New gearing in my SRT6 - from 3.07 to 3.27 - Success!
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Re: New gearing in my SRT6 - from 3.07 to 3.27 - Success!
Mike, maybe just me, but I really don't see why so many go back to the muscle car days and think 4-speed. I ran a modified turbo400 from B&M with a stall converter. I drove over to JEGS, who had not been in business all that long, pick it up installed it the same night. It shifted backwards from regular transmissions, and I installed a Hurst shifter just for this tranny. Quite the set up for it's time. The old big block would turn 7200 rpms. It would bang gears just like dropping a clutch. Many didn't even know it was an automatic. They were 3-speeds in those days, even though 2 was all you needed for the quarter for the most part. All the guys I ran with in those days spent all their time fixing and adjusting linkages, fixing or adjusting clutches, putting band aids on their knuckles...lol... I have had my share of sticks, but autos even in the day, were something they had to deal with.
I'd go to the drags with my older brother in the early 60's and watch the 413 and 426 Max Wedge cars (with their push button automatic's) walk all over the 409 Chevys, and 427 Fords with their 4 spds.
That's why I ordered an automatic in my AMX because I was planning on taking it to the drags every once in a while, and on the street where it was practically unbeatable in 1st. and 2nd gear.
But with the exception of my AMX, every other "Sports Car" that I've owned, I chose a manual transmission because "drag racing" wasn't part of the equation.
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Re: New gearing in my SRT6 - from 3.07 to 3.27 - Success!
I'm still on my 1st try and it's by myself. It's a huge PITA!!!!!!! lol
Of course I have extra to remove and such but still, removing the diff sucks lol.
Re: New gearing in my SRT6 - from 3.07 to 3.27 - Success!
Yes it is...held my breath on doing both cars with help...but I really hate to do it again, but I figure in the long run it will be worth it...but with having my right shoulder down...not looking forward to it...going to have to some young help this time...
Re: New gearing in my SRT6 - from 3.07 to 3.27 - Success!
Without bottle would be hard. Anyone know about stage 3 heads from needswings?
Last edited by srt6Master; 03-27-2019 at 08:31 PM. Reason: Wrong response
Re: New gearing in my SRT6 - from 3.07 to