Supercharger, What's the difference between 5, 7 or 8 PSI pulley?

[HARDVIPER]

Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

Available with 5, 7 or 8 PSI pulley.AND WHICH ONE SHOULD I GET?
Thanks,JC

 

[Yellow Fever]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

The size of Pulley changes to accomdate more boost...I beleive the smaller the pulley the more boost.

 

[lleone]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

If you still have the stock 2001 pistons, stick with the 5# pulley. If you have put forged pistons in, you should be safe up to 8# without intercooling... but you want to be careful.

Figure 125 HP gain for the 5# setup and 20 HP for each # after that.

When in doubt... call Sean Roe!

Lou

Lou

 

[HARDVIPER]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

If you still have the stock 2001 pistons, stick with the 5# pulley. If you have put forged pistons in, you should be safe up to 8# without intercooling... but you want to be careful.

Figure 125 HP gain for the 5# setup and 20 HP for each # after that.

When in doubt... call Sean Roe!

Lou

Lou

I want all the power I can get Obviously But I do have stock pistons. What will or might Break?? if we go 7 or 8?

 

[1TONY1]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

No more than 5 psi. You will bust the pistons.

 

[lleone]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

Seriously, with a single detonation you can crack/break one of those pistons... in which case there will be numerous shards of metal being recirculated thoughout your motor, grinding away at the rest of your pistons, your cylinder liners, your camshaft, your main bearings, your crank shaft, and lots of other parts that don't take kindly to being gnawed at by little sharp gnarly pieces of what was formerly a piston... Please do a search on the topic, you'll learn a lot. Have you been to any driiving schools? They are a much better investment.

Lou

 

[Real Hummer]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

I went with 5 lbs and my car is at heffners with a broken piston.

 

[RedGTS]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

I'm in the process of replacing my pistons as well, a process I undertook because I wanted to up the boost. Now I'm really glad I did, because when we got inside we found this:

You must be registered for see images

You must be registered for see images

I've also been running the 5 lb pulley, and while I'd had some high rpm audible pinging off and on since installing the blower, the car ran and dynoed fine, and never pinged on the dyno to my knowledge. But driving on the street moves a lot more air into the car, and it was worst last fall when the air got cooler and denser. I might add that I put around 1,000 miles on my car with the blower, with 5-6 dyno runs for tuning purposes and no dragstrip use. I have no idea how long it would have been before this piston disintegrated, but I'm glad I didn't find out. Bottom line: stay with the 5 lb pulley with cast pistons, and if you have any pinging at all, investigate it and get it fixed.

 

[FE 065]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

That's 2 too many..!

 

[Kiaser]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

Really, if you are looking into boost you gotta consider all the other requirements. With a project and car like that you shouldn't invest in a SC until you can afford all the other stuff that should go along with it (intercooler, engine internals, etc).

Which brings up a question, how high of PSI have any of you seen that stock heads/gaskets seem to hold up with?

 

[RedGTS]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

That's 2 too many..!

Sorry, I may not have been clear--it's the same piston. The others look ok.

 

[Tim]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

I want to upgrade my 94 RT10 and get into a 2001 or later to get the ABS brakes. Down the road I will be putting the blower on. How much will it cost a guy change the pistons and can we do with out pulling the motor and by dropping the crank and oil pan then pulling the pistons out the bottom?

Is this all that was changed for the worst in 2001, the pistons?

Tim

 

[FE 065]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

That's 2 too many..!

Sorry, I may not have been clear--it's the same piston. The others look ok.

You must be registered for see images

No, it was me...

 

[RedGTS]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

Tim, pistons themselves are around $1,000, but the labor to install them is significant unless you do it yourself. The other big question is how much boost you plan to run, and whether you think you'll be happy with a basic 5-7 psi system. You could just replace the pistons and keep the costs down, but if you think you may want to crank up the boost later, while you're in there you probably should upgrade the lifters and add roller rockers and stronger pushrods as well. It would also make a lot of sense to have your heads ported (or swap them out for a ported set), and consider a cam change. And yes, any or all of the above can be done with the engine in the car by someone who is careful and knows what they're doing, although most tuners won't do it that way as they prefer to have the block bored etc.

As far as anything that changed for the worse in 2001 from a blower perspective (actually it was in 2000), the pistons are the only thing.

