Your HP after exhaust mods

[NCVCA]

I'd like to make a spreadsheet that can be used for comparisons for aftermarket exhaust upgrades.

If you have before and after dyno numbers (corrected preferably, with smoothing set to 3 preferably) please post here or email me in the following format:

Model Year Exhaust Mods before hp/tq After hp/tq other mods
GTS 2000 Snake Oyl rear sub 444/444 444/444 K&N's

"Other Mods" are important for comparison. If your dyno numbers can't be isolated to exhaust ONLY please do not post. We need before and after exhaust only mods. Non drivetrain mods aren't needed (IE MGW gas cap). Be sure to include what type of CAT if changed or removed.

Thanks. I'll post the results in order of best increase down by GEN. Should be interesting.

 

[ElDiablo Viper]

2002 GTS 1500 Miles, Corsa, K&N 430RWHP, 467RWTQ

 

[Tom Welch]

1997 GTS

Bone Stock: 405 rwhp

Headers/Exhaust/NO Cats: 461 RWHP

Tom

 

[jimandela]

random tech substrate cats, B&B catback
not yet dyno'd SOTP dyno..much better throttle response
will try and dyno this summer.

 

[Fast Freddy]

i picked up 31 rwhp and 43 rwtq after my exhaust mods. check out my sig below 4 more info.

 

[NCVCA]

THANKS!

Remember before AND after is most helpful.

 

[GTS Bruce]

Lets get together and go to Kennedy's dyno. Bruce

 

[SoCal Rebell]

2000 RT/10 with 3.54 gears, on the same dyno 3 days apart, SAE corrected #s are:

400.3 RWHP 432.3 RWTQ

With Bellanger headers, Randomtech hi-flow cats & Bellanger 3" catbacks:

431.4 RWHP 472.4 RWTQ

 

[Jerry Dobson]

Ron,

Good post. We want to time factor as you state 3 days.

If you Dyno one summer, wait a year and put the exhaust on and dyno again. The mileage increase alone will help some.

You also have a 354 so your effective pwr is right where it should be factoring in about a 2% loss.

 

[Viper Specialty]

BRUCE and JIM- I am in on the Dyno, let me know!

 

[GTSACR2002]

2002 GTS ACR Stock = 422.8RWHP
2002 GTS ACR with Corsa Catback added = 441.5RWHP
ACR comes stock with smooth tubes and K&N suppose to be 10hp for those items.

 

[J DAWG]

No dyno here in MS, but my muffler delete and Roe cats gave me over 2 tenths at the strip. Numbers are great to look a, but I need real proof.

 

[Nexus-6]

No dyno here in MS, but my muffler delete and Roe cats gave me over 2 tenths at the strip. Numbers are great to look a, but I need real proof.

Agreed.

I used to chase dyno #s like mad but I rely on actual track times to gauge my real gains these days. It's all that matters...after all, gaining 20rwhp should get you down the track faster, right? Doesn't always work out that way.

 

[FE 065]

Interesting. Back in 1996 or so adding a homemade forward mounted H pipe on my'94 Viper (which already had no cats and straight through aftermarket mufflers) dropped my ET from high 12.30s to 12.16 backed up by a 12.12 in back to back before and after runs (I installed the H pipe at the strip). According to ET to HP calculators I've found on the internet, I gained over 20hp by adding this H pipe made from about $50 worth of tubing! Makes one wonder what's really going on in the exhaust department...Does the exhaust need to actually exit the car more easily via headers and larger diameter pipes etc, or just kind of need 'somewhere to go' momentarily, like my H pipe gave it? ..I remember, a few years ago some big roadrace bikes, like out of Pops Yoshimura's shop were running little canisters on each pipe about 10" from the head.. they were supposed to give quite an increase in mid-range hp, and the rpm point where the gain came could be altered, depending just how far from the head you mounted them. Like some sort of 'overflow'for the exhaust I guess, no? I still have a second H pipe kit I made for my'96GTS, and can adapt it to my new 2002FE. 'IF' I get a similar gain on the '02 as I did on my '94 ..could adding something simple like less retrictive cats and a Snake Oyl type rear muffler delete system add up to an even better horsepower gain?? It would seem so. Maybe very close to what some of these $4000 systems are giving people. It could be argued getting the same gains I had on the '94 to the 2002GTS could be a bit of 'apples and oranges' at this point, but I think there's every reason to believe it'll produce similar results. I've seen countless cases in the magazines where big block cars pick up 25hp or more with a pipe intalled.

 

[99 R/T 10]

Hey ViperGTS2002FE,
I would like to see how you adapted the H pipe and where you placed it in the exhaust system. Do you have any pictures or diagrams?

Mike

 

[XS TORQ]

I would like to see the H pipe setup also! How low did it hang, etc.

 

[Newport Viper]

Finally a good (cheap) Gen 1 mod. Please show us how to do it! I will get before and after results!

 

[FUSCUCLA1]

Im willing to try this as well. Please give details.

 

[FE 065]

Here's the URL: http://community.webtv.net/surfinusa/Hpipeinstallation I took these pictures after I built the second system for the '96GTS. Never did take that car to the strip though. The H pipe does cut ground clearance by 2.5" mind you (If you use 2.5" pipe as I did). The H part of it meeets right tight in front of the trans skid plate. Below the trans..I had it meet there instead of under the oil pan-just in case the lesser ground clearance had the pipe bumping into something on the road. If I welded tabs onto the outside of the pipes just before they turn to meet each other,the tabs would bump against the frame and not allow the pipe to rise up much if at all should the pipe hit something. JonB says the 2003 Vipers have a balance tube in the system somewhere... Note, I did try running the '94 that day with the flanged T sections open - like an exhaust 'dump' or cut out as we used to call it, and the car's ET didn't change at all, still high 12.30s Then I went back to the pits, bolted up the big H section and ran the 12.16, and 12.12. I was running BFG Drag Radials, so the traction was consistent...Food for thought!

 

[meggleto]

It always amazed me that everyone spends roughly $3000 for 30 to 50rwhp over stock. The stock system seem pretty good and the $3000 could be used to get a supercharger system which would give about 150rwhp to 200rwhp or more.

 

[J DAWG]

It always amazed me that everyone spends roughly $3000 for 30 to 50rwhp over stock. The stock system seem pretty good and the $3000 could be used to get a supercharger system which would give about 150rwhp to 200rwhp or more.

Especially when all you see is this

I have around $400 in my system.

$250 Roe oval cats
$80 X-pipe
$40 tips
$40 labor

 

[Daffy Duck Viper]

It always amazed me that everyone spends roughly $3000 for 30 to 50rwhp over stock. The stock system seem pretty good and the $3000 could be used to get a supercharger system which would give about 150rwhp to 200rwhp or more.

I think it's just that some people want the best in all areas of their Viper. So, to them, it's not about the money. They just want the best, and they pay for the best.

You must be registered for see images

You must be registered for see images

You must be registered for see images

 

[NCVCA]

If you spend $3000 for 30HP thats $100 per hp. Buy a supercharger for $10000 and get 150hp thats $67 per HP. Some people don't have $10k and others can't run superchargers because they track the car in classes that don't allow them.

I think a lot of people feel that exhaust upgrades are the most bang for the buck on a Viper - at least it seems to be the most common aftermarket performance mod other than K&N air filters...

my .02 worth (about .00002985 HP in supercharger terms)

 

[slaughterj]

I'd like to see NCVCA get some real useful data for this, so in order for it to be sufficiently useful please list:
1. HP-relevant mods (or if stock) prior to an exhaust/cats/headers change, including manufacturer
2. Which components (exhaust, cats, and/or headers) were changed, which manufacturer's components were used, and what gains were gotten.

 

[NCVCA]

Please also note if airflow might be restricted by a deer carcass...

 

[BigCarrot]

ttt

 

[slaughterj]

Please also note if airflow might be restricted by a deer carcass...

Doesn't inhibit airflow, but does create a nice odor...

 

[Bandit3]

check my signature. John

 

[BigCarrot]

Well, I slapped my car on the dyno yesterday. Last week I removed the 3 stock mufflers and the cats, and replaced them with Dynomax bullet mufflers and straight pipe. I went from 436 to 445, and my torque went from 490 to 485. I overlapped the graphs, and the previous stock torque was only higher at the peak. Other than that, it pretty much gained a little all the way across the graph. It makes a lot of noise to make a tad more power, but every little bit counts, and I'll take it! It sounds MEAN now!

 

[RC Viper]

First Dyno I did with my '97 GTS with Borla cat back system was 440 RWHP.

One year later after adding Randomtech high flow cats and Ballanger headers
I got 463 RWHP. Please note that the headers and cats were added the day before the dyno so my computer may not have fully adjusted yet.