<DIV>We at Street Pro need some advice on interpreting dyno results. Here is the background that has lead us to this state of confusion.</DIV>
<DIV>We started our company almost 2 years ago with the sole mission to make exhaust cutouts for the gas engine guys. We developed what we think is the best looking and performing (not cheapest) cutout on the market. Upon testing several cars and trucks (gas) we saw a consistent 5-6% increase in both torque and hp at the rear wheels regardless of the baseline power, open vs closed. Everybody loved it and away we went. Then a few months back we were told by several shops that our real market for this product was in the light duty diesel, which we knew nothing about. So we set out to create the big brother diesel exhaust cutout that we now call the 4" Power Master.</DIV>
<DIV> </DIV>
<DIV>Like the gas 3" cutout, we wanted to test the product and see what was really being gained in terms of power. We secured a DuraMax that has an Edge Attitude 5 stage chip and stock exhaust (no cat model). The first dyno test was done with the results being inconclusive. The dyno shop said their dyno (an older model) could not test at such low RPM / high torque. So we then went to the local Caterpillar shop that has an over the road truck dyno. I must say the test was unlike anything we had ever seen in that the truck was allowed to run at load for what seemed to be 2 - 3 minutes per pull. The tests were done with the cutout open vs closed with the chip set at level 3 (90 hp ???). After a lengthy head scratch session the dyno operator reported to us - 257 rwhp closed and 289 rwhp open and an EGT drop of ~ 100 degrees in the open position.</DIV>
<DIV> </DIV>
<DIV>Since that time, a member of this forum was given a unit to test to help validate the numbers and he got a VERY different result. His truck is equipped with a Banks Six Gun (hp ??) and a Banks Monster Exhaust (with cat). With our part installed after his cat, his test indicated only 4 rwhp.</DIV>
<DIV> </DIV>
<DIV>On another truck tested at Garmons Diesel Performance in McDonough, GA last weekend we saw a 4 rwhp on a stock '04 Dodge using the cutout to bypass the muffler.</DIV>
<DIV> </DIV>
<DIV>The obvious question: Why did the DuraMax at the Cat dealer show such a strong gain and the other 2 were so low in comparison ?? Any help would be appreciated so we can properly present our product in the market.</DIV>
<DIV> </DIV>
<DIV>Richardhttp://www.dieselplace.com/forum/smileys/Approve.gif</DIV>Edited by: Street Pro

If you're speaking of "Terrain Twister", his test was done with a stock configuration. The HP and Torque numbers on the dyno sheet of this particular post look like stock numbers.

In the topic posts we discussed the fact that the cutout might help a chipped truck but a stock truck might not need help because the exhaust wasn't too restrictive in that configuration.

That is probably your answer...

If you want to I can confirm that to you if you send me a unit http://www.dieselplace.com/forum/smileys/HiHi.gif Edited by: Maxter

What kind of dynos and what kind of test parameters were used? And were there multiple tests performed at each, to evaluate repeatability? Turbocharged diesel engines are fairly sensitive to load, they tend to make their best power when loaded down and most chassis dynos and gas motor people don't like to load their engines down on a dyno. A proper chassis dyno test on a light duty diesel engine should accelerate the motor over its usable rpm range in a 1:1 ratio gear over a 20-30 second time span. Unfortunately, some people/shops don't use very scientific testing methods and will believe as fact any spike numbers they see in just one test, without regard for repeatability.


Obviously your product is going to shine in a situation where the ex system is seen by the motor as a restriction. The worse the restriction the better your product will perform. Light duty diesel engines will pass less air under an acceleration test and more under a load test.


Hope this helps! http://www.dieselplace.com/forum/smileys/Embarrased.gif

With regard to instrumentation accuracy and system noise, I'd think a 4HP gain would be challenging to see on one test run. That's about 1% of the max RWHP for power modified diesel trucks.

I think stree pro is reffering to this thread:

Street Pro Exhaust Cutout Tested! (http://www.dieselplace.com/forum/forum_posts.asp?TID=12812&KW=street+pro)Edited by: Maxter

OK, The test was Done at Jand D performance on a Mustang Dyno. We did 2 tests stock and 2 tests open to show consistancy. As far as the Banks equipment, it was ALL disconnected and the stock exhaust was put back on which are the Dyno sheets I posted. Doing it any other way would be an unfair test. I tried to fair and unbiased for the testing. If any one is interested, yes I did install the 6-Gun after the testing to see how it would do. The numbers for that test (1 run) where 349.3 @3250 RPM on horsepower and 666.6 @2750 RPM for torque. Eliminating the CAT and going to the Banks Exhaust (Yesterdays Dyno Day) yielded an improvement of 47.0 horsepower and 111.3 foot pounds of torque.


Is the factory muffler restrictive? YES


Is it enough to justify the cutout? That depends. Do you want the most horsepower you can get on a stock exhaust? I personally think that deleting the CAT is the first thing to do. Then the Exhaust cutout.


I also agree that the more hosrepower the vehicle makes, the more you'll see results against a stock system.