 

[HARDVIPER]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

Thanks Guy's, Looks Like I Really Don't Want To Afford This Power At This Time.
What Is Safer That I Already Haven't Done Yet?

 

[STUGOTS]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

jesel j2k 1.7 rockers and hardend pushrods,S&B filters (wayyy better then k&n),70mm TB's,vec 2,180 degree thermastat,fluidyne radiator,aluminum flywheel,dual friction clutch,ported and polished heads,cam and lifter upgrade anyone of these wpuld be ideal and personaly I would get get forged internals and get that Roe S/C.

Good luck

 

[Tim]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

Ron,

How many hours labor to change out the pistons if we leave the engine in the car? 12 hrs, is that a realistic amount of time?

Maybe it's more cost effective to get a 1999 RT10 and upgrading that car with ABS brakes as it already has the forged pistons and better cam?

Tim

 

[PRVT JET]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

To add abs to a viper will cost about $8000.00. I think it would be cheaper to get new pistons.

 

[HARDVIPER]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

I went with 5 lbs and my car is at heffners with a broken piston.

How much HP did you get from the SC

 

[FE 065]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

Tim, pistons themselves are around $1,000, but the labor to install them is significant unless you do it yourself. The other big question is how much boost you plan to run, and whether you think you'll be happy with a basic 5-7 psi system. You could just replace the pistons and keep the costs down, but if you think you may want to crank up the boost later, while you're in there you probably should upgrade the lifters and add roller rockers and stronger pushrods as well. It would also make a lot of sense to have your heads ported (or swap them out for a ported set), and consider a cam change. And yes, any or all of the above can be done with the engine in the car by someone who is careful and knows what they're doing, although most tuners won't do it that way as they prefer to have the block bored etc.

As far as anything that changed for the worse in 2001 from a blower perspective (actually it was in 2000), the pistons are the only thing.

..It's been mentioned more than once by Dan Cragin et al that the OEM connection rods shouldn't be pushed past 650hp or so.

 

[Real Hummer]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

Hardviper,
I had blower on the car for about a month and about 800 miles. IO bought the vec2 software from roe and wasnt sure how to really tune so i took it to heffners to tune and he had 540 rwhp and then found the piston was broke. Jason called me and said he thought I had a valve train noise and wanted to pull valve cover but I easnt that lucky. my problems are most likely driving car and not tuning sooner?

 

[HARDVIPER]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

The size of Pulley changes to accomdate more boost...I beleive the smaller the pulley the more boost.

Is this the wAY TO GO???????aND hOW mUCH??????????????
2001 RT/10 - Heffner Twin Turbo "835 RWHP - 933 RWTQ
It seems Mr Twin Tubo Is My new Ideal!

 

[RedGTS]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

Ron,

How many hours labor to change out the pistons if we leave the engine in the car? 12 hrs, is that a realistic amount of time?

Maybe it's more cost effective to get a 1999 RT10 and upgrading that car with ABS brakes as it already has the forged pistons and better cam?

Tim

Tim, I don't really know because I couldn't do it in 12 days. However, that sounds like a reasonable guesstimate to me for someone who knows Vipers and has done this sort of thing before. And I agree with Prvt Jet, whatever it is would be less expensive and less hassle than trying to retrofit ABS.

It's been mentioned more than once by Dan Cragin et al that the OEM connection rods shouldn't be pushed past 650hp or so.

This is true, but I think the potential problem with the stock rods Dan refers to is related more to sustained high RPM at that power output than it is to maximum power output alone. You have to remember that Dan builds quite a few road course cars for which this could be a problem. For street and dragstrip use where you don't spend more than a few seconds at a time near redline, I don't think it's much of an issue. And numerous blown and turbocharged cars have made much more power than that with the stock rods (and stock forged pistons in many cases) without a problem.

 

[HARDVIPER]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

Are the same problems still existing with the Paxton Supercharger?

 

[lleone]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

Are the same problems still existing with the Paxton Supercharger?

Yes.

