Roe vs. Paxton

[DEADEYE]

I barely ever get into boost on my Roe GTS. 99% of the time I'm running under vacume pressure. If you drive normaly, the motor has more than enough torque to pull you. I've had my Roe at 10 lbs for about 2.5 years so far. I've refilled the methanol bottle about 3 times and it sprays when I boost.

[Steve 00RT/10]

Originally Posted by mjorgensen

Well I'm not disputing the facts about the quality of the Roe and it's attributes, the reason I believe what I do is that under normal driving the Paxton car sees no real added wear and I think that even under normal driving the Roe will "stress" the engine etc. more thats all I think. it's just MY opinion.

Thank you,

I'm always reading your opinions. You are one of the authorities here. I think I undestand what you're saying about normal driving. Being positive displacemt, those twin screws are turning all the time pushing air in -- even with no boost.

My temp gauge (170F) this last track day -- 75F -typical -- only goes about a needle and a half past the 3rd bar. One cool down lap and I'm back on the 1st/2nd bar after getting to the parking place. Based on speedo readings on the straights, I evidenced no heat soak over the 20 minute sessions. I also used only a 1/4 qt of oil over the 1100 mile run down to the event (100 track miles). These things and the longevity so far (knock on wood) make me quite satisfied with this set up. The low down street grunt is what I like the best. I don't drag race at all so that's not a factor for me.

Steve

[black mamba1]

Traction is hard enough w/ my cream puff 528 rwhp. Having 600 to 700 rwhp at 1800 rpm is just craaaaaazy to me. Torque is already monstrous in Vipers, which I think is one reason for the 3.07 rear end. From what the Paxton guys tell me, of the two Paxton is the way to go. Now, if TT enters the picture, that is a totally different story.

[SquadX]

Sean mention that the Roe puts less wear and tear on the engine because it makes such huge power down low (2krpm) that the engine doesn't have to turn high rpms just to make power and therefore causing wear and tear.

I was/am a little tore by this as higher rpms puts more stress on engine/drivetrain but does huge power actually put more stress on the engine at low rpms? Hard to tell. I've only heard good things about reliability on the Roe and mixed about the paxton.

The paxton, since it makes more power the higher the rpms would be prone to breaking tires loose unexpectedly then the Roe as the Roe is an instant hit apposed to the build up of the paxton. I do like the fax that the paxton does have a intercooler as apposed to the water/meth for the Roe.

Just my thoughts.

[plumcrazy]

ive seen first hand what a ton of torque (nitrous) can do to the cylinder walls

[RTTTTed]

Originally Posted by Steve 00RT/10

I'm always reading your opinions. You are one of the authorities here. I think I undestand what you're saying about normal driving. Being positive displacemt, those twin screws are turning all the time pushing air in -- even with no boost.

My temp gauge (170F) this last track day -- 75F -typical -- only goes about a needle and a half past the 3rd bar. One cool down lap and I'm back on the 1st/2nd bar after getting to the parking place. Based on speedo readings on the straights, I evidenced no heat soak over the 20 minute sessions. I also used only a 1/4 qt of oil over the 1100 mile run down to the event (100 track miles). These things and the longevity so far (knock on wood) make me quite satisfied with this set up. The low down street grunt is what I like the best. I don't drag race at all so that's not a factor for me.

Steve

You're thinking of a Roots blower. The Roe PD does spin according to the crankshaft, same as the Paxton, but the Power Valve releases the extra air back into the non-pressurized side of the intake making the blower "idle" and allowing vacuum to the intake runners. The screws spin, but don't actually make any boost or use any hp to turn until boost is built.

Ted

[RTTTTed]

Originally Posted by SquadX

Sean mention that the Roe puts less wear and tear on the engine because it makes such huge power down low (2krpm) that the engine doesn't have to turn high rpms just to make power and therefore causing wear and tear.

I was/am a little tore by this as higher rpms puts more stress on engine/drivetrain but does huge power actually put more stress on the engine at low rpms? Hard to tell. I've only heard good things about reliability on the Roe and mixed about the paxton.

The paxton, since it makes more power the higher the rpms would be prone to breaking tires loose unexpectedly then the Roe as the Roe is an instant hit apposed to the build up of the paxton. I do like the fax that the paxton does have a intercooler as apposed to the water/meth for the Roe.

Just my thoughts.

My opinion is that the Paxton spins so fast (100,000rpm) that it heats the air more than the twin screw - that's why it needs an intercooler. The Roe spins much slower and that's why it doesn't need oil changes every 6,000mi. like the Paxton.

Ted

[00prowler]

The Roe Looks Nicer...Al...

