GEN 5 whipple 60-130 dragy ?

[mejohn50]

Very nice! 4 10ths with basically just a pully change!! And safe to boot! Well done!

Thanks. I have had a lot of help along the way to get here. It's great to see the efforts actually work.

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[engineermike]

Pulley changes are underrated…

 

[Platinum_5.0]

Thought I would share this comparison for anyone who is interested.

Both runs were taken on the same day within about 3 hours of one another. The left run was earlier in the day so the DA was a hair better, but similar enough conditions for this comparison. Both runs starting in 3rd gear, though I can start in 2nd. I didn't start in 2nd to eliminate the wheel spin variable, but in my experience starting in 2nd rather than 3rd is worth about 0.15-0.2 second improvement. Both runs on pure pump 93 octane. No booster, no splash of race gas, just regular old 93 from the gas station in my small town.

Left run is 3.75" pulley and right run is 3.25" pulley with a load limiter in place at 1.8 air load to make sure I didn't run out of fuel or spark (and also to keep the pistons and connecting rods happy). I could have removed the limiter and made another run since I wasn't out of fuel or spark, but this is already pushing harder than I had ever expected on pump gas. I was holding right at 1.8 air load in the data log and it was hitting 16 degrees of timing at 7500rpm, which is also where it was shifting. Saw no knock other than one event on one cylinder on the 4>5 and 5>6 shifts.

Based on this data I am very confident a mid to low 5.x is possible on just pump gas at full weight.

That's awesome, our 3.75 pulley runs are basically identical! lol

 

[CORNYOTE]

mine on a 3.0/stock lower does well. still trying to hit the elusive 3.xx club.

 

[mejohn50]

That's awesome, our 3.75 pulley runs are basically identical! lol

Dang. Exactly the same. Was that starting in second or third?

 

[mejohn50]

mine on a 3.0/stock lower does well. still trying to hit the elusive 3.xx club.

That’s moving for sure. How much more to get it into the 3s?

 

[CORNYOTE]

That’s moving for sure. How much more to get it into the 3s?

Guessing 2.75 pulley or a shot of nitrous

 

[Angrey]

Guessing 2.75 pulley or a shot of nitrous

The bigger issue is traction. At some point, the limitations on how much you can put to the pavement become the dominant factor. We're in an era where making gobs of torque and power is fairly easy (compared to the past) but we still have the limitations of a rear wheel drive chassis.

On dragytalk, it makes you want to vomit to see Audi RS3's doing sub 4 second rips, but the reality is, there's a reason that outside of the Dodge vipers, the roll racing community is dominated by AWD Lambos and GTR's and R8's and such. As we come down in the 60-130 time ranges, it starts to become all about traction.

 

[engineermike]

I agree Angrey. But do you remember when 60-130 replaced 0-60 because traction? What next? 100-150?

 

[Angrey]

I agree Angrey. But do you remember when 60-130 replaced 0-60 because traction? What next? 100-150?

I think it was a combination of things.

1) 60-130 (rolls) is easier to execute on the "street" than finding a spot where you can do standing starts. It's easier to replicate and do multiple times in a session than a fixed location.

2) Going to rolls removes much of the "skill" associated and turns it more into "my car vs your car" deal

3) It seems the race enthusiast community is suffering from the same challenges of the firearm/shooting community, which is ever growing population and zoning/use challenges of new facilities which are large, noisy and usually have to be way out in the sticks for the economics to make sense. As development creeps, facilities get sold and redeveloped to some other more fruitful/revenue generating use. The result is the number of facilities per capita continue to dwindle. More tracks are closed and redeveloped than new tracks opened. Add in ever increasing insurance costs and requirements, point is, there's less place to race and there's more load at tracks these days. Where I'm at, you have to drive several hours to get to the nearest 1/4 track and even when you do, there's nights that you might only get one run in because there are so many people.

Between traction, between the popularity of pitting car vs car (rather than skill of driver vs driver) and between decreasing opportunities, I think we've seen the rise in popularity of roll racing and associated devices/metrics.

 

[Platinum_5.0]

Dang. Exactly the same. Was that starting in second or third?

I can't honestly remember if I had my drag rears on or not. Looking at the video I had to gently roll into it so I'm thinking it was 3rd with my street tires. They are Indy 500's, 325's.

 

[CORNYOTE]

The bigger issue is traction. At some point, the limitations on how much you can put to the pavement become the dominant factor. We're in an era where making gobs of torque and power is fairly easy (compared to the past) but we still have the limitations of a rear wheel drive chassis.

On dragytalk, it makes you want to vomit to see Audi RS3's doing sub 4 second rips, but the reality is, there's a reason that outside of the Dodge vipers, the roll racing community is dominated by AWD Lambos and GTR's and R8's and such. As we come down in the 60-130 time ranges, it starts to become all about traction.

Very true.

I have a 15” rear conversion running a 325/50R15. If traction is really bad I’ll go to a 15W Hoosier C07 slick. I also have a Ron G no-prep long travel front end. That and the weight bar all help out quite a bit.

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