4.56's slowed down my Coyote - advice, please

[Five Oh Brian]

Looking for advice. My '11 GT came from the factory with 3.73 gears, but I had 4.56's installed last week to get my launches sorted out.

With the 3.73's and drag radials (26" tall earlier this year, and 28" tall later), the car would bog on launch unless I launched off idle. Felt like it was pulling timing and nosing over for more than a second, before powering up. This happened with stock tune and with the 87 & 91 octane SCT "strategy" tunes. Best 60' times were in the 1.85 - 1.95 range. 1/8 miles averaged about 7.90's @ 91 and 1/4 miles averaged 12.40's @ 115 hot lapping in cool weather. Car has gone a best of 12.15 (with a long cool down in mineshaft air) and trapped over 116 mph on a number of occasions with the 3.73's.

So, 4.56's are in and I ran last night for the first time with them. Weather was pretty good for racing. Launches felt awesome, with 60' times ranging from 1.68 to 1.75. Definitely got rid of the bog and I was launching at a variety of rpm's w/o issues. Same 7200 rpm shift points, but I have to shift into 5th now, but cross the 1/4 mile at about 6300 rpm's, so I'm using a lot of 5th gear. ET's averaged the same in the 1/8 and 1/4 mile compared to the 3.73's, but my mph went down 3-4 mph at both marks.

I'm okay with the lower mph given the extra shift I make before the 1/8 mile and in the 1/4 mile, but given the much improved 60' times (two tenths), why are my ET's no better? I lift for shifts, but feel I shift very quickly. Even the 4-5 shift is quick and easy (MGW shifter makes it a breeze). There is a slight lag in the throttle when I hit each next gear. Is this part of the factory tuning and SCT's strategy tuning? Would a reknowned national tuner (i.e. Lund, Brenspeed, Bama, etc.) cure this and would it really matter much? I was sure the 4.56's would get me into the 11.90's, but came up way short!

Here's my two best passes last night. I'm car #2061 in the right lane....

 

[HEMI LOL]

i know that with the canned tunes the TB is not fully open. the canned tunes just dont command it.

id just get a BAMA tune, they are safe and, well you saw how matts car ran. id say with a "full" tune that car is going to hit 11.70s. i just fear its too much gear. i know, "dont fear the gear".

oh and OT P.S. made 380/363 today at TMS.

 

[dragpac]

Tune more rpm and speed shift.ya baby!

 

[VTXFrank]

For sure get a good tune and not going with the strategy tunes. You'll be very pleased with the results.

 

[Five Oh Brian]

i know that with the canned tunes the TB is not fully open. the canned tunes just dont command it.

id just get a BAMA tune, they are safe and, well you saw how matts car ran. id say with a "full" tune that car is going to hit 11.70s. i just fear its too much gear. i know, "dont fear the gear".

oh and OT P.S. made 380/363 today at TMS.

I guess the canned tune needs to go, even though it put down 409 rwhp & 382 rwtq. Performance on the dyno and on the track aren't always the same. Marc & Matt were both at the track Friday and told me to go with Bama for now until Matt is up and ready to tune next summer. After Marcc mentioned the TB not being command fully, I ran a couple passes to see if I could notice it, and sure enough, there is a slight lag on each gear change, dammit! Gotta get a good tune for sure.

Your 380/363 #'s are for the stock tune, Louie? If so, that's a nice start to build on! I'd really love to see you and Caleb bring your '13's out to the track sometime!

Matt's car fricken rocks with the 4.10's! My first two passes were against him Friday night. I had just driven 1.5 hours to the track, so my car was hot and I ran 12.67 @ 111 to Matt's 12.22 @ 114, then we hot lapped for a 2nd run and I went 12.56 @ 110 to Matt's 12.30 @ 114. He let is car sit for a long time to cool down, then ran that 11.93 @ 117. Man, that was cool to watch him break into the 11's!!! I was working on my launches with the new 4.56 gears and hot lapped all night. I really need to try cooling my car a lot to see if there is an 11.9 in my car (12.15 is still my best pass in the car, and that was after a long cool down earlier this spring).

