Latest dyno results for '01 RT/10

treynor

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Latest dyno results for \'01 RT/10

Stock: 408 HP, 442 ft/lbs
add K&Ns and tubes: 415 HP, 448 ft/lbs
add Belanger headers & catback, stock cats: 431 HP, 475 ft/lbs

I'll admit to being disappointed at the HP figure with the exhaust -- I had been expecting 445 - 455 HP, and the gain of only 16HP was surprising. I'm not yet sure why the HP gain was so small; my A/F meter showed the car running a slightly richer mixture on the dyno than I had seen in normal driving, although I do not know why. Theories / comments / questions welcome.
At any rate, for practical purposes midrange torque counts for far more than peak HP, and here the exhaust system does well, picking up 27 ft/lbs at 4200 RPM.

Here's a link to my current Viper modification webpage, and I've included the combined dyno charts below:

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jp

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Re: Latest dyno results for \'01 RT/10

For how long did you run the car before performing the test after installing the Headers?
When I installed my Belangers, was the instant feeling of performance gain not as clear as it was after a cople of hundred miles.
btw I run it without cats and "almost" 3" straight through.
 
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Re: Latest dyno results for \'01 RT/10

I had driven around with the exhaust for 500 miles before the dyno runs I just posted. Immediately after installing the exhaust, the car made 420 HP and 461 ft/lbs; the other 11 HP and 14 ft/lbs came after the ECU "learned" new fuel & timing curves.

The other data point I have was from a '97 GTS with Belanger headers and Borla exhaust -- that car made 443 HP with stock cats and 456 with no cats, and his car made 404 HP when it had stock exhaust + intake mods. Thus, my car seems to be down 12 HP from his results.

The one other variable which I can fairly easily modify is catalytic converters. I'm going to try installing high-flow cats when I get the NOS system put in next month, and we'll see how much HP that frees up...
 

Sean Roe

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Re: Latest dyno results for \'01 RT/10

Hi Ben,
You bring up a good point about the cats. I know of a few instances where the catalytic converters were unusually restrictive on some showroom stock cars in SCCA Club racing. In one instance, the two cars were equally prepared, but one was always faster on the straights than the other (both Vipers with stock cats). It is worth looking into.
 
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Re: Latest dyno results for \'01 RT/10

16 horsepower???? Don't they guaranted like 50 or your money back? I know there might be variables between the sessions, but not nearly that big. I bolted on a set of Hennessey headers to my '01 ACR and there was a VERY noticable difference. I'll take it back to the dyno soon enough and let you know, but I can guarantee it picked up way more than 16 horsepower.
 

FikseGTS

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Re: Latest dyno results for \'01 RT/10

sounds like your missing at least 25HP for sure...

my 1996 GTS has similar mods, k&n's, smooth tubes, edelbrock headers, and catback borla exhaust.....

and I got:

STD: 464 rwhp, 514 torque
SAE: 453 rwhp, 501 torque

I think the guaranteed 50 rwhp is without the cats.... but still, you won't pick up 34 HP to make that claim by dumping your cats....

maybe the dyno your using is measuring low?

my dyno graphs are at:

http://viper.miamisci.org


Brooks
 

Tom Welch

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Re: Latest dyno results for \'01 RT/10

Gentlemen,

Mr Treynor has had an increase of 23 rwhp from his stock dyno run of 408. The average increase from a complete Belangers exhaust system is 60rwhp.(without cats). His numbers are LOW, no doubt, and his cats could very well be the reason. Not only are they restrictive, they also can inhibit the cars computer from giving the proper amount of timing and fuel which results in a mismatch in his combination. Also his car is an 01' model year of which not many have had upgrades tested on them. Everyone knows that these cars seem to have minor changes from year to year. I have faith in the exhaust system and believe that should he elect to test it without cats a considerable difference will be noted. It goes back to the basic phrase that I like to use "A restriction in the exhaust system of the viper is like Arnold Schwarzenegger trying to fight while breathing through a soda straw". The system is only as good as its smallest part.

As for the dyno facility, no doubt again that going to 10 different dyno shops will probably result in 10 different readings. Mr. Treynor has used the same dyno shop all along which is a good thing as he has a solid baseline and his stock numbers seem to be within the norm for a gen 2 viper(stock)

Should his car not show an increase of 50 rwhp (without cats) then Mr. Treynor can elect to excersize our performance guarantee(he will be the first of over 200 sets of exhaust that are in service). Should your car not show the increase that you are looking for, what guarantee do you have?(no flame intended). Also, we are not in the business of destroying the environment and do not encourage removal of the cats. It is the decision of the consumer and his local laws. We provide all necessary hardware for the installation of factory cats with every system that we ship out. Our performance numbers though are based upon the testing that we conducted on several cars, all of which had the cats removed for maximum performance. The market for catalytic convertors seems to be moving forward very rapidly and there are a few good cats available that have shown very little hp loss over no cats. We will be testing a 3" convertor soon.

