1/4 mile and gears

#1stangFAN · Sep 15, 2009

So this may be a kind of stupid question but ill go ahead anyways. I have 4.10 gears that i installed in my 05 GT this summer and i love um compared to stock, but i know it gets you 0-60 faster but does it help out in the 1/4? Because i know you might have to switch into 4th at the very end and it just seems to me like you might go faster 0-60 but slower 60-100 than stock gears would. Am i right or wrong on this cause this one has me kind of stumped.

blackgt460 · Sep 15, 2009

If it get's you more 0-60mph it def. gets you more in the 1/4. But yea it's a good mod for 1/4 mile improvements, probably more so with an auto but wither way definately worth it with 1/4 mi gains. I can't wait to get gear and a converter in my car.

#1stangFAN · Sep 15, 2009

But i think of it like this (correct me if im wrong)and im making up numbers to make it easier, lets say a GT with stock gears goes 0-60mph in 6 seconds and 60-1/4 mile in 7 seconds thats a total 1/4 mile time of 13 seconds. But does it make sense to say that the same GT with 4.10's goes 0-60mph in 4.5 seconds and 60-1/4 mile in 8.5 seconds which still adds to a total 1/4 time of 13 seconds?

blackgt460 · Sep 15, 2009

Well I can tell you that increasing you 60ft time at the track by a tenth will most likely get you close to 2 tenths in the 1/4 mile. Not always accurate but a rule of thumb some follow. The 60ft times are a big deal, getting those under control will result in a solid 1/4 mile time....tire spind will f a run up and the 60ft is where it happens and if you have 4:10s and drag radials and can drive then youm should be good.

#1stangFAN · Sep 15, 2009

alright thanks and i have an auto as well but havnt done much drag racing with it latly, what rpm do you ussually like to lauch at to get the least amount of tire spin? o/d off or on? and i know to turn the traction control off as well

blackgt460 · Sep 15, 2009

Yea I still have 3:31 gears so I launch at 1200 RPM and let the converter flash and it really doesn't spin the stock tires. But with your 4:10's I hope your using drag radials and I would launch it as high as the stock converter will allow considering that's what you have. Auto S197's roll out pretty good man if you drive them right which is a good launch and let you tuned car do the shifting itself. I don't have the balls to pay 400 a month for a stick car and launch it at like 5kRPM but I def respect those that do. Traction control and OD off.

SpartaPerformance · Sep 15, 2009

#1stangFAN said:
But i think of it like this (correct me if im wrong)and im making up numbers to make it easier, lets say a GT with stock gears goes 0-60mph in 6 seconds and 60-1/4 mile in 7 seconds thats a total 1/4 mile time of 13 seconds. But does it make sense to say that the same GT with 4.10's goes 0-60mph in 4.5 seconds and 60-1/4 mile in 8.5 seconds which still adds to a total 1/4 time of 13 seconds?

Doesn't work that way, acceleration is a constant. The more RPM the more torque the more HP. If you're shifting into 4th at the very end perhaps you are shifting too short between 1-2 and 2-3 or you're not making enough HP in the higher RPM. What other mods do you have?

#1stangFAN · Sep 15, 2009

just a C&L CAI, 91 bama tune, 4.10 gears, and its an auto

Five Oh Brian · Sep 16, 2009

#1stangFAN said:
just a C&L CAI, 91 bama tune, 4.10 gears, and its an auto

With nearly identical mods as you (JLT CAI, 92 octane tune, 4.10's, and automatic trans), my 07 GT ran 13.40's to 13.50's @ 102+ in the 1/4 mile. I never ran the car stock with the 3.31 gears, but most magazine tests showed them to run high 13's to low 14's @ 99-100 mph in the 1/4 mile, so I figure the gears, tune, and CAI combined netted me a 1/2 second and 2-3 mph improvement in the 1/4 mile.

I later added a big stall converter and the car launched harder and ran 13.20's @ the same 102+ mph. The stall converter allows me to hold about 2500 rpm's against the brakes and then it instantly flashes way up at launch (3800 rpm's before I had the supercharger, and now it's 4800 rpm's with the supercharger). The stall converter was good for about a 1/4 second improvement in the 1/4 mile - probably as good an improvement as the gears gave me, and for the same cost as the gears.

Five Oh Brian · Sep 16, 2009

#1stangFAN said:
just a C&L CAI, 91 bama tune, 4.10 gears, and its an auto

Next time you go to the track, plot a graph of your results to various mph points. Here's #'s from an all-stock 05+ GT automatic from a well-know magazine's test....

