Whipple question. Can you run 91 Octane safely with 21# pulley?

[lthlvpr]

Just curious for all of you Whipple owners out there. I know many people running the 21# pulley on the Whipple but most of them run 93 Octane or race gas. Is 21# boost too much for 91 Octane? Is it too close to the edge?

 

[BlackICE]

I don't have any real data on the 21 psi pulley. However in theory there is a point of dimishing returns where the added boost increases both charge temperatures and pressures, thus requiring the spark retardation to prevent detonation. At some point this loss of power from spark retarded is greater than the power gain from more boost. Also the intercooler setup will be working harder making heat soak at bigger problem. It really depends on how you are going to drive it and under what conditions. If you only do 10 seconds pulls with rest periods in between in cool weather, it probably will work fine with the right tune. If you plan to do an open track on a road course during the summer time in TX is wouldn't be wise.

e.g. I am using the 19 psi pulley and at Thunderhill and driving like granny, on a cool ~70F outside temperatures, my air intake temps were 84F pre-blower and 138F post blower. This was data from a 7 second pull from 2400 to 5900 rpm. ACT2 started at 128F and rose to 138F during that time. I was running 91 octane. I think even on this cool day the 21 pulley would have been too much since ACT2 would surely be much greater than 138F. Just think what the temp would be an a hot 105F day in AZ!

 

[Shadowman]

Just curious for all of you Whipple owners out there. I know many people running the 21# pulley on the Whipple but most of them run 93 Octane or race gas. Is 21# boost too much for 91 Octane? Is it too close to the edge?

IMO; yes

Certainly you could detune her to the point that she would be happy however IMO the the benefit of the 21 PSI pulley would be lost and in the end likely produce less power when compared to the 19 PSI

Takes care

Shadowman

 

[B O N Y]

21lbs on 91 octaine gas with Dustin's tune.
I'm in regular contact with him regarding available upgrades, so far her hasn't called #1153 back into his development center.

 

[Shadowman]

21lbs on 91 octaine gas with Dustin's tune.
I'm in regular contact with him regarding available upgrades, so far her hasn't called #1153 back into his development center.

I should have mentioned your gal as I knew that she was twisted a bit tighter by the Whipple Doctor himself aka Dustin however I thought that your gal has a special hand hand pulley too.

There is no doubt that your gal is very happy

All the best

Shadowman

 

[BlackICE]

I think Bony has the one and only 20 psi pulley, maybe 3.33"

 

[B O N Y]

I think Black seriously know more about my Whipple than I do. Mine is a one off and I am 100% happy and have more power than I can handle. That said, I still need more....:thumbsup:lol:thumbsup


Also, if I could pick one shop on the West Coast, it would be SHADOWMAN.:cheers

 

[DoctorV8]

21psi can be run on the street, with 91 octane and will out perform the 19psi. It's much closer to the edge of detonation and engine temp becomes far more important.

Thanks,
Dustin

How has your experience been with the 21 psi pulley on 93 octane? Significantly better numbers than 91 Octane? Any dyno curves you can share with us?

Thanks....

Sanjay (in TX)