C230K Rev limit

[John Jones Jr.]

Guys,

Anybody know why the M111 C230K engine's rev limit is at such a modest 5800? Is it due to cam timing, a limit on supercharger speed or piston stroke?

Thanks in advance.

[Mike51809]

I was told by my tuner that the supercharger is maxed out at 5800 so if you go higher you cavitate the air and generate more heat

[John Jones Jr.]

Yeah Mike, that might be a reason alright. If that is correct and considering these over sized crank pulleys being fitted with seemingly good results, maybe Mercedes were being conservative about the 5800 rev limit?

[Mike51809]

Thats a good point, mercedes doesnt disclose anything to find out

[John Jones Jr.]

I'm wondering now did Merc set the 5800 limit for hard autobahn use i.e prolonged high speed, something like 120mph plus? If so, it would seem to be even more of a justification to improve the cold air feed to the S/C and also fit a better intercooler.

[Denlasoul]

At 120, I dont think my car is running close to 5800…

[John Jones Jr.]

No it wouldn't be, as top speed is 140+mph I understand. The point I was trying to make is, prolonged high speed use or more to the point prolonged max rev use, Mercedes decided to keep max rev limit at a modest 5800 to keep excessive heat build up occurring in S/charger?. I don't really know, just making guesses but would love to know as I'd really like to improve on the standard power without spending mega bucks.

Anybody on here know or tried water injection, pre compressor? I considered a water spray system for the intercooler but again I'm unsure of the ins & outs.

All comments & advise greatly received.

Keep on Rocking! :D

[anf6789]

meth will raise the octane theoretically to 116. it also will cool the charge down a good amount. it would be good if you were running higher boost out of the supercharger to prevent detonation.

[Dearlove]

they would have set it so low because they were able to obtain enough power with out revving it so high, therefore increasing engine life. the engine could handle a lot more.....

[John Jones Jr.]

meth will raise the octane theoretically to 116. it also will cool the charge down a good amount. it would be good if you were running higher boost out of the supercharger to prevent detonation.

Interesting you mention that. I was just looking at a specialist site for water/met systems and if their figures are to believed it's possibly well worth investing in but, cost would be a slight issue if I was going down that road. Pump, Controller, Tank, Loom, Injector, Piping etc all add up to a pretty sum. Now I'm sure a home made job could be rigged up and save a lot of $$$, just it's hard to beat the professional set up imo.

[Denlasoul]

JJJ- my remark was more alongs the lines of what Dearlove said. Not trying to brag. I do recall my 280 performing the same though.

[John Jones Jr.]

:cool: Understood Denlasoul

[John Jones Jr.]

they would have set it so low because they were able to obtain enough power with out revving it so high, therefore increasing engine life. the engine could handle a lot more.....

I don't altogether accept that or rather I've my doubts. We are in agreement that the engine could handle or produce more power safely without affecting it's lifespan so it would have I presume, in theory very easy for Mercedes to have given the C230K more power if it really wanted to. I suspect that it was a marketing decision or cost reasons that power was pegged @ 193PS & 5800RPM.

Anyway, regardless of what I think, presume or suspect, I'd still really like to know the exact reason why the rev limit was set @ 5800. Mike51809 made a good point about the S/charger (or maybe even it's installation, come to think of it) being max'ed out at any higher rev's as far as Mercedes were concerned, if this is the case why is it max'ed?. According to Eaton themselves the M62 is suitable for engines between 2.5-4.0lt's, so that implies that the M62 is not max'ed out but as I mentioned earlier would it more likely that the installation is not up to the job thus there's no point in having a higher rev limit than 5800?

I don't have the answers, thus all my questions! Sorry.

Rock on! :D

[Dearlove]

the rev limit has nothing to do with the s/c speed, they could have made what ever sized pulley they wanted for what ever rpm they wanted.

If they could have gotten enough power by 4k rpm they would have limited it there. It would have been the magic number the engineers came up with for the perfect compromise of power/drivability and engine longevity

the faster an engine spins, the sooner it dies. That's half the reason the diesel merc last so long...

[John Jones Jr.]

