What pulley are u paxton guys running?

[NoRice]

I am considering my options for more power, either upgrade pulley or nitrous kit. I am currently running the stock pulley. Who here is running more than the stock pulley, where did you get it and have you had any problems? I was told DLM sells a 10-11lb pulley.

 

[Paul Hawker]

For those of us running relatively stock engines, the standard pulley is about as small as we should go. If your engine is built with better components, those components will determine how much boost your engine can tolerate.

Reports of dependability/drivability issues have surfaced when going beyond the basic kit.

My problem is more of traction than additional power.

 

[NoRice]

Yeah I know. I guess my question is more for those guys who have built engines then. I am just looking to pick up about 100rwhp and wondering if going to a 10-11lb pulley will achieve that without throwing belts and be as reliable as my 8lb setup on there now is.

 

[Viper TT/10]

are you gearing up to race danny again? how much boost are you running currently? what type of piggyback are you using? go talk to gil at nrp, up by the track, i'm sure he can resolve some power issues.

 

[NoRice]

I am running the stock 8lb pulley. Vec2. Gil tuned this car when it arrived in Vegas over the summer. Just looking for more power now that I have my traction issues resolved. If Danny is ready to roll again before I move down to So Cal at the end of the month, then I will run him again. He is the only competition up there for me besides the bikes, and I really don't like running the bikes. If I had another 100rwhp I could probably beat anything that shows up including the bikes. I need about 10mph more to beat the bikes that matter, like the modded R1 from last weekend or the modded ZX10.

 

[ViperGMC]

Quick answer is yes, a smaller pulley can get you to 100, 150 or more. But life is never that simple. Assuming the engine has beefed up rotating components there are a host of other issues. First those little pins that come with the Paxton kit to secure you crank pulley will shear instantly. A keyed crank is mandatory but then you will you will experience major belt slippage after that. The fuel system is about maxed out with the Paxton so a fuel system upgrade is necessary too.

The facts - -stock pulley on the Paxton is 3.75, going to 3.25 will get you 12psi. The stock pulley for the crank is 7, going to 7.25 will get you 12 psi. Changing both will get you 18 psi. The things we’ll do for more HP. I would tell my best friend to stay with the stock Paxton, the reliability is fantastic, venturing beyond is a whole lot of time and $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$

 

[KenricGTS]

Go with a 13psi pulley from dlm. My old car made 900rwhp on pump with the 8 rib 13psi pulley.

 

[Viper X]

NoRice,

I'm guessing that you are all forged, have solved your fuel system issues and have upgraded to the ATI damper. If not, switch quickly to the ATI before you loose your damper. In that case, ATI offers larger crank pulleys and you can get a smaller supercharger pulley - though I'm not sure where my tuner got the supercharger pulley, he may have had it custom made.

My supercharger pulley is currently the 3.25 version and and I've had no belt issues in 6000 miles. It makes only 9.5 lbs peak boost though - likely due to the larger heads and larger bore size of my engine (530 ci), so I just ordered the 12 lb crank pulley from ATI. We'll see how that works out.

Do you know what your peak boost level is currently and at what RPM?

Keep in mind that with more cubes, you may not get quite as much boost as you think when changing pulleys.

Let me know where you end up in so Cal and we can get together and terrorize some Vettes, Porches, Lambo's, Ferraris etc.

Dan

 

[2MANYTOYS]

I am considering my options for more power, either upgrade pulley or nitrous kit. I am currently running the stock pulley. Who here is running more than the stock pulley, where did you get it and have you had any problems? I was told DLM sells a 10-11lb pulley.

Doesn't Cragin have the 10-11 lb. pulley setup as well.

 

[Dave T (BADVENM)]

2many, I believe your right. Some of the SRT truck guys are running about 10-11lbs in their Paxtons. I'm looking to hopefully have Dan do some of his magic on my truck early next year. With upgraded pistons already inside the motor I think I can get another 2-3 safe lbs of boost. The tune is the key and from what I've seen their work is excellent.

 

[bigmike32172]

there has to be someone that sells a pulley that can increase me 1 or 2#'s of boost without have to jump up to 12#'s?!?! by the way what is the highest amount of boost that is safe on a stock motor?

 

[NoRice]

I will be in the Northridge area of So Cal. I will be working out of Woodland Hills. I do plan on attending a Crystal Cove meetign to see the great cars I see on the net and apparently they have a local meeting every Sunday in Woodland Hills also.


Back to the question. I don't know about my crank pulley, I will have to look and see what Underground Racing installed. This car was like this when I bought it. I know it has a 522" built bottom end, worked stock heads, s/c cam, extrude honed intake, 65lb injectors with the fuel system to go with them. So I think I have all the upgrades needed to go with more boost.

When going from the stock pulley are you required to go to a 8 rib system?

