Gears vs trap speed discussion!

[TonyN]

I was talking to some friends the other night about my before & after 1/8 times with the addition of 4.10's and the 127200 comp cams. We all had different "opinions" and I was wondering what you all thought? I honestly never thought about it. Of course we were talking about "NSR" style cams and some of the others having issues with losing ET/speed with them. So I decided to pull my slips and compare.

Do gear changes effect trap speed?

I was comparing my most recent 1/8 time slips to ones from last year, only difference being the 4.10's and cams. All the runs where done on my 19's and street tires. I know they are hurting me, but I finished off my M/T DR's midway last year and haven't gotten new ones yet. Basically, I want to know if my MPH gains is from the cams themselves or do the gears contribute as well?

Last year my best 1/8 run was a whopping 8.8@83mph (2.0 60ft). Last month I ran 8.19@88mph (1.8 60ft). Same track and similar weather conditions. I didn't even realize I gained 5mph though. I thought it was only 2-3. I was originally hoping for high 7's. I know I need some new sticky tires, especially since the blower will be going on soon!

I need to take my ass to the 1/4. The 1/8 is just so convenient since it's closest and right up the street from a good buddy of mines house. Basically the 1/8 is for launch practice, haha.

 

[RED09GT]

This should be interesting as I lose a full MPH when I shift into 4th right near the stripe as opposed to leaving it in 3rd with 3.55 gears-but my ET is within hundredths and sometimes better going into 4th. I think that you would gain MPH if your car is fairly under-geared seeing as we have fairly heavy cars and a small cube motor.
In your case, it would seem that instead of shifting into 3rd near the stripe and being below the powerband, you are well into it at the stripe. As for my case in the 1/4, I'm above the powerband in 3rd and below it in 4th.

 

[NotQuik]

With the mods below and 3.31 gears the car went [email protected] with a 1.922 60' and after 4.10's it went [email protected] with a 1.81 60'. Best mph after gears was 108.68 on a 1.992 60' and it went 12.75 on that pass. Best mph with the 3.31's was 107.02 on a 13.0 pass. So I gained mph from a gear swap and no changes with nearly identical weather conditions.

 

[06whipple]

If you increase your rate of acceleration with a gear change...your end velocity is going to increase to a certain extent. If traction is the issue then you are losing et yet gaining mph. You are probably spinning with the 4.10s more than you realize so you end up going faster but your et suffers. The better you hook the slower you go (mph) but you get there sooner. I've ran an 11.9 at 121 and an 11.65 at 117.

 

[jroc07gt]

look at how much trap matt and kona picked up going to 4.56's. its all about the right combo to put you at the right rpms as you cross the traps.

 

[TonyN]

Cool, thanks fellas. My side of the debate was that a little mph should be gained but I honestly wasn't 100% sure if that was true as I had nothing to back up my thoughts. It's was just me and a couple buddies bs'ing about cars while drinking a few beers.



So gears and weight reduction should net higher trap speeds. Makes sense! I just personally never paid attention in the past whether or not my trap speed increased from gear ratio changes. Plus I have never done actual before and after runs with just gears. Like someone above said it all depends on the combination of mods/traction as well. I was comparing my best runs from each night.

 

[06whipple]

One thing I have learned from talking to guys at the track...spend your money on drivetrain and traction first. Its all about the 60 foot. The guys running the best ets launch hard as hell and have sick 60 foot times.

 

[jroc07gt]

these cars weigh so much and have little power so you need more gear

 

[qwikhuh]

look at how much trap matt and kona picked up going to 4.56's. its all about the right combo to put you at the right rpms as you cross the traps.

They also run taller tires so the overall drive ratio is not that much greater than a 26 in tire and a 4:10 gear. The 117-118 that Matt and Adam are running are not the result of the gear. Both had other modifications including power and weight loss. Adam has had the 4:56s for awhile.

 

[Vapour Trails]

Gears will increase trap speed, all other things being equal.

 

[jroc07gt]

They also run taller tires so the overall drive ratio is not that much greater than a 26 in tire and a 4:10 gear. The 117-118 that Matt and Adam are running are not the result of the gear. Both had other modifications including power and weight loss. Adam has had the 4:56s for awhile.

yea but he still gained trap back when he switched to 4.56s.

 

[Airborne2000]

With the mods below and 3.31 gears the car went [email protected] with a 1.922 60' and after 4.10's it went [email protected] with a 1.81 60'. Best mph after gears was 108.68 on a 1.992 60' and it went 12.75 on that pass. Best mph with the 3.31's was 107.02 on a 13.0 pass. So I gained mph from a gear swap and no changes with nearly identical weather conditions.

Dude how in the world are you running 12.75s?!?!

I have tons of mods done to my car, 3000k stall, long tube, udps, delete plates, long tubes, 4.10s, full suspension, cai, etc. and Im only about 4 hours north of you and I CAN NOT for the life of me break into the 12s!

13.006 @ 104.5 1.8 60ft is my best.

 

[KungFuHamster]

Dude how in the world are you running 12.75s?!?!

I have tons of mods done to my car, 3000k stall, long tube, udps, delete plates, long tubes, 4.10s, full suspension, cai, etc. and Im only about 4 hours north of you and I CAN NOT for the life of me break into the 12s!

13.006 @ 104.5 1.8 60ft is my best.

which stall do you have? if its a TCI, youd be best to shitcan that piece of shit and spend the extra $$ on a PI

 

[Airborne2000]

no, i have an utimate converter concepts that works really good.

 

[luillo]

One thing I have learned from talking to guys at the track...spend your money on drivetrain and traction first. Its all about the 60 foot. The guys running the best ets launch hard as hell and have sick 60 foot times.

So the better the 60 ft the faster you finish 1/4 mile right???

better 60 ft = better ET???

 

[chad05gt]

FWIW... 4.56's, n/a stock shortblock, 117+ trap in 3720lb daily driver...

 

[06whipple]

a tenth in sixty foot is around 2 tenths in et (roughly). I wouldn't focus on mph at the traps.