Comparison of Dyno Runs for 2008 Viper with and without Belanger Exhaust Kit . . .

[rcl4668]

This thread is a placeholder for a comparison of dyno runs before and after installation of the Belanger headers, high flow cats, magnaflow muffler and sidepipe exhaust kit (referred to collectively as the "Belanger Exhaust system").

Today I brought my 2008 convertible to Wong’s Performance Engineering in Vancouver, WA for a baseline dyno with the stock header and exhaust system. (The entire drivetrain is completely stock.) The dyno used is a Mustang dynamometer. Mileage on the car was 1617 miles. Ambient Temp was 70 degrees F, air pressure was 29.9 inches of mercury and humidity was 34.27%. Car had half a tank of Chevron E10 blend premium fuel rated at 92 octane. Tire pressures were set to 29 psi cold as recommended by Chrysler.

Three dyno runs were taken with cool down periods of several minutes between runs. A graph of the average dyno data is as follows (sorry for the huge picture but it is the only way the numbers are legible):



The average of the three runs showed a maximum wheel horsepower of 529 and maximum wheel torque of 505 ft lbs. Could someone please check my math (am I doing this right?): Using a correction factor of 12% this would yield 601 flywheel hp and 574 ft lbs of flywheel torque. Using a 15% correction factor would yield 622 flywheel horsepower and 594 ft lbs of torque. I am still not clear on which correction factor to use (Tom recommended 12-15% based on previous Vipers he has dynoed) but I am assuming that because the 12% correction factor got me closer to what Chrysler rates the engine (600-602 flywheel hp), that this is the more accurate correction factor.

For others that have dynoed their 2008s, does the graph look normal to you? Specifically, Tom was curious about the weird "double bump" in the torque curve. I mentioned that the 2008 Vipers had gone to a drive by wire throttle system and he wondered whether the programming in the drive by wire incorporated some form of torque management whereby torque was reduced at certain throttle positions to address potential traction issues.

At any rate, I will bring the car into my dealer for install of the Belanger system in the next few days, drive the car with the system for about 500-1,000 miles and take another dyno at Wong's and report the results back on this thread.

/Rich

[mjorgensen]

Here is what we did with the FRIST install, We had only 30 miles on the car when we did the swap so the computer had not "optimized" the tune for them yet.

Re: 1st 08' Belanger install!
Quote:
Originally Posted by mjorgensen
The gains were across the board with a 20ft/lbs gain starting at 2875rpm and peaking at 44 at 6200rpm! I will have Chris M. try and post some of the graphs for you tonight.

Sorry I am a little bit late!

Baseline Dyno



Belanger Dyno



Combination Graph

[PhoenixGTS]

Those before and after charts are for a complete system head-to-tips with cats?

[mjorgensen]

Yes this was with the FULL Belanger 08' system.

[rcl4668]

Mark --

Thanks for the replies. If I may ask, what dyno correction factor do you use on your Mustang Dyna? 12% 15%?

/Rich

[pteam]

Shouldnt you not even be doing a dyno test during break in period? Doesnt it say not to go over 5000 rpms until xxxx miles?

[mjorgensen]

The dyno we use is a 25% correction factor, the engineers say this is actually closer than the Dynojet inspired numbers but that is another debate I will not get into online. This is why or numbers at the wheels are always "low" compared to others.

As far as dynoing the car, the factory does it also for quality control. Most of the break in period is based on the gears and the transmission needs I believe. These motors are not built like they were back in the day of the rings and liners needing to be seated. Sure there is some of that but not like before. We are not banging through the gears either on the dyno. 1-4 pulls in 4th gear from 2500 - 6000 is not going to hurt anything and we have been doing this on new cars with mods for about 14 years.

[rcl4668]

Mark --

Now I am really confused. By my calculations, if I applied a 25% correction factor to my Mustang dyno numbers, I would get 529 rwhp x 100 / 75 = 705 flywheel hp which can't be right. Is your 25% correction factor unique to your Mustang dyno? Since my dyno guy could not give me a definitive correction factor, is there a way I can figure out what my flywheel hp is? Thanks for any insights you can provide.

/Rich

[mjorgensen]

Rich,

Any dyno can read ANY number based on the inputs of the operator. This is why I always have a hard time hearing these numbers thrown out there. We have always talked with Dodge about the dyno and the "way" they conduct the test. Our numbers at the wheels are always very close to what they are seeing and we have used the exact computations on every car we have done so the numbers stay consistent.

Now I will not profess to be a Dyno "expert" by any means, I am just regurgitating what I have learned over the years. When the Dynojet came to the market and gained popularity the numbers shown at the wheels were always much higher than other (load bearing) dynos. I feel this and cost are why they have been so widely accepted as fact. Since we have run our cars on both and the crank numbers are the same for the most part (on an Eddy current Dynojet) the only difference is how they calculate the rear wheel hp. We do not care about making a great number for us or our customer, just consistent repeatable ones that translate to the crank hp really measured.