I see some of you guys with numbers over my 770rwhp, are those numbers on pump gas or race gas? Viper X and ViperGMC you are both making 850rwhp. Is that pump or race gas and what boost are you running? From what I was told I am only making 7-8lbs of boost due to the bigger engine and worked intake/heads. I don't have a boost gauge.

 

[ViperGMC]

My motor is stock displacement with a Comp Cam custom grind. I am running an AEM PCM and have the ability to log all engine data. I have personally spent about 30 hours on the dyno playing with different setups and observing and learning all the crazy things that go on with these high HP configurations.

Running the 3.25” pulley I can get about 11.5 psi cold, well not hot. One of the first things I noticed was that when things warmed up a little the boost would fluctuate in the higher RPM’s which indicated that the pulley was slipping. DLM makes a tensioner (very simple) that works well and it eliminated the slipping. However, the tension on the belt has to be so tight that I was afraid that the belt would break or that the bearings on the SC would wear prematurely. The other issue is that the shear pins will shear. I know that DLM and WCV key the cranks when they do an engine rebuild. I did not key my crank, but after talking to Doug when I got the tensioner from him, I went backed and pulled off the damper and sure enough they were sheared. That was after only 200 miles. WCV uses the bigger pulley on the crank (as apposed to the smaller pulley on the SC) to help with the belt slipping.

I can get to almost 900RWHP with a cold engine on a cool day, advanced timing etc, the glory run, but more realistic 820-850 hot and under normal conditions on 93 octane gas. Any more than that and I get detonation.

I am on my third engine rebuild since I started messing with my motor. I have made a bunch of mistakes and learned a ton. I have a collection of mangled internals adorning my office as a reminder of my humility in this never ending pursuit of HP. I know the tuners want to upgrade everything and sometimes it seems a little over the top and you think you can get it done for less by cutting a few corners but don’t. Granted, I drive my car hard, very hard, I am a road racing *****. I just completed designing a new set of cogged pulleys that are being machined as we speak to eliminate the slippage and tension issues. I am going to 18 psi with a new set of heads and cam so we’ll see what happens next.

 

[NoRice]

ViperGMC,
How does your car run on the road courses? Have you done anything to keep it cool, like upgraded radiator? Just wondering as after my high speed runs, I am still only at 200 degrees, but thats just after a mile or so run, not extended periods. I have contemplated taking my car to Spring Mountain, but I was concerned that the paxton couldn't take the extended abuse. What brake pads are you running?

 

[ViperGMC]

Great questions. Car ran like a bat out of hell with no issues for extend periods of full throttle driving for many track days with the stock Paxton. After I increased the boost the temp started going up. I recently picked up a new radiator from Alan’s Performance, but have no feedback as of yet. I run PFC pads.

 

[repiv]

ViperGMC,
How does your car run on the road courses? Have you done anything to keep it cool, like upgraded radiator? Just wondering as after my high speed runs, I am still only at 200 degrees, but thats just after a mile or so run, not extended periods. I have contemplated taking my car to Spring Mountain, but I was concerned that the paxton couldn't take the extended abuse. What brake pads are you running?

james,
When I had my SC Viper, i ran it a bunch of times at spring mountain and a few times at the speedway roadcourse, never any issues. I even ran it on a 105 degree day, for about 30 mins, never got above 210 or so on that day

 

[NoRice]

NoRice,

I'm guessing that you are all forged, have solved your fuel system issues and have upgraded to the ATI damper. If not, switch quickly to the ATI before you loose your damper. In that case, ATI offers larger crank pulleys and you can get a smaller supercharger pulley - though I'm not sure where my tuner got the supercharger pulley, he may have had it custom made.

My supercharger pulley is currently the 3.25 version and and I've had no belt issues in 6000 miles. It makes only 9.5 lbs peak boost though - likely due to the larger heads and larger bore size of my engine (530 ci), so I just ordered the 12 lb crank pulley from ATI. We'll see how that works out.

Do you know what your peak boost level is currently and at what RPM?

Keep in mind that with more cubes, you may not get quite as much boost as you think when changing pulleys.

Let me know where you end up in so Cal and we can get together and terrorize some Vettes, Porches, Lambo's, Ferraris etc.

Dan

Dan,
Just found out from the builder that I do not have the stock pulley on it as I thought. They installed a slightly smaller DLM pulley so I am making more boost than I thought. It makes 8.5lbs of boost up to about 4500roms and then it has boost creep up to about 9.8lbs at redline. I also have the ATI balancer and the crank keyed, so I should be good to go for more boost. I will probably look into the 13lb kit that DLM has. The previous onwer had talked to DLM and they sell a 13lb pulley and tensioner fairly cheap. WIth that setup they said there shouldn't be any belt slip, but anything over the 13lb pulley and you will have problems they told him.

 

[bigmike32172]

NoRIce, let me know if and when you are going to part with that pulley, i think that might be the one i need!