Dyno Pull for the 2002 GTS

[Luisv]

Went to an event held at a local shop here in South Florida. it was called "Cars, Coffee and Octane". basically a morning get together for car nuts. This time it was held at a shop that was simply amazing! Basically and old warehouse/barn that had been converted. Raised wood floors a ton of vintage parts, books, manuals and decorations make this a great looking place. The folks were awesome and wonderful hosts. they are working on some amazing cars including a Jag, a late 60's Shelby 500KR, a B Body Chrysler (i'm guessing a GTX)' a 65 GTO, and others.

The event was small but really nice. The event was to benefit a local university's SAE Formula Race team. It is a group of engineering students that build a race car and compete in an international competition.

For me it was a treat when the shop asked if they could throw my car up on the dyno. They wanted "cool cars" up there.They asked me before I even parked. I have been wanting to do it to get a baseline, so I took them up on the offer. They threw me up there and it instantly drew a quick crowd. One of my fellow club members (local club I am a member of that went up together with me) that went up with the group shot a simple video of the pull. I'll post it when they share it on YouTube....

So here is the result. It was just one pull and was done after the car cooled a bit after the 45 min drive to the shop.

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So the numbers at the wheels:

417 HP
453 ft/lbs of Torque

Pretty cool as all I have done was the delete of the rear muffler and the change of smooth tubes for the intake. Other than that, she's bone stock. I don't know what the driveline loss is on the Viper. However, I think I am safe assuming 15% so we'll go with that. If I am wrong, Please let me know what the loss should be.

So using 15% loss to the transmission and rear end, that would be about 490 HP at the flywheel. Assuming the same 15% for torque we would be at 532 ft/lbs at the flywheel. I'm smiling! Looks like I have a Wednesday car!

 

[FastMatt]

good numbers for a realy stock car. My 2001 GTS only put 399 to the wheels stock.

 

[Roysviper]

My 1st Viper was a 1997 GTS, Bone stock........participated in The Power Tour in Panama City around 2000, and they put it on theDYNO.... DYNOED 423 rwhp and 469 rwtq...I thought that was good for bone stock and did not know what the norm was for the Gen 2..... raced it more then any Viper I have ever owned .....It ran 7.80s 1/8th mi, 12.20 1/4 mi with the factory tires....my 60, were 1.90s........and I owned it 7 yrs, put 60,000 mi on it, never changed the plugs, just the oil every 3000 mi, and when I sold it was looking like new still and excellent mechanical condition....NEVER broke down ever, only had to replace battery one time and I thought that was killer to own a factory car as it came from Dodge and be sooo reliable and race it hard at the track and baby it on the street and get 21 mpg hwy and 17 in town....That proved to me OUR VIPERS were made and built to perform and still be very reliable....That made a true VIPER holic for me, ha.......just one of my good Viper experiences of MANY....

good numbers for a realy stock car. My 2001 GTS only put 399 to the wheels stock.

 

[Next Phase]

Nice baseline numbers... mine put down 424 rwhp / 456 rwtq bone stock w/ smooth tubes. With headers, high flows and exhaust it put down 435 rwhp / 480 rwtq.

 

[slitherv10]

was that with a tune? Nextphase?

 

[EllowViper]

I was in the Formula SAE program in the early '80s when it first came out. Lots of fun. we participated in the high MPG competition. Took third with around 1400 MPG on our test mule.

 

[plumcrazy]

power is right in line wth your mods. now go add to the power

 

[Luisv]

power is right in line wth your mods. now go add to the power

OK... So I do have some future plans... But I have a '77 Vette Resto-Mod I have to finish....

Having said that I do plan on doing some things as I go.... ;-)

First thing is a custom tune. What I don't know is how these cars react to that. In other words will i see a benefit to a custome tune through an SCT custom tune? i'd be happy with even a 5% boost in power and anything on the fuel economy. Next step would be an upgrade to roller rockers. From there.... We'll see.... Considering I threw a supercharger in my 2010 SRT8 Charger at 4,000 miles.... I won't wait long.... I might not be that quick on the Viper though.... We'll see... Lol

 

[denniskgb]

Sct would make a difference for sure. I had mine done by Shawn at roe racing before the headers and dyno tune and I definitely noticed crisper acceleration and overall better performance.

