Educate me on valves/springs

[C///M]

During my cam and rockers install, I was going to throw in some new springs. Not that it's a great time for me to spend more money, but I was thinking I might as well do exhaust valves while I'm at it.

I had initially planned to pick up some CSL exhaust valves. I can't remember exactly what the difference was; I'm pretty sure the head is the same so not sure if the margin/face/fillet of the valve is sloped or angled differently or something. Both stock and CSL are identically sized and sodium filled from what I've been told.

I know the differences are negligible, but if I was set on replacing the valves, is aftermarket a smarter choice for slightly less money? Pretty sure I can get stock-sized inconel exhaust valves for less than CSL.

[Obioban]

Why are you changing the springs. The increased heat, wear, and hp losses from stiffer springs are detrimental if you don't need them.

The face of the CSL exhaust valves are different. Sodiium filled (stock and CSL, but not all aftermarket) is nice if you put real heat through the engine. Stock is also quite light.

... you're headed down the road that most people end up regret going down.

[C///M]

Why are you changing the springs. The increased heat, wear, and hp losses from stiffer springs are detrimental if you don't need them.

The face of the CSL exhaust valves are different. Sodiium filled (stock and CSL, but not all aftermarket) is nice if you put real heat through the engine. Stock is also quite light.

... you're headed down the road that most people end up regret going down.

I guess I wasn't super clear since I put springs in the title, but I was not planning on stiffer springs, just new OE. I don't know much about aftermarket, so I suppose that helps me stick with my plan on springs at least. Though there are a couple spots I'd like to be able to hold a gear a bit longer, so was thinking about upping redline to 84-8500.

Car is mostly track with some street. Airbox, full exhaust, 288/280, etc.

[ethan]

From the "S54 Stroker Build" thread:

I've done a bit of research on valves for my next engine build. The BMW valves are actually lighter than some aftermarket valves.

Stock Valve Weights (grams):
Intake: 47.5
Exhaust: 45.2 [CSL Exhaust: 43.1]

Ferrea
Competition Plus/Single Groove Radial Cut
Intake: 45.4
Exhaust: 48.4

Supertech
Single Groove
Intake: 48.5
Exhaust: 47.7

Triple Groove
Intake: 48.3
Exhaust: 48.5


There are different designs to help flow, etc. To spool at the RPM you are considering I've got to think you'll want a single groove valve stem like most race cars..

Price, well those light CSL exhaust valves alone are around $2,000 from ECS plus around $595 for the stock intake valves. The Ferrea range in price from around $35-$50 each and the Supertech $25-$40 each. The intake valves are stainless and the single-groove exhaust valves are iconel. Ferrea can do titanium valves but if memory servers me correctly, they are around $200 per valve so I didn't ask about weight. I've spreadsheet all this if you want the Excel spreadsheet e-mail Feffman@MVPTrackTime.com

Feff

Keep in mind when you set the redline that if you run it right up there, you'll probably have events jumping a couple hundred RPM above your cutoff.

[Feffman]

...The face of the CSL exhaust valves are different. Sodiium filled (stock and CSL, but not all aftermarket) is nice if you put real heat through the engine. Stock is also quite light...

CSL valves (BMW part #11347833676) at 43.1 grams are 2 grams (about 5%) lighter than stock M3 valves but expensive. The least expensive I've seen them for sale are from Schmiedmann (https://www.schmiedmann.com/en/produ...1-34-7-833-676) in Germany for about $92 per valve. In contrast stock exhaust valve is around $45-$50 per valve.

Aftermarket valves from Supertech or Ferrea, say stainless steel for the intake and iconel for the exhaust rage from $35 to $50 each. Most are about the same weight or actually slightly heavier than the stock BMW valves.

Feff

[Obioban]

I guess I wasn't super clear since I put springs in the title, but I was not planning on stiffer springs, just new OE. I don't know much about aftermarket, so I suppose that helps me stick with my plan on springs at least. Though there are a couple spots I'd like to be able to hold a gear a bit longer, so was thinking about upping redline to 84-8500.

Car is mostly track with some street. Airbox, full exhaust, 288/280, etc.

