Exhaust cam timing - Page 3 - PeachParts Mercedes-Benz Forum

JayRash · #31 09-06-2009, 05:45 PM

Quote:

Originally Posted by Pagz

Jay,the little cover is for access to the exhaust sprocket bolts,the sensors are oil temp and oil pressure taken from the oil feed to the turbo,though iv got an oil thermostat with room for sensors so will shift those sensors to it at some stage!

Its the sensors i was wondering abt. Thanks.
Great idea.

Pagz · #32 09-06-2009, 06:21 PM

Quote:

Originally Posted by JayRash

Its the sensors i was wondering abt. Thanks.
Great idea.

Thanks!,its a handy location for them as it routes the oil feed up beside the oil dip stick away from the hot manifold then across to the turbo,so when i shift the sensors i think i will just install bungs and keep the oil flowing this way!

Pagz · #33 09-25-2009, 11:04 PM

RESULTS:

Retarding the cam gave a ok increase throughout most if the RPM range,not bad for such a cheap mod.

The runs were done with no boost control and a 10psi spring on the wastegate.notice the exhaust cam in full advance made for a slightly better peak hp.

cheers,
Paul

whipplem104 · #34 09-26-2009, 01:14 AM

Looks like a good 10hp. I was wondering what rpm that goes up to? Also did you play with the intake cam adjustment at all on the dyno.

JayRash · #35 09-26-2009, 01:20 AM

What abt the intake side? and what would u be going with in the end rtd or adv?

Pagz · #36 09-26-2009, 01:49 AM

Hey guys,yip played with the intake advance too heres the results without boost control,you were right about the switching needing to occure higher in the RPM range than the original 4300rpm switch point!.
We have a 6300rpm limit instead of the 5800rpm factory limit,the tuners think it would quite happily make more power past 6300 but im not willing to find the valve train limits.

Heres the new power curve Vs the one we did late last year which had two bent rods/possible incorrect timing and a faulty injector.
Now we have the exhaust sprocket,new split spray injectors,new rods and 100% correct timing....Power now peaks at 236.5kW @ the wheels,we estimate that's around 385Hp at the crank!...it feels great on the road.

JayRash · #37 09-26-2009, 01:58 AM

gr8 to see the car performing man, but i am more than sure your engine can rev with ease to 6900+ with no risk, the low RPM limit from factory is only due to the S/C.

Any way whats the cranck throw on this engine? A Mitsubishi engine stroked to 2.3 runs an almost 100mm cranck and still revs past 7600RPMs

Pagz · #38 09-26-2009, 08:25 PM

thanks!,maybe we will look into raising the limit alittle more at some stage,it does run tappered valve springs which are said to be better for high lifter/high rpm!? but really would need to be tested.
Im not sure what the throw is,i would assume it to be fairly large as it had always produced healthy torque for its size!.

Even with the incredibly long gearing,when we had the limit at 6000 i hit limit way too quickly,6300 made a huge difference,7900 and i would never have to change gear

.

JayRash · #39 12-22-2009, 01:45 PM

pagz
quick question; if i unplug the cam timing and give it my own ground and +ve will that be enough to advance the cam?
On my M104 AMG as i said before i feel the engine pull hard up to 4k rpm and then it hit a sort of flat spot then picks up at 5500 rpm again. I feel its something to do with cam retard which happens to be at abt 4k rpm.
I want to try advance til abt 5200 ther on retard and see if it feels any better.
Wont have time to dyno the car but still worth trying it. If it works out i can use an rpm window switch to control the cam to my liking.
What do u think? And is there any polarity i should follow in powering the cam?

Pagz · #40 12-22-2009, 03:51 PM

Hi Jay,
The polarity on the coil will not change its operation,you can unplug the original and feed it 12v and it will advance the timing when energized.

As with changing any timing,your VE and fuel ratios will change also,so i guess be careful.

When we tuned mine we found it hard to tune the transitions from retard-advance and vice-versa,the problem being the speed at which the transition happens is proportional to oil pressure/RPM,so if the engine is decelerating down past ~1200rpm(low oil pressure) and you are heading into retard for idle then you suddenly put moderate power back on,the ecu then goes back to advance and now an then i get a slight hesitation.
We also had some minor problems with the transition at 5300 going advanced to retard,but the changeover is much quicker and we managed to smooth it out.

Edit:
actually,in this graph you can see the blue line is the older tune with 4300 as the switch to retard,you can clearly see the drop in power,then in the red line the new switch point is ~5300 with still a slight drop but no where near as course.

Cheers,
Paul

JayRash · #41 12-22-2009, 05:36 PM

thanx man, i did give the transition some thought for i figured the responce time should be affected as i head into higher revs.
As i said the cam in retard makes power at abt 5500 but i will start retard at around 5- 5200 to give the gear time to reset by 5500. As for the 1200 point i guess ill keep that as it is, for the converter always makes the engine spin above that range unless almost coasting.
The graph kinda makes me sure i am on to something here. I just need to find me a window switch, last one i ordered from the usa never made it here. Time to order another one i guess.

Merry Xmass all and a happy new year.

JayRash · #42 06-16-2012, 09:23 AM

I know it's an old thread. When the exhaust cam was retarded did u move the cam clock or counter clock?

I mean to retard the exhaust cam which way was the cam moved?

Joreto · #43 06-17-2012, 01:33 AM

You move it counter clockwise(oposit to the engine rotation), that way the events happen later in the stroke(i.e. retarded). Jay are you going to move ot 1 tooth or have you made an adjustable sproket?

JayRash · #44 06-17-2012, 03:09 AM

I am not going to move it a tooth. My sprocket is a modded one by Amg and I'm trying to confirm that it's with slight retard.

Pagz · #45 07-25-2012, 02:45 AM

Hi Jay,
I picked up a used M104 exhaust cam and slotted it on a CNC mill, my original one was the same timing but had less "meat" around the bolts which ment I couldn't slot it,I did think maybe it would come loose but I ran it for ages at factory tightening settings and when i pulled the engine last time it was very tight still!. If we had have removed the overlap in the M111K it could have been much better but I think new cams were the only way.