M5x and S5x over M20.. Why?

[2mAn]

yeah, I don't think you're going to get 250whp out of 2.8l - but 225whp isn't bad at all. :)

Why not?...The 225whp is a stock motor with stock cams. I think the S52 is a 246 duration or something. The ITBs clearly are helping out on the top end, and if paired with a proper set of Cams with a ~270 duration I could see a 10% bump in power... granted it will cost like $4k to get that, but still we're talking NA power which is never cheap.

and for the record, the 225whp was plenty in my car, but mine was also a bit lighter than most E30s. It weighed 2450 fully dressed and a little over 2300 in HPDE form. I am sure I couldve dropped more weight by fully gutting it, but it likely wouldve been replaced when going from roll bar to a full cage

edit: damn you guys... everytime I start to reminisce about my M52 I start looking at 97-98 Z3s haha

[nando]

Because you would need a lot more revs to get that power out of a smaller engine. S52s hardly do that and they have .4l more displacement. You're basically talking about matching a stock S54 with a smaller motor and an inferior head..

[Bearmw]

Which is why a well cofigured M30 (at least 10:1 c.r preferred.) is still a valid candidate. High revs aren't required to have fun.

[digger]

M52 is a seriously underrated motor from the factory. Mine was essentially a stock BMW motor. OEM cams (S52 variety) and an OBD1 intake and it was making nearly 100bhp/liter. (Mine dyno'd 225whp, so ~265bhp)

Add 20 whp to that, and possibly some real cams and you can call it 250+whp out of 2.8L... Id say thats pretty damn amazing, and I loved the power delivery of the square motor (84B x 84S)

Have you seen 20whp from an m52 from the itb over the obd1 manifold ? I've never seen a proper apples to apples comparison

I tend to agree if you want 250whp it wouldn't be that difficult with some of the aggressive cams on offer. It would be quite fun especially with alloy block

[varg]

M52 is a seriously underrated motor from the factory. Mine was essentially a stock BMW motor. OEM cams (S52 variety) and an OBD1 intake and it was making nearly 100bhp/liter. (Mine dyno'd 225whp, so ~265bhp)

Add 20 whp to that, and possibly some real cams and you can call it 250+whp out of 2.8L... Id say thats pretty damn amazing, and I loved the power delivery of the square motor (84B x 84S)

I think your dyno was quite optimistic.

[redsubdivisions]

I'm late to the discussion but I am one of the few people who advocate boosting an M20 over swapping for a few personal reasons. The first and important one is that it is cheaper. If you blow it up, chances are you'll be able to find replacement parts for cheap or possibly nothing (as most people toss out M20 components to make room for M5x/S5x swaps and such). There is absolutely nothing wrong with swapping a more efficient motor. The only issues I have run into were cost and modifications that I wasn't comfortable with at the time. Now swaps are going for some dollars, which makes me wonder if I should have bought a 24V motor to put on a stand to build in case my M20 takes a shit and I give myself a reason to do a swap.

I'm not going to lie, I seriously thought I would have blown up my M20 by now by cramming anywhere from 15-18 lbs of boost down it's single cam throat. It's taken down some newer cars that have surprised many people, including myself. 4 years later and it's held up pretty well. Whenever I beat on it, it's almost as if the car likes it. lol

[varg]

I love a good turbo M20 but there's definitely something to be said for NA response and simplicity. In my years of having heavily modified turbo DDs, I've had more problems with the turbos themselves than anything else and there's not enough room for anything other than a compromise when it comes to intercooling a powerful turbo M20 unless you're going to take out your air conditioning. If you're going after track days, anything NA will be more tame than a turbo M20. Even if I felt like spending the money on one my car is no good for a track day since there's no room for an oil cooler and the power delivery is far from ideal for someone who has never driven a fast car on a track before. When the surge of torque breaks the tires loose it has to be throttled out since backing off causes it to snap, and it probably is too fast for the brakes.