 

[fuelman]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

I have been running the 5 lb pulley on my cast piston car for 1.5 years, I have more than 6000 miles on the supercharger. I have raced the car quite a bit, attended most of the V10 Nationals, and I shift at 6000 rpm through the 1/4 mile. However, from the beginning I had a professional install and tune the supercharger. Macedo has installed a lot of the Roe Superchargers, I took it to him because I knew that you just can't slap any forced induction system on any car that was not designed for it. My miles have been trouble free and even in hot Florida I have not had any detonation. The car runs hard for just 5 pounds of boost. You can put this supercharger on your car, it is a good system, just have it tuned by a professional.

 

[RedGTS]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

I have been running the 5 lb pulley on my cast piston car for 1.5 years, I have more than 6000 miles on the supercharger. I have raced the car quite a bit, attended most of the V10 Nationals, and I shift at 6000 rpm through the 1/4 mile. However, from the beginning I had a professional install and tune the supercharger. Macedo has installed a lot of the Roe Superchargers, I took it to him because I knew that you just can't slap any forced induction system on any car that was not designed for it. My miles have been trouble free and even in hot Florida I have not had any detonation. The car runs hard for just 5 pounds of boost. You can put this supercharger on your car, it is a good system, just have it tuned by a professional.

All of John's points are good, and I think Larry is as good a tuner for the Roe blower as there is (not to mention being a great guy). However, in the interest of full disclosure, Larry also tuned my car, and I still had pinging on the street later on. As stated earlier, we didn't notice any pinging on the dyno, and my air/fuel ratio on the dyno was fine. Obviously, I have no idea whether my piston broke before or after Larry tuned the car. But given the fact that I did have pinging afterward and also drove the car more afterward than before, if I had to guess I'd say it was after. Either way, the pinging and broken piston are not Larry's fault, because I also had pinging before he tuned the car--maybe he didn't make it go away, but he didn't cause it either; it didn't ping while he was tuning it; and my air/fuel ratio was golden. Nor do I blame Sean simply because he supplied the other cards I ran. There are a number of factors that can cause detonation, and the fact is, I don't know what made my car ping. All of which is to say, I completely agree with John's recommendation to use a professional tuner, and Larry is as good as it gets, but no tuner can guarantee you won't pop a piston--especially a cast one.

 

[Sean Roe]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

Mahle, the piston manufacturer, told us 5 PSI was max on the cast pistons of 2000 and newer. In my opinion, they're correct, and we've worked hard to make the programming as safe as possible at this boost pressure (I personally would not run higher than 5 PSI and would make sure I keep my RPM under 5,400 for maximum engine life). However, some engines are more prone to detonation than others, due to variables such as fuel quality, production machining tolerances, climate, etc.. The new cars are the same. Higher RPM's will reduce the life as well.
1992-1999 is the way to go if you want to keep the bottom end stock and run higher boost, safely. Otherwise, you could go the path others are going and change out the pistons with an "in frame" engine rebuild.
To the original question, run the highest boost you can without engine damage. Here's what I recommend based on our experience:
Stock Cast Viper pistons (4mm above upper ring land), 5 PSI regardless of fuel octane.
Stock Forged Viper pistons of 1996-1999 Gen2 (7mm above upper ring land) 5 to 6.5 PSI on 91 octane, 8 PSI on 93+ octane, 8+ PSI on lower compression and 93 octane (head work to reduce compression).
Stock Forged pistons of 1992-1996 are similar to above, but the compression is lower and more boost can be run (these can be especially good motors to Supercharge as they make a lot of torque and will never have to spin over 5,200 RPM to drive away from most everything on the road).
Regards,
Sean

 

[proracer1]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

SEAN....What do you think is ok with Oliver rods anf JE forged Blower pistons @stock compression......Can I go 10lb? Or should I stick with the 8lb baby pully I have now?

 

[Sean Roe]

Re: Supercharger, What\'s the difference between 5, 7 or 8 PSI pulley?

Hi Jeff,
The 9.6:1 compression will limit the boost you can effectively run on street gas, even though the bottom end of the motor is strong. Lower octane is easier to self ignite when compressed. With 93 octane fuel, I would not go higher boost than you have now. It seems to be working well.
If you run 100 octane, you should be able to go to 10 psi. However, I would reserve this for track events where you can spend most of your time at full throttle. The blower spins faster, which builds more heat in bypass mode (recirculating during vacuum street driving). When you're full throttle, the air goes through the blower only once, and the charge temperature actually drops (from street driving). This is where the intercooler will help. We plan to show it at VOI.

Regards,
Sean