Tune more rpm and speed shift.ya baby!

Shifting at 7200 rpm's is high enough as there's not much power after that anyway and my car is a daily driver, so no speed shifting for me - gotta lift on each shift to keep from breaking stuff.

For sure get a good tune and not going with the strategy tunes. You'll be very pleased with the results.

I sure hope so. I had high hopes that SCT did a lot of R&D into their tunes, but they obviously left a lot of work for the tuners out there to improve on.

 

[fdjizm]

Shifting at 7200 rpm's is high enough as there's not much power after that anyway and my car is a daily driver, so no speed shifting for me - gotta lift on each shift to keep from breaking stuff.

Sometimes you gotta wind it out to profit in the next gear.

 

[kdanner]

Can you post your previous best timeslip so I can compare splits?

Looking at them compared to your slip here http://www.s197forum.com/forum/showthread.php?t=83031
your car was previously quicker after 330, even the 1000-1320 was quicker and you said that was on the limiter.
http://www.s197forum.com/forum/showthread.php?t=83031

 

[86GT351]

Shifting into 5th gear is hurting you. Going into 5th gear due to the Higher numerical Gear Ratio is forcing you into Overdrive. You are theoretically cutting your torque downa dn hurting performance. You have too much gear for your needs!

 

[retfr8flyr]

I also think he has too much gear but 5th on the 5.0 is not an overdrive gear it's 1:1.


Earl

 

[86GT351]

I also think he has too much gear but 5th on the 5.0 is not an overdrive gear it's 1:1.


Earl

LOL! You are correct sir. I was thinking of a T56 6 speed.

 

[Five Oh Brian]

Can you post your previous best timeslip so I can compare splits?

Here's my previous best with 3.73 gears and awesome weather (DA was about 300' below sea level). It was a fluke run that I never came close to repeating (12.27 was my next best). Both of those timeslips are below and I was car # 2061 then, as well...

 

[Five Oh Brian]

I also think he has too much gear but 5th on the 5.0 is not an overdrive gear it's 1:1.


Earl

I agree that 4.56's are a lot of gear. However, the car wouldn't launch worth a damn with the 3.73's (would bog most of the time and very inconsistent sixty foots in the 1.85 to 1.95 range off idle or 2.00 to 2.10 when it bogged).

So, I calculated how much gear would let me use most of 5th gear in the 1/4 mile so I wasn't shifting right before the stripe, plus staying under 3,000 rpm's on the highway at 80 mph. 4.56's meets those two requirements perfectly.

Now it launches great and very consistently, plus I love it on the street. But I gave up mph & didn't lower my ET's at all. Highway fuel economy dropped a few mpg, too, not that I really care about that as I don't drive it very far. Oh, and did I mention the increased noise from the gears (quite normal for 4.30/4.56/4.88's from everything I researched before the install, but still noisy none-the-less).

So, I'm keeping the 4.56's in the car, just need a good tune from what you're all saying. No long tube headers, cams, or head work, though, as I'm not willing to spend that kind of money on a daily driver.

I have the stock exhaust with GT500 AxleBacks and the stock airbox. Perhaps an aftermarket intake for the bigger mass air meter and high flow cats with a better X/H-pipe, as well?

 

[wbt]

3.90 is the best gear to use on the manual with a 28" tire. I would move to that and a Lund tune. You will be happy with tye results.

 

[HEMI LOL]

I agree that 4.56's are a lot of gear. However, the car wouldn't launch worth a damn with the 3.73's (would bog most of the time and very inconsistent sixty foots in the 1.85 to 1.95 range off idle or 2.00 to 2.10 when it bogged).

So, I calculated how much gear would let me use most of 5th gear in the 1/4 mile so I wasn't shifting right before the stripe, plus staying under 3,000 rpm's on the highway at 80 mph. 4.56's meets those two requirements perfectly.

