Gear Change from: 4.11 (Rear Gear) to: 4.56 in my GT350

[M.A.N.]

Does going up one set of gears make a big enough difference? I would think two or more would be noticeable.

I'm sure that's one of those things you could ask people and get different answers, just like what's the best motor oil. lol

But I think it's an improvement, it does make a difference [ for the good in my opinion ]. With that being said for my use I
would like to of had a 4.30, but don't think anyone makes it. I'm sure 4.56 would be ok also, but for me it came down to
the 4.56 or 4.09 so I decided on the 4.09.

As for going up one set, I would think it could be counted as two. They make 3.91 also, I put them in my F150.

I don't think there's a right or wrong answer. you know we just have to change things on our cars [ that's what I tell the wife ].

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[MandoGt350R]

I'm sure that's one of those things you could ask people and get different answers, just like what's the best motor oil. lol

But I think it's an improvement, it does make a difference [ for the good in my opinion ]. With that being said for my use I
would like to of had a 4.30, but don't think anyone makes it. I'm sure 4.56 would be ok also, but for me it came down to
the 4.56 or 4.09 so I decided on the 4.09.

As for going up one set, I would think it could be counted as two. They make 3.91 also, I put them in my F150.

I don't think there's a right or wrong answer. you know we just have to change things on our cars [ that's what I tell the wife ].

 

[Racsirx]

I wish there was a way to test drive 4:11s & 4:56s so I can decide which one, back in the day on my Foxbody I thought 3:55s was the best for me until I drove one with 3:73s and made me switch to 3:73s on the street and 4:30s at the track for my setup, gears make a difference

 

[Racerx009]

John can you tell me what year your car is and does it have the cross traffic and blind spot detection system [ don't know if it will make a difference ], I have bought a new 2019 GT350 and it has it. I was wondering if a gear change would cause a problem.

Why I ask and I know it maybe different on the GT350, but I just traded a 2019 Bullitt in on the GT350. I had changed the gear to a 4.09 in it and it screwed up everything lol. Before I got out of the driveway I got default for cross traffic, blind spot, hill side assist, couldn't change drive modes and by the time you got to about 30 mph you would get the wrench in the dash [ see service manual ].

Anyway long story short after talking with several places and FP, I could not find any fix for it [ maybe a tune ]. I did try changing the hex in the BCM but that didn't do anything. So I had to change it back to the 3.73. Cleared the codes again, everything went back to normal.

I really liked the 4.09 in it and still have them and would love to put them in the GT350, but it would be really nice to know that it wouldn't be a problem like it was in the Bullitt before I did it.

Maybe someone else has changed theirs, like to here some feed back before I try it. Thanks

Just put 4.09 in my 19 Bullitt and have the same problem

 

[Racerx009]

Mike,
My GT350 is a 2016 (Doesn't have the: blind spot detection) Honestly I have not heard of that problem before. What the heck...
I have had both 4.11, and 4.56 in my car with absolutely no problems throwing codes. I too could change the Gear Ratio setting in the BCM with Forscan, but did not affect anything.
Please keep us informed if you find out anything more on this subject.

I have the same problem with 4.09 gears I have tried everything and my buddy at the speed shop is lost

 

[M.A.N.]

I have the same problem with 4.09 gears I have tried everything and my buddy at the speed shop is lost

I'm sorry to here that, but I knew it would, as the saying goes [ been there and done that ].

The Bullitt is different when it comes to changing the gear. What are you going to try now? A tune, change it back or you got another idea?

I have installed them [ 4.09 ] in my 2019 GT350, with no issues.

 

[Racerx009]

I'm sorry to here that, but I knew it would, as the saying goes [ been there and done that ].

The Bullitt is different when it comes to changing the gear. What are you going to try now? A tune, change it back or you got another idea?

I have installed them [ 4.09 ] in my 2019 GT350, with no issues.

Been working with Lunds & VMP on the issue what I did notice on my tuner my strategy # is not listed any more.

 

[M.A.N.]

Been working with Lunds & VMP on the issue what I did notice on my tuner my strategy # is not listed any more.

Very interesting, please keep us informed of what you end up doing. I'm sure it will help others.

 

[Racerx009]

I'm sorry to here that, but I knew it would, as the saying goes [ been there and done that ].

The Bullitt is different when it comes to changing the gear. What are you going to try now? A tune, change it back or you got another idea?

I have installed them [ 4.09 ] in my 2019 GT350, with no issues.

Also my ecu strategy # is gone its blank even when back to stock

 

[Racerx009]

Very interesting, please keep us informed of what you end up doing. I'm sure it will help others.

In between drinking lol I have spent hours even my speed shop has the same equipment as the dealer and cannot figure it out.

 

[Racerx009]

Very interesting, please keep us informed of what you end up doing. I'm sure it will help others.

OK I spoke with lunds they gave me a different tune it still did the same thing. So I changed the options like I did on his original tune. I put 28in for tire size, 373 gear and 30 tmps. I did Crank relearn and Kam reset no codes drove it and it worked great no more issues so far. Vmp I did the same and still a issue so he sent me a new tune with open options so I will try that later. I hate computer stuff I barely can work my smartphone

 

[Havinfun13]

I guess I should test it out at that RPM with the valves shut...

On my old GT, it could definitely get droney at that RPM with the Borla.

I am jumping into a thread that is a while back. However, I have some questions as I track often and am looking to make gear changes. For the track do you like 4.11 or 4.56? I do not drag race my car, so top speed at some tracks is important. Just looking for your thoughts.

 

[2JZFAN]

I am jumping into a thread that is a while back. However, I have some questions as I track often and am looking to make gear changes. For the track do you like 4.11 or 4.56? I do not drag race my car, so top speed at some tracks is important. Just looking for your thoughts.

IMO it's more about where you're racing throughout the year, what RPMs you're spinning, and what gears you're hitting most often..

I'd find or make a tool to compare speed in gears at specifics RPMs and tailor it to your home track or favorite tracks.. The attached image is something I modified, not sure where I got the base file but I know I didn't create the formulas.

From here you can compare your runs gear and speeds and make a determination on what's best for you.

 

[Havinfun13]

IMO it's more about where you're racing throughout the year, what RPMs you're spinning, and what gears you're hitting most often..

I'd find or make a tool to compare speed in gears at specifics RPMs and tailor it to your home track or favorite tracks.. The attached image is something I modified, not sure where I got the base file but I know I didn't create the formulas.

From here you can compare your runs gear and speeds and make a determination on what's best for you.

Thanks I appreciate the feedback. I have been searching the web for a program that does just what your picture above states. No luck yet. I will be running slicks so I want to make sure rear tire diameter is accurate. Most of my tracks have a top speed less than 130 mph and have turns where 3rd gear is a little too low, but can't run the complete turn in 2nd.

 

[trusktr]

Since I'm a top-end guy I'm going the other way with my gearing, most likely to a 3.55. I'm just going to keep taking gear out of it until I can't hit the limiter in 5th.

Does this reduce your acceleration? What's your goal with the lower ratio? What does the "top end" achieve? (Genuinely curious newb here)

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