2.5 head on eta block???

[davide30]

me im runnin 8 psi with my eta and they are very fine , but now i going to put an 2.5 head with all the parts , motronic 1.3 all fuel injection systeme. but i know if we run the 2.5 head you suppose to get new pistons but me i run a turbo and lower cmopression its better for turbo engine. but i would like to know which compression it suppose to do with 2.7 stock piston??

THANK you

Dave

[Jonathan M3]

I believe it would drop you down a bit too much, to somewhere around 7:1, but someone may need to verify that.

[LowR3V'in]

CR will be cool 7.9:1. ;)

[nando]

CR will be cool 7.9:1. ;)

that's going to be a dog until your turbo spools up.. can you say laaaag?

[LowR3V'in]

I don't know, I've been told by two people that's done this that it feels like a normal 2.5 off boost will alittle more botten end. :?

[reelizmpro]

I say do it. A ratio of about 8:1 is ideal for running high boost! And with the 2.7 and high flow "i" head it'll be awesome. I would definately do it if you expect to make any serious power.

[bmdubya84]

DONT DO IT!!! the stock ETA crank is CAST it can not handle anything higher than 5400 RPMs before exploding into pieces...trust me a friend of mine did it and lost a good block and head...you need a forged or billet crank to handle the rpms...not worth it...trust me...

[LowR3V'in]

Is the 2.5 crank forged ?

[EverWiser]

DONT DO IT!!! the stock ETA crank is CAST it can not handle anything higher than 5400 RPMs before exploding into pieces...trust me a friend of mine did it and lost a good block and head...you need a forged or billet crank to handle the rpms...not worth it...trust me...

This is news to me...Maybe someone else can chime in but the reason for the lower RPM's on the eta's (from what I've read/heard) was due to the single valve springs and concerns that the valves wouldn't get out of the way of the pistons at higher RPM's. Also, there are a lot of engines redlined at well over 6000rpm running on cast cranks. Can someone else chime in and clear this up? :shock:

[bmdubya84]

Is the 2.5 crank forged ?

to my knowledge it is yes...i have heard this from several dfferent places now...but i have lso heard of successful conversions from various sites...so i dont know but from experiance it could not handle it..

[nando]

DONT DO IT!!! the stock ETA crank is CAST it can not handle anything higher than 5400 RPMs before exploding into pieces...trust me a friend of mine did it and lost a good block and head...you need a forged or billet crank to handle the rpms...not worth it...trust me...

BZZZT! sorry, the 2.5l crank is also cast, and it easily can handle 6900rpm. you'll be breaking rocker arms long before you break a 2.7l crank! Also, the forged TD 2.7 crank is quite a bit heavier and essentially gives no benefits over the e crank, unless you were planning mad boost, but even then it's not really neccesary (look at TCD's stock 2.5 turbo).

[EverWiser]

That's what I thought.... :up:

[Ryan Stewart]

The only thing I think you might want to consider is bearings/lubrication. Im not an M20 internals expert but I think I recall the B25 having another bearing and journal.

[Jonathan M3]

DONT DO IT!!! the stock ETA crank is CAST it can not handle anything higher than 5400 RPMs before exploding into pieces...trust me a friend of mine did it and lost a good block and head...you need a forged or billet crank to handle the rpms...not worth it...trust me...

BZZZT! sorry, the 2.5l crank is also cast, and it easily can handle 6900rpm. you'll be breaking rocker arms long before you break a 2.7l crank! Also, the forged TD 2.7 crank is quite a bit heavier and essentially gives no benefits over the e crank, unless you were planning mad boost, but even then it's not really neccesary (look at TCD's stock 2.5 turbo).

[bmdubya84]

oddd........hmmm then explain to me why this happened twice in 2 situations...? just curious