C4 Low gear?

Bobby Fazio · 05-30-2016, 09:11 AM

Is it possible that going to 2.92 can actually slow the car down from a 2.75 or even a 2.46? It seems both my stocker and maverick super stocker have had best sixty foot times with 2.75. And maverick was better with 2.46 and 2.75 than 2.92. Here's the part I'm not quite getting:

In my stocker I have tried 4.88 with 2.92 but that was 200lbs heavier in N. Sixty foots were 1.62 back then. 4.88 x 2.92 = 14.25 most aggressive torque multiplier?

Next I tried 4.88 with 2.75 in L and 200lbs lighter and sixty foot was usually 1.53-1.56. 4.88 x 2.75 = 13.42

Next I tried 4.56 with 2.75 and sixty foots were 1.58, ok I expected that to slow up. 4.56 x 2.75 = 12.54 weak torque multiplier?

Next tried 4.56 with 2.92 and nothing really changed. Still 1.58 short times and now we are at 4.56 x 2.92 = 13.31 should have been damn near close to the 4.88 with 2.75 right?

Lastly tried 4.71 with 2.92 and sixty foots are 1.60. 4.71 x 2.92 = 13.75 should have been a perfect scenario?

All this was done with same converter which always seems to flash at same spot and 28 in radials. Is there more to it than just the ratios? Is there more drag in the trans? Is converter agitated? Has anyone else experienced?

Alan Roehrich · 05-30-2016, 09:21 AM

Bobby,
The big problem with a lower first gear is that it creates a larger drop between first and second. The lower your HP and torque, the less the engine likes the RPM drop between first and second, and the larger the drop, the harder the engine struggles trying to recover from the shift.

Lou Jeffery · 05-30-2016, 09:41 AM

Bobby, I can back you up at least on the outcome of the 2.92 ratio C4. We ran a 2.92 with a 4.88 in a crate motor Mustang 302. It was hard to drive, inconsistent and noisy 60 ft. 1.53. We went back to 2.46 - 4.88 60ft 1.51 and picked up over the whole run, much easier to drive 1-2 shift. I am not a fan of low ratio first gear. Louis Jeffery

BRETV · 05-30-2016, 12:06 PM

I ran a 2.92 first gear w/5.13 and a 30 inch tall radial with a 87 mustang in M/SA and went 1.49-1.51 every pass, even went a 1.47 at Indy one year, was stoked after that one. The 2.92 was always quicker than the 2.75. The KEY is the shift point coming out of first. Gotta be low rpm and quick. Just my $.02

Bret Velde
2003 SS/LA (hopefully soon)

05-30-2016, 09:11 AM	#1
Bobby Fazio VIP Member Join Date: Nov 2009 Location: Egg Harbor Township, NJ Posts: 1,469 Likes: 1,450 Liked 4,365 Times in 501 Posts	C4 Low gear? Is it possible that going to 2.92 can actually slow the car down from a 2.75 or even a 2.46? It seems both my stocker and maverick super stocker have had best sixty foot times with 2.75. And maverick was better with 2.46 and 2.75 than 2.92. Here's the part I'm not quite getting: In my stocker I have tried 4.88 with 2.92 but that was 200lbs heavier in N. Sixty foots were 1.62 back then. 4.88 x 2.92 = 14.25 most aggressive torque multiplier? Next I tried 4.88 with 2.75 in L and 200lbs lighter and sixty foot was usually 1.53-1.56. 4.88 x 2.75 = 13.42 Next I tried 4.56 with 2.75 and sixty foots were 1.58, ok I expected that to slow up. 4.56 x 2.75 = 12.54 weak torque multiplier? Next tried 4.56 with 2.92 and nothing really changed. Still 1.58 short times and now we are at 4.56 x 2.92 = 13.31 should have been damn near close to the 4.88 with 2.75 right? Lastly tried 4.71 with 2.92 and sixty foots are 1.60. 4.71 x 2.92 = 13.75 should have been a perfect scenario? All this was done with same converter which always seems to flash at same spot and 28 in radials. Is there more to it than just the ratios? Is there more drag in the trans? Is converter agitated? Has anyone else experienced? __________________ '65 Mustang SS/L & L/SA DriverInterviews.com \| App.DragInsights.com Last edited by Bobby Fazio; 05-30-2016 at 11:06 AM.

05-30-2016, 09:21 AM	#2
Alan Roehrich Veteran Member Join Date: May 2006 Location: Murfreesboro TN Posts: 5,118 Likes: 1,576 Liked 1,837 Times in 417 Posts	Re: C4 Low gear? Bobby, The big problem with a lower first gear is that it creates a larger drop between first and second. The lower your HP and torque, the less the engine likes the RPM drop between first and second, and the larger the drop, the harder the engine struggles trying to recover from the shift. __________________ Alan Roehrich 212A G/S

05-30-2016, 09:41 AM	#3
Lou Jeffery Junior Member Join Date: Nov 2013 Posts: 91 Likes: 0 Liked 0 Times in 0 Posts	Re: C4 Low gear? Bobby, I can back you up at least on the outcome of the 2.92 ratio C4. We ran a 2.92 with a 4.88 in a crate motor Mustang 302. It was hard to drive, inconsistent and noisy 60 ft. 1.53. We went back to 2.46 - 4.88 60ft 1.51 and picked up over the whole run, much easier to drive 1-2 shift. I am not a fan of low ratio first gear. Louis Jeffery

05-30-2016, 12:06 PM	#4
BRETV Senior Member Join Date: Oct 2003 Posts: 568 Likes: 4,185 Liked 776 Times in 199 Posts	Re: C4 Low gear? I ran a 2.92 first gear w/5.13 and a 30 inch tall radial with a 87 mustang in M/SA and went 1.49-1.51 every pass, even went a 1.47 at Indy one year, was stoked after that one. The 2.92 was always quicker than the 2.75. The KEY is the shift point coming out of first. Gotta be low rpm and quick. Just my $.02 Bret Velde 2003 SS/LA (hopefully soon)