I'd love to have a powerful NA E30 (with torque) that has enough room for a good cooling system and cold AC. S54s are too expensive, too heavy, and don't make much torque. What ever shall I do? it needs a V8

[nando]

N52 - 250whp capable, lighter than an M42. ;)

[cwlo]

Another vote for the N52. Brings a big upgrade to the e30 chassis, without overdoing it. Perfect balance.

[Staszek]

N52 - 250whp capable, lighter than an M42. ;)

N52 is such a lovely engine. I was efficient, fast enough in the E90, smooth and sounded great.

In a car that's over a 1000 pds lighter, it would be seriously nice.

[lambo]

This hits home for me because I was like 90% of the way through an M52 swap with S52 cams and M50 intake plus the supporting stuff... and I couldn't bring myself to remove the M20. Now I'm letting go of any idea of power goals and I'm just going for taking the M20 up a notch. I don't even think I'll be doing a turbo. Just a good refresh on the M20 and a nice exhaust.

[DesertBMW]

How come no one keeps the M20 and turbo it? I feel like everyone is so quick to want to get rid of the M20. Am I wrong for wanting to keep my M20 and turbo it to keep the engine true to the car? I feel like good reliable power can be made from it

I got 4 E30s two with M52 swaps and two with M20. Everything is better with M52B28, they are very cheap now, get better gas mileage, better power band, better throttle response, smoother idle, better resale value.

Give me a Turbo car that acts like an NA and we'll talk.

My N55 swapped E36 318ti has no lag that I can feel, power response is instant, that is most do to N55 making 300 torque at 1500rpm and lighter chassis than E90

https://www.youtube.com/watch?v=y69Ay-O7BU8

[2mAn]

M5x and S5x over M20.. Why?

I think your dyno was quite optimistic.

Search through this and tell me I’m wrong or that my dyno was optimistic

https://www.r3vlimited.com/board/showthread.php?t=327183

Dave own beater M52 makes 217whp and mine was a freshly rebuilt motor with ~16k I think when I dynod it

[digger]

it comes down to personal preference but if i was to swap it would have to be a decent jump in both torque and hp over what a decent m20 could do but not enough that its constantly frying tires or needs body work to get enough rubber and it should look like it belongs in the engine bay.

s54 or s50b32 would fit the bill nicely.....S38b38 might be a bit too much as you cant leave it stock. anything non BMW just looks wrong regardless of how much it make sense

[varg]

Search through this and tell me I’m wrong or that my dyno was optimistic

https://www.r3vlimited.com/board/showthread.php?t=327183

Dave own beater M52 makes 217whp and mine was a freshly rebuilt motor with ~16k I think when I dynod it

It's nothing personal, just my impression based on the fact that most dynos are optimistic and 94hp/l (based on the 265bhp number you posted) from an M52 with cams and an intake manifold seems a little high. I'm highly skeptical of shop dynos, they have an incentive to inflate, as does the dyno manufacturer. When people see dyno numbers of a stock car and go OMG IT'S UNDERRATED FROM THE FACTORY!!! Most of the time I say no, dynos at tuning shops are usually optimistic, and the manufacturer would have no incentive at all to underrate, barring some sort of limit like the infamous 276hp japanese car. When more horsepower is always a good selling point, why underrate your engines? Car companies are trying to make money from a wide audience, not make inside jokes that "real" car guys will get, like "BMW underrates their engines!"

So, when I see that an M52B28 is rated at 190bhp, and I see a dyno which is showing numbers like 178whp for that engine (stock aside from the muffler), my first impression isn't that the driveline is incredibly efficient (~6% loss) or that the engine actually made over 200bhp from the factory instead of 190bhp, I'm thinking the dyno number is a little inflated. It's great for comparison to see the gains of the cars with the tunes, but the actual numbers are of less important than the shape of the curves and the gap between the lines.

That's why when I tune someone's car, I tell them that dyno numbers are more of a ballpark figure, and a dyno is only truly useful for comparisons such as before and after tune.