Your comments still don't enlighten me, I'm sorry to say. Also, it still doesn't answer the original question I asked simply because most forced induction engines of it's era have higher rev limits. And I for sure wouldn't want a narrow 4k power band from a petrol engine, may as well just buy a diesel.

Lets say we agree that rev limit & S/c speed are not connected - as you say pulley size on the engine & S/c can be tailored to suit. So, that automatically eliminates the S/c as having any bearing on the engines max rev's. Then, would I be correct in saying, all we are left with is either the installation set up of the S/c (i.e. pipe work design, S/c location, Intercooler efficiency etc), the Cam timing or the piston stroke? From what I recall, as I haven't got the figures to hand, the bore/stroke was O.K.- the engine is not considered a long stoke design. So, that leaves the Cam timing and/or the installation set up. Any ideas if the standard Cam timing could be limiting the rev limit?

[C43inNC]

Get a tune and take the rev limiter off. Bam!

[Mike51809]

The m111 has so much potential...

[John Jones Jr.]

The m111 has so much potential...

Funny you mention that Mike. I've been offered this...but no raised limiter. Bull or what?

Mercedes C 230 Kompressor 193 hp>220 hp 280 NM>340 NM

''30 Day Trial When an ECU is ReMapped for Performance or Economy we offer a 30 Day Trial. If needed we can Revert your ECU back to Standard and offer a full refund''.

[Mike51809]

What company is it? I know a place called speedtuningusa where i got my tune and they do custom tunes too... But with the rev limiter im not sure honestly, talk to pagz or slammedc maybe, they have done alot with the m111

[John Jones Jr.]

It's well respected family run company here in Ireland, they are exhaust specialists too and well known within the tuning scene here and on top of all that they are great to deal with too. Now, having said that, they are just buying in the electronic know how, they remove the ECU, down load the info and after that I'm unsure of where the download is sent too. What they have told me is the new map is not a basic generic one, i.e. the map will be custom to my engine? Will keep you posted. I've still doubts about a 27hp gain. But I'd be happy with 10hp and improved drive-ability.

I've another plan hatching too. I've just purchased a C230K crank pulley from Germany (€60 delivered), so I'll be giving that to an engineering shop to see if they can increase the diameter. I'm hopeful, fingers crossed.

[Dearlove]

ah i see what your asking,

Okay so whats stopping the engine revving harder? besides the rev limiter? nothing....

i think with the stroke at 3.48" it reaches a mean piston speed of 3500 FPM at only 6034 rpm...
i say 3500 because i remember hearing that that the max you want to go with stock cast pistons.

but this is a little contradicting because if you do the same math for the c36 a 'safe' redline is 5700 or 6600 if you use a higher 4000 fpm, when in actual fact the limit for the c36 is about 6800.... but that engine uses forged everything....

[John Jones Jr.]

ah i see what your asking,

Okay so whats stopping the engine revving harder? besides the rev limiter? nothing....

i think with the stroke at 3.48" it reaches a mean piston speed of 3500 FPM at only 6034 rpm...
i say 3500 because i remember hearing that that the max you want to go with stock cast pistons.

but this is a little contradicting because if you do the same math for the c36 a 'safe' redline is 5700 or 6600 if you use a higher 4000 fpm, when in actual fact the limit for the c36 is about 6800.... but that engine uses forged everything....

I'm glad now that you understand what I'm actually asking. :D

Still, I'm doubtful the 5800 rev limit has anything to do with non forged internals, actually I'm almost certain my 2.5-16 has cast pistons and that runs to 7250. I'll be speaking to a guy who's been involved with Merc's and has massive experience (40 years of it) and see what he says. I'd really like another 500rpm without any disadvantages or associated problems.

[Dearlove]

yeah im sure 500 rpm would be fine. dont forget the cams would be pretty optimized for the standard rev range, so after 5,500rpm you'll probably see the power dropping off quite a bit

[Mike51809]

The pistons at least on the c230k have to be forged or the boost would be lower and you couldnt turbo at 15psi and not blow something

[John Jones Jr.]

yeah im sure 500 rpm would be fine. dont forget the cams would be pretty optimized for the standard rev range, so after 5,500rpm you'll probably see the power dropping off quite a bit

You see, this is why I asked originally in the thread about the cams, as I don't have an idea about them. Would I be correct in saying then, if I want another 500rpm without any disadvantages or associated problems like excess power drop off I should look into getting another set of cams?

