Supercharger vs Normally Aspirated?

[Steve 00RT/10]

Winter withdrawal is in full swing for this part of the country. Visions of spring time are still a long way off. It gives one plenty of time to think of potential things to do to the beast. I'm Looking for a little advice on the below scenarios.

There is a fair amount of history for superchargers out there now. I'm wondering the consensus as regards supercharged or normally aspirated modifications? More specifically....SC versus a heads/cam package. Runnability is a huge issue for us as we put between 10 and 12,000 miles per season on our car--long trips(1000+ miles) are common. I also try to get on a track at least once a year as well as autocross when I can.

It seems some of the Roe chargers have had some fuel problems at high boost and are a little finicky to tune. Having a 2000 car would mean a 5 pound pulley. Are the fuel/tuning problems more minimal at lower boost? The closest dyno to us is 400-500 miles away, as is any 'current' top notch Viper tech. How about the Gen II Paxton? I have heard the Gen III kit is a little more refined and less troublesome?

Would a heads/cam set up--say with a VEC 2-- be more dependable and require less maintainance given the long distance running we do?

The more SOTP bug is always there, but runnability is as big a concern. To date, (knock on wood)our Viper has been trouble free. Over 55,000 'spirited' miles of fun. Except for an oil cooler line failure a year ago, the engine has never been touched or had any problems whatsoever. Turn the key and rocket away. Any additional HP adder would have to provide the same trouble free runnability.

Thanks--Steve

 

[RichieSRT10]

I went with a Paxton supercharger because I will drive about 12,000 miles a year with mine. The first 2 months I already have 5,000 trouble free miles. The gas mileage has not been affected under nomal driving conditions and you hear just a faint whistling noise. On the interstate the car now has the power to satisfy most. Whenever I have touched the heads or cam in the past I have always lost some driveability.

 

[2002_Viper_GTS_ACR]

I personally prefer NA power over boosted. Usually you will find your power is brought on more lineraly vs Centrifigual SC which build exponentially. Also heat soak can sometimes be an issue with S/C. Finally, you take significant trips of 1000+ miles. Well reality is, there is a possible of a failure on your car over time, and if it happens on one of these trips, how many dodge mechanics have been trianed on a boosted viper, vs, the standard parts that are expected on a viper (NA) but only better


Boosted makes more power per dollar, Heads and cam is less risky both in potential detonation, and in servicability of the motor if something needs to be done.

my tree fiddy.
Jon

 

[Schulmann]

NA or SC ?


It depends on what you want to do.

It is great to win with a Viper that looks stock but has several hidden features:
Cam, heads, headers, Vec2. At the dragstrip you will hit easily 12 sec at the 1/4 mi.
You will be a sure winner but your engin will look average.


When you add a SC you fall into a special unlimited category where most real
racers don't care about the number of times they rebuild their engin.
Likely you are not within this category of guys.
So you will rarely win but your engin will look great.


I strongly recommend the Roe SC.
This year I put more than 15000mi on my SC Viper.
We sometimes talk about issues on this forum.
This are not big troubles but we are trying to improve our Vipers.
Last couple of months we have focused a lot on making our SC Vipers a 100% perfect daily driver.
Tuning a Supercharged Viper as a daily driver is not an easy task.
We have identified some issues which were fixed.
And this is where the Roe SC is different from the other superchargers.
Sean Roe gives an unlimited support.
I can tell you that my supercharged Viper now drives like my supercharged Mercedes.

I don't think that other companies spend so much time to improve their product.

Fuel problem ?!
Only those that run above 10psi have this trouble and this is the case with ALL superchargers.
Above 10psi you have to upgrade the fuel system.


Finicky to tune ?!
This is the strong part of the Roe system. You can adjust all the parameters in your engin.
And this is why you hear more Roe owners to talk about tunig. We can easily change our tuning.



Realiablity ?!
Stay at mild boost, like 6psi.
No matter what supercharger you install Fuel quality will be your primary concern.
At mild boost you can get away with 91oct fuel.

 

[kwkshift]

Cam, heads, headers, Vec2. At the dragstrip you will hit easily 12 sec at the 1/4 mi.

If my car only ran 12's with all of that, I'd kill myself.

