M5x and S5x over M20.. Why?

[DBShiznit]

Honestly I think these cars are perfect between 250-300 hp, anything more than that you lose some of the characteristics about the car that make it awesome.

I liken it to my buddy who has a Scion FR-S that just supercharged it, always felt under powered but now that it is like 300 hp in that light/small of a car it is perfect. Too much more and it would be a handful to drive aggressively.


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I agree. I was always told by guys who go to the track, 300-350 is what you want and shed all of the weight as much as you can. If you have a good platform with that power you’ll have a pretty good track car


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[E's-30]

Thats the thing, No one throws a turbo on an M20 to have low end torque. It's going to be big turbo big high end power. Also I wonder how many people are running a twin scroll for quicker spool? All of that needs to be taken into account

Honestly I think these cars are perfect between 250-300 hp, anything more than that you lose some of the characteristics about the car that make it awesome.

I liken it to my buddy who has a Scion FR-S that just supercharged it, always felt under powered but now that it is like 300 hp in that light/small of a car it is perfect. Too much more and it would be a handful to drive aggressively.


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[DBShiznit]

I have a pretty modified e90 with an n54, still a little lag I guess but nothing like an EVO or a 90’s car. Very smooth power delivery and I’m hitting full boost before 3,000. Much more low end torque than my m20, lol.

That being said, in my opinion, everyone is using too large of a turbo on the m20. I think a 16g or something similarly sized would be well matched to the car and give you boost below 3,000 and pull to redline and be north of 300hp and be a ton of fun! Area under the curve would be huge.


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Thats the thing, No one throws a turbo on an M20 to have low end torque. It's going to be big turbo big high end power. Also I wonder how many people are running a twin scroll for quicker spool? All of that needs to be taken into account

[E's-30]

On a e90 it may not because it depends on boost plus e90s are heavier

I have a pretty modified e90 with an n54, still a little lag I guess but nothing like an EVO or a 90’s car. Very smooth power delivery and I’m hitting full boost before 3,000. Much more low end torque than my m20, lol.

That being said, in my opinion, everyone is using too large of a turbo on the m20. I think a 16g or something similarly sized would be well matched to the car and give you boost below 3,000 and pull to redline and be north of 300hp and be a ton of fun! Area under the curve would be huge.


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[DBShiznit]

The post above talking about the n54/n55 still not having that pickup.

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On a e90 it may not because it depends on boost plus e90s are heavier

[jeenyus]

What engine are you referring to?

The post above talking about the n54/n55 still not having that pickup.

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[digger]

How can an inline-6 with a larger displacement not have the same pickup down low as the m20?

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What engine are you referring to?

[jeenyus]

How can an inline-6 with a larger displacement not have the same pickup down low as the m20?

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[Staszek]

This debate could go on back and forth forever (and has on this and many other boards).

I struggled with this myself. If my M20 was in great shape (or even good) I would have probably kept it and done something with it.

But I always loved the S54 its still one of my favorite BMW engines, and the E30 was always one of my favorite bodies. The idea of marrying the two seemed like heaven.

Beautiful classic body with a reliable fast NA powerplant.

I still cant get into the turbo thing. I did love them in 90's cars back in the day mostly because it was just a kick to have nothing then that huge surge of power. But as I became a better driver and got track time I realized that the lag and the unpredictable nature of turbo boost was a turn off for me. I love the linear power of an NA engine.

I can't imagine a turbo M20 will not be near as fluid as an N54. The N54 which is awesome (we have an N55) still has enough lag that it bothers me when I drive them, so an M20 turbo has no appeal to me personally.

[Kershaw]

Kershaw: RHD ITBs on a bone stock M20B25 will destroy any stock M5x swap. And its still lighter, without all the pain of a swap in an ix.

I have a set and I used to have them on my street ix. I took them off because 2 cylinders went down to 90psi and the rest are at 130. So I put them on my Asymmetrik teammate's rallyx car. At least the CF intake cleans up easily, haha.




But you can put ITBs on an m52 as well. I can't even imagine how good that would sound.

http://racehead.com.au/products-page/throttle-body-kits/bmw-m50-52-itb-kit/

[erynapolean777]

Availability? I have a 86 325es with no motor. I plan on swapping in a m50 in it from a parts car. At my local junkyard in north west Arkansas they have about 5 or 6 of those M5x motors. Not a huge classic bmw scene over here so I make do with what is available

[McGyver]

I disagree somewhat - 50lbs is noticeable. the engine may be further back, but it's also longer. I don't see how it could possibly match the same balance - and it's not going to be even close to something with an even lighter engine (M42, N52, M54, etc).

M30 is mostly cool because it's old-school and you can (or could) get them dirt cheap.

True, I would say that it's noticeably heavier and it obviously messes with weight distribution. An m/s/n5x would be lighter and more balanced. Then again, adding a tool box in the trunk or a passenger also noticeably messes with weight distribution. I guess it depends on what you're using the car for.

[nando]

You find an m30 for $100, and I'll gladly give you $200 for it. It's starting to get hard to find them. I'm rebuilding mine right now and could use some spare parts.



As said above, an m30 is about 50lbs heavier than an m20, so not much. It also sits closer to the firewall than an m20, further reducing the weight addition to the front. Plus all the late model e30 stuff bolts right up, including the stock e30 AC compressor.

I was DDing an m30b35 for several years with working AC and heat. It was awesome. I suppose the nose was a little heavier, but the added torque more than overcame that.

I disagree somewhat - 50lbs is noticeable. the engine may be further back, but it's also longer. I don't see how it could possibly match the same balance - and it's not going to be even close to something with an even lighter engine (M42, N52, M54, etc).

M30 is mostly cool because it's old-school and you can (or could) get them dirt cheap.

[SkiFree]

(as has been discussed in these hallowed pages many times before)

Wait... I remember now. Dang, the photobucket nuke did some damage, but the good stuff is still there.

https://www.r3vlimited.com/board/showthread.php?t=313593

[McGyver]

The obvious answer here (as has been discussed in these hallowed pages many times before) is the M30 swap rules them all :D

All the positives of the M20, around the same weight as an iron block M50 or M52, with more displacement, more torque and no timing belt to mess with :D

Engine can be had for $100.

You find an m30 for $100, and I'll gladly give you $200 for it. It's starting to get hard to find them. I'm rebuilding mine right now and could use some spare parts.

I can get an M30 for next to nothing but I'm still not sold on that idea. All the added weight to mess with the cars balance. If anything I'd like to shed weight off the front and make it more nimble. I like a well balanced car not just a fast straight line car. Obviously everyone is different.

As said above, an m30 is about 50lbs heavier than an m20, so not much. It also sits closer to the firewall than an m20, further reducing the weight addition to the front. Plus all the late model e30 stuff bolts right up, including the stock e30 AC compressor.

I was DDing an m30b35 for several years with working AC and heat. It was awesome. I suppose the nose was a little heavier, but the added torque more than overcame that.