Considering a cam regrind? Dyno graphs say no?

[st.petebiodiesel]

So mechanical lifter conversion then?

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[st.petebiodiesel]

I think the average for a stock s52 is 200-205. Obviously every dyno is different. Try to compare an eddy current dyno to a inertia flywheel dyno, a flywheel dyno will always read higher.
What is important is that he went to the same dyno on the same day under similar weather conditions and got an increase. Don't get hung up on peak numbers, focus on the differences.

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[ForcedFirebird]

Don't see where he said same day, but going to the same dyno is obviously best. There are a lot of variables, sure, but if a dyno is calibrated, the brands usually correlate to each other. For NASA racing we are to use a Dynojet set to STD and smoothing 5. They will occasionally have a dyno at the track and I haven't seen any noticeable differences from the one I use.

[CoreyZ]

The unfortunate thing about 24v lifter trays is the lifter can't move much before it hits the bottom of the cam bearings. You've got less than 1mm of room which means lash caps won't work - you'd need to deck the trays and then you'd be fucking with timing chain tension

[ForcedFirebird]

The unfortunate thing about 24v lifter trays is the lifter can't move much before it hits the bottom of the cam bearings. You've got less than 1mm of room which means lash caps won't work - you'd need to deck the trays and then you'd be fucking with timing chain tension

Shaving the trays was my first thought prior to mentioning lash caps.

I wouldn't think chain tension would be a big of issue as cam timing.

The chains stretch pretty significantly over its lifetime and the tensioners have no problem picking up the slack - but OTOH decreasing the distance between the cam and crank gears will change valve timing. Not sure how much it woild effect it, or if it woild cause issues with vanos operations.

[st.petebiodiesel]

The unfortunate thing about 24v lifter trays is the lifter can't move much before it hits the bottom of the cam bearings. You've got less than 1mm of room which means lash caps won't work - you'd need to deck the trays and then you'd be fucking with timing chain tension

Schrick already makes a solid lifter conversion for these engines. You still retain the stock lifter bucket, just remove the hydraulic tappet from under the lifter.

https://www.turnermotorsport.com/p-359938-schrick-solid-lifter-conversion-kit-convert-hydraulic-lifters-to-solid-lifters/

It would take forever to set this up.you would have to remove and reinstall the cam trays and cams several times till you filed down the tappets to the right height.

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[ForcedFirebird]

^^^or convert to any other OHC solid lifter. Problem is the 24v uses a non-standard 33mm where most mfgr are using 35mm (including older BMW).

[TheAxiom]

I must have missed it - but what tune are these running?

If you’re going to tell me there is no tune, well then this is a useless comparison.

[ForcedFirebird]

I must have missed it - but what tune are these running?

If you’re going to tell me there is no tune, well then this is a useless comparison.

I dyno tuned them both. If you would like to know my method, I first find MBT and knock thresholds, fuel to suit, then fine tune fuel based on feedback. The base s52 file is a straight drop out of a 1999 m3, long block dropped straight into 1995 m3 (no tune).

[TheAxiom]

I dyno tuned them both. If you would like to know my method, I first find MBT and knock thresholds, fuel to suit, then fine tune fuel based on feedback. The base s52 file is a straight drop out of a 1999 m3, long block dropped straight into 1995 m3 (no tune).

Vanos?

[Eliminare]

Interesting. I have a set of Riot regrinds in my car with an RK tune for them. I honestly couldn't tell a difference after installing the cams. I had attributed that to my car being down for a month and my butt dyno being out of calibration, but maybe not.

Edit: I did notice a slight difference in sound FWIW.

[Andre3127]

Do you have specs for the cams?

[ForcedFirebird]

Vanos?

Yes, cam timing affecting area under the curve is taken into consideration and adjusted. Nice thing about sitting on a chassis dyno, is you can see the results of your hard work.

Interesting. I have a set of Riot regrinds in my car with an RK tune for them. I honestly couldn't tell a difference after installing the cams. I had attributed that to my car being down for a month and my butt dyno being out of calibration, but maybe not.

Edit: I did notice a slight difference in sound FWIW.

Brrr, brappp, brapp, cahcunk. :P

Do you have specs for the cams?

I would love to see a measurement of actual cam lift/duration vs valve lift. No matter how you slice the bread, the hydraulic action of a lifter is not enough to overcome the forces of a valve spring (the whole point to zero lash/adjustment for hydraulic lifters).

[Eliminare]

I would love to see a measurement of actual cam lift/duration vs valve lift. No matter how you slice the bread, the hydraulic action of a lifter is not enough to overcome the forces of a valve spring (the whole point to zero lash/adjustment for hydraulic lifters).

All I was able to measure on my set was the lobe lift. Both cams were identical at 11mm.

[TheAxiom]

Sure they were installed correctly? That just doesn't seem right.