2.5 head on eta block???

[grapedrink]

I am going to say you are going to snap you crank. But if you must just try it and find out for your self and then show everyone who said so (me) that they are wrong. I want 500-1000 miles (if you make it) with a full report back on your motor. Good luck :D

[bmdubya84]

agreed same here

[nando]

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

maybe you had weak/damaged cranks? or you screwed up the build/breakin? strokers using the cast 2.7 crank are not new, there are many more than two that run just fine.

[chrisd]

The Eta lacks 2 oil journals that the I has. The reason for failure would not be the crank itself, but a crank that is unsupported over much of its length. The oil journals and bearings can be added to the 2.7 block, or you can just start with a 2.5 block, and lower the CR with pistons, which is a MUCH better idea, and the reason my eta does not have a turbo.

[ragehardintothebendies]

This question is a little OT but somewhat related.

Does anyone know, or could figure out roughly what the static compression would be using an I Crank, (I Rods or e Rods?) and ETA pistons?

Just looking for an affordable way to lower the static CR for boost.

[mikeedler]

some of the people who are putting thier 2 cents in here, have no idea what they are talking about. the blocks are the same, it is the oil journal in the head, for the cam that is missing, since you are putting a 2.5 head on, not a problem! As for it being slow, not true at all, I have a 2.7, had the head milled to bring the cr up a little, and I ran a 15.5 the other day at the track, not really fast, but I killed a 325i out of the hole with all the extra torque! the cranks can handle it with no problem, my last 2.7 took a REALLY HARD 100,000 plus kilometers before the head came apart, and killed the bottom too. I ran the car at 5500 rpms and above for 3 to 4 hour periods every weekend for a year driving across germany. the setup you are talking about is what I am planning on doing.

[davide30]

2.5 head on eta block???

thank you mikeedler , but i would like to know more on your setup , send you a email about that, but if you wont rewrite me an email .

thank you
david

[Hortos]

Hey!

What ever happened to that rumor about either I crank or the harmonic balancer shattering at about 7200 or 7400 rpm? Because I have a spare M20 and I can get a cam made for dirt cheap and 7500rpm with a "low" for that engine speed 3.73 differential would be quite entertaining.

[nando]

your thinking of the M42.. and the M20 will crack a rocker before the bottom end goes. doubt it will make it to 7500.. highest chip I've seen is 7200 (from that E3gumball guy), most are 6900 or less.. I bounced off the 6900 limit on my car once by accident, almost scared me :P

[alpino]

there are two cranks to. the best is the forged steel shaft from a 2.4 litre diesel 324d-324td,524dand524td.The con rods on the diesel are the sam as on the petrol engines. the crank is unbreakable and is what you need if running forced induction-its what Alpina used for the C2.

[atmh]

I am researching turboing my 325e, this is what I have found:

e crank is the weak point in the e engine, the valve springs are an issue too if you want to increase the redline. The e crank is cast, and the i crank and TD crank are both forged. While the e crank is cast, it is still pretty strong, problems are usually to to overrevving, and not really running a lot of boost. The i head on the e block gives it about an 8:1 compression ratio, which is perfectly fine for turbocharging.

My goal is ~250 HP at the wheels while maintaining the stock 4800rpm redline. The e engine should handle that without a problem, the i head will just make it breathe better. Of course the higher your goals, the more money and problems your going to have.

I would recommend www.e30tech.com for anyone who wants to turbocharge an e30, its the best source of information on the topic I have found, and there are a lot of people who have done it there.

[Sean]

I am researching turboing my 325e, this is what I have found:

e crank is the weak point in the e engine, the valve springs are an issue too if you want to increase the redline. The e crank is cast, and the i crank and TD crank are both forged. While the e crank is cast, it is still pretty strong, problems are usually to to overrevving, and not really running a lot of boost. The i head on the e block gives it about an 8:1 compression ratio, which is perfectly fine for turbocharging.

My goal is ~250 HP at the wheels while maintaining the stock 4800rpm redline. The e engine should handle that without a problem, the i head will just make it breathe better. Of course the higher your goals, the more money and problems your going to have.

I would recommend www.e30tech.com for anyone who wants to turbocharge an e30, its the best source of information on the topic I have found, and there are a lot of people who have done it there.

Did you not read nando's post?

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).

Which one is it? :?

[mikeedler]

using the diesel crank, when it is a used, is a very bad idea according to the machine shop I go to here in germany, and he builds alot of Buggatti v12s. he said something about not mixing the diesel parts and gas parts, dont really know why though. Once again. I have built 4 different 2.7 stroker motors here in germany and none of them have had a problem with the cranks BREAKING. thats horse shit! we run these motors constantly on the autobahns(remember- no speed limits). Our favorite thing to do with them is to put a 4,10 diff behind them and bounce them off the rev limiters in 5th at about 235 km hr. we have had a few motors, built different ways, and the favorite has a special chip made here in germany with no rev limiter. the car has a 4,27 LSD and when its reved past 7200 it sounds terrible, but hasnt come apart. You are all refering to an old wifes tale made up by Korman Motorsports in the 90s so he could ell 2.7 stroker kits for exagerated prices. you may have more vibration in the crank cause of the longer stroke, but it has yet to cause problems.

[nando]

the i crank is cast, we've been over this a million times already.

good luck getting 250rwhp out of an e motor with a 4800rpm redline.. :rofl:

[M-technik-3]

the i crank is cast, we've been over this a million times already.

good luck getting 250rwhp out of an e motor with a 4800rpm redline.. :rofl:

I think he plans on boosting it.