 

[ViperNM]

No sh*it! I ran 11.98 on my 01 ACR in a head/cam car at over 5000 ft. elevation. At sea level it would be low 11's.

 

[kwkshift]

[******]. I went 11.6 @ 121 with only a cat-back and a K&N intake.

 

[Steve 00RT/10]

Richie--your car is a Gen III. I'm not sure the Gen II kit is as reliable or trouble free. Glad you're happy and working well. I have a friend with the same set up and his works quite well too.

Jon---Good point about servicing a supercharged car if it's on a trip. I would like to think anyone proficient with OBDII engine diagnostics would be at least able to isolate the trouble area---and then, if it were a Roe, a call to Sean would be in order. Detonation problems are a concern. What kind of gains could one expect from a head/cam/VEC2 makeover? Cost?

Schulmann---Drag racing plays a very small role in our Viper's life. I'd much rather go to a track, autocross, or eat a few ZO6s here and there. Without changing pistons and trying to get more boost, I believe you are saying that 5 pounds of boost should be the easiest to tune. You mention 15,000 miles on your SC. Were you ever down while on the road?

Anyone out there with a creampuff and Roe SC running 5 pounds? What kind of power increase running 5 pounds of boost?

Thanks for the input.

Steve

 

[Sean Roe]

Hi Steve,
You have a lot of modification options available that would make your use of the car more enjoyable (street, road course and general driving fun).
Let's start by asking; do you have a particular horsepower or torque figure in mind, looking to reduce lap times by a certain amount, or do you have a particular amount you'd like to spend on the car?
What modifications do you currently have on the car, engine, exhaust, suspension or brake related?
HP can be great fun, but if lap times are a primary concern, there are other items that need consideration also.
Let's hear what your goals are and where your car is at in terms of modifications as of now.

Regards,
Sean

PS, The stock fuel system on a '96-'02 can support 680 RWHP with a voltage booster. With W/M injection, you can get to 710 ish. Regarding tuning, since we've been using the WM, we've found it beneficial to fine tune each car, where we used to be able to use a fairly standard tune on all cars. When the kit was first developed with 5 psi, tuning was pretty easy. There are sooooo many combinations on the 300+ SC cars (5,6.5,8,10,12 psi boost, WM, heads, headers, rockers, TB's, etc) that it seems we have a custom tune on almost every car. It's always best to verify the tune on any modified car. Even stock ones can benefit at times.

 

[Schulmann]

Schulmann---Drag racing plays a very small role in our Viper's life. I'd much rather go to a track, autocross, or eat a few ZO6s here and there. Without changing pistons and trying to get more boost, I believe you are saying that 5 pounds of boost should be the easiest to tune. You mention 15,000 miles on your SC. Were you ever down while on the road?

Anyone out there with a creampuff and Roe SC running 5 pounds? What kind of power increase running 5 pounds of boost?

Thanks for the input.

Steve

You are right Steve drag racing plays a minor role in most cases but this is what might change the mind of somebody who is wondering about supercharging.

You know what is my game with the viper ? Getting up at 5AM saturday morning and racing down the empty hwy at full throttle in 5th gear .... With my supercharger it is likely being in a Jet at take off.

I was never down but I had some minor issues which were fixed in 2 min. => Disconnecting and reconnecting the battery to reset the PCM and reprogramming the VEC2. As I am telling you I spent a lot of time to make my Viper a perfect daily driver. Th only trouble is to get the right Fuel when you run above 6lb.

The boost level doesn't have any influence on the tuning difficulties. The tuning methode is the same from 4psi to 60psi. Mild boost will provide you high reliablility in all fuel and temperature conditions. Your primary concern seems to be daily drivability. Then stay around 6lb boost.
When going to higher boost you will have to reprogram the VEC2 to take care of the fuel quality. Again it is the same with all superchargers and turbos.

I also strongly recommand to change your pistons to forged ones.

With 5psi and W/M you should get into the 540hp.

 

[Steve 00RT/10]

Hi Sean,

Thanks for chipping in here. I've been on the fence post between a little more power and trying to stay as trouble free as I've been since day one of buying the car. ---Trying to hear enough good things about superchargers and drivability to spring for one--most likely yours.

