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Project Viper GTS Part 4 Intro Dyno

Project Viper GTS: Part 4 – Baseline Dyno and K&N Intake Test

by Billy Johnson

The Viper is truly a car built around its engine.  In Part 4, we take Project Viper GTS to the dyno for a baseline power audit and see if our mighty 8.0L V10 is cranking out the factory claimed 450hp and 490lb-ft of torque.  From there we add K&N replacement air filters and change out the disruptive corrugated plastic intake tubing for a set of ROE Racing polished aluminum smooth intake tubes to see if we can squeeze out a few more ponies.

This test is a little out of sequence since we went to the dyno prior to the Baseline Track Test in Part 3 but after we went through a few Maintenance items in Part 2 to get the ignition system and a few fluids up to snuff.

For the dyno work, we took Project Viper to our friends at Power by the Hour Performance in Boyton Beach, Florida.  With a team consisting of Factory Ford certified technicians, fabricators, and tuners, PBTH is known for modifying Mustangs with everything from bolt-on supercharger kits to in-house developed turbo systems, suspension, brakes, fabrication, and dyno tuning.  In addition to being a great bunch of talented guys, they also have the same 2,000-hp capable Dynojet 224xLC that we used on Project NSX, Project E36 M3 (silver), and Project E90 M3.  This consistent dyno allows us to (relatively) accurately compare and overlay various project cars, which we will do later.

Our pristine 1997 Viper GTS has less than 8,000 miles on the clock and is completely stock other than the addition of High Performance AB “Quality” (Spark Plug) Wires, Gen-3 sized 18x10 and 19x13 Forgeline ZX3P wheels with Michelin Pilot Sport PS2 “C1” 275/35-18 and 345/30-19 tires, and a rear muffler delete. 

 

Viper GTS Dyno Rear Tire CloseThese massive 345/30-19 rear tires have a 27.15” overall diameter, which is 1.24” and 0.92” larger than the factory (99-02) 335/30-18 tire and the original 335/35-17 tire respectively.  The larger diameter changes our effective final drive ratio from 3.07 to 2.97 which increases our top speed in each gear, but hurts our acceleration by reducing the torque that is transmitted to the ground.  It also puts us at 59mph in 1st gear at redline, just shy of eliminating the shift to 2nd gear which would have greatly improved our 0-60 acceleration time.
Viper GTS Exhaust Straight PipeThe stock Gen-2 Viper exhaust consists of 2.5” pipes with one catalytic converter and one resonator in each side sill, as well as a muffler at the rear of the car.  The previous owner retained the stock cats and resonators but replaced the rear muffler with 3” straight pipes; a common modification that makes the car a little louder and more aggressive sounding.
Viper GTS Running on DynoWith our car strapped to the rollers, we were ready to put down a baseline number.  Only the bottom fan was used during all of the runs to blow air in to the radiator.
Viper GTS 1997 Stock Dyno Chart BaselineAt 431.15hp and 468.02lb-ft of torque at the tires, we were surprised that our relatively stock 1997 Viper GTS produced numbers close to the factory rating at the crank!  Before jumping to the conclusion that this is an optimistic dyno; bone stock 5.0L Coyote Mustang GTs consistently put down similar numbers on this dyno as they do on Roush Yates’ own Dynojet 224xLC that we used on Project E90 M3

While we have upgraded to high performance plug wires and removing the factory rear mufflers likely contributed to some power increase, our large rear wheels changed our effective gear ratio from 3.07 to 2.97 and lowered the peak thrust in 4th gear (1:1 ratio) from 1,246.24lbs of thrust to 1,205.65lbs, which may have lowered the power reading compared to if we used the smaller factory 17” wheels.

Having compiled over 100 dyno charts of Gen 1-5 Vipers, our car’s 431.15whp and 468.02lb-ft torque is one of the highest of any stock Gen 2 Vipers that we’ve seen, since they typically put down between 415-425whp on a Dynojet.  Some cars dyno between 395-405whp, on lower reading dynos like Dyno Dynamics, which lines up perfectly with the car’s 450bhp factory rating and a commonly accepted 13% drivetrain loss.  Due to the overwhelming amount of cars that make more than that, it’s likely that the Gen 2 Viper was under-rated from the factory and should be rated at 477hp (415whp/0.87).  This drivetrain loss would put our relatively stock car at an impressive 496hp at the crank! 