Thanks again for everyone's input.

Tom
 
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treynor

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Re: Latest dyno results for \'01 RT/10

Woah here -- let me clear something up. I do *NOT* think the problem has to do with the exhaust system or headers. I know several others who have bolted on the same system and seen much larger performance improvements. I personally inspected the system Tom shipped me, and it looked first-rate and had no visible flow restrictions, which pretty much rules out the possibility of a defective system.

Now -- the Viper engine is a system, and any system is only as strong as its weakest link. From inspection of the dyno charts, my power curve is similar to others below 4,000 RPM, but down about 10HP from cars with no cats. So far so good. However, above 4,200 my power curve levels off and torque begins to drop, while Tom's other results don't peak until 4,400 and then hold a sizeable advantage until redline. This looks like either a flow restriction or a mixture problem to me. I have several theories about why this may be the case: unusually restrictive cats, suboptimal intake or heads (luck of the draw), unusually fussy '01 ECU (as I said, mixture was leaner in driving than on the dyno). I would be VERY interested to see anyone else's '00+ model before & after dyno figures, including correction factor for each dyno run.

An interesting factor to consider is the dyno correction factor (cf). While we assume that cf is valid because it compensates for air density available to the car, this assumption is only valid if the car's ECU is environment-insensitive. If my Viper ECU is responding to denser air by overly richening the mixture, the dyno's cf will understate horsepower. An example: on BTR Viper there is a dyno run with a car using the Belanger headers & exhaust and no cats to make 460 HP / 499 ft/lbs of torque. However, the cf on that run is 1.03, while my runs have a cf of .97. This which means my uncorrected HP/Tq were 445 / 490, while the BTR website car is making an uncorrected 446 / 484. I'd love to see CFs posted along with dyno charts.

In conclusion, I don't currently believe that the 'missing' HP from my car have anything to do with the exhaust system itself. I'd like to see other dyno figures, especially from '00-'01s with the new pistons, cam & ecu. I will be installing high-flow cats in mid-March and re-dynoing at that point, and I'll certainly post results as soon as they're available. Finally, I should note that I have full confidence in Tom's products, so much so that I'll be installing his NOS/Propane system next month.
 

LTHL VPR

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Re: Latest dyno results for \'01 RT/10

Ben-
You brought up good points. To correct, Tom though, your car did only make 16hp with the headers and exhaust, not 23. Your car made 23 with the filters and tubes, and I think the guarantee is for 50hp with exhaust only (w/ no cats).

My 98 GTS made 404 hp with filters and tubes, and then made 443 hp immediately after installing Borlas with the Belangers and cats; an increase of 39hp, or 23hp more than you made. Once the cats were removed, I saw another 7-12 hp throughout the rpm range with a peak of 454 hp.

Also keep in mind your car has about 500 more miles than when you tested it last, and the engine is continuing to break in. Some of the hp increase you see is no doubt from this. Between 900 miles and 1700 miles my car picked up another 6hp and 5 ft. lbs.

The problem with removing the cats on a 2001 (other than emissions) is that your Service Engine light will come on and stay on all the time (annoying). This even happened on my 98 after longer trips (>50 miles). On 99+, the computer will set it off immediately and it will stay on. I don't know if anyone has found a a way to trick the rear O2 to keep the light off. I would assume you could see another 4-6hp will hi-flow cats. Make sure you purchase cats with a long warranty, as many "hi-flow" cats are prone to failure/breakdown after low miles....
Good Luck!
 

Sean Roe

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Re: Latest dyno results for \'01 RT/10

High Flow cats:

Our high flow cats carry a 5 year 50,000 mile warranty. As long as you don't send them back damaged from a crash, the manufacturer and Roe Racing will replace them. We have them in 2.5 and 3 inch inlet / outlets and they have half the restriction of stock while meeting emissions. No check engine lights on the '01's so far with the 4 inch round bullet cats. No power loss compared to straight pipes with no cats. Cooler side sills too.
2.5 inch bullet cats: $99.95 each
Larger 2.5 and 3" cats: $124.95 each
How's that compare to others?
You think they might be marking there's up too much?
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pauls

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Re: Latest dyno results for \'01 RT/10

Dyno's are great for braggin, but take it to the track for real world results. My numbers on the dyno are pathetic, 421HP and 453 torque. But it is a half second faster than cars with 50 more dyno HP.
 
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Re: Latest dyno results for \'01 RT/10

This is true -- at the end of the day, I care about how fast the car is on the road, not how much I can make it read on the dyno. I'll have track figures when I head up to Sears Point on 3/21...
 
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