Now it launches great and very consistently, plus I love it on the street. But I gave up mph & didn't lower my ET's at all. Highway fuel economy dropped a few mpg, too, not that I really care about that as I don't drive it very far. Oh, and did I mention the increased noise from the gears (quite normal for 4.30/4.56/4.88's from everything I researched before the install, but still noisy none-the-less).

So, I'm keeping the 4.56's in the car, just need a good tune from what you're all saying. No long tube headers, cams, or head work, though, as I'm not willing to spend that kind of money on a daily driver.

I have the stock exhaust with GT500 AxleBacks and the stock airbox. Perhaps an aftermarket intake for the bigger mass air meter and high flow cats with a better X/H-pipe, as well?

i think a good tune is all you really need. possibly an intake. once its dialed in, with your driving you should be a solid mid 11 car @ 116+.

ill be out there with you next season. i need some LCAs and probably relocation brackets so i can run a nice sized DR too. this car wheel hops so violently it wasn't even worth trying to run it on stock suspension.

 

[Five Oh Brian]

3.90 is the best gear to use on the manual with a 28" tire. I would move to that and a Lund tune. You will be happy with tye results.

3.90 just isn't enough diffence from the 3.73's to justify the expense. Plus, that would put me into 5th gear anyway, but just before the traps, so IMO that would be a wasted shift. A good tune is definitely my next step.

 

[Five Oh Brian]

i think a good tune is all you really need. possibly an intake. once its dialed in, with your driving you should be a solid mid 11 car @ 116+.

ill be out there with you next season. i need some LCAs and probably relocation brackets so i can run a nice sized DR too. this car wheel hops so violently it wasn't even worth trying to run it on stock suspension.

Tune and intake sounds good (as much as I was trying to keep the stock airbox for a stock appearance under the hood).

My '11 had horrible wheel hop until I installed dual-adjustable LCA's and had TMS adjust the pinion angle to -2 degrees. Would have liked -1.5 degrees to get all of the hop out, but the LCA's wouldn't adjust that far. 95% of the wheel hop is gone though. In fact, it rarely ever happens now.

I bought 275/40/17 M&H Racemaster D/R's from Marc at TMS and they dead hook awesome! The BFG D/R's I used to run on my '03 Mach 1 and '07 GT worked good, as well, but they don't make one in the right size for our cars. If you go to buy the M&H's for next season, I have a discount code that'll save you $70 bucks on the pair direct from M&H.

 

[wbt]

3.90 just isn't enough diffence from the 3.73's to justify the expense. Plus, that would put me into 5th gear anyway, but just before the traps, so IMO that would be a wasted shift. A good tune is definitely my next step.

I am thinking along the lines of the Boss intake and 7,600+ RPM (self induced tunnel vision). I suppose that will make a difference for you on gearing. Going by that and a 7,300 RPM shift point...the 3.73 looks good for staying in 4th which would be my preference/recommendation.

I would move back to the 3.73 and get a better tune.

 

[retfr8flyr]

The 4.56's will make everything louder, just due to the higher rpms' your turning but if the gears are set up correctly they shouldn't be making any noise. If yours are making noise then they aren't set up correctly.


Earl

 

[kdanner]

Here's 2 comparisons of your splits. Make sure I got the numbers right, those pictures weren't very good. I took the 12.15 out of the 2nd comparison since it was more of an outlier. Red=worst, Green=best. Lots of green in those older runs. You've improved the car to 60, but looks like you've killed it after that. 60-1320 was much quicker before. DA shows as worse on your previous runs, something like 242' now vs. 718' then, so there's a little more difference than the numbers show. Take the gear out.

 

[HEMI LOL]

Here's 2 comparisons of your splits. Make sure I got the numbers right, those pictures weren't very good. I took the 12.15 out of the 2nd comparison since it was more of an outlier. Red=worst, Green=best. Lots of green in those older runs. You've improved the car to 60, but looks like you've killed it after that. 60-1320 was much quicker before. DA shows as worse on your previous runs, something like 242' now vs. 718' then, so there's a little more difference than the numbers show. Take the gear out.

imaginary rep for you sir! interesting compare!