wonderful sounds of the m20b27

[EtaSport]

Okay, this might seem odd to some, but heres a nice topic. We all know the m20 with a decent exhaust sounds pretty great. I've driven my friends 89 iS more than several times and it is a great sounding engine. Then there's the eta. It has quite a distintive sound, almost like a quiet diesel.

I dont suppose there are too many people with high rpm engines that use an eta bottom end, but have any of you heard an eta at 6500 rpm? It sounds ok, but you can tell its screaming. Its like you know that its not supposed to rev that high whereas the b25 sounds right at home at any rpm. I know the combustion chambers are different, and the pistons are different, but is there any other reasons why this engine just sounds different?

[Jand3rson]

I love the sound of my engine when I wind it up to the top of 2nd and 3rd. Even with the JimC chip, the rev limit was raised at least some, and combined with my Magnaflow exhaust, it has a very deep, throaty tone to it.

[SpecM]

-Not many people have heard an eta at 6500. ;)
-Yeah I believe the head/piston combo makes the different sound.

[silversleeper]

my 325i sounds like a beast with the exception of the *tick tick tick*

[James Crivellone]

My ETA did have a much nicer growl at upper RPM's them my B25 Does.

However the fact that I can rev her up to around 6500 is much nicer..

I don't go much higher then that.

[EtaSport]

It definitely roars up there. I've got a resonator delete pipe with a freer flowing muffler. It sounds right at home around 2000 rpms which is about all i run in town. My engine is just like a regular eta except for the big boost of power from 3500 up. It pulls all the way to 6k+ just like stock does to 5k redline.

It just doesnt have that refined mechanical sound of the b25.

[E30 Wagen]

It definitely roars up there... It just doesnt have that refined mechanical sound of the b25.

My eta, everything completely stock except for a K&N panel filter, roars too, which can be annoying. My redline is still at 5000, and at around 3500 is when the roar begins.

However, if i punch the gas while rolling in third gear, my engine seems to whir at a higher pitch around those higher rpms, pulling nice and strong all the way from 2000 to ~4600 and I'm at 80 mph in no time which is great for merging on the freeway.

Go ahead and laugh you b25 boys, but I love my eta, roaring and all.

[EtaSport]

Ive been thinking about doing a big port 731 head swap, but I can probably just as easily port a spare e head I have and see similar gains as the valves are the same. I went a little conservative on the port work with this head as I wanted to retain good fuel economy which I did, so I'm not affraid to go further. I dont think I'll get much of a different sound though.

[Jand3rson]

Ive been thinking about doing a big port 731 head swap, but I can probably just as easily port a spare e head I have and see similar gains as the valves are the same.

That's what I've got, a spare eta head in excellent condition, as well as a set of brand new dual i valve springs.

I hope to hear my B27 hit 6500 RPM this spring, along with a dual i exhaust and possibly even headers. :D

[Mot]

Well any one local is welcome to come hear what a b27 sounds like at 5k+ rpm with a magnaflow and 2.5" single.. sounds pretty darn good imo.

edit: Im really really happy with my 731 casting b27 combo.. motor pulls good and hard, and this summer she will only be getting stronger.

[EtaSport]

Yea, I forgot that you had an eta bottom end with the 731.

When spring time comes, I will be swapping in the single mass flywheel and clutch, 325i exhaust with catless mid section, and ill try the 3.73 diff out. Might try the headers too. The cool things about my set-up is that I really havent even done anything to try and make power. Ive always got the exhaust, driveline weight reduction, chip/tuning, gearing, and increased fuel pressure.

If this doesnt make me happy, then the b25 is going in with a turbo.