 

[Next Phase]

No tune on my car...

Couple of guys had their cars dyno'd w/ a "canned" Roe tune and barely made any additional peak numbers (more power under the curve)

 

[Luisv]

Sct would make a difference for sure. I had mine done by Shawn at roe racing before the headers and dyno tune and I definitely noticed crisper acceleration and overall better performance.

Was your tune done on the Dyno? Data logging emailed? In other words, is it canned or custom?

No tune on my car...

Couple of guys had their cars dyno'd w/ a "canned" Roe tune and barely made any additional peak numbers (more power under the curve)

Nothing wrong with canned tunes. Some minor tweaks on a factory tune that are "knows" can go a long way. A custom tune, agreed, would be specific to my engine so I could see more gains in mileage and power. Even just "smoothing" the torque line would be awesome.

 

[plumcrazy]

dont waste money on canned tunes, do it right, get on a dyno and let the tuner do his job right

 

[SoCal Rebell]

Nice baseline numbers... mine put down 424 rwhp / 456 rwtq bone stock w/ smooth tubes. With headers, high flows and exhaust it put down 435 rwhp / 480 rwtq.

Pretty much the same #s I got on my 2000, smoothies, headers, hi-flows and catback I put down 434.4 RWHP & 474.4 RWTQ, on a Dynojet 248C SAE corrected, also had 3.55s & an aluminum flywheel, I don't know if those affect the #s.

.

 

[Luisv]

The flywheel will allow you to spin up faster but under load on the Dyno, it will not transmit more torque. The 3.55's however will. These produce more torque. Similar to the gains you'll get with smaller tire diameters. Smaller tire diameters gives you faster acceleration.

 

[Dom426h]

Stock Gen2's put down a about 400hp dynojet SAE. Forget about the % drivetrain loss... 450hp flywheel - 400 = 50hp flat drivetrain loss for a stock to bolt-on car. Ive heard people claim 60hp loss but the math dosnt add up to me. (unless dodge under-rated our motor by 10hp... )

My 1997 GTS put down 460hp 498tq with every bolt-on but RR's and i have seen others like frog do the same. Its nice that a bolt-on gen 2 is capable of producing similar power to a stock Gen3.

Dont expect much from a tune. 15tq on the bottom end and maybe a few peak #'s. Nothing compared to the power unleashed by letting the beast breath with headers, hiflow or no cat's, and a full 3" freeflowing exhaust.

 

[Indy]

Which years generally put down higher numbers? 708 cam or cream puffs? Seems like most Gen2s are slightly under rated in hp and torque.

 

[Dom426h]

The flywheel will allow you to spin up faster but under load on the Dyno, it will not transmit more torque. The 3.55's however will. These produce more torque. Similar to the gains you'll get with smaller tire diameters. Smaller tire diameters gives you faster acceleration.

Luisv, give the following info from hotrod mag a read. It dosnt agree with your statement.

Will different final drive ratios affect the dyno readings?

This one's tricky. First, there are potential discrepancies because different gears have different inertia values, generate more friction, and change the amount of tire slip. Higher numerical gears tend to be more inefficient, so as gear ratios increase numerically, power levels tend to slightly drop, particularly on an inertia dyno. When torque is multiplied by steeper gears, tire slippage also tends to increase.