[Dearlove]

before you go too crazy do you have a way off raising the rev limit? why not just get a different pulley for more boost and remap the ecu?

[John Jones Jr.]

The pistons at least on the c230k have to be forged or the boost would be lower and you couldnt turbo at 15psi and not blow something

Another interesting point there Mike. I presume there's been no problems with retro fit turbo's? If that's the case I shouldn't be at all concerned with having any problems with pistons or rods raising the rev limit.

Looking more & more like the cam design is the stumbling block to a higher rev limit . Sadly, I don't know much about cam design which I suppose means using the pro guys and the only downside to that is cost I'd presume.

[John Jones Jr.]

before you go too crazy do you have a way off raising the rev limit? why not just get a different pulley for more boost and remap the ecu?

Dearlove, you are spot on. The 'plan' is to first relocate the MAF, modify the inlet (do away with the air box) and then a remap. I'd like to change the pulley but I'm unwilling to pay 750 bucks plus shipping, plus import duties & tax. So, I just this morning purchased another pulley and I'll give that over to an engineering shop and see what they say - fingers crossed. If the pulley works out o.k. I'll possibly look into getting a better intercooler and then another remap. That's the 'plan' so far!

[Mike51809]

Have you heard or degreeing a camshaft before? Thats what you have to do and theres places that make custom cams for your specs too. Theres 2 guys on here with turbo m111 with the kompressor block, pagz had the stock block at 15psi. Also remember when you enlarge the crank pulley you are overturning the alternator as well, the kleeman kit with the bigger pulley includes a larger alternator pulley to compensate for that

[John Jones Jr.]

Have you heard or degreeing a camshaft before? Thats what you have to do and theres places that make custom cams for your specs too. Theres 2 guys on here with turbo m111 with the kompressor block, pagz had the stock block at 15psi. Also remember when you enlarge the crank pulley you are overturning the alternator as well, the kleeman kit with the bigger pulley includes a larger alternator pulley to compensate for that

Yes, I understand the basics of cam timing, profiles etc but ain't got a clue as to what type of cams I'd need for the C230K as I've had no luck finding any for sale.
Should I really be concerned if I manage to fit an over sized crank pulley that I'll be increasing the rev's of the alternator? It's not like I'll be pulling 5000rpm all the time as there will be little if any Autobahn work. May look into getting a bigger pulley from a similar alternator, might be a direct swap, just for peace of mind.

[Mike51809]

You would have to make some specs and have someone make one, many times overlap plays a role in NA applications to make sure the mix isnt dilluted with exhaust gas but on a supercharged engine you want only 6-12 degrees of overlap since the boost shoves it out. Im not sure if it makes a big difference, just a thought lol

[John Jones Jr.]

Thanks Mike.

[Mike51809]

No problem, i wish i knew more about it to really help you with this

[Dearlove]

http://www.dbilas-shop.com/Products/Performance-camshafts/Mercedes/1-8-2-3-4-Zyl-16VM111-Vanos/Regrind-standard-camshafts:::7_2504_2662_2671_3161.html

[John Jones Jr.]

Thanks for that Dearlove.

[Dearlove]

no worries, there is another site as well but i cant find it. was link on this forum a while back

[John Jones Jr.]

Don't go to any trouble finding the other site. I've more than enough to be going on with, haven't even properly started looking into the basics of what needs doing, I know I've something worn on the front suspension, an electrical fault, crap tyres and a slight exhaust blow. A full service is in order too, plus both V belts have seen better days. A few minor spots of rust to attend to too and that's without a proper full inspection being done! I'm sure the list will increase, ha, ha - wouldn't mind if I needed this car put I don't. But once I know what's what, I'll crack on with fitting new suspension, MAF relocation, remove the air box & get the crank pulley to an engineering shop.
Maybe, I should do a write up with some photo's over the next coming months?



Anyway, thanks for your input guys. And keep on Rocking :D

[John Jones Jr.]

Right a little bit of info I just received, possibly old news but here goes anyway.

