Re: BG 2009 Videos Drag Strip
 

Pete

Great seeing you again and your car is a finely tuned machine!@!!

The buick guys were so gracious and the dates are set next year to hang / drag with them again.

Looking forward to another great year next year (20th anniversary)

:cheers:

David

Re: BG 2009 Videos Drag Strip
 

I have thought about this a lot also. Here are my thoughts, and I am asking for feedback.

Imagine a ZR-1 with gears for wheels and sitting on a toothed track. From a standing start, to get a rapid acceleration, you would have to slip the clutch until the car speed is fast enough to get the engine rpm at usable rpm. Then you want to get to peak torque rpm as quickly as possible. With a higher rear end gear ratio (ie 4.10:1 versus 3.45:1), the engine will get to peak torque sooner (sooner meaning a lower car speed).

In other words, during the time it takes to get from a standing start to engine at max torque rpm with the wheels gripping and the clutch fully engaged, you are not making maximum acceleration.

In a poor launch, when the clutch pedal is released, the car bogs down because the engine rpm is low enough that engine torque can't sustain the rapid initial acceleration. With a higher rear end gear ratio, the engine rpm is higher when the bog occurs, so it should not be as severe.

Am I thinking right? (I am in no way an expert about drag racing and I want to learn.)

Jim

Re: BG 2009 Videos Drag Strip
 

Bob, yes this was my best so far.
You my recall first time out last fall at Capital Raceway I broke a spindle on the very first pass and had to be trailered home. (thanks again David and Jeff for bailing me out)
I believe the 4.10 gears are a good match for the quarter mile with the way I have my car set up. RPMs appeared to be right around 6500 going though the traps in 4th gear on my best run. Traction was tricky business though. It was great right after they put the sticky stuff down however, it seemed to drop off quite a bit after 25-30 of those storming Buicks worked it over. The run of my car in video 5115 was taken when the track was at its poorest and the tires still at 35 psi so I had a lot of wheel spin coming out even though launching at 1500 rpm. On my best run later in the day the track had about 15 runs on it since last prep and I had the tires down to 20 psi. Came out at around 2000 rpm and this time the car hooked very well but bogged bad. My target at BG was to make the twelve's and not break anything. With this accomplished I called it a day.

Re: BG 2009 Videos Drag Strip
 

Engine bog should be the same as it is with tires on the car. In both cases, the traction exceeds the engine's ability to deliver force.

With 4.10's you should be able to drive through bogging better, because the shorter gearing means it takes less acceleration/time to get back into the powerband.

With unlimited traction, 4.10's should certainly be better as you can't blow the tires/cogs away, and the gears get you into the powerband sooner. Once in the powerband, I believe both cars would accelerate more or less the same. The 4.10's should help the short game primarily, and help you make the most of more traction. You'd just rev it up and dump the clutch, and keep an eye out for where your driveline parts land. ;)

For me the problem is not having that extra traction, and not having the skill to dance the fine line without blowing away what I've got.

Last year I don't think I ever ran in the 13's unless I missed a shift. Yet my best time wasn't much better than you or Phil ran this year. It's just I could generally be in that ballpark vs the wild variation when you smoke the tires with 4.10's.

That's my take. But I'm no expert either. :hello:

Re: BG 2009 Videos Drag Strip
 

"Imagine a ZR-1 with gears for wheels and sitting on a toothed track."

Jim,

Pete wants to know "Where you get these tracks?" :sign10:





Bob,

Interesting because Lgaff and I have very similar '92 setups including the same headers (Watsons 1 7/8"). I'm running the Magnaflow with resonator and Xpipe, while he has Xpipe, no res, and Borlas. He has 4.10's and I have the 3.45s behind a Fidanza FW.
Lee has always gotten better 60' times and 1/8 mph. His et has been
.2-.3better. The last time we raced heads up our traps speeds were within .01 of each other.

Re: BG 2009 Videos Drag Strip
 

I don't doubt the 4.10's result in better short times. I'm guessing he's a good driver. I'm sure if I were a good driver, I might find the 4.10's more appealing. ;) But it's about what the car will run with me at the wheel that matters. :D

Re: BG 2009 Videos Drag Strip
 

I did learn one thing about 4.10:1 gears on this BG trip. There were 5 ZR-1's running together for part of the trip. We all filled up and drove together and then filled up again. My '93 has 4.10:1 rear end. The other cars have stock rear end. The average to fill them up was just over 9 gallons. I put in about 10 gallons. Glenn may have the actual numbers and the miles we covered, but I used more gas, as you would expect.

Jim

Re: BG 2009 Videos Drag Strip
 

I traded in my 4.10's for 3.33's and am pleased with the results. Didn't care much for the traction issues in first gear plus I can now complete the quarter mile in three gears instead of four. Maybe with some race rubber the 4.10's would have been more to my liking but I prefer a run what you brung approach - off the highway straight onto the track.