I was unable to have it ready for testing yesterday against the Banks system but will hopefully be able to soon. I will be doing a load test at that time. If any one is interested in meeting me that day that is running a stock system and installing it to do a load test on J and D's dyno, Please PM me to see what we can set up. I believe 'McRat' might be interested in this. If I recall correctly, he has deleted the CAT but wants to run the stock Exhaust.

street pro: Your first post on this topic shows 257-289 rwhp for a truck with a 90hp juice setting. The 90hp setting should give you at least 325 rwhp going on 350 for some truck. Your figures don't look realistic but it is probably due to the testing methods.

I believe that the gain between your open and closed configuration reflect a real, if not conservative, gain.

Maxter, Yes Terrain Twister is the member referred to. I did not realize he had tested in a "stock" setup http://www.dieselplace.com/forum/smileys/Embarrased.gif my bad. Thanks to you and Terrain Twister for clearing that up for me. As for the HP numbers reported (257-289 with juice) I have spent a lot of time looking at various threads and beginning to see that we had something bad wrong in the (what should have been expected) numbers.


Trippin, Parameters used; unknown. Repeatability; no. Acceleration test vs a load test, I've heard that before and think that may have also played a part in all this. "The worse the restriction the better your product will perform". Also makes sense esp as more fuel/air is introduced into the engine as was also pointed out by Maxter.


Terain Twister, Thanks for the reply and explaination of the as tested setup. I agree with you on all points about justifing the cutout on aftermarket vs stock exhaust.


It looks as though our one time test was a flash in the pan that may very well have been invalid for several reasons including what may have been a sick truck to start with.


Another question: Should we even concern ourselves with trying to test / publish numbers given all the possible variables involved?


Thanks for the help,


Richardhttp://www.dieselplace.com/forum/smileys/Approve.gif

Street Pro,


Every performance product these members buy is tested on a base vehicle in it's stock configuration. It is the only fair, real evaluation of a product and what it can or can not do in the real world. Different types of Dynos do present different HP results, but if the same truck is run on the same dyno within the same day to keep barometric pressure and temp relatively equal you will get a fair test.


This is why I was so excited to have Terrain Twister do the test for us and for you. He is a third party that was willing to do all the wrenching and he also paid for the dyno time. He did exactly the correct testing procedure that will show gains or losses. First a stock truck without mods, then a modded truck with the same test etc to see if there were any gains or losses. The other tests that have shown similiar HP and EGT results as Terrain Twister are very close to what same HP EGT resuslts that he got during his tests. That should pretty much show how the product performs.


Mark @ DPPIEdited by: Mark Craig

Mark,


I agree and we are appreciative of the work done by Terrain Twister. He has applied the detail that we lacked in our testing effort.


Thanks for your comments.


Richard

Mark, when you say:

"That should pretty much show how the product performs."

You should add "In that given situation".

For example, someone with a stock truck who install a Suncoast Stage III upgrade kit will see little or no change in the power applied to the ground because the stock tranny can handle it. Add a Quad 215 to the equation and you instantly gain a few 10s of seconds on the track because more power gets to the ground. Obviously there's also a gain in reliability but I'm letting that out of the equation for now. The tranny does not generate any power but it "can" lose some if it's to weak to handle the power.

The same can be said of a stock exaust with a stock truck wich is adequate. Even if you put a 5 inches system or a cutout you will see little or no gain in power. Add that same Quad 215 to the mix and the equation changes and sudently, you liberate more power with a cutout or a bigger pipe.

I did the testing at Garmon's. I won't go into load vs inertia because that debate will never end.


On Matt's 04.5 600 Dodge I saw a 4 hp change with it on and off. I don't remember much else but Richard, was it put before or after the Catalytic Converter? Something tells me after. But at any rate, 4 more hp everytime I opened it up.


I've done exhaust testing for ANSA and the typical gain for an exhaust was 2 - 7hp depending on what the original configuration was. 7hp was achieved with a dual system, removing the CAT.


I like this product because it allows you to open up your exhaust when you want to and return it to it's quiet self when the wifes in the truck. http://www.dieselplace.com/forum/smileys/Big Smile.gif


That is how I would market it.

Hi David,


Thanks for the comments on the truck you tested at Garmon's. We really enjoyed meeting all the guys and hope to see you again at another gathering.


On Matt's truck the cat had already been removed before our part was installed. Much to our disappointment, we were not able to get a baseline with cat.


Thanks again for the input,


Richard

Send someone here with it. I can map boost, egt, etc in real time, sampled at 100x/second then filter to show data points every 50 RPM or so.





I can also test either with inertia or under load...





Heck, come on up and install one Labor Day weekend and we'll do before/after tests... Edited by: Kennedy

I would like to see the results on John's truck. http://www.dieselplace.com/forum/smileys/Thumbs Up.gif

Hell, I will be there and I am feeling lucky! http://www.dieselplace.com/forum/smileys/Wink.gif

I would like to see the results on Brandon's truck. http://www.dieselplace.com/forum/smileys/Thumbs Up.gif

I would like to see the results on John's truck. http://www.dieselplace.com/forum/smileys/Thumbs Up.gif








But John doesn't want to butcher up his pipes...


Then again, that darn marmon clamp at my exhaust brake wants to turn all the time and I've been thinking about redoing it to tighten things up...