Ah, in that case I'd say why replace the springs with new stock? I haven't seen any evidence of them wearing out.

[C///M]

Ah, in that case I'd say why replace the springs with new stock? I haven't seen any evidence of them wearing out.

Yea I'm not really sure. I'm already in there, just hit 100k, car sees a lot of track, and I was hoping to bump up redline. For the life of me I can't remember where I read it, but I thought I came across some data regarding stock springs being ok up to 9k (as stated I was hoping for 84/8500).

I know the smart thing is probably no higher than 8200. I haven't logged, but I thought that ridiculous overrev situation was mitigated somewhat in later software updates?

[Feffman]

Link to the Supertech dual valve springs for triple groove (stock style) valves: https://www.supertechperformance.com...lve-spring-kit

New stock BMW springs are about $300 (cheap insurance): https://www.ecstuning.com/b-genuine-...s/11317830890/

Feff

[C///M]

Link to the Supertech dual valve springs for triple groove (stock style) valves: https://www.supertechperformance.com...lve-spring-kit

New stock BMW springs are about $300 (cheap insurance): https://www.ecstuning.com/b-genuine-...s/11317830890/

Feff

Thanks Mark. If I replace my springs, I'm pretty much set on stock. This is not a race engine and I have no plans to go nuts with revs.

Any experience with aftermarket valves? In the scheme of things, an extra grand on the CSL exhaust valves isn't a big deal while I'm in there. Where I'm totally lost is the specs on aftermarket valves. For stock size, are they just made to exact OE dimensions and it's just all about weight and material? Or do they have different profiles for the face/fillet? Again I'm assuming the valve heads are identical to stock to avoid messing with compression unless you're completely rebuilding with custom pistons/valves/etc.

[terra]

Thanks Mark. If I replace my springs, I'm pretty much set on stock. This is not a race engine and I have no plans to go nuts with revs.

Any experience with aftermarket valves? In the scheme of things, an extra grand on the CSL exhaust valves isn't a big deal while I'm in there. Where I'm totally lost is the specs on aftermarket valves. For stock size, are they just made to exact OE dimensions and it's just all about weight and material? Or do they have different profiles for the face/fillet? Again I'm assuming the valve heads are identical to stock to avoid messing with compression unless you're completely rebuilding with custom pistons/valves/etc.

The face of the valve (facing the piston) is shaped differently. Also appears to be made of some different sort of metal which may transfer heat differently. P54b32 also uses a very similar looking valve (but the part number is different).

Per BMW:

[C///M]

The face of the valve (facing the piston) is shaped differently. Also appears to be made of some different sort of metal which may transfer heat differently. P54b32 also uses a very similar looking valve (but the part number is different).

Per BMW:

Thanks Terra - I have the CSL "Participant Manual" and totally forgot about it until you posted that. So the head is different while the face and fillet (sloped connection to stem) are probably the same as standard M3. Considering how much lighter the exhaust valves are vs standard, it wouldn't surprise me if the valve heads are a different metallurgic compound.

Thanks for that.

[terra]

Yeah I don't have good pictures of the other side anymore, but from what I remember they looked about the same. Maybe precision measurements would reveal a difference.

Hard to say how much the valves would help. I presume BMW didn't do it for no reason. And if they did it on the P54b32 as well, there's probably some sort of advantage. Could well promote some sort of scavenging effect. But how much of a real world difference that translates to? Who knows.

[digger]

Sounds like a waste of money. Spend money on stuff that’s going to make a tangible difference

[C///M]

Sounds like a waste of money. Spend money on stuff that’s going to make a tangible difference

I can appreciate your sentiment, but this car has everything else. After this, the only other changes will be vincebar and CF roof panel.

My goal is to retire this car from track duty in the next couple years and build a w2w car.

[terra]

I can appreciate your sentiment, but this car has everything else. After this, the only other changes will be vincebar and CF roof panel.

My goal is to retire this car from track duty in the next couple years and build a w2w car.

Replacing the springs would truly be a waste of money IMO. There will be zero benefit, even long term.

CSL exhaust valves... probably not truly worth the money, but if you’re trying to squeeze out every last drop of volumetric efficiency, then I can see the argument.