We have a 2000 RT/10. I purchased your VEC1 in Nashville at the VOI. It produced 14 HP and 20# more torque. Engine mods to my car are bolt on: Belanger Headers/3" Belanger exhaust/no cats/Mopar tubes/filters/Unitrax 3:45 Assembly/Fidanza Flywheel. My front O2s are drilled per your advice...and mounted in the correct location. I have rear O2 SIMS. I also have Tom Hayden's rear brake upgrade(very worthwhile addition!) and Brakeman 3 pads.

I really have no set goals for HP or torque--- just looking for a little more SOTP thrill. It's an infectious thing. Most of the track laps I do are not timed. Lap times for me, while always trying to improve, will probably never be real good, because the closest track is 500 miles from here. In reality, once or twice a season to a track will be about it. Hardly enough seat time to improve much. I probably only have 700-800 track miles total the last 6 years including the 3-day Bragg-Smith school a few years ago........in a ZO6. In reality, I will probably never test the suspension limits of the stock ride much less a more tuned suspension. Therefore suspension mods are not a priority. I get on a track just to have fun in a controlled environment. Drag racing is a very low priority. I basically just need a little more ZO6 punishing capablility, but still want to be able to jump in the car and drive to Nashville, Dallas, Las Vegas--all multiple thousand mile rides for us. I am fully aware that all cars break once in a while. I just don't want a supercharger kit to be the cause of failure if possible.

Do you recommend changing the pistons? How many hour job for a Viper Tech to change the pistons? What's the power difference between 5 and 6.5 pounds boost? Is the W/M system necessary for 5 pounds boost?

Schulmann---thanks for sharing a little of your daily driving history. 15,000 miles and minimal problems is the kind of history I'm looking for.

Thanks--Steve

 

[GR8_ASP]

Okay Steve, let's be truthful. You just want to keep up with the Jones', right?

j/k. Hopefully more owners with Paxton and Roe superchargers and some with head/cam alone will chime in and give you some history. Because when it comes down to it nothing beats real ownership experience.

 

[Sean Roe]

Hi Steve,
Ok, that's a much clearer picture of what you have and what you want.
With your current mods, you could still add some more bolt on items that will help both naturally aspirated and supercharged.
The easy ones would be 1.7 roller rockers with heavy duty pushrods. That will get you additional lift and help move more air / fuel through the motor. Rockers cost from $599 for Harland Sharp to $1650 for the top of the line Jesel rockers, with T&D in between. Pushrods are $129. The power gain should be about 15-18 RWHP naturally aspirated with quicker and smoother engine revs.
Next up for NA would be heads, which can add 40-50 RWHP. Those run about $2,700.
A new cam and lifters would be next. You could go to the earlier "708" cam and a set of standard "non bleed down" lifters and pick up more mid range torque, though your peak HP won't increase that much. That combination would run about $900 including the lifters.
At this point, you'd need tuning to get the engine running the correct AF ratio and timing. That requires a VEC2 or custom flash, running about $1000.
With the above combination, you'd be running about 525 RWHP (considering how the gear you're running lowers your HP reading on the dyno). Cost would be "about" $6500 for parts, including head gaskets and fluids.
On the pistons, they are the absolute weak link in the engine when trying to make big power. That said, about 30-40% of the 300 cars running our style of Supercharger have cast pistons, so it can be done with the tuning set properly and verified. If you wanted to change pistons, they're about $1100 for a set of custom pistons and rings. It should take a guy about 16 hours to swap them, start to finish (less time if he's experienced).
On the SC side, what we offer is unique compared to the other blower and turbo kits available. My personal preference is to add power (torque) to a Viper engine without having to spin it high RPM. The street motors just aren't made to spin above 5,800 RPM for long. There are large main bearing journals (leading to high bearing speeds), no cam bearings, light pressure valve springs (relative) leading to valve float, marginal oil system, etc that just scream "don't spin me high RPM if you want me to live". So, I like to add power without having to beat on the engine. Realistically, you never hear of anyone loosing an engine under 5,200 RPM. It's almost always at the absolute top of the RPM range or on an over rev. If you can add 40 to 50% more torque at low RPM (starting at about 1,800) and keep the engine below 5,200, making a boat load more torque, the car will be as fast or faster than one with more upper RPM peak HP, but without the additional risk associated with higher RPM.
A positive displacement SC kit will add about 150 RWTQ at low to mid range RPM and 105-125 peak RPM RWHP with 5 psi and nothing else (2000-2002 cams produce the lowest gains). The beauty of the SC kit is that you can add more value (HP) by simply changing a pulley. The system becomes very cost efficient when you start getting into the 8-10 psi range. The last 3 cars we completed all were 702-706 RWHP and 722 to 750 RWTQ with 10-11 psi and W/M injection. It's quite fun to have 600 ft/lbs RWTQ at less than 2000 RPM and over 700 by 3,500 RPM.
So, you have quite a few choices and options. What should you do, I don't know?
The best may be to work toward a certain budget, HP level, or HP to dollar point. Anything under $65 per HP is generally a good deal.
None of the above parts should cause you any trouble going long distances providing the parts are properly installed, the engine is in good shape, the tuning of the engine is proper and the RPM is kept below 5,200 RPM regularly with peaks at 5,700.
I hope the information helps.
Regards,
Sean