0- 60 mph = 5.1 seconds
0- 70 mph = 6.8 seconds
0- 80 mph = 8.6 seconds
0- 90 mph = 11.0 seconds
0-100 mph = 13.7 seconds

#1stangFAN · Sep 16, 2009

Five Oh Brian said:
With nearly identical mods as you (JLT CAI, 92 octane tune, 4.10's, and automatic trans), my 07 GT ran 13.40's to 13.50's @ 102+ in the 1/4 mile. I never ran the car stock with the 3.31 gears, but most magazine tests showed them to run high 13's to low 14's @ 99-100 mph in the 1/4 mile, so I figure the gears, tune, and CAI combined netted me a 1/2 second and 2-3 mph improvement in the 1/4 mile.

I later added a big stall converter and the car launched harder and ran 13.20's @ the same 102+ mph. The stall converter allows me to hold about 2500 rpm's against the brakes and then it instantly flashes way up at launch (3800 rpm's before I had the supercharger, and now it's 4800 rpm's with the supercharger). The stall converter was good for about a 1/4 second improvement in the 1/4 mile - probably as good an improvement as the gears gave me, and for the same cost as the gears.

when you go to the track do you have drag radials or lower the pressure in your tires, and what converter do you have?

Five Oh Brian · Sep 16, 2009

#1stangFAN said:
when you go to the track do you have drag radials or lower the pressure in your tires, and what converter do you have?

I always run drag radials (BFG 275/40/17's) at the track, otherwise it's a wasted effort fighting for traction, IMO.

My converter is from Fuddle Racing in Utah. Super tough, great warranty, holds lock-up at WOT even with the supercharger, etc. They have a few different stall speeds to choose from. I picked the one that's rated to flash to 3600 rpm's in a stock GT. With mild mods, mine flashed to 3800 rpm's, and with the supercharger it flashes to 4800 rpm's. For most street/strip cars, I suggest getting one rated to flash to about 3000 rpm's.

#1stangFAN · Sep 16, 2009

dumb question but what does the stock converter flash at?

Five Oh Brian · Sep 17, 2009

#1stangFAN said:
dumb question but what does the stock converter flash at?

IIRC, the stock converter flashes to somewhere around 2200-2300 rpm's, which is why the stock automatics feel a bit sluggish at launch.

I've been told that the best flash point to maximize acceleration is just a few hundred rpm's below peak torque. A stock GT's peak torque is at 4500 rpm's (mine is now at 5100 rpm's with the centrifugal supercharger's top-end influence).

Marc S · Sep 17, 2009

Even though you have to shift into 4th with 4.10 gears in the 1/4, my car is still faster with them than with the stock 3.55 gears. I have a bet with a friend that I can get my 08 into the 12's with the stock tune, airbox and the stock tires. Other than the 4.10's and road race springs my car was in stock form and last weekend I ran a 13.12 @ 106 with a 1.73 60' on stock tires with a big head wind. The gears make a big difference. You have to have really good throttle and clutch control to get it to hook up though.

#1stangFAN · Sep 17, 2009

Five Oh Brian said:
I always run drag radials (BFG 275/40/17's) at the track, otherwise it's a wasted effort fighting for traction, IMO.

My converter is from Fuddle Racing in Utah. Super tough, great warranty, holds lock-up at WOT even with the supercharger, etc. They have a few different stall speeds to choose from. I picked the one that's rated to flash to 3600 rpm's in a stock GT. With mild mods, mine flashed to 3800 rpm's, and with the supercharger it flashes to 4800 rpm's. For most street/strip cars, I suggest getting one rated to flash to about 3000 rpm's.

When you installed your converter did you also install a tranny cooling pan as well?

Five Oh Brian · Sep 18, 2009

#1stangFAN said:
When you installed your converter did you also install a tranny cooling pan as well?

You mean like a pan that's finned for better heat disappation? I should have but didn't. I am also still using the stock transmission cooler, even though I really should have added a bigger cooler. A looser converter generates more heat, and heat cooks trans fluid and kills transmissions.

#1stangFAN · Sep 18, 2009

Five Oh Brian said:
You mean like a pan that's finned for better heat disappation? I should have but didn't. I am also still using the stock transmission cooler, even though I really should have added a bigger cooler. A looser converter generates more heat, and heat cooks trans fluid and kills transmissions.

im a noob here sowhat does a loose converter mean?

Five Oh Brian · Sep 18, 2009

#1stangFAN said:
im a noob here sowhat does a loose converter mean?

The "looser" the converter, the higher rpm's it will flash to before launching the car. A tight converter starts to transfer power from the engine at lower rpm's to launch the car. "Looser" means the converter is slipping, and slippage creates heat as a byproduct. Much like slipping a clutch in a stick shift car will wear it out sooner, but allows for higher rpm launch with a manual trans.

Steel Horse · Sep 18, 2009

#1stangFAN said:
im a noob here sowhat does a loose converter mean?

Doesn't lock up until a higher rpm. If you equate it to a manual a looser converter is like slipping the clutch and a tighter converter is like letting off the clutch much quicker. If that makes sense?

1/4 mile and gears

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