I have been doing some investigation regarding the diesel spike vibration that seems to me more noticable on a SMF truck. Though a diesel with an auto tranny also has diesel spike the auto tranny seems to absorb a fair amount of the vibration (just my observation).

There are other threads on the dieselplace.com which also discuss this subject. But I did learn some information regarding a company which has been making dampners for diesel trucks for a very long time. Very interesting info regarding the company, FLUIDAMPR, which invented the viscus fluid dampner for diesel engines:

FLUIDAMPR invented the viscous fluid damper in 1946 for diesel engines under
their old name of Houdaille Ind., which became Vibratech / Idex, which
became Vibratech TVD (check their website regarding all the engines they make this product for. . . will suprise you!) FLUIDAMPR is the brand name of the product manufactured and marketed to the performance industry (racing cars and diesel pickups) since 1985.

Nearly every class 8 and bigger diesel truck (18 wheeler) on the
highway use a viscous fluid damper invented by FLUIDAMPR or a copy by some
other manufacturer.

FLUIDAMPR invented the viscous fluid damper which all large construction vehicles and equipment powered by diesels use (though some made by competitors).

All General Electric Locomotives use a FLUIDAMPR viscous fluid damper.

Huge natural gas pumping stations powered by natural gas and diesel that
pump natural gas to your home and business use a viscous fluid damper.

Oil drilling rigs engines use viscous fluid dampers.

Larger generator sets making big power use viscous fluid dampers.

Large ships, including the ones that you can enter the engine while it
is running, use viscous fluid dampers.

There are many more.

There can be no down time due to broken cranks.

Rubber dampers can not be used on these applications because they can't
control the torsional vibration to an acceptable level and also because
the rubber can't take the load.

FLUIDAMPRs don't break cranks, they extend the life of the crank and
bearings.

After the patents ran out, why have so many companies through out the
world copied the viscous fluid damper invented by FLUIDAMPR?

So, even though there are competitors who complain, lie and argue about a product developed and used by the vast majority of diesel engines long before they could steal the design, the original inventor and manufacturer still makes more and better products than their competitive "Yakkers", and that is why I carry their products. Check my website: www.dynadroitDIESEL.com

JOhn have you had a chance to try one on your truck, dose it seem to calm the diesel spike that causes the trans to rattle? I was going to try one out after i sell my gm clutch kit, if i sell it:confused: .

Thanx,
Caleb

I like my rattle! I am very used to it now

Have not tried one yet but plan to pretty soon. Have several customers who will be able to supplly some findings in the near future. more later . . .

I finally installed a Fluidampr on my duramax and did some testing.

Very interesting. The SBC SMF/DDC rattled a little less loud than before but not much. However, the rpms were right on.

At idle the rpms are 680-682 !!! No bouncing. Crusing on the highway at 1800 rpms, when the road is flat and smooth, the rpms only change + or - 4 !!!

Last weekend the guy running the dyno mentioned that the accel was very smooth and was also shown to be so on the graph though the rpms did not go past the rev limiter.

More testing will come later and will place some posts. In the next couple of weeks guy is going to do another set of rpm testing before and after his Fluidampr install. Will be documented and photographed. Will show up in a magazine in a couple months.

Anyhow, for my useage I really like it and the diesel spike seems to considerably reduced.

Ask Fluidampner to supply the test results for a Duramax that show 2nd, 3rd and 4th order harmonics.

I'd like to see the differences between stock and their product.

Guy;

Good request! I will ask them.

-J

Ok, I sent the request.

I will dig out our test result graphs to post on this thread. For now if you click on the link below (from our website www.fluidampr.com (http://www.fluidampr.com)) you will see the 4th order comparison between the stock rubber damper and the Fluidampr.
http://www.fluidampr.com/downloads/diesel_fluidampr.pdf (http://www.fluidampr.com/downloads/diesel_fluidampr.pdf)

Once I convert the test results I will attach them to this thread.
Thanks.

Dan Oddy

Dan;

Thanks for your rapid response.

John

Ask Fluidampner to supply the test results for a Duramax that show 2nd, 3rd and 4th order harmonics.

I'd like to see the differences between stock and their product.

I have attached a graph showing the 2 1/2, 3rd, & 4th order comparison between the Fluidampr and the stock damper on a tuned Duramax engine. As you can see the solid lines are the results from the stock damper and the dashed lines are the results from the Fluidampr as a function of peak to peak displacement (degrees) vs. RPM. Since Fluidampr does a better job controlling torsional vibration, we notice a small performance gain.

If anyone has any questions about this graph please let me know.

Thanks,
Dan

I have attached a graph showing the 2 1/2, 3rd, & 4th order comparison between the Fluidampr and the stock damper on a tuned Duramax engine. As you can see the solid lines are the results from the stock damper and the dashed lines are the results from the Fluidampr as a function of peak to peak displacement (degrees) vs. RPM. Since Fluidampr does a better job controlling torsional vibration, we notice a small performance gain.

If anyone has any questions about this graph please let me know.

Thanks,
Dan

Thanks. :ro)

Would you tell us a little about the testing procedure and how these results were derived?

Thanks. :ro)

Would you tell us a little about the testing procedure and how these results were derived?

No problem, We use an (expensive) rotec FFT analyzer to record the vibration at the damper. The FFT analyzer is hooked up to a laser tachometer that points at the damper. We put a black/white tape strip around the damper and as the engine revs up on the dyno, the tachometer measures how long it takes the black/white sections on the tape to pass thru the laser. If there was no torsional vibration the black/white segments would take an equal amount of time to pass by the laser. Since there is vibration present, the crankshaft actually twists ahead of it normal rotation and then rebounds back the opposite direction. The analyzer is measuring how far ahead and how far back the crank rebounds in degrees. Remeber we are only talking around one degree forward and back at MOST! One degree doesn't sound like much but it is, especially when some of our OEM's we supply heavy duty dampers require .25 degrees MAX.

I hope I made sense in my description, it may sound confusing but it is pretty simple. If any one has any questions let me know.

Thanks,
Dan

Thanks for the quick post and response, Dan.

If anyone is interested, I noticed something interesting the other day. My Edge Monitor on RPMs before the fluidampr was kinda a pain. On the highway I could easily see the thousand and hundred rpm digits but below that they were moving so fast it was hard to actually and accurately tell how much the rpms were changing on a flat highway with the cruise on. Now I can read every rpm and they dont change much while cruising. maybe by 3 or 4 but not very fast. What still amazes me is that at idle my rpms are 680. They have NEVER moved below 679 or above 683! Usually they move slowly between the 680 and 682 rpms at idle. I would never have noticed this without a digital rpm gauge. If you have a digital guage one you might want to check and see how fast and far the vibration changes the rpms.

Were these tests performed in a truck with all belts and accessories in tact?

Manual or Automatic trans

Under load on a dyno?

Free rev?

Were these tests performed in a truck with all belts and accessories in tact?

Manual or Automatic trans

Under load on a dyno?

Free rev?

All the tests for the tuned trucks were on a chassis dyno with all belts and accessories hooked up just like you were going down the road. The Powerstroke was an automatic, the Cummins was a manual, and the Duramax was an automatic but we ran it in manual mode.

Good questions.
Dan

All the tests for the tuned trucks were on a chassis dyno with all belts and accessories hooked up just like you were going down the road. The Powerstroke was an automatic, the Cummins was a manual, and the Duramax was an automatic but we ran it in manual mode.

Good questions.
Dan

I'm sorry for being such a pest.
Just a couple of more questions...........
What type of chassis dyno? How long (time)was the test? What gear was used?

Guy;

You are not being a pest. :funnypost These are good questions from a guy ):h who has used a similar product before.

More info is better for all of us :cool2:

I'm sorry for being such a pest.
Just a couple of more questions...........
What type of chassis dyno? How long (time)was the test? What gear was used?

You are not being a pest, that is why Fluidampr decided to become a supporting vendor, that way I could answer your questions on our product.

As far as the dyno questions, again those are all very good questions. I am not sure what kind of chassis dyno it was. I am not that familar with chassis dynos, I would have to ask the shop. It looked like just a conventional dyno like most others I have seen. For all the testing we did we recorded the data between 2000-3500 rpm. The Powerstroke was run in 3rd gear and took about 3 sec. to cover the rpm range. The Duramax was in 5th gear and also took about 3 sec. to go thru that repm range. The Cummins however was run in 4th gear and took about 8 sec to go thru that rpm range. I never realzied the difference until I looked though our data to respond to your quesiton.

Dan

Was there any hp realized by dampening more vibration that the stock harmonic balance?

Was there any hp realized by dampening more vibration that the stock harmonic balance?

We did see a small increase over the stock damper on a Duramax engine, on average it was about 6 hp & 18 ft-lbs. of torque improvement. This is because we are controlling the crank vibration better than the rubber damper. Let me know there are any other questions.

Thanks.
Dan