[RTTTTed]

Originally Posted by plumcrazy

ive seen first hand what a ton of torque (nitrous) can do to the cylinder walls

I have installed Nitrous on every muscle car I've built since back in the early eighties when I melted a piston doing some research on Nitrous and blowers (NOS and B&M sc). Turned out that Holley used to make the fuel holes in their regulators too small to support enough fuel for the bigger Nitrous systems (I had a Proshot fogger). Now they're super reliable so I instal a kit on all my cars. Not for constant use, just when you meet that guy in the vette that's "soooo fast" and you need a "little more" to put him in his place, you know?

It also has the advantage of chemical intercooling supposedly worth an extra 50rwhp at 10psi boost.

I spoke to Larry Macedo about the stress of the extra hp on my bottom end and he assured me that his engine will have no problems with it.

Ted

[Bobpantax]

Originally Posted by SquadX

Sean mention that the Roe puts less wear and tear on the engine because it makes such huge power down low (2krpm) that the engine doesn't have to turn high rpms just to make power and therefore causing wear and tear.

I was/am a little tore by this as higher rpms puts more stress on engine/drivetrain but does huge power actually put more stress on the engine at low rpms? Hard to tell. I've only heard good things about reliability on the Roe and mixed about the paxton.

The paxton, since it makes more power the higher the rpms would be prone to breaking tires loose unexpectedly then the Roe as the Roe is an instant hit apposed to the build up of the paxton. I do like the fax that the paxton does have a intercooler as apposed to the water/meth for the Roe.

Just my thoughts.

500 ft lbs of torque at 1800 RPM means a bigger explosion in the cylinders at 1800 RPM. A bigger explosion means more stress on the components. If you look at the boost curves above, you will see that there is, therefore, far less stress on a Paxtonized engine. With that said, the Vipers before 2000 had forged pistons and were/ are very strong engines. 2000 to 2002 things got weaker with cast pistons. The Gen III and Gen IV engines are not as strong as the pre 2000 Gen II engines. If someone disagrees, please jump in.

[RTTTTed]

I agree.

Larry Macedo put 9-1 Ross pistons in my engine back in 2003. I recommend all cream puffs get a piston change for sc and Nitrous just for longevity and reliability.

Ted

[dun4791]

Originally Posted by RTTTTed

My opinion is that the Paxton spins so fast (100,000rpm) that it heats the air more than the twin screw - that's why it needs an intercooler. The Roe spins much slower and that's why it doesn't need oil changes every 6,000mi. like the Paxton.

Ted

The Autorotor (Roe) actually does need an aftercooler/heat exchanger, but there is no room for an aftercooler on the Viper engine. Space constraints are why there is no aftercooler on the Autorotor, not because it doesnt need it.

Also you are wrong the Autorotor need oil changes every 5-6000 miles. The Paxton uses oil from the crankcase.

[dun4791]

Originally Posted by RTTTTed

You're thinking of a Roots blower. The Roe PD does spin according to the crankshaft, same as the Paxton, but the Power Valve releases the extra air back into the non-pressurized side of the intake making the blower "idle" and allowing vacuum to the intake runners. The screws spin, but don't actually make any boost or use any hp to turn until boost is built.

Ted

The speed of both blowers is determined by the pulley size, not just the engine rpm. If the engine is turning the screws, they are using HP. Neither blower builds boost at idle. Load determines boost.

[RTTTTed]

Originally Posted by dun4791

The Autorotor (Roe) actually does need an aftercooler/heat exchanger, but there is no room for an aftercooler on the Viper engine. Space constraints are why there is no aftercooler on the Autorotor, not because it doesnt need it.

Also you are wrong the Autorotor need oil changes every 5-6000 miles. The Paxton uses oil from the crankcase.

Really? Here's a copy/paste from Roe Racing Performance Parts

What kind of maintenance does the Supercharger add?

Next to none. The oil in the unit does not come from the engine oiling system, which gets contaminated from blowby and the combustion process. Therefore, the compressor oil stays cleaner and in better condition longer. We suggest the case oil level be checked at each engine oil change. The oil color will be the first indication that a change is due, which should be at approximately 50,000 miles.

Ted

[RTTTTed]

Originally Posted by dun4791

The speed of both blowers is determined by the pulley size, not just the engine rpm. If the engine is turning the screws, they are using HP. Neither blower builds boost at idle. Load determines boost.

The Paxton Novi also uses gears and shafts to up the impellor speeds so that it can spin fast enough to boost. Most centrifugal sc's use a belt and gears inside the case.

Horsepower used to spin rotors while not making boost is insignificant and doesn't even affect mileage.

Ted