However, there's another, often overlooked, factor in the brew: rpm and torque are inversely related to calculating horsepower, so changing the rear axle ratio or testing in other than a 1:1 transmission gear seemingly shouldn't change the horsepower numbers. But this doesn't take into consideration the fact that changing gear ratios changes the engine's rate of acceleration. For example: We know that on an engine dyno, if you change a sweep test's acceleration rate from, say, 300 rpm/second to 600 rpm/second, the flywheel power number (bhp) drops due to the faster rate of acceleration. As an engine accelerates at a higher rate, the power required to accelerate the engine increases, and a greater portion is consumed before it gets to the flywheel. Going to numerically higher gear ratios-whether in the trans (testing in a lower gear) or in the rearend-is like increasing the rate of acceleration in a sweep test. Whether this actually changes a given chassis dyno's reported results depends on how the specific dyno manufacturer does its math. For the most consistent results, always test in the same trans gear (generally 1:1) and rebaseline the vehicle after a rear-axle ratio change.
http://www.hotrod.com/techfaq/hrdp_0405_chassis_dyno_guide/viewall.html

Also, read this one:
http://www.dreamscience-dynos.co.uk...ential-gear-change-say-a-342-to-410-gear.html

 

[denniskgb]

Was your tune done on the Dyno? Data logging emailed? In other words, is it canned or custom?



Nothing wrong with canned tunes. Some minor tweaks on a factory tune that are "knows" can go a long way. A custom tune, agreed, would be specific to my engine so I could see more gains in mileage and power. Even just "smoothing" the torque line would be awesome.

I had it downloaded before we did headers and car went on a dyno to be dialed in. But again felt a lot more response even before all that.

 

[Luisv]

Luisv, give the following info from hotrod mag a read. It dosnt agree with your statement.

Will different final drive ratios affect the dyno readings?

This one's tricky. First, there are potential discrepancies because different gears have different inertia values, generate more friction, and change the amount of tire slip. Higher numerical gears tend to be more inefficient, so as gear ratios increase numerically, power levels tend to slightly drop, particularly on an inertia dyno. When torque is multiplied by steeper gears, tire slippage also tends to increase.

However, there's another, often overlooked, factor in the brew: rpm and torque are inversely related to calculating horsepower, so changing the rear axle ratio or testing in other than a 1:1 transmission gear seemingly shouldn't change the horsepower numbers. But this doesn't take into consideration the fact that changing gear ratios changes the engine's rate of acceleration. For example: We know that on an engine dyno, if you change a sweep test's acceleration rate from, say, 300 rpm/second to 600 rpm/second, the flywheel power number (bhp) drops due to the faster rate of acceleration. As an engine accelerates at a higher rate, the power required to accelerate the engine increases, and a greater portion is consumed before it gets to the flywheel. Going to numerically higher gear ratios-whether in the trans (testing in a lower gear) or in the rearend-is like increasing the rate of acceleration in a sweep test. Whether this actually changes a given chassis dyno's reported results depends on how the specific dyno manufacturer does its math. For the most consistent results, always test in the same trans gear (generally 1:1) and rebaseline the vehicle after a rear-axle ratio change.
http://www.hotrod.com/techfaq/hrdp_0405_chassis_dyno_guide/viewall.html

Also, read this one:
http://www.dreamscience-dynos.co.uk...ential-gear-change-say-a-342-to-410-gear.html

I think it does agree with what I said, the second link is more clear though...

Remember... I mentioned torque delivered to the tires. Not Horsepower.... Torque is a rotational force. Horsepower is a measure of work capability. How much "work" the engine can do. The Torque is effected by the driveline. Cars do not accelerate as hard in second gear as they do in first... right? The transmission/driveline multiplies torque coming from the engine. The gear ratio, including the final drive gear (rear end) effect this factor. So as mentioned in the bullets of the second link you gave me... The taller gear will give you a higher peak force to the ground and a higher average force to the ground. Torque is rotational force. You will get lower peak power (horsepower) and lower top speed. Bottom line, more torque to the ground which translates to better acceleration.

Hence the comment of the tire diameter doing something similar to running a taller gear. For example, on my SRT8 Charger that I take to the track from time to time runs about 5 hundredths to a tenth faster 60 foot times with 17 inch rims (overall tire diameter is smaller) than it does with 20 inch rims. Both were drag radials.