Max power on om602 with 7 mm elements, everything else stock. - PeachParts Mercedes-Benz Forum

Deni · #1 08-08-2009, 03:10 AM

Hi,

What do you reckon would be the max power that can achieved with 7 mm elements on a stock om602 (appart from turbo set to about 15 psi)?

Currently with 1 1/4 turns on the full load and 5700 rpm max engine speed (pulls strongly to about 5000 rpm) I reach 1250 F at about 140 kph in 3rd at about 5000 rpm flat out. Though I need shorter bursts of power like 0-50 mph for quick pull off and 60 - 80 mph for highway.

The car is no slouch with the lpg injection, but want to keep it diesel only.

auspumpen · #2 08-08-2009, 02:43 PM

I would be extremely nervous about running it without a means of mitigating your EGTs (via intercooler or h2o injection) -- in fact, I'd go as far to say that I wouldn't even think of running that size element without an intercooler and a pyrometer in place.

tomnik · #3 08-09-2009, 03:50 AM

Quote:

Originally Posted by auspumpen

I would be extremely nervous about running it without a means of mitigating your EGTs (via intercooler or h2o injection) -- in fact, I'd go as far to say that I wouldn't even think of running that size element without an intercooler and a pyrometer in place.

Theoretically EGTs should be lower with 7 mm elements.

My SD was more or less stock when I installed my 6mm elements (MW IP).
(AAZ injectors with 293 nozzles and 2.47 rear end).
The stock IP was not very strong (governor setting).
After just changing the elements top speed raised from 170 to 185 km/h.
Unfortunately my pyrometer was not installed that time so I can not verify the theory of lower EGTs.
The potential of power that can't be used because of lack of air will give you a much better mileage.

Tom

Deni · #4 08-09-2009, 04:40 AM

Hi Tomnik,

I apologize I didn't write you anymore, as I've agrred with myself that if I don't sell the car until the end of the summer than it stays with me. The first expenditure will be 7 mm elements from you, if you still have them

.

I've set my turbo at about 15 psi now. How much power can I get from 15 psi worth of air? I know the answer is far more complicated as it depends on many factors, but roughly speaking.

tomnik · #5 08-09-2009, 05:12 AM

Quote:

Originally Posted by Deni

Hi Tomnik,

I apologize I didn't write you anymore, as I've agrred with myself that if I don't sell the car until the end of the summer than it stays with me. The first expenditure will be 7 mm elements from you, if you still have them

.

In October the 7.5 elements will be available. Wait for them!

Quote:

Originally Posted by Deni

I've set my turbo at about 15 psi now. How much power can I get from 15 psi worth of air? I know the answer is far more complicated as it depends on many factors, but roughly speaking.

Up to now I never did a dyno run. For me the # of hp is not important, it's more the feeling and top speed that I can "measure".
Just put your boost to 15 psi and check it. I am more interested in getting better drive ability (mileage, emission, better efficiency,...) than pushing to the limits for racing, so I limit boost to max. 1 bar and max. rpm to 5000/min but just for governor setting. I can not remember when I ever rev'd beyond 4500/min. Nice running engine without idle issues and smoke are my goals instead of just one super race then loosing the engine...
I have an IP of a 602 turbo waiting for the elements but it will be installed in a boat of my friend and I have only my 603a and 617a, otherwise I would send you a modified IP for testing.
Try to get a VTG. This will be a good up-grade for stock IP and later do the IP.

Tom

Deni · #6 08-09-2009, 05:23 AM

Quote:

Originally Posted by tomnik

In October the 7.5 elements will be available. Wait for them!
Tom

Won't the 7.5 mm elements give too much fuel for a regular idle?

tomnik · #7 08-09-2009, 06:44 AM

no, idle quantity is calculated identical to the 5.5.
Idle quality is also a question of element quality, which is poor for the after market 7 mm.
With full load screw adjusted accordingly the 7.5 deliver the same amount of fuel, but can also deliver approx. 100ccm/1000 rev within the same range of end of delivery compared to the 5.5.
As soon as I have my 6.5 MW elements ready (the Ms will be ready later) I will "test" the capability of the new bench guy in setting the governor.
This guy is successfully doing some IPs for race trucks but never thought of using custom elements (up to now

).

Tom

auspumpen · #8 08-09-2009, 01:18 PM

Quote:

Originally Posted by tomnik

Theoretically EGTs should be lower with 7 mm elements.

My SD was more or less stock when I installed my 6mm elements (MW IP).
(AAZ injectors with 293 nozzles and 2.47 rear end).
The stock IP was not very strong (governor setting).
After just changing the elements top speed raised from 170 to 185 km/h.
Unfortunately my pyrometer was not installed that time so I can not verify the theory of lower EGTs.
The potential of power that can't be used because of lack of air will give you a much better mileage.

Tom

I'm unfamiliar with that theory, but I'm willing to entertain the idea if you can help me understand. More fuel should produce more heat, which is why all the modern high(er) performance turbo engines have some form of intercooler from the factory.

auspumpen · #9 08-09-2009, 01:22 PM

Quote:

Originally Posted by tomnik

no, idle quantity is calculated identical to the 5.5.
Idle quality is also a question of element quality, which is poor for the after market 7 mm.
With full load screw adjusted accordingly the 7.5 deliver the same amount of fuel, but can also deliver approx. 100ccm/1000 rev within the same range of end of delivery compared to the 5.5.
As soon as I have my 6.5 MW elements ready (the Ms will be ready later) I will "test" the capability of the new bench guy in setting the governor.
This guy is successfully doing some IPs for race trucks but never thought of using custom elements (up to now

).

Tom

Please consider me very interested in your 7.5mm elements (M-pump).

babymog · #10 08-09-2009, 06:18 PM

Compressing air makes it hot.
Air compressed by a hot turbocharger makes the air hotter still.

The aftercooler/intercooler removes some of that heat.

Overfueling will cause heat where you can't remove it.

tomnik · #11 08-10-2009, 12:50 AM

overfueling of a stock IP will cause heat mainly because the additional fuel means longer duration of injection. End of injection is getting late, causing black smoke and heat besides some extra power, plus the plunger speed is beyond its max. (cam profile/plunger travel). That means the additional fuel is injected late and slow. All that leads to more heat compared to the power gain.
With correctly calculated elements end of injection is just before/at the max, speed of the plunger. More fuel is injected within a shorter time and can burn better due to better atomisation and more "distance" to TDC (more time).
Now given the same amount of air with Deni's stock engine he can burn a little more fuel with larger elements due to the above said.

Tom

Tymbrymi · #12 08-10-2009, 02:31 PM

Quote:

Originally Posted by auspumpen

Please consider me very interested in your 7.5mm elements (M-pump).

x2!!!

How are you going to address the reliability (re: idle) over the 7mm elements?

tomnik · #13 08-10-2009, 05:30 PM

Quote:

Originally Posted by Tymbrymi

How are you going to address the reliability (re: idle) over the 7mm elements?

poor fabrication quality. I have some of them on my table. My bench guy was unable to adjust individual quantity through the range of rpm. Either good idle and poor high rpm or the other way round.

Tom

auspumpen · #14 08-11-2009, 09:47 AM

Quote:

Originally Posted by tomnik

overfueling of a stock IP will cause heat mainly because the additional fuel means longer duration of injection. End of injection is getting late, causing black smoke and heat besides some extra power, plus the plunger speed is beyond its max. (cam profile/plunger travel). That means the additional fuel is injected late and slow. All that leads to more heat compared to the power gain.
With correctly calculated elements end of injection is just before/at the max, speed of the plunger. More fuel is injected within a shorter time and can burn better due to better atomisation and more "distance" to TDC (more time).
Now given the same amount of air with Deni's stock engine he can burn a little more fuel with larger elements due to the above said.

Tom

Having been inside these M-pumps, I'm having a hard time imagining how one adjusts the elements (plungers and barrels) themselves. Rather, it seems that issues with duration and lift are dealt with by regrinding the pump camshaft profiles. Myna told me that they can't install 7mm elements in a 603.97 pump because the cam profile wasn't a good fit. Which leads me to believe that there's still room for improvement in these pumps if we carefully match the element size to a custom cam profile--this is clearly well outside of my skillset.

Tymbrymi · #15 08-15-2009, 03:56 PM

Quote:

Originally Posted by tomnik

poor fabrication quality. I have some of them on my table. My bench guy was unable to adjust individual quantity through the range of rpm. Either good idle and poor high rpm or the other way round.

I was referring to the elements you're designing... Is your fab house more reliable? I hope so!!

Thanks for going through all the effort of designing these things...