E30 Stroker - The why.

[FunkySwerve]

I've looked up many threads online about this very topic, perhaps I've missed a post in the many many pages of Stroker science and math...but there doesn't seem to be a short answer as to why you would stroke your engine in the first place.

So why stroke a m20B25 engine? Advantages? Disadvantages? I understand this may lean more towards subjectivity, but it'd be nice to know any and all reasons.

Also...because I live in CA, is it CA smog compliant and street-able?

[biodose]

I've always been told that there's no replacement for displacement. Stroking = more displacement = more torque. People mainly do the 2.7i for the turbo application because it lowers the cr from 8.8 to 8.5:1. Not sure if that's what you're looking for, but hope it helps.

[FunkySwerve]

I've always been told that there's no replacement for displacement. Stroking = more displacement = more torque. People mainly do the 2.7i for the turbo application because it lowers the cr from 8.8 to 8.5:1. Not sure if that's what you're looking for, but hope it helps.

That does help, thank you! It makes a lot of sense given how light it is(and can be) and of course the rear wheel drive!

[Hooffenstein HD]

Why? Increased displacement.

[digger]

Stroking an engine provides a means to increase mass flow of air through the engine

When you move more air through the engine and add a corresponding amount more fuel and it is burnt efficiently you get more power

the advantage of stroking the engine is that the mass flow has the potential to be increased at all rpm, though more typically the lower end and midrange torque and power show the biggest gains and the top end less gains but it depends.

[FunkySwerve]

Well that answers my street-able question. Will it past inspection? =0

[wilholl]

Well that answers my street-able question. Will it past inspection? =0

generally there are no visible indicators on the outside of the engine to determine if the displacement has been increased. So, visually it should pass.
As long as the engine is running well with the proper air/fuel ratio then it should pass the tail pipe emission.

[FunkySwerve]

generally there are no visible indicators on the outside of the engine to determine if the displacement has been increased. So, visually it should pass.
As long as the engine is running well with the proper air/fuel ratio then it should pass the tail pipe emission.

Excellent! I've read a lot of things need to be bought new and customized to some extent. I reckon it's quite expensive just on parts alone?

[Hooffenstein HD]

It can be pretty much as simple as a head gasket replacement, or a full race build. Depends on the size of your wallet and goals for the car.

[digger]

yeah budget stroker are cheap, expensive strokers are expensive

[KIRIEIW]

For what its worth, I engine swapped my car from a M20B27 to M20B25. The smog stations here in CA smog it as a B27 and I've never had an issue, always passed with flying colors. It's been smoged 3 times now.

[FunkySwerve]

What's the median cost on the low end and the high end?

How much work may you do yourself and what are the things best left to professionals?

[digger]

how long is a piece of string? you can do it for free or spend 15k and anywhere in between

the important question you need to answer is how much do you want to spend?
what skills do you have?
and what are your goals?

[FunkySwerve]

how long is a piece of string? you can do it for free or spend 15k and anywhere in between

the important question you need to answer is how much do you want to spend?
what skills do you have?
and what are your goals?

I'm willing to spend North of 5k.
I have a basic understanding of most everything about a car. I would say I have an above average understanding of E30s. My wrenching experience is average DIY'er at best, so I have most tools to take things apart, one way or another...and I also have good knowledge on how to put it back together p-r-o-p-e-r-l-y.
My goals in terms of power? Exactly what stroking suggests: lots of low end torque so I can take off from a stop or put my foot down(safely) on a straight road while driving to work at 4 in the morning. BHP is merely a factor in the equation for me, but I understand I can expect a little over 200BHP with just a stroker build on it's own? Just want a fun daily driver, with more emphasis on fun rather than daily driving. ;D

***When I take a minute to think up more questions, perhaps we can open up this thread to questions about stroking that may not be easy to find on a google search because it's so specific or uncommon!

[Hooffenstein HD]

5k spent wisely with you doing a majority of the wrenching should be able to get you 200-220rwhp.

I don't think a 5k build aligns with your goals though. You could get away with a basic build and half the dollars invested.