 

[Steve 00RT/10]

Thanks Sean. Very helpful. I believe there may be a Roe supercharger coming this way in the near future.

Steve

 

[KWIK96]

Quote:
--------------------------------------------------------------------------------

Cam, heads, headers, Vec2. At the dragstrip you will hit easily 12 sec at the 1/4 mi.



-------------------------------------------------------------------------------
Quiote:

If my car only ran 12's with all of that, I'd kill myself.

-----------------------------------------------------------

I'd kill myself rather than tell anyone that.

 

[Fishtail]

Hi Steve,
Ok, that's a much clearer picture of what you have and what you want.
With your current mods, you could still add some more bolt on items that will help both naturally aspirated and supercharged.
The easy ones would be 1.7 roller rockers with heavy duty pushrods. That will get you additional lift and help move more air / fuel through the motor. Rockers cost from $599 for Harland Sharp to $1650 for the top of the line Jesel rockers, with T&D in between. Pushrods are $129. The power gain should be about 15-18 RWHP naturally aspirated with quicker and smoother engine revs.
Next up for NA would be heads, which can add 40-50 RWHP. Those run about $2,700.
A new cam and lifters would be next. You could go to the earlier "708" cam and a set of standard "non bleed down" lifters and pick up more mid range torque, though your peak HP won't increase that much. That combination would run about $900 including the lifters.
At this point, you'd need tuning to get the engine running the correct AF ratio and timing. That requires a VEC2 or custom flash, running about $1000.
With the above combination, you'd be running about 525 RWHP (considering how the gear you're running lowers your HP reading on the dyno). Cost would be "about" $6500 for parts, including head gaskets and fluids.
On the pistons, they are the absolute weak link in the engine when trying to make big power. That said, about 30-40% of the 300 cars running our style of Supercharger have cast pistons, so it can be done with the tuning set properly and verified. If you wanted to change pistons, they're about $1100 for a set of custom pistons and rings. It should take a guy about 16 hours to swap them, start to finish (less time if he's experienced).
On the SC side, what we offer is unique compared to the other blower and turbo kits available. My personal preference is to add power (torque) to a Viper engine without having to spin it high RPM. The street motors just aren't made to spin above 5,800 RPM for long. There are large main bearing journals (leading to high bearing speeds), no cam bearings, light pressure valve springs (relative) leading to valve float, marginal oil system, etc that just scream "don't spin me high RPM if you want me to live". So, I like to add power without having to beat on the engine. Realistically, you never hear of anyone loosing an engine under 5,200 RPM. It's almost always at the absolute top of the RPM range or on an over rev. If you can add 40 to 50% more torque at low RPM (starting at about 1,800) and keep the engine below 5,200, making a boat load more torque, the car will be as fast or faster than one with more upper RPM peak HP, but without the additional risk associated with higher RPM.
A positive displacement SC kit will add about 150 RWTQ at low to mid range RPM and 105-125 peak RPM RWHP with 5 psi and nothing else (2000-2002 cams produce the lowest gains). The beauty of the SC kit is that you can add more value (HP) by simply changing a pulley. The system becomes very cost efficient when you start getting into the 8-10 psi range. The last 3 cars we completed all were 702-706 RWHP and 722 to 750 RWTQ with 10-11 psi and W/M injection. It's quite fun to have 600 ft/lbs RWTQ at less than 2000 RPM and over 700 by 3,500 RPM.
So, you have quite a few choices and options. What should you do, I don't know?
The best may be to work toward a certain budget, HP level, or HP to dollar point. Anything under $65 per HP is generally a good deal.
None of the above parts should cause you any trouble going long distances providing the parts are properly installed, the engine is in good shape, the tuning of the engine is proper and the RPM is kept below 5,200 RPM regularly with peaks at 5,700.
I hope the information helps.
Regards,
Sean

