m42 schrick cams and chip

[e301988325i]

Did you get an air fuel ratio vs rpm print out?

[B15NAC]

no should i have? he said the fueling was good tho!

[DHFiS]

How often has the engine run at 8000rpm?

[B15NAC]

not often maybe once! the engine is nice an quiet no taps or knocks if i ever rev high i dont go higher than 7000rpm

[DHFiS]

I'm running out of suggestions, can you post a scan of your dyno run?

[B15NAC]

yes will put it up tonight when i get home. its got me to i dont no what it could be! unless the chip is at fault im not sure if evolve chips are good?

[DHFiS]

Mine had an Evolve chip in it when the dyno run on this thread was done.

http://www.e30zone.net/modules.php?name ... +dyno+plot

It didnt increase power over the standard chip but it removes the rev limiter.

[B15NAC]

just looking at my dyno results my power doesnt drop much till well past 7000rpm? when before it droped at 6300rpm.

[B15NAC]

Here are the printouts of the dyno results:


First time, pre-Evolve chip and Schrick cams




Second time, after mods

[Cook318IS]

It does appear to have shifted the power up the rev range a little, im still surprised that you are at exactly where you were before all the mods though.

[B15NAC]

yes true its a bit odd! but i did make 145bhp when we went last october time! im putting that down to slightly warmer weather! im still not sure what to think maybe the cams need properly setting up?

[Jozi]

Don't know much about them but would you not need it rolling road tuned to take advantage of the cams?

Lightened fly does transform the engine! I drove kedge's is (the current owner gave me a spin) and stalled it first lift of the clutch quite different to a standard fly wheel.

[Dave_M3]

RE: how much to take off the M20 flywheel...

To make it fit, just machine the back edge down until flush with the ring gear. You can lighten them down to under 6 though. I've brought a few down to 5.9 with good results.


The JBR or TTV flywheels are sweet though if you can afford them!



Very odd that the cams haven't made a difference or any gain at all. Cams do just mostly shift power to different areas of the rev range but you still get gains with them!

Look how much the M52s gain with shrick cams. The stock M42 cams aren't that bad though to be fair to them. have reasonable lift just could do with abit more duration.

[DHFiS]

Don't know much about them but would you not need it rolling road tuned to take advantage of the cams?

I think that is the only thing left to do - a remap and have the fuel injection and timing optimised to the Schrick cams.

[B15NAC]

its a little lumpy on idle with the cams in do you think by putting a lightend flywheel on will make it really bad on tick over?

[tim_s]

Most of the advice on here is completely contrary to what I'd do. I'd work on figuring out why you're not getting good power rather than bolting on more bits, emdog's various suggestions of lightening the fly giving you more power, playing with the inlet and putting in bigger injectors (why?!) are not at all helpful when clearly there are issues with what's on the car at the mo, you need to identify why adding a component which should allow more mixture into the engine at higher rpm fundamentally isn't doing what you'd expect it to before trying anything else. Tuning engines is not a case of just bolting on x + y and getting z amount of power, it's a much more complex science.

-Your peak power on the standard engine is at far too low rpm for an IS at around 5,7k. Power most definitely shouldn't be dropping off before 6k, that's uncharacteristic of these engines. Your r/r operator if experienced with these engines (well actually even if not knowing that it's a 1.8 16v with a 6,750rpm limit) should have picked up on that. I'd suggest those are actually quite generous figures from those rollers, a standard IS doesn't make 140bhp at the fly at under 6k rpm from experience. I reckon that r/r is indicative of an engine with some issues. May just be somethign as simple as cam timing, not unusual for the chains on m42s to havee stretched over 20 years, most are ripe for replacement
-Warmer weather will not give you better r/r results
-A light flywheel is going to make naff all difference to your output
-Exhaust is unlikely to be causing any probs unless you have the normal cracked manifold or blows etc - the standard system is pretty free flowing, add to that that you've got a suspersprint system in there you should be set.
-Shrick cams should not give you a rough idle - your cams are prob incorrectly timed or you're not fuelling well - once you're happy they're timed right, get a CO meter in it and the afm screw twiddled. You should get a pretty smooth idle on them.
-you should def never get to 8k rpm - your engine's not built for that, and your r/r result shows your peak power is at 6,5k ish so it's totally pointless
-the graphs are rubbish, and we need to see AFRs, power at the wheels etc on both runs (standard and with mods)
-suggesting different injectors etc is a terrible idea until you know where you're fueling at the moment.

There's so much missing information here. What compression are you getting across the cyls? I'd have thought a standard engine should make the power you're seeing, and peak power should be at over 6k rpm for sure.

If you want to properly understand what's going on, bung the standard cams back in, get them correctly timed, put the standard chip in, get a proper set of graphs done with good curves, AFR, wheel power etc and measure the compression. from experience, you should see a graph pretty similar to the one you've got with the schricks at the moment and nice high compression across all cyls, AFRS at about 13.5:1 on WOT. If not, something's wrong. Then try with the chip and make sure all is well.

Once everything's in order with the standard engine, then measure your schricks - make sure they're not worn and are actually giving a longer duration and high lift than your standard cams (should be about 256 degrees, 10.4mm lift), stick the cams back in, correctly timed, re-measure compression on all cyls and get another set of graphs done.
Or if not, before throwing any more money at it, book it in somewhere which knows what they're on about. I built a 1.9 with kent regrinds (not as good as your schricks) a while back and it made 161bhp on paul sheps' rollers and a lovely strong curve and peak power up at 6,5k rpm or something and holding that power up to 7k. It's not just the peak power but the shape of the curve and how long it holds near peak power that you should be interested in.
Having said all that, my money's still on incorrectly timed cams, that or not getting great compression.

