Attention 11 second 455 racers

[Tony]

I just wanted to hear some feedback from the 11 second runners out there on gear selection and rpm shift points. I am currently running 4.10 in my car and shift at 5500. Too much gear not enough gear? Reving too hard or over reving? I am just curious to hear some input that all.
Thanks,
Tony

[gotbuick]

With my "turd" tranny I was running 11.80's with 3:73 gears. New tranny should cure this with some lower et's with the same gears.

[Jeff Kitchen]

Tony said:I just wanted to hear some feedback from the 11 second runners out there on gear selection and rpm shift points.

There are a lot of variables that go into those decisions. How much does your car weigh? What rear tire size? Where does your engine make HP and TQ peak? A lot of this is trial and error. As a rule, I think a 4.10 is a good starting point, but you might go faster with a 3.90 or even a 3.73. You won't know until you try.

You might also try some of these programs where you enter your tire size, rear gear, and MPH and it gives you the RPM. Depending on where you are in the elevens, you will probably be in the 107-115 MPH range.

Hope this helps. Have fun.

[11SecondGS]

tony whats wrong with those gears?

I had 4:10 and I enjoyed them very much.

I will probably switch to 4:35 or 456 next year though. I havn't given it much thought, so I can't say for sure what I will do. No less than 4:10 guarenteed for me

josh

[buick535]

11SecondGS said:tony whats wrong with those gears?

You have a turbo car so isnt the high[er] rpm where you get your power from.

I had 4:10 and I enjoyed them very much.

I will probably switch to 4:35 or 456 next year though. I havn't given it much thought, so I can't say for sure what I will do. No less than 4:10 guarenteed for me

josh



As a general rule of thumb, nitrous injected, supercharged, and turbocharged cars tend to work better with less gear. The power added with these systems adds great amounts of torque, a smaller rear gear allows you to use that torque rather than just instantly rpm up through the torque band wothout the car really going any where. Jim Burek

[11SecondGS]

Yeah, my is just a regular breather.

What do you suggest then for cars with n20, blowers, and turbos?

[buick535]

11SecondGS said:Yeah, my is just a regular breather.

What do you suggest then for cars with n20, blowers, and turbos?




I would probably lean towards a mid 3 gear , maybe up to 3.73.
Alot depends on what size tire you will have as well. Jim Burek

[Tony]

Thanks for the info guys. There are just three of us buick guys at the drag strip that I run at and all three of us use different gear ratios. All three of our motor combos are close, but I run more gear than the other two guys. I was just looking some feedback.
Thanks once again,
Tony:Comp:

[killrbuick66455]

Hi Tony, My car ran best 11.70's with 3.73's 3800 stall best shift pont was a low 4800 rpms believe it or not.....it suprised me to. :TU:

[Tony]

Eric, what size tire are you using, what camshaft and what are your rpm's when you go through the finish line? Thanks for the info,
Tony

[RED GS 1]

4000LB.'70 stage1,3500 stall converter,28"tall 10"slicks,shifts at 5400RPM's in Drive,3.73gears-11.78@113.2MPH.still experimenting:laugh: :TU:

[killrbuick66455]

Hi Tony,I was using a 28-9 inch slick. My rpm was at 5600 at the finish line.The cam i have is the sp235 492 lift 238-248 duration..hope this helps.. My next gear will me 3.42 and tighten the convertor sum of 200 rpms, It seams like the convertor slips to much at the top end and im loosing MPH. Im going thought the traps at 112.5 on average.. :TU:

[D STAGE 2 455]

I have 3.90 gears in my 455 powered '72 skylark. I'm considering 3.73's, because I think the engine is rushing thru the RPM's, and not taking full advantage of the engines torque.

[nailed]

As Jeff mentioned there are alot of variables
our car weighs 3475 lbs
s/s 455 30 over hemi-killer cam
3200-3500 Neil Chance converter
launch at 2000 shift @ 5600
373 gears
best 11.56 @ 114mph 1.59 60'

[Tony]

Any of you guys using a block girdle?
Tony

[72GSX]

I am running 4.10 gears in mine at mid to high 11s at up to 116 mph, about 113 mph most days. I shift at 5800 rpm and hit 6000 at line on a good pass. I had to go to 29.5-10.5 tires because it would get into rev limiter on 28" tire. I have a 10" B&M3600 hole shot converter, works OK but I wish it sliped less in high gear. No block girdle, stock unpolished rods with sealed power forged pistons. Rods have ARP bolts and big end resized. Poston 105A cam. Best of 1.52 60ft. Tom

[D STAGE 2 455]

72GSX said:I am running 4.10 gears in mine at mid to high 11s at up to 116 mph, about 113 mph most days. I shift at 5800 rpm and hit 6000 at line on a good pass. I had to go to 29.5-10.5 tires because it would get into rev limiter on 28" tire. I have a 10" B&M3600 hole shot converter, works OK but I wish it sliped less in high gear. No block girdle, stock unpolished rods with sealed power forged pistons. Rods have ARP bolts and big end resized. Poston 105A cam. Best of 1.52 60ft. Tom I had a B&M superhole shot converter, & I got rid of it for the same reason( to much slippage in high gear) ordered an ATI treemaster. Satisfied with the ATI. I am not using a block girdle. No need yet, my engine is all done at 6000 rpms, plus I'm making less than 600 h.p.

[killrbuick66455]

Same Here NO girdle... stock rods,crank, pistons are TRW Heavy slugs :TU: