MyE28.com

I am having a hard time to decide wich way i will be getting my m30b28 with stock 184hp to produce 220 horsepower or more.
First off, i want the 2,8, i know it is easier to get big bhp from a 3,5, but i have two 2,8 blocks and one more available from a friend.
I have been thinking alot about building a strong na engine, but the thought of it being and worse to drive is bothering me a bit.

As the build process progresses i will probably replace every gasket, bearing, pump, nuts and bolts to assure that the engine is in good condition and will not fail because of old worn parts,

So, cost aside, what would give me a relatively strong engine that does not need to rev over 5500 RPM to give some good power?.
I am considering, supercharging, turbocharging and naturally aspirated engine.

The time required to build is not a factor, i am not in a hurry.

The electronics will be a complete engine managment unit controlling everything, (ignition timing, fuel injection, boost, traction control and so on) it is a KMS unit by the way.

I'm curious if it'd be possible to bore out the block.

A turbo or supercharger is going to be far spendier than finding an M30B34 in a junkyard.

I got a used but good 745i turbo setup bought it for my 535 but haven't installed it, not sure if im going to keep my car or not. Its complete all you need to do is bolt it up, you can run 10psi

I took it off a running car so I know everything is good

Everyone here will tell you to turbo the thing. Even if you got a 3.5 it would cost quite a bit of money to get it to 250-260hp, whereas you could find some 745i parts and probably build yourself a 260hp 2.8 for about the same price. If you buy a TCD kit it will cost more all at once, but definitely save you a lot of trouble and you will have everything you need.

Thanks.
What about the internals of the engine?, it is 9 to 1 compression ratio, lower than the 3,5.
How far can i go in boost before having to lower compression?.
The stock pistons are crowned, does anyone have any experience using a lathe and turning down the top of the pistons to lower the compression?, i assume this would be a time consuming task, including fine matching the weight of each piston to the lightest one.
Getting 260 hp from a 2,8 sound great, is this with a ported engine or stock head?. i am not afraid of spending lots of time reshaping the ports to give it more power.

How about the stock valves and valvesprings?, i guess it would need to double up on the valve springs with a new cam, but how will the valves react to the hotter exhaust?.

Then turbo will probably be the way to go for me.

to e28535is, thanks for the offer but i will probably go for a custom buildt turbo system, i know of a company here in norway that produced a M5 with 1182hp and a M3 with 1400hp the latter being the worlds fastest bmw

The M30B34 had 8:1 compression, actually. Which years are these motors from, out of curiousity? 9:1 is a great C.R. for turbocharging, unless you're hoping to have high boost levels. I'd recommend using a nice F.I. aimed head gasket (i.e. Cometic) and pushing 10ish psi through there (0.7bar or so) with a good intercooler, fuel system, and management, and calling it a day.

I know of the company you're talking about (they post on bimmerforums.com)... could you possibly link me to info on the 1400hp M3 though? I haven't seen that beast yet.

e28stian wrote:Thanks.
What about the internals of the engine?, it is 9 to 1 compression ratio, lower than the 3,5.
How far can i go in boost before having to lower compression?.
The stock pistons are crowned, does anyone have any experience using a lathe and turning down the top of the pistons to lower the compression?, i assume this would be a time consuming task, including fine matching the weight of each piston to the lightest one.
Getting 260 hp from a 2,8 sound great, is this with a ported engine or stock head?. i am not afraid of spending lots of time reshaping the ports to give it more power.

How about the stock valves and valvesprings?, i guess it would need to double up on the valve springs with a new cam, but how will the valves react to the hotter exhaust?.

Then turbo will probably be the way to go for me.

TCD has answers to all of your questions.

Hi, and thanks again for your help.
I am guessing that the b30b34 is a u.s. model?, i just read from ye olde manual that a 535 and m535 with 218hp m30b35 had 10 to 1, here in norway these numbers were used from -82 to 86, probably on to 87.

Here is a link to vs motors homepage and the beasts:D
http://www.vsmotor.no/bilder.html

i appreciate the fact that a tcd kit probably is best, but the norvegian customs agencies would make it THREE times more expensive than buying it in the u.s. and when i am going to spend my money on the car i do not want to give away more money than i have to to the state, 90 percent of the average norvegians income goes straight to the state wich is using it to feed their politicians with money plus trying to save it in the oil fund , you would have been frightened by the extra taxes on tuned cars younger than ten years, about 4000 dollars per extra hp:shock: , doesent apply to my car though, another benefit of loving older cars.

Sounds good that the stock engine is ok for turbo regarding the compression, i have heard of using thicker head gaskets to decrease compression, How does this work.

And does anyone have experience of porting a turboed engine, if there is much to be gained by doing a moderate port and polish?.

If i can get the 260hp with 9 to 1 i probably will go for that ratio.

The low compression (8:1) m30b34 was the only engine available on the e28 535i cars sold in North America. It's also found on any factory catalyzer equipped e28 cars sold in Europe.

Porting and polishing always helps, but most of the power will come from the turbo, so its value is debatable depending on yours goals. For a relatively modest 260bhp, it wouldn't be neccessary.

As for the customs thing. What if they're "used parts"?

Jeremy

well i dont think the customs agencies care, if i paid money for it, they probably want their part of it anyway, like greedy rats with wings they are

I think i will treat my car to a new turbo, and maybe make a exhaust manifold myself, or get it made by v.s motor when i get enough money.

I probably will port it because i love working with all parts of my cars, and if there is a couple of hp to be made, then nothing of labour time is wasted in my book, even if it means hundreds of hours.

i checked out my setup with a t3 40 on the turbo calculator, looks good, at 15 psi with 80 percent volumetric efficiency it calculated 340hp,

At 10 psi with 70 percent volumetric efficiency it gave closer to 260.

I now know what i will be working towards, cant wait til i really can get started on this project.

e28stian wrote: i checked out my setup with a t3 40 on the turbo calculator, looks good, at 15 psi with 80 percent volumetric efficiency it calculated 340hp,

At 10 psi with 70 percent volumetric efficiency it gave closer to 260.

The VE for a FI engine will be over 100%.

Really?, checked it out and at 10 psi it gave 364 hp, thats pretty good from a 2,8 but i think that the e34 535i brakes will be suffering a bit at that point, good thing i will be getting traction control.
Thanks for the info.
By the time i am done me in the car equals a hyena with coffeine shock and nitrous and lots of sugar

After going through the forced induction forums i suddenly got the urge for even more power when i somewhere in the future learn to handle the 260 hp turbo engine.
As to increase the performance, where are the biggest gains hidden?.

Performance cams?
Water injection?.
Pro flowed head?.
Big ass intercoolers?
dump valves and pop off valves?.
Nitrous to build earlier boost?.
When i am talking about bigger power, some low comp turbo pistons will probably be in order.

Some pretty wild ideas started to pop in my head when messing around with the turbo calculator, with 15 psi i was getting some good numbers.