Stock M20B27 rebuild with turbo questions

[amwafa]

Hi all,

I'm a newb in the US and currently starting a restoration on my 1986 325e, has 270k miles. Goal is to be a daily driver with occasional fun and ability to keep up with current cars (ideally around 200 HP) on the road while loaded with a few people, no race tracks. Goal is to keep it looking stock as well. I'm thinking of sending the engine to get rebuilt to original stock by Korman given it's time to change everything rubber anyway, and to prepare for HP upgrading. They'll give me a price estimate later this week. Their description is here: http://www.kormanautoworks.com/e30.htm under "Stock engine" and "Engine plus program." However, the HP will obviously not be around 200 HP after a stock rebuild.

Questions:
1) Turbo vs their stage 2 clean engine option? Other engine rebuild company?
2) If turbo, from my readings, I believe I can get to around 200 HP with around 10 psi, which is all I would hope for:
a) What kit do you recommend (for longevity, dependability, and daily driver use)?
b) I'll likely need new ARP head studs, what else would be needed? Can anyone point me in the right direction? I'm sure ignition timing would have to change, but not sure how?

Thanks

[tha881]

Never heard of Korman but that page was an interesting read. Would you not be better off using an 'i' head rather than the eta one? Seems a shame to spend all that money and have an eta engine at the end?

[amwafa]

If I change the engine, I feel like I'm doing myself a disservice by changing the soul of the car, which I want to keep given its sentimental value. I also in some ways prefer the better gas mileage and higher torque of the 325e, just want a little more horsepower with a turbo kit.

[flybynite]

If I change the engine, I feel like I'm doing myself a disservice by changing the soul of the car, which I want to keep given its sentimental value. I also in some ways prefer the better gas mileage and higher torque of the 325e, just want a little more horsepower with a turbo kit.

To be honest you are going to change the soul of the car more by bolting a cobbled-together turbo kit and stand-alone engine management system to it than anything you could do internally to the engine.

If you want to keep the soul of the car I would turn it into a "super-eta" like the 325e of around '88 It has the "i" head and pistons to suit. Built right and tuned properly it should make 200bhp and still have it's torque

[amwafa]

If I change the engine, I feel like I'm doing myself a disservice by changing the soul of the car, which I want to keep given its sentimental value. I also in some ways prefer the better gas mileage and higher torque of the 325e, just want a little more horsepower with a turbo kit.

To be honest you are going to change the soul of the car more by bolting a cobbled-together turbo kit and stand-alone engine management system to it than anything you could do internally to the engine.

If you want to keep the soul of the car I would turn it into a "super-eta" like the 325e of around '88 It has the "i" head and pistons to suit. Built right and tuned properly it should make 200bhp and still have it's torque

That sounds more like it! It sounds like Korman can do that, maybe avoiding turbo is best then.

[reggid]

yeah a good old fashined but proper 2.7/2.8 is pretty decent thing.

Avoid the basic 2.7 which is nothig more than swapping a 325i head onto an eta bottom end, while that's an improvement over a stock eta but its only half of a proper job and a true "i" based 2.7/2.8 is much better

[steve_k]

a 2.7 m20 built properly can be a very expensive & time consuming build, there's so much to it,
but when it's all built up, mapped & running properly you'll wonder why you didnt do it before.

my 2.7 is/was based on a hartge H27, but now has a lot more done to it as when i stripped it down it became a case of "while i'm in here....".

as reggid says avoid the basic aka "burger king" 2.7 build as you are not really gaining that much at all.

have a dig through the forum for 2.7 builds & you should get an idea of what you are looking at.

[flybynite]

I was only suggesting a basic build as the OP wants to keep the feel of the original. Once you go down that rabbit hole (as I am doing) the engine becomes a different beast.

A lightened and balanced 2.7 with a free-flowing head and hot cam will make more power but will lose the feel of an eta

There are still some very good builds with 731 and 200 heads that might not be high rev high power screamers but are good usable torquey engines for daily driving

It is not what I am doing with my 2.7 but I can see why you might want to go there. Making a basic 'super-eta' would not be as good as a properly sorted 2.7/2.8/2.9 but would be a lot less effort and expense

[steve_k]

I was only suggesting a basic build as the OP wants to keep the feel of the original. Once you go down that rabbit hole (as I am doing) the engine becomes a different beast.

A lightened and balanced 2.7 with a free-flowing head and hot cam will make more power but will lose the feel of an eta

There are still some very good builds with 731 and 200 heads that might not be high rev high power screamers but are good usable torquey engines for daily driving

It is not what I am doing with my 2.7 but I can see why you might want to go there. Making a basic 'super-eta' would not be as good as a properly sorted 2.7/2.8/2.9 but would be a lot less effort and expense

i totally agree that a basic super eta will be a torquey lil number & a pretty fun point & squirt type engine,

the main problem of going down the rabbit hole of a sorted 2.7/8/9 is the cost soon spirals out of control (i dread to think how much i've spent on mine over the course of the build).

as you say there have been some very good 2.7 builds using the 200/731 heads as the are claimed to be less likely to crack the 885 heads, ive been in an e21 with a 2.7 using a heavily reworked 200 head & the torque was impressive to say the least,

when most folk go for a stroker they seem to focus mainly on HP & seem to forget the area under the torque curve is the bit you should be looking at,

also as for changing the character of the car? yes it wil do but it will also give you an as new engine in the process.