Eta 2.7 block with is 885 head question

[digger]

Uhh ... I daily drive this and it's a hoot. People hating on flat top builds have probably never seen a well sorted one. It might lose a couple of hp compared to a higher compression build, but saying it won't work is just blatantly false. If you do it right, you get a smooth, torquey engine that pulls hard to 6k and still gets decent MPG. Ask me how I know.



Yes, absolutely. Even with ~8.3:1 compression it's still an excellent motor. Remember, BMW shipped M30s with 8.0:1 compression from the factory.



YES. I'm using an Sssquid tune and it's FANTASTIC. Worth every penny.

Of course it physically works but it’s far from ideal is what people actually mean, even BMW redesigned the b25 with a completely different combustion chamber and piston profile which is not a small undertaking.

When you start upping the compression with mismatched chambers that’s where you start getting knock as you don’t have enough mixture motion that comes from good squish, while it doesn’t show up at low comp because its an inefficient setup it gives up some power across the whole rpm.

ive driven many 2.7L, ones with 885 on eta, 731 head on eta, and the only budget ones that are good are good compression engines with b25 style piston and 885 head

The M30's are woeful for the displacement….a proper 2.7L basically out torques a bone stock 3.4/3.5L with 700cc less displacement. Throw in a higher comp m30 with mild cam and tune and it’s a different story, they come alive.

[modernist]

the only budget ones that are good are good compression engines with b25 style piston and 885 head

eh. to each their own, I guess. that's a blanket judgment that I disagree with. there's a lot of dreck floating around that low comp 2.7 M20s are gutless dogs (they're not), but it's night and day over a stock eta, and not everybody has the cash to throw at building fancy high strung M20s. so, might not be completely ideal (but neither is any flat tappet SOHC 12v six), but a well sorted one is still good fun.

at least nobody here has chastised me for not doing a 24v swap (because that has happened to me elsewhere)

[digger]

eh. to each their own, I guess. that's a blanket judgment that I disagree with. there's a lot of dreck floating around that low comp 2.7 M20s are gutless dogs (they're not), but it's night and day over a stock eta, and not everybody has the cash to throw at building fancy high strung M20s. so, might not be completely ideal (but neither is any flat tappet SOHC 12v six), but a well sorted one is still good fun.

at least nobody here has chastised me for not doing a 24v swap (because that has happened to me elsewhere)

im talking about budget builds.....it does not take much to build a 2.8L with M52 crank, eta rods, b25 pistons, 885 head or a 2.7 using eta rod, eta crank, b25 piston and decked block and cam gear.

if you start with an eta the 885 head swap makes sense as you cant exactly do any worse than an eta and its a pretty easy job to swap heads but this isnt the case here.

my understanding is the OP is wanting to pull out his b25 and build something better with parts comprising of a b27 and b25 , may as well maximize what you've got when you are pulling an engine vs a head change only.

otherwise just get a good running b25 and swap the whole thing

[Corsair89]

Well to clarify. I have an eta and an is. The eta has a new rebuilt engine. The is has almost 400k miles on the engine and I don't trust it. I want to keep my eta block and I want to keep the is intake manifold, throttle body, ect. I was checking that with my current stuff or rather setup I'll be able to swap it and drive without it exploding. As for making it fast that will come in time.


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[ForcedFirebird]

eh. to each their own, I guess. that's a blanket judgment that I disagree with. there's a lot of dreck floating around that low comp 2.7 M20s are gutless dogs (they're not), but it's night and day over a stock eta, and not everybody has the cash to throw at building fancy high strung M20s. so, might not be completely ideal (but neither is any flat tappet SOHC 12v six), but a well sorted one is still good fun.

at least nobody here has chastised me for not doing a 24v swap (because that has happened to me elsewhere)

I have done various swaps, and actually dyno'd them. The 885 head on an eta engine is an upgrade over a full eta, but that's where it stops.

high mile block with refresh head (all "i" components) I will typically see around 150-157whp/tq

eta block with "i" top end and electronics: 134whp 145wtq
eta block, 885 head, eta manifold, "i" throttle body: 145whp 170wtq


Now what Digger is saying (b28 crank, eta 130mm rods, "i" pistons): 169whp 174wtq



I left my SD card and reader plugged in the dyno PC when I was there last week, or I would go ahead and post screen shots the graphs.

[Corsair89]

Eta 2.7 block with is 885 head question

I really appreciate the input guys. Thank you and I'll keep on chugging toward a faster 2.7i.

[jeffnhiscars]

I have done various swaps, and actually dyno'd them. The 885 head on an eta engine is an upgrade over a full eta, but that's where it stops.

high mile block with refresh head (all "i" components) I will typically see around 150-157whp/tq

eta block with "i" top end and electronics: 134whp 145wtq
eta block, 885 head, eta manifold, "i" throttle body: 145whp 170wtq


Now what Digger is saying (b28 crank, eta 130mm rods, "i" pistons): 169whp 174wtq



I left my SD card and reader plugged in the dyno PC when I was there last week, or I would go ahead and post screen shots the graphs.

I hope to have numbers for a stock ETA w a 731 +2 with ETA externals and then again with a full "I" motronic upgrade....for your database

[Andy.B]

high mile block with refresh head (all "i" components) I will typically see around 150-157whp/tq

eta block with "i" top end and electronics: 134whp 145wtq

eta block, 885 head, eta manifold, "i" throttle body: 145whp 170wtq

Can you clarify this for me, because I think I am misreading your post.

For "eta block with I top end", do you mean an eta block/head with motronic 1.3 and throttle body?

The way I'm reading it sounds like all things being equal, on an eta block/885 head/motronic 1.3 engine, an eta manifold makes more hp/tq than an I intake. Is that correct?

[ForcedFirebird]

Flat top pistons with 885 head and "i" ECU. Typical "2.7i". I did the swap in my eta and took it to the dyno, then had a chance to mess with a customer's eta later on and experimented with the eta intake manifold. You can read more about my experimentation with various m20 inductions...

http://www.r3vlimited.com/board/showthread.php?t=261381

[modernist]

http://www.r3vlimited.com/board/showthread.php?t=261381

way cool. makes me want to dig out my old eta intake manifold :)

[tricars]

I have an SETA with the 885 and wish to use the 325i intake manifold, throttle body and 1.3 Motronic, anyone has that going on? How are the results compared to a regular SETA or a stock 325i?

[digger]

john did you ever compare the eta and i manifold on the dyno on same engine?

[ForcedFirebird]

john did you ever compare the eta and i manifold on the dyno on same engine?

Yes. And even tuned each setup. Max HP is what I listed above. We made several tunes for it to compete in different race classes. Gave it handicaps with spark timing instead of using a restrictor plate to meet hp/wt ratios. It won both classes in Time Trials that weekend, two ECU's with different tunes and a whole lot of removable ballast. :)

[ForcedFirebird]

way cool. makes me want to dig out my old eta intake manifold :)

It's a very strong combination. You get more TQ than an eta, but the better breathing of the head and cam, so more HP to boot. It does choke a bit at the top end, drops off pretty rapidly at 6000 or so.

[digger]

Yes. And even tuned each setup. Max HP is what I listed above. We made several tunes for it to compete in different race classes. Gave it handicaps with spark timing instead of using a restrictor plate to meet hp/wt ratios. It won both classes in Time Trials that weekend, two ECU's with different tunes and a whole lot of removable ballast. :)

so basically its a SETA with i cam and TB? and custom tune? noting that the SETA manifold is skinnier than the I manifold