[Dave_M3]

its a little lumpy on idle with the cams in do you think by putting a lightend flywheel on will make it really bad on tick over?

I wouldn't be worried. The gains far outweigh the disadvantages.

A lightened M20 flywheel and 325 clutch will be perfect.

[harry_p]

not being funny, but the second dyno run they havent even bothered to change the scale to suit the power output, leaving a silly little graph at the bottom of the page. 8 year olds are taught to draw better graphs than that

they both look like pretty basig tie it down and do a run type of graphs rather than an attempt to properly tune the car. almost totally pointless, and the outputs can be pretty much whatever the opperator decides he wants them to be.

the only time graphs like this are any rear use is whan comparing mods on the same car on the same day using the same correction figures, even then the actual final bhp figure needs taking with a pinch of salt.

i would also suggest that unless the chip is specifically written for an is engine with cams it will need some degree of remapping, you can't expect a chip for a standard engine to cope with the extra breathing capacity of lumpier cams.

[B15NAC]

thanks for the advice the cam timming is spot on it has new chain and gears ect and was all set up with the bmw locking tools. then i had the mixture adjusted with a co meter up the exhaust and screwdriver adjusting the air intake?

[B15NAC]

ive been told that maybe i should adjust my AFM when the engine is above 3000rpm because maybe its running weak higher in the revs

[tim_s]

I'd still be a tad concerned that the idle is lumpy... I don't think it should be noticeably more lumpy than factory on cams with that duration. All the plugs the same colour? Compression look good? If you're 100% the cam timing is bob on, might be worth checking for air leaks. How did you set TDC? I'd imagine the timing would have to be out by quite a bit too to make it lumpy.
How did the emissions look when set up? btw I think you're saying you adjusted the TB on the throttle screw to change the mixture on idle - that's not the correct way to set up the emissions and will just screw around with the idle valve. that may be responsible for the dodgy idle, but not convinced - if you say the emissions were set and look ok, it's surprising that you've got a lumpy idle. What do the HCs and CO look like?
The r/r printout for the standard engine certainly looks very much like the cam timing's out, but it's not the only candidate. The curve on the new cams looks more reasonable, still... how many miles has the engine done? I'd def compression test - you want to make sure the basics are absolutely spot on before adding go faster bits.

[B15NAC]

Well to me the engine is sweet sounds spot on no smoke nice sparkplugs pulls and goes really well faster than my other IS oil is the best i can buy 5w40 fully synthetic oil and i put it in 4000 miles ago and its still as clean as when i put it in. The emissions are good. The only fault i feel is when its cold if i put my foot down when its cold it holds back a tad but when its warm it flys!

[tim_s]

ive been told that maybe i should adjust my AFM when the engine is above 3000rpm because maybe its running weak higher in the revs

Why don't you actually find out whether it's running lean or not, rather than this complete guesswork?! Why do you think it's lean over 3k rpm? With the information you have, there's no way you can tell if it's lean or not, and pissing about with the AFM isn't gonna help. Even if it is lean, Imessing with the carefully calibrated AFM spring is gonna make it run any better, trust me. And the AFM screw will not impact WOT.

[B15NAC]

I have spoken to a chap at fritz bits an he said he would think its lean over 3000rpm with the better cams!

[tim_s]

On emissions - it's not likely for you to at once have a lumpy idle and good emissions. The two are linked: if you have good emissions, you'll very likely have a good idle. In your case I'd suggest that the emissions might assist with figuring out why you have a lumpy idle.
On the cold running, you probably want that sorted too before trying to make it go quicker! Might be linked to trying to set up the idle using the throttle stop?

[tim_s]

I have spoken to a chap at fritz bits an he said he would think its lean over 3000rpm with the better cams!

Ah I see! Well I can see why they'd say that, but I don't necessarily agree. There's far too many assumptions in there! Firstly, if more air is going in as a result of the cams, the AFM will respond appropriately and more fuel will enter the engine, up to a point. The point is more valid with regards to the VE of the engine altering as a result of the cams - but they're really not that dramatic a change. Secondly, they're assuming that the car wasn't rich to begin with etc, there's simply no way they can know that. Thirdly, messing with the AFM will not help. Before doing anything of the sort, you need to know the AFRs on full load.

[B15NAC]

yea i may just leave it as it is! it does seem to go really well i must say just i was wondering if the power i was getting was right and if the results look ok. I cant really afford to spend more money on the car at the mo as ive spent so many thousands in the past 18months

[DHFiS]

If you are happy with it then just leave the engine alone and drive it.

If you want someone who knows M42s and can remap properly go and see Paul at Circuit Motors, Castle Combe.

[B15NAC]

Ok thank you may do that because I'm sure it could be a tad better

[Andyboy]

What would happen if you accidentally swapped over the inlet and exhaust cams..............?

[B15NAC]

not sure? but mine are 100% the right way around

[tim_s]

What would happen if you accidentally swapped over the inlet and exhaust cams..............?

Good call - if you do this on an m42 the timing is out by at least 10 degrees... esp as the one marked E is the inlet cam on the factory cams too iirc.

[tim_s]

If you are happy with it then just leave the engine alone and drive it.

If you want someone who knows M42s and can remap properly go and see Paul at Circuit Motors, Castle Combe.

A good idea. He'll do you proper, useful rolling road printouts too which you can cross reference against other 318is cars including his own, my old one etc.

[Brian28]

Mine is on his system for comparison too, was done with standard engine and chip so a good benchmark.

[B15NAC]

ok thanks for you advice and you think E is the inlet and A exhaust on the cams yea?