I spoke with guy who's spent a lifetime involved with Merc's and he explained to me why the rev limit is 5800. Simply, Merc designed the engine with economy in mind while not lacking power. He reckons there's no point in having a higher rev limit without changing the cams and doing a remap. His attitude was go for more torque & hp via pulley etc and leave the rev limit as per factory. But I think he's of the school that wouldn't modify the engine at all.

So, I did a bit of digging on interweb and found this from what I think came from Merc's marketing dept. dated Nov 1997.

'' Peak performance has been deliberately muted in favour of fuel economy: the Kompressor provides the performance of a six cylinder engine with the economy of a four cylinder ''.

So, it all makes sense to me now and I'm happy with the explanation I received. Cam's are the key it seems.
HTH

[SLAMMED_C]

This is something that I have wanted to do as well. The engine revs so low, it could easily use a bit of a bump up.
I don't see why the engine cant handle higher rpm, just like people have mentioned its because the engine was economical, so no need for high revs. I think it needs to be in the 6500-7000rpm range.
I will raise mine up a bit when I do a retune.
I thinks cams are a good idea, and also some solid lifters instead of our hydraulic ones. I know they make solid lifter kits for vw engines, older vr6 ones. The stock hydraulic vr6 ones look identical to the M111 and M104 hydraulic lifters, so I wonder if I could buy the solid ones nd use them. If they are indeed the same, it will be on the short list of mods!
I think it's something that needs to be played around with, on a dyno to see if there are any gains at all. That will be the real proof to if its making a good difference or bad difference.

[MikeD]

(delete)

[John Jones Jr.]

This is something that I have wanted to do as well. The engine revs so low, it could easily use a bit of a bump up.
I don't see why the engine cant handle higher rpm, just like people have mentioned its because the engine was economical, so no need for high revs. I think it needs to be in the 6500-7000rpm range.
I will raise mine up a bit when I do a retune.
I thinks cams are a good idea, and also some solid lifters instead of our hydraulic ones. I know they make solid lifter kits for vw engines, older vr6 ones. The stock hydraulic vr6 ones look identical to the M111 and M104 hydraulic lifters, so I wonder if I could buy the solid ones nd use them. If they are indeed the same, it will be on the short list of mods!
I think it's something that needs to be played around with, on a dyno to see if there are any gains at all. That will be the real proof to if its making a good difference or bad difference.

I don't think off hand I'd bother fitting solid lifters. My reasoning is I'm only looking to increase max rev's to 6250-6500, also there's the cost of 16 lifters & a shim set plus they are pain in the butt too as they need to be shimmed every 10,000 miles. That's just my view at present. Ask me next week and there's a good chance I'll have changed my mind! :D

[zmatt]

Pagz was able to adjust the cam timing and get around 6000 with little work I believe. Don't forget about the Schrick cams. They are probably your best bet. IMO though with the stupid torque this thing makes and the added wear on the engine there is little point to going any higher than 6kish. This isn't a Honda, we don't have to rev the balls out of our cars to get power. I can easily spin the wheels form a start in 1st and that's with nice khumos too. Intake, exhaust, 1bar pulley mod and map will get you plenty of power and torque and you won't miss the revs at all. Our engines have the character of larger displacement NA engines, stock they feel Like V6s. Tuned they feel like V8s. Higher revs are likely more important if you go turbo just to get the exhaust flow to spin the turbo. If you stay SC it's not necessary.

[John Jones Jr.]

All very good points Zmatt.

And I think you have summed up the situation very well by saying ''plenty of power and torque and you won't miss the revs at all'

[anf6789]

also upping the revs will put more stress on the rods, bearings ect. Im sure the benz rods could take it, but if your not doing anything crazy I dont see a point in raising the RPMs drastically...

[John Jones Jr.]

Agree Anf, no point in upping the rev's if not required. But the reason I started the thread was to try to understand the engine design and also in case I do at some stage decide I really want those extra rev's and if it's worthwhile having them.

[zmatt]

Also just remember, most of our motors, while overbuilt, are pushing quite a bit more than 100k on the clock already. High revs is just going to exacerbate the wear.

[John Jones Jr.]

Also just remember, most of our motors, while overbuilt, are pushing quite a bit more than 100k on the clock already. High revs is just going to exacerbate the wear.


+1.