We have done well over 100 S/C cars and can show all the dyno sheets and a variance of less than 35 hp on brand new and used cars with just a cat back added to the S/C. Most of these variations are because of the year the car was or how many miles are on them. Our numbers are "usually between 585-615 at the wheels on our dyno. We have seen 1 car hit 639 but I think he spiked the tank before he dropped it off ;-)

[adamlotus]

Originally Posted by pteam

Shouldnt you not even be doing a dyno test during break in period? Doesnt it say not to go over 5000 rpms until xxxx miles?

500 miles of easy driving should be enough of a break in imo

[pteam]

Well mjorgensen said they did dynos with only 30 miles on the car.

Also if what mjorgensen says is correct, would be be ok to redline during the break in period just as long as you **** slowly afterwards? Since that is the same thing done during a dyno.

[Larry Macedo]

There has been quite a bit of debate regarding break-in of engines over the years. 500 miles is more than adequate for the transmission, clutch and differential as well.

[pteam]

Originally Posted by Larry Macedo

There has been quite a bit of debate regarding break-in of engines over the years. 500 miles is more than adequate for the transmission, clutch and differential as well.

Ok let me post it again: Well mjorgensen (at woodhouse) said they did dynos with only 30 miles on cars. (probably thousands of other places too)

Yet I hear guys on this forum talk about oh so how important it is for a proper break in period for the first thousands of miles , blah blah.

[black mamba1]

"Our numbers are usually between 585-615 at the wheels on our dyno"

Is that for 08's or for your s/c Vipers of all gens?

[mjorgensen]

Originally Posted by black mamba1

"Our numbers are usually between 585-615 at the wheels on our dyno"

Is that for 08's or for your s/c Vipers of all gens?

Sorry I guess I should have clairified that. These are what we see on the S/C gen 3 cars.

[rcl4668]

Originally Posted by mjorgensen

Rich,

Any dyno can read ANY number based on the inputs of the operator. This is why I always have a hard time hearing these numbers thrown out there. We have always talked with Dodge about the dyno and the "way" they conduct the test. Our numbers at the wheels are always very close to what they are seeing and we have used the exact computations on every car we have done so the numbers stay consistent.

Now I will not profess to be a Dyno "expert" by any means, I am just regurgitating what I have learned over the years. When the Dynojet came to the market and gained popularity the numbers shown at the wheels were always much higher than other (load bearing) dynos. I feel this and cost are why they have been so widely accepted as fact. Since we have run our cars on both and the crank numbers are the same for the most part (on an Eddy current Dynojet) the only difference is how they calculate the rear wheel hp. We do not care about making a great number for us or our customer, just consistent repeatable ones that translate to the crank hp really measured.

We have done well over 100 S/C cars and can show all the dyno sheets and a variance of less than 35 hp on brand new and used cars with just a cat back added to the S/C. Most of these variations are because of the year the car was or how many miles are on them. Our numbers are "usually between 585-615 at the wheels on our dyno. We have seen 1 car hit 639 but I think he spiked the tank before he dropped it off ;-)

Thanks Mark --

The results on my 2008 (529 rwhp/505 rwtorque) were also from a Mustang (load bearing) dyno and am just trying to get an estimate of how much flywheel horspower is being generated. Just to add fuel to the fire, I spoke with my Viper tech at my dealership and he recommended multiplying by 1.255 which yields 664 flywheel hp and 633 ft lbs of torque. That seems awfuly high for a stock 2008 Viper.

Regarding the break in procedure, I actually drove the first 1,000 miles using the conservative "progressive" break in approach recommended by Herb Helbig:

BREAK-IN PROCEDURE (0-1,000 MILES)

WARM UP ENGINE FIRST

MAX SPEED 70 MPH (113 KPH)

AVOID EXTENDED ENGINE IDLING

NO FULL THROTTLE STARTS/ACCELERATIONS

VARY ENGINE RPM

CHECK ENGINE OIL EVERY FUEL FILL

FROM 0-200 MILES:

LIGHT THROTTLE RUN-UPS THROUGH GEARS: MAX SHIFT POINT 2,500 RPM

CHANGE ENGINE OIL AT 200 MILES

FROM 201-400 MILES:

LIGHT THROTTLE RUN-UPS THROUGH GEARS: MAX SHIFT POINT 3,500 RPM

FROM 401-600 MILES:

LIGHT THROTTLE RUN-UPS THROUGH GEARS: MAX SHIFT POINT 4,000 RPM

FROM 601-800 MILES:

LIGHT THROTTLE RUN-UPS THROUGH GEARS: MAX SHIFT POINT 4,500 RPM

FROM 801-1,000 MILES:

LIGHT THROTTLE RUN-UPS THROUGH GEARS: MAX SHIFT POINT 5,000 RPM

FROM 1,001-1,500 MILES

DRIVE CAR HARD WITH FULL THROTTLE ACCELERATIONS SHIFTING NEAR OR AT
REDLINE THROUGH ALL GEARS

During this last phase I really drove the car aggressively, taking 100-200 mile trips in fairly isolated road areas where I regularly drove the car to redline and with frequent full throttle acceleration. I basicalyl tried to simulate how the car would be driven on a dyno (drive the car in 1st gear for 7 full seconds going up the rev range, then the same in second, third and, where possible, fourth gear). Then follow with quick and hard bursts of full throttle etc. During these extended runs I would also turn the car on and off at least once to allow the ECU to learn and adapt to the new harder style of driving.

Once this break in process was completed, I did the baseline dyno run.

/Rich

[wallbanger]

i don't think i can limit max speed to 70mph for the first 1000miles

[mjorgensen]

Rich,

We also use the 1.25 for our Mustang dyno BUT the operator needs to set it up for this loss or you will read very high. I would no be surprised for your car to be +20 hp after your meticulous break in though 60+ is doubtful. Great numbers though either way.

[rcl4668]

Originally Posted by wallbanger

i don't think i can limit max speed to 70mph for the first 1000miles

Tell me about it. This break in procedure was like root canal but I got through it as quickly as I could (a lot of 3-5 am drives during the weekends).

/Rich

[rcl4668]

Originally Posted by mjorgensen

Rich,

We also use the 1.25 for our Mustang dyno BUT the operator needs to set it up for this loss or you will read very high. I would no be surprised for your car to be +20 hp after your meticulous break in though 60+ is doubtful. Great numbers though either way.

Thanks for the feedback Mark. Frankly, my main objectives in doing the dyno were to (1) check that the engine was operating within expected parameters and (2) get a baseline before installing any drivetrain/engine mods.

Regarding (1), regardless of which corrrection factor I use, it apppears that the engine is developing at least in the range of 601-622 flywheel hp and 574 to 594 ft lbs of flywheel torque which is consistent with dyno data from Chrysler, your data and the data from other 2008 owners who have posted baseline dyno data on this site.

Regarding (2), I guess the only important thing is to see if the Belanger system actually results in a net increase from my baseline. I will report on that later.

/Rich

[mjorgensen]

Rich,

It will really wake her up! you will see an immediate 55-60hp with more to come after a couple hundred more miles.

[rcl4668]

Originally Posted by mjorgensen

Rich,

It will really wake her up! you will see an immediate 55-60hp with more to come after a couple hundred more miles.

Mark --

I would love to see those gains. My plan again is to actually drive the car 500-1,000 miles after the Belanger install to get an accurate measurement of the full potential of the system. I trust that will be enough miles to do the trick.

/Rich

[mjorgensen]

500 miles will be more than enough and I'm sure you will see the gains.

[black mamba1]

I had to do a break in after Chuck built my new engine...talk about FRUSTRATION!! I could not go past 70 mph at first, and Vettes would pull up besides me..and I couldnt do squat!

I would rather have an enema using octane boost w/ crushed glass in it than go thru that again!

[rcl4668]

Originally Posted by black mamba1

I had to do a break in after Chuck built my new engine...talk about FRUSTRATION!! I could not go past 70 mph at first, and Vettes would pull up besides me..and I couldnt do squat!

I would rather have an enema using octane boost w/ crushed glass in it than go thru that again!

Thanks for that visual.

/Rich

[rcl4668]

Just as an FYI, posted some video of 2 of the 3 baseline dyno runs on my car on youtube:

YouTube - 2008 Dodge Viper (Stock) Mustang Dyno Baseline Runs

/Rich

[rcl4668]

Just an FYI for others doing or considering the Belangers for the 2008 Viper: My tech recommended the installation of "Snake Sock" insulation to protect the {ignition?) wires underhood. These "socks" are available from PartsRack. It was also determined that additional heat shielding was not only unnecessary but could be counterproductive.

/Rich

[Richie7]

How much louder is your car with the new exhaust compared to stock?

[rcl4668]

Originally Posted by Richie7

How much louder is your car with the new exhaust compared to stock?

Richie --

Here you go; these are sound clips before and after the Belanger installation:

YouTube - 2008 Viper Stock Exhaust Sound Part 2

YouTube - 2008 Viper with Belanger Headers and Exhaust (External)

/Rich

[Richie7]

Thanks your exhaust sounds great, real mean sounding! Its tough to tell just how much louder it is from the video. I would be hesitant to change out my stock exhaust if it is much louder, because I don't want every cop in a 5 mile radius to hear it.