Budget High Compression

[BimmerScreamer]

To all you bimmer engine guru's out there, is their a way for me to build a high comp m20 using assorted bmw internals? I'm not really concerned with hp as much as throttle response and higher redline.

I am starting with my 230k mile m20b25

[jlevie]

High compression has little, if anything to do, with throttle response or redline. The former is related to the intake, throttle assembly, AFM, head and exhaust. The latter is mostly related to the cam and valve springs.

[zav3n]

just shave the head down until its flush with the valves then you have really high compression..

[BimmerScreamer]

High compression has little, if anything to do, with throttle response or redline. The former is related to the intake, throttle assembly, AFM, head and exhaust. The latter is mostly related to the cam and valve springs.

is there any other options for intake manifold than just extrude honing the factory piece? I was already looking in the MAF conversion. It just seems like a lot of money for not knowing a true outcome.

I already have headers and exhaust and chip

I do have a S54 intake manifold sitting around but thats pretty drastic, but i do get bored

Is it true the euro spec b25 is 9.7:1 (euro spec 85-89), if so what bumps it up?

[BimmerScreamer]

found my own answer, pistons

[jlevie]

A properly executed MAF replacement for the AFM will help with throttle response as it has no moving parts and less restriction.

Improving the flow in/out of the head and reducing the dead volume on the intake side would help with throttle response. A different intake with less volume would unfortunately have a negative affect of the power bad. Those long tubes are there for a reason. Head porting, port matching, and honing of the intake is about all that can be reasonably done. And even that is going to be expensive for little gain.

[BimmerScreamer]

i have been looking into the IE MAF replacement but I dont want to lose my tuner chip. I have been trying to contact them about the kit but I cant say there responses have been timely or informative.
Does anyone know if the chip required to run the MAF also helps out performance or is it just a conversion.

[TimR]

First thing i would do is get a 4:10 LSD diff if you don't have one, i have the M30 AFM, ITG foam filter Turner sells, CAI, 19lb injectors, adj. fuel pres. reg, headers, good flowing exaust and a chip and thats the easiest bolt-on E30 mods. I had an 84 E with CAI, chip, exaust and a 3:46 Diff and many i owners hated that E kicking it. Tim

[BimmerScreamer]

4.10s are something i am looking for but having an iX makes alittle harder. All the assorted bolts ons will get done in time but I plan to pull my engine and give a rebuilt since it has 230k on it and I picked it up as a dedicated project car anyway, so thats where the idea for this thread came from.

[eugeman]

Does anyone know if the chip required to run the MAF also helps out performance or is it just a conversion.

I contacted Miller Performance directly and the owner told me that the chip that comes with the kit is for both performance and the conversion, so it is a 100% necessity. The benefit of buying the kit directly from Miller is they can custom tailor the chip to either a stock or modified engine setup.

[BimmerScreamer]

^^wow good to know, thanks