Drag times, fuel questions with 8lb/10lb Pulley on Roe blower

[Schulmann]

I have been using the 6.5lb pulley with a lot of succes since more than a year.
My Viper runs great on 91oct fuel and delivers an outstanding performance on 94 oct fuel (601rwhp/600rwtq).
My drag times are also good with my Michelin street tires (1.7/11.3/130).


In my area it is not easy to get 93/94 oct fuel and now I often end-up using real 103/109 oct VP race fuel.
So why not to switch to higher boosts ?


I was thinking to switch to the 8lb pulley or maybe even to the 10lb pulley.

How well these pulleys run on 91 oct fuel ?
How much timing should I pull compared to the 6.5lb pulley ?
I drive more than 10000mi a year on street so it is important for me to keep my reliability on long trips.


What are the best drag times with these pulleys on Street tires ?
(I can only take the fuel no place left for drag radials ...)

Anybody has one of these pulleys that he wants to sell ?

[Mccarlin]

What year is your car? Roe sells pulleys for 130 bucks i beleive. You might see another 30rwhp or so with an 8lb pulley.

[BlueGTS]

Just to help people respond, can you give a list of your other mods on the car, headers, RR, etc. Also what does your VEC2 show as your actual boost? Hitting over 600rwhp with only 6.5 actual lbs is very healthy.

I currently have the 8psi pulley on my car and see 7psi climbing to 9psi at redline. I will be changing to a 10psi pulley this weekend. Talking to Sean, he did not recommend I rev as high with the 10psi pulley, but that recommendation might vary depending on what other modifications you have. I do not have any head or valve train upgrades so I will be creating more heat with the 10psi pulley. For that reason Sean said I would only get a torque gain going to 10psi. If I were drag racing I would probably have stuck with the 8psi pulley as HP is what gets you MPH. Since I am just looking for SOTP feel, the added torque of the 10psi will be fun.

[Shelby3]

You may not see much in the way of gains unless you do your heads for better flow especially with the 10lb pulley. Boost creep.

[mntngts99]

I tried the 10lb pulley and just went back to the 8lb. The 10lb was nice in the fall and spring but with temps being over 100* in the day the 10lb just made to much heat.

My best with a stock motor on 8lb is 624 rwhp/661 rwtq.

With your 130 mph trap speed you should get into the 10's.

[ViperBing]

Are you running water/meth injection?

[BlueGTS]

Brad, now you are scaring me into thinking I should just stick with the 8psi pulley. What is the max temperature you think the 10psi pulley works well at?

[Schulmann]

My modifications (All parts 100% from Roe Racing) :

1.7 R.R., Alum fly wheel, B&B Headers and exhaust, W/M, NGK FR5 plugs, 2 sets of WBO.

I have this power and torque mainly thanks to the WBOs.
(And naturally also thanks to Sean Roe).

[Shelby3]

I tried the 10lb pulley and just went back to the 8lb. The 10lb was nice in the fall and spring but with temps being over 100* in the day the 10lb just made to much heat.

My best with a stock motor on 8lb is 624 rwhp/661 rwtq.

With your 130 mph trap speed you should get into the 10's.

I run twelve pounds of boost in the heat with no problems. If you don't have the water/meth, it would definitely help.

[plumcrazy]

Shelby3, id think you can run that kinda boost cause you have heads and a cam.

right ?

[Shelby3]

Shelby3, id think you can run that kinda boost cause you have heads and a cam.

right ?

No, it's the water/meth that keeps things cool.

[mntngts99]

I do have water/meth,In mid summer my car for what ever reason will run 11.00 to 11.09 all day long at the track on my 8lb setup. With the 10lb pulley I'll run high 10's for the first few runs the start loosing a tenth ever pass after that. The 8lb on my stock motor is just more consistent in the heat.

BlueGTS
If your looking for in-town driving the 10lb water/meth should make you happy. If you all ready have water/meth you will only see about 35rwtq,if adding the water/meth and 10lb pulley you should see closer to 70rwtq. Untill I do some motor work I doubt I'll ever put the 10lb pulley back on.

[Schulmann]

It seems that the 10 lb pulley is only for those with sever addtition to higher concentration of HP. I haven't reached that level of dependence yet.

Last Question:

How well the 8lb pulley runs on 91oct fuel during moderate racing and on highway ?

[BlueGTS]

mntngts99, I have the W/M and noticed a big SOTP torque jump due to adjusting my time from -6 to 0. I am hoping for the same thing with the 10psi pulley. When you put on your 10psi pulley did you go to the smaller idler pulley?

Schulmann, Do you know what boost you were hitting when you dynoed 601rwhp? Due to running rich and not having time to play with tuning, even though I have two widebands, I doubt I am even at 600rwhp with the 8psi pulley.

[mntngts99]

I did go to the smaller Idler pulley, But had to mill the spacer/washer to get it to fit.

Schulmann
Had no problem with 91oct.
8lb,93oct with W/M I can run +5 on my timing.