'2.7' vs '2.8' stroker

[mkcman17]

That's what i've heard! I have a pretty strong b25, and I can pull on 4.10 guys.

[Eecen]

<engine specs>

Good stuff, thanks man.

[Pedaaa]

Wooo

small question got way out of hand...
guy wants stroker for little money
2.7 is cool but gets pulled by nice b25
so I would go 2.8..
885 head (you have)
325I pistons (you have)
eta rods (you have)
m52 crank 84mm (you can get cheap) sell eta crap...
totaly pull on b25 and smoke 2.7 convertions...

2.8 duh..

Yes, thats what i wanted to suggest:

There are several ways to build a 2,7L engine. But most of them will not give you great benefits over a good 2,5L.

So if he wants an affordable conversion that can easily smoke a 2,5L there are only two ways to go (in my opinion):
- 2,7L conversion with 325i pistons (as described above) or
- 2,8L conversion with 325i pistons

[MonkeyMadness]

Yes, thats what i wanted to suggest:

There are several ways to build a 2,7L engine. But most of them will not give you great benefits over a good 2,5L.

So if he wants an affordable conversion that can easily smoke a 2,5L there are only two ways to go (in my opinion):
- 2,7L conversion with 325i pistons (as described above) or
- 2,8L conversion with 325i pistons

---This^^^ ;)

[Kev]

That's what i've heard! I have a pretty strong b25, and I can pull on 4.10 guys.

never ;)

[mkcman17]

let's roll, home boy!

[e30trooper]

never ;)

let's roll, home boy!

i wants to play too, maybe on the way to van Nuys friday? :D
And! ive got two exhast manifold bolts not on lol

[mkcman17]

i wants to play too, maybe on the way to van Nuys friday? :D
And! ive got two exhast manifold bolts not on lol

i call your missing bolts and raise you a header system that leaks like a mofo with no o2 sensor.

[e30trooper]

i call your missing bolts and raise you a header system that leaks like a mofo with no o2 sensor.

ok i must add my car is running pig rich cuz the new 71* thermo lol

[mkcman17]

i have no o2! i think i'm 'richer'

[E30Kaiser]

This will only end in tears....from laughter!

[mr.vang]

you guys still up?

[e30trooper]

This will only end in tears....from laughter!

[e30Squid]

I have been looking into the stroker or 2.7i build myself....it is not so much that I want to "Pull" someone in a b25 car, but more for driveability. I currently have a 2.5i engine in my car, and although it is a blast to drive the torque doesn't really come into play until around 4k rpms. I have owned eta cars in the past, and it is nice to have the ability to put the pedal to the floor around 2k and have readily available torque, especially on a daily driver that might only see a couple of track days a year.

I am looking at using the early euro 11.0:1 eta pistons in my build.

http://www.bmwccn.no/rogaland/Mahle_m20.html

I do not see why seta pistons would be a bad route for someone on a budget. Although it may not change the top end and hp much, it will change the overall dynamic and torque curve by having the eta crank.

Any input is appreciated.

[Pedaaa]

The 11:1 Euro ETA pistons are VERY rar, so I did not considered those at all, sorry. They were only used in some 525e cars before 85.

You could build a very interessting engine with those...
But you would get a lower CR than 11:1, because this value is considering a 200 or 731 head. With the 885 head it would be a little lower.
And also keep in mind, that those pistions have a little ridge or increment in the middle.
So, you most likely will need to cut some valve pockets into these pistons, if using a sporty cam.
I have never came across such a engine. But it definitly would be a interessting one ;)


Super ETA pistons would give you only 8,5:1 CR.
Thats good for a budget engine, but not for a performance engine.
You could increase this CR by shaving the block and head a little, but then you would also need to cut some valve pockets again. (if using a aggressive cam)
And then you are far away from a cheap conversion... So if spending so much efforts, why not with the right pistons?