[Mike51809]

Just upgrade your pulley, get a better intercooler with smooth bends and piping, put some 42lb injectors in it and some headers then tune it and you will never worry about that rev limit :D

[Mike51809]

Its all uncharted but youre making it more complex than it needs to be... All engines are the same, the more air you pump through it the more power

[John Jones Jr.]

Just upgrade your pulley, get a better intercooler with smooth bends and piping, put some 42lb injectors in it and some headers then tune it and you will never worry about that rev limit :D

Yes, Mike no doubt you are basically correct but there's one little problem with that - I'm on limited budget (which is a real pain in the butt) that I've got to stick too. So, at present a purpose built I.C. and headers (ex. manifold) are not on the cards. In an ideal world, I'd have just bought all you've mentioned plus, cams, f/pump, complete exhaust system and maybe even a head job too. Life eh? :(

[Mike51809]

Im just gonna do it kinda slow over time, i know what you mean though

[John Jones Jr.]

You see Mike, I'm not actually being mean with money. I bought the C230k because I reckoned it was good value but didn't need it as I have two cars already and one of those is crying out for $$$$ to spent on it, also I have to admit I like having several cars around the place. But, it needs a few bits - shocks & springs, tyres, a general service, and few rust spots & an electrical fault need to be attended to. So, by the time I get those sorted I'll have spent well over double the purchase.

Just hopefully within the next 6-12 months I'll have it all sorted, exactly the way I want it without breaking the bank.



BTW, what would you think of those EVO alloys on the C230K, I have a set just a matter of getting 225/50/16 tyres.



1118

[Mike51809]

I see what your goin for now more, i thought you were more for the performance earlier thats why i was saying all that.. Those arent bad wheels, just not my style on looks. Do what you like :) When i tell people what i wanna do with my car they tell me im dumb all the time but i dont care, the easy way is when performance or any parts are everywhere and thats no fun to me :p

[John Jones Jr.]

Yeah, I know those wheels aren't to everybodies taste but hell I had them on my 2.5-16 (they looked great!) and I'm going to stick them on the C230K and see what they are like - they're very low key, not blingy so we'll see.

No, you are right as there's so many people buying cars especially the likes of BMW's and then buying all the performance bits off the shelf - that's not as much fun when there's little modified parts available for the likes of the W202's.

[zmatt]

And cams and everything that goes with that are?

[John Jones Jr.]

Don't get you Zmatt?

[zmatt]

Cams aren't cheap and hot ones require new springs and retainers often. Also don't forget the time in tearing down the head, which if you don't know how to do that then will cost $$ for someone to do it.

[John Jones Jr.]

Got you now Zmatt. Yes, I do understand the implications of replacing the cams. I think if I was going to do it, it would be the last thing on the list.

[Mike51809]

I wanna get all new rings, bearings, hoses, seals, and rebuild the transmission then make my dream 202 :) I can get everything but the piston rings but if i can find those build it in our pole barn and maybe shed some light on some custom camshafts. I found the specs on all data :) as well as all the torque specs for a rebuild plus diagrams

[Mike51809]

Hey john have you compression tested your motor? I just did and got 10.8bar accross all cylinders at 165,000 miles, its like i never ran it...

[John Jones Jr.]

No, not yet Mike. I have a compression tester and I'll be changing the plugs soon so I'll do it then. Any idea what the figure should be from new?

[Mike51809]

New spec is 7.5 to 10.5 bar and no more than a 1.5 bar difference between cylinders, i got a huge stack of papers from school on specs lol I got 10.8 (160psi) bar on every cylinder with those miles so you should be good :D

[John Jones Jr.]

That's a great result with that mileage. I'll let you know what figures I get, hopefully the same as yours.

[Mike51809]

I hope so too! If you need specs on something just ask btw

[John Jones Jr.]

Thanks Mike.

[KrumB]

Hi,

When I remapped mine the tuner set the rev limiter to 6500 rpm. I've got both pulleys reworked and run 14.5 psi of pressure.
The engine takes it more than perfectly.

:)

[dokotela]

So you're using the stock ecu, just remapped?

[KrumB]

Yes the stock ECU. They just changed the main chip. The cost was someware around 250 EUR for the whole thing.