CSL exhaust valves or a good replacement

[HanSooloo]

Looking at the differences between the regular M3 and the CSL, one of the items is the exhaust valve. I believe they are made of different material and have a different shape.

Was able to get them last year, but now they show August 2022 availability in ECS (maybe other places too).

Are there aftermarket parts that are a like for like replacement for those that are more readily available?

Any experience with the original CSL parts or the replacement parts?


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[Slideways]

Supertech and Ferrea are the two aftermarket options for the S54 that I have read about in past threads. Not sure if they are shaped like the CSL exhaust valve with the point in the middle of the valve.

[Feffman]

The CSL exhaust valve is the lightest of all the valves I've looked into at 43.1 grams, nearly two grams lighter than stock S54 valves (45.2). Surprisingly the Ferrea and Supertech exhaust valves are heavier at 47.7-48.5 grams depending on design. When I do the engine next Winter (assuming it survives the 2022 season) I'm going Supertech single-groove instead of a triple-groove design.

Feff

[maw1124]

Are these what account for the increased output per liter (in addition to higher RPM)? I suppose in connection with catless headers and tune? Valves seem like they could be drop in and the computers will adjust.

maw

[stash1]

Are these what account for the increased output per liter (in addition to higher RPM)? I suppose in connection with catless headers and tune? Valves seem like they could be drop in and the computers will adjust.

maw

CSL engine was vastly different...it was also cams, intake, exhaust, and tuning that contributed to the extra rpms/power increase.

[maw1124]

CSL engine was vastly different...it was also cams, intake, exhaust, and tuning that contributed to the extra rpms/power increase.

Understood. I'm parsing the system down to its elemental parts, because I'll take incremental gain. I'm not so pressed about the intake; cams and exhaust stand on their own. Which is why I only focused here on the valves. I don't think anyone knows how much of the extra power was due to valves alone (it seems more about RPM increase than power), but if anyone does, that's what I'm asking. TIA...

maw

[jet_dogg]

Are these what account for the increased output per liter (in addition to higher RPM)? I suppose in connection with catless headers and tune? Valves seem like they could be drop in and the computers will adjust.

maw

What accounts for the 17hp difference in the csl is,
- airbox (hence no maf)
- cam profiles (very subtle difference)
- tuning
- header/exhaust questionable

Nothing on the list is worth pursuing except the airbox in my humble opinion. There are far better cam profiles with same quality, better tuning, and better exhaust options. If money is no object, there lies little to no value in pursuing the above except the airbox. You will not notice a difference or very slight with the remainder of items on the list so unless you just like burning money to say you have negligible csl engine mods there isn't much of a point.

[maw1124]

What accounts for the 17hp difference in the csl is,
- airbox (hence no maf)
- cam profiles (very subtle difference)
- tuning
- header/exhaust questionable

Nothing on the list is worth pursuing except the airbox in my humble opinion. There are far better cam profiles with same quality, better tuning, and better exhaust options. If money is no object, there lies little to no value in pursuing the above except the airbox. You will not notice a difference or very slight with the remainder of items on the list so unless you just like burning money to say you have negligible csl engine mods there isn't much of a point.

Thanks. See, I was headed the wrong direction, skipping the airbox in favor of cams, exhaust and then maybe lighter valves as a throw in. The thinking was more aggressive cam profile could make better use of the available air, rather than spending double or triple for the sake of more and maybe better air flow. Either way I’m on the fence of whether even that is worth it for what looks like a 5% gain.

To me it’s clear most of the CSL benefit is in the L and then the C (call it L-Prime) neither of which I’m chasing anyway. So will I even notice that gain without the weight loss, is the question. Burning cash for bragging rights is definitely not my thing. Poor ROI.

maw

EDIT… TBH I’m wondering if half or more of the airbox difference isn’t about lighter weight as well, compared to all that heavy black plastic in the nose of the non-CSL cars.

[heinzboehmer]

Thanks. See, I was headed the wrong direction, skipping the airbox in favor of cams, exhaust and then maybe lighter valves as a throw in. The thinking was more aggressive cam profile could make better use of the available air, rather than spending double or triple for the sake of more and maybe better air flow. Either way I’m on the fence of whether even that is worth it for what looks like a 5% gain.

To me it’s clear most of the CSL benefit is in the L and then the C (call it L-Prime) neither of which I’m chasing anyway. So will I even notice that gain without the weight loss, is the question. Burning cash for bragging rights is definitely not my thing. Poor ROI.

maw

EDIT… TBH I’m wondering if half or more of the airbox difference isn’t about lighter weight as well, compared to all that heavy black plastic in the nose of the non-CSL cars.

Just the airbox made 16 whp over stock on my car.

Airbox + a canned tune from Paul Claude made 25 whp over stock.

https://nam3forum.com/forums/forum/main-forum/e46-2001-2006/1925-s54-dyno-database?p=126356#post126356

IMO, even if there was no increase in power, the sound it makes is worth the price.

[maw1124]

Just the airbox made 16 whp over stock on my car.

Airbox + a canned tune from Paul Claude made 25 whp over stock.

https://nam3forum.com/forums/forum/main-forum/e46-2001-2006/1925-s54-dyno-database?p=126356#post126356

IMO, even if there was no increase in power, the sound it makes is worth the price.

That’s a nice looking power curve at post #230 over there. Well done, and thanks.

maw