It’s somewhat of a hot topic for Gen-2 Viper owners, but the overwhelming belief that 1996-1999 motors make slightly more power than the 2000-2002 “creampuff” motors may be valid.   With a 13 car sample size of bone stock Vipers or those only with intake work, 96-99 cars average 430whp while 00-02 cars average 411whp.  Although there are a ton of variables from weather conditions and the dyno used, according to the data there is a noticeable trend of 96-99 cars being stronger

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Comments
Dusty Duster
Dusty Dusterlink
Tuesday, May 12, 2015 5:06 AM
Those are some impressive gains from a drop-in filter and some mandrel-bent tubing!
Protodad
Protodadlink
Tuesday, May 12, 2015 11:29 AM
Having no experience with them, how does a water to air IC work on a street car? I guess I really mean how often do you have to refill it?
Benjamin
Benjaminlink
Tuesday, May 12, 2015 12:00 PM
I went to this shop last year, the boss was very nice and did his best to understand my awfull french accent !

Nice horsepower to price ratio with these mods !

Pilun
Pilunlink
Tuesday, May 12, 2015 3:24 PM
Those Roe Racing smooth tubes look like they are just Spectre Performance modular intake pieces, same stuff you can buy at Pep Boys.
BillyJ
BillyJlink
Tuesday, May 12, 2015 3:29 PM
It does not look like it from the pictures, but the ROE tubes are not symmetrical. One end is longer than the other in order to have the proper angle to the factory airbox.
Mike Kojima
Mike Kojimalink
Tuesday, May 12, 2015 5:49 PM
The 120 degree lobe separation angle is probably more responsible for the smoother idle than the lifters redesign.
spdracerut
spdracerutlink
Tuesday, May 12, 2015 7:14 PM
What the heck was Dodge thinking with the stock air filter?!
Van_1986
Van_1986link
Wednesday, May 13, 2015 11:47 AM
Those dual stage foam/paper filters are really good for filtration. We used to use them on our motorcycles in the desert. If you just used a K&N your intake tubes would be all full of dirt.
Bradl3y76
Bradl3y76link
Wednesday, May 13, 2015 10:14 PM
Gorgeous car, but with the K&N, that's not the way I'd like to make power. I feel it's the same logic as running a thinner oil. Yeah, you can get away with it, and if the podiums justify sponsorship dollars, awesome; but on a personal car, no way.
spdracerut
spdracerutlink
Thursday, May 14, 2015 7:20 AM
Van, I agree the dual stage is very good at filtering, but I've never seen a dual stage on a street car before. For an off-road vehicle, it makes perfect sense. For a street car though? Unless Dodge expected their owners to frequently go off-track...

I personally used a K&N on my old Nissan for 130k miles, used in Texas and Florida. I understood their was less filtration, but for the driving environments I was in, I didn't feel I was making a compromise as neither place was particularly dusty/dirty. If I lived in AZ where sand and dust storms are common, I would not.
Pablo Mazlumian
Pablo Mazlumianlink
Sunday, May 17, 2015 8:23 AM
How does that saying go? "there's no replacement..."
I can't wait to see what a good full exhaust system does for this car. I'm a big fan of turbos, but the thought of also getting close to 500whp NA, yet with still a stock-like feel to the engine, sounds like heaven.
Only reason I don't like this article is I'm now off to peak at autotrader prices for early gen Vipers with a full family and an empty bank account.
I, too, have run K&N and K&N-like filters on cars since 1991 with no problems, and many of which had their motors opened up. Nothing every looked crazy in there (cylinder walls, etc, and my MAFs never took a dump due to excessive oil or anything at the filter). Just my experience. Probably helps to keep the engine bays clean as well.
Ole-M
Ole-Mlink
Sunday, May 17, 2015 9:56 PM
@protodad
I had no issues with water to air.
I tried it to prove a point, stuffed a small 250 hp 4 AG setup on a SR20 putting down 400whp.
however, 70C on the track after using two tanks of fuel, but still made 370 whp then! on the onsite dyno.
on the streets it had consistently temps at 30C which was just a tad warmer than ambient and actually was lower than air to air. (had a fan on the tiny radiator for the setup)
Gone to ac condenser and now for a properly sized air to water IC and does seem to work really well.
yet to test in 30C and on track, but they give response, easy to install, and really isn't complex like people complain about.
Can be hilariously compact too.
Anonymous User
Anonymous Userlink
Monday, April 11, 2016 11:10 PM
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