't a problem.

Todd

What will the head gasket lower it to?

RussC

russc wrote:What will the head gasket lower it to?

RussC

~9.0 to 1

Wow,
I didn't know it would lower it that much!

RussC

OK, so here's my understanding so far.

The alpina engine isn't as suitable for turbo charging due to it's higher compression. However, this can be lowered to something similar to the standard M30 using a different head gasket, presumably sacrificing a few bhp. The engine is then suitable for turbo charging but will exhibit the same 'more rev happy' characteristics of the alpina engine. i.e. Produce max output about 300 revs further up the range (6000 against 5700, torque both at 4000).

So I wouldn't necessarily be looking at an engine swap.

I've been looking into this further and I've found the following compression ratios for UK cars.
These are all a bit of a worry as I believe the TCD figures apply to the USA cars with a much lower 8:1 ratio.
Has anyone turbo'd cars with these specs? Did you lower the compression ratio? How? Different head gasket? Other?

Might be worth selling on the Alpina engine for some turbo project funds and starting with a normal 9.0:1 M30b35 ?

MXH_RHD wrote:I've been looking into this further and I've found the following compression ratios for UK cars.

Code: Select all

		   535i	B9	   B10
E28/24	10:1	10,2:1  10,6:1
E34/32	 9:1	 	     9,8:1

These are all a bit of a worry as I believe the TCD figures apply to the USA cars with a much lower 8:1 ratio.
Has anyone turbo'd cars with these specs? Did you lower the compression ratio? How? Different head gasket? Other?

Bolt a turbocharger on that bad boy!

Pull the cylinder head and cc the combustion chambers. I'm guessing you'll be able to get the comression down into the 9.0:1 > 9.5:1 range by some judicias unshouding of the valves, sinking them a bit into their seats (not too much!) and using a thicker (MLS) head gasket (with studs). Install a stand alone ignition/fuel system and finnish with a dollop of high octane fuel. Your car will pull like a fraight train!!!
"" -http://www.performore.com/technical_art ... o/main.htm

MXH_RHD wrote:I've been looking into this further and I've found the following compression ratios for UK cars.

Code: Select all

		   535i	B9	   B10
E28/24	10:1	10,2:1  10,6:1
E34/32	 9:1	 	     9,8:1

These are all a bit of a worry as I believe the TCD figures apply to the USA cars with a much lower 8:1 ratio.
Has anyone turbo'd cars with these specs? Did you lower the compression ratio? How? Different head gasket? Other?

Most of us with the 8.0:1 compression did not make any modifications to the engine. 8.0:1 is a low enough number as it is, and is quite boost friendly... I think Todd found the max PSI on the 8.0:1's to be about 22psi before the engine really starts to take a beating? 9.0:1 is also friendly towards boost, around about 15psi with some engine management and proper intercooling.