Sorry, buts that's VERY opinionated and PARTIAL so I don't agree with your theory.

-lou

 

[Shelby3]

Hi Steve,
Ok, that's a much clearer picture of what you have and what you want.
With your current mods, you could still add some more bolt on items that will help both naturally aspirated and supercharged.
The easy ones would be 1.7 roller rockers with heavy duty pushrods. That will get you additional lift and help move more air / fuel through the motor. Rockers cost from $599 for Harland Sharp to $1650 for the top of the line Jesel rockers, with T&D in between. Pushrods are $129. The power gain should be about 15-18 RWHP naturally aspirated with quicker and smoother engine revs.
Next up for NA would be heads, which can add 40-50 RWHP. Those run about $2,700.
A new cam and lifters would be next. You could go to the earlier "708" cam and a set of standard "non bleed down" lifters and pick up more mid range torque, though your peak HP won't increase that much. That combination would run about $900 including the lifters.
At this point, you'd need tuning to get the engine running the correct AF ratio and timing. That requires a VEC2 or custom flash, running about $1000.
With the above combination, you'd be running about 525 RWHP (considering how the gear you're running lowers your HP reading on the dyno). Cost would be "about" $6500 for parts, including head gaskets and fluids.
On the pistons, they are the absolute weak link in the engine when trying to make big power. That said, about 30-40% of the 300 cars running our style of Supercharger have cast pistons, so it can be done with the tuning set properly and verified. If you wanted to change pistons, they're about $1100 for a set of custom pistons and rings. It should take a guy about 16 hours to swap them, start to finish (less time if he's experienced).
On the SC side, what we offer is unique compared to the other blower and turbo kits available. My personal preference is to add power (torque) to a Viper engine without having to spin it high RPM. The street motors just aren't made to spin above 5,800 RPM for long. There are large main bearing journals (leading to high bearing speeds), no cam bearings, light pressure valve springs (relative) leading to valve float, marginal oil system, etc that just scream "don't spin me high RPM if you want me to live". So, I like to add power without having to beat on the engine. Realistically, you never hear of anyone loosing an engine under 5,200 RPM. It's almost always at the absolute top of the RPM range or on an over rev. If you can add 40 to 50% more torque at low RPM (starting at about 1,800) and keep the engine below 5,200, making a boat load more torque, the car will be as fast or faster than one with more upper RPM peak HP, but without the additional risk associated with higher RPM.
A positive displacement SC kit will add about 150 RWTQ at low to mid range RPM and 105-125 peak RPM RWHP with 5 psi and nothing else (2000-2002 cams produce the lowest gains). The beauty of the SC kit is that you can add more value (HP) by simply changing a pulley. The system becomes very cost efficient when you start getting into the 8-10 psi range. The last 3 cars we completed all were 702-706 RWHP and 722 to 750 RWTQ with 10-11 psi and W/M injection. It's quite fun to have 600 ft/lbs RWTQ at less than 2000 RPM and over 700 by 3,500 RPM.
So, you have quite a few choices and options. What should you do, I don't know?
The best may be to work toward a certain budget, HP level, or HP to dollar point. Anything under $65 per HP is generally a good deal.
None of the above parts should cause you any trouble going long distances providing the parts are properly installed, the engine is in good shape, the tuning of the engine is proper and the RPM is kept below 5,200 RPM regularly with peaks at 5,700.
I hope the information helps.
Regards,
Sean

I agree, which is why I'm running the Roe blower.

 

[kwkshift]

I'd kill myself rather than tell anyone that.

That's funny!