284 cam too much for a 2.5L M20?

[ForcedFirebird]

OP said he is personally sending it in for a regrind. This is not the typical situation where he purchased a regrind from a company that can't provide specs (probably because they are sending in a pile at a time).

And if the cam card carries the lobe lift, rocker ratio doesn't need to be considered by the grinder, but by the installer/builder. The grinder is simply going to give you the max lift/duration you request, within the limits of the core.

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[ForcedFirebird]

That was my original point. You cannot achieve proper cam specs when you have the limits of the core.

But....it's a RE-grind. What else can be expected?

Even the "billet" cams these companies are not, they are new cast blanks. Billet round lobe cores (unlimited lobe capability within the min base circle:cam journal ratio) start at about $800 per blank up to about 50 units. I priced them out not long ago. Granted, that particular engine has a pinion for the distributor dummy (oil pump drive), which added cost, the m20 shouldn't be far off for cost...

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[ThatOneEuroE30]

Ive got an ireland engineering reground 284 on my car with no issues. Didnt get a cam card though but just doing basic math its a 284 like advertised

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[ThatOneEuroE30]

What CR and fuel?

Running on 91 octane and believe its the stock 9:5:1 compression? No issues once i got it tuned. At first it idled like poo but i got got it tuned and it runs like a raped ape

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[ThatOneEuroE30]

284 cam too much for a 2.5L M20?

9.5:1 is too low for a 284. It is even low for a 272. Stock is 8.8:1 with a cam under 256.

The only reason for BMW going from 9.7 to 8.8 CR is you American guys. Get some decent fuel and some decent CRs.

That being said, 91 octane is good for nothing. At least in European standards.

After getting it tuned i have no real issues a couple small things and it pulls really hard. I love it. How is 91 good for nothing? Besides 93 its the highest octane you can get on pump but is way easier to find otherwise you’re stuck running race fuel or e85/e90 which gives shit gas mileage and takes work to get the car to run on it usually with a stand alone ecu. Im running a custom tune on a chip and it runs great. Have a couple small issues to iron out but the the chip i get on Monday should take care of them all. We don’t get 98 octane like you europeans. Its usually 87,89,91 and 93 then you have e15,85 and 90 after that its race fuels which is 9 bucks a gallon on average.

[apostate]

Wgf?

[ThatOneEuroE30]

Wgf?

Huh?

[LowR3V'in]

what do you think about cat cams specs? false info?

i have like a 294 or something and drives great on the street
it's an m30 though so idk if that translates to m20s

[2mAn]

Not worth it for a couple of bucks less.

Get the real Schrick 284 instead.

More than double if you shop around....

https://www.ecstuning.com/b-schrick-parts/schrick-camshaft-284-degree/05601840-00/

This is Step 2 in Schrick's line of performance cams. The 284 degree cam will be great for owners who want to retain their driveability on the street and only need a modest boost in top-end RPM.

Schrick recommends replacing the valve springs with high-performance springs for this application.

Valve Springs necessary or good insurance?

[digger]

OP said he is personally sending it in for a regrind. This is not the typical situation where he purchased a regrind from a company that can't provide specs (probably because they are sending in a pile at a time).

And if the cam card carries the lobe lift, rocker ratio doesn't need to be considered by the grinder, but by the installer/builder. The grinder is simply going to give you the max lift/duration you request, within the limits of the core.

its one thing to have a cam card its another for it to measure out like it says, never trust them. the only thing that matters is what the valve motion is. its the cam grinders problem to make the cam lobe the right shape to give the right valve motion and they should verify this happens on a proper installed height valvetrain, new OE rocker etc which is what i use for measuring

bought a cam from catcams 283/273 would have smashed the engine to smithereens with about 0.25" lift at tdc on both valves instaed of 0.1" and 0.07" , got a no questions asked replacement seemed ok by eye lol so been running it since have no idea what it is though. makes it hard if you want to get something different/better when you have no confidence in the camcard. couldn't be assed measuring it while in the car. they now call the cam a 298/285 cam which seems to because they spec a tighter lash than a decade ago.

bought a catcam 296 lsa was way off such that instead of 4.5mm lift at TDC both valves it was 3.15mm, by eye you cold tell it was F'ed ....duration of lobe and lift was ok from memory yet a schrick 288 and OE was fine in same head and valvetrain.

an ENEM Z58 had the basecircle different on some cylinders, they sent are replacement and it plotted out with less lift than spec by somewhat measurable amount

there was another member with dbilas 276 or whatever that was totally different to cam card

ive not had a problem with schrick but only measure one cam properly, its a shame lobes are not very modern and that they dont offer something between 288 and 304 off the shelf or a straight 284/284

some serious quality issues around some of them are major

my RHD292 cam was on the money but had some advance built in but not an issue with adjustable camgear

[ForcedFirebird]

9.5:1 is too low for a 284. It is even low for a 272. Stock is 8.8:1 with a cam under 256.
The only reason for BMW going from 9.7 to 8.8 CR is you American guys. Get some decent fuel and some decent CRs.
That being said, 91 octane is good for nothing. At least in European standards.

Odd because I built a 9.4:1 2.8 m20, it made 217whp/202tq, and based on the dyno graph, it was under-cammed.

We get 93oct in most places here in the states which equates to 98ron. There's an 11:1 3.1 m20 with a 284 Schrick sitting here in the shop parking lot waiting to be Dyno'd, it's running on pump 93 oct with a decent timing table.