Performance Upgrade Estimate Needed

Talon · Oct 21, 2013

All,

I just recently purchased my first ever Dodge Viper. It's a beautiful 1999 GTS that's Red with Silver racing stripes. Still trying to find accurate build info on it but that's a different journey to find good numbers. I've already engaged on the forums for figuring out more info... including talking to Chrysler.

My question here is roughly what sort of horsepower/torque gains I am looking at on my car.
The car has high flow cats and a full cat back Corsa exhaust. The only other "performance" mods on it are the forged ACR wheels and a Hurst Short Throw.

I'm considering putting in some headers too. If anyone has some thoughts/feedback on that I'd love to hear it. If I do, will I be looking at impacts to my NOX sensors and how they read? Would I need a tune? How much power should I expect from a tune and does anyone have a suggestion on a tune shop in Texas (Hennessey isn't too far down the street, but I don't know if they do tunes except for on their own upgrades).

Thanks!

Talon

speedracervr4 · Oct 21, 2013

Don't worry about the Knock sensors, your Viper does not have any. I would guess mid 400s with the upgrades you listed, but there are a bunch of factors that will determine your results. Headers will probably give you 15-25rwhp. You won't see huge gains until you do heads/cam, forced induction, or nitrous.

I'm not sure I would go with Hennessy considering the issues they have had in the past. I would look at getting an SCT tune and taking it to a dyno to tweak the tune once the tuner sees the A/F #s.

Rare Snake · Oct 21, 2013

My 01 GTS has no cats, B&B Exhaust and a K&N intake, I hit 450hp and 486tq on a dyno back in the spring. Talon, you should be fairly close to this.

I found out a few weeks later that 3 plug wires were cracked right through, and one plug was loose! I'll hit the same dyno again next spring to see if there's any difference.

Talon · Oct 21, 2013

@Speed, I didn't mean "knock" sensors I actually meant NOX sensors as in NOx (Nitrous Oxide) the pollutant put out of the car. I didn't want the sensors tripping and giving me a service engine light... or if it would, then what I need to do to adjust for it.

I don't plan on getting too aggressive with modifications on this thing since it's my first viper, and up until now I've had a fully custom bagged chevy Silverado on 22's. It was fun and I enjoyed it but the upkeep associated with that level of custom work got to be a hassle, and frankly throwing a supercharger/turbo etc on it puts me back in the same place. I want something nice and still very reliable for a while. Maybe one day though... I've only owned the thing for about a week and a half though so who knows maybe I'll get "the itch".

Thanks for all the feedback though fellas I appreciate it!

Anyone see a reason for a tune or do you think the minor add-ons at the moment probably aren't worth the expense? What point do you think it is worth the expense?

Will at RSI · Oct 21, 2013

Give us a call, we are not too far away from you!

speedracervr4 · Oct 21, 2013

Talon said:
@Speed, I didn't mean "knock" sensors I actually meant NOX sensors as in NOx (Nitrous Oxide) the pollutant put out of the car. I didn't want the sensors tripping and giving me a service engine light... or if it would, then what I need to do to adjust for it.

You mean the o2 sensors, I've never heard them be called NOX sensors. Adding headers will not affect them, if you remove the high flow cats and go catless then you "may" set a CEL. This can be adverted by using spark plug foulers or the rear o2 sensors can be turned off via an SCT tuner.

You're probably not going to see huge gains from getting a tune, maybe another 15rwhp or so if that.

DrumrBoy · Oct 21, 2013

As stated above, headers and a tune will be your most cost effective power mods. With headwork and a cam, you could probably see 550+ RWHP (some make as much as 600); with a lot more work you can make a NA motor produce 650+ RW....but the cost per HP is pretty high compared to headers and a tune.

Talon · Oct 21, 2013

speedracervr4 said:
You mean the o2 sensors, I've never heard them be called NOX sensors. Adding headers will not affect them, if you remove the high flow cats and go catless then you "may" set a CEL. This can be adverted by using spark plug foulers or the rear o2 sensors can be turned off via an SCT tuner.

You're probably not going to see huge gains from getting a tune, maybe another 15rwhp or so if that.

Yea there are many ways to write it. We're getting into semantics a bit here, but NOx is just an abbreviation for Nitrous Oxide. It's basically the same as saying O2. They measure Oxygen because they need to optimize the balance...the reason to optimize this balance for rear sensors is purely for environmental purposes by reduce NOx emissions. I suppose it's just how one learns it. In my mind the reality is it is a Nitrous Oxide sensor because that was the reason it was ever put on in the first place (again the rears)... yet technically speaking it's an oxygen sensor because it measures Oxygen levels.

O2 sensors started out as a great engineering feat to optimize combustion and efficiency, but was quickly turned into environmental protections by adding a second bank of sensors behind the cats.

Bugman Jeff · Oct 22, 2013

I'm catless and it doesn't throw a code. If it does throw a code, the spark plug anti-fouler trick does work, though as stated, if you're going to have it tuned anyway you can just have them switched off.

Performance Upgrade Estimate Needed

Talon

Viper Owner

speedracervr4

Enthusiast

Rare Snake

Enthusiast

Talon

Viper Owner

Will at RSI

Enthusiast

speedracervr4

Enthusiast

DrumrBoy

Enthusiast

Talon

Viper Owner

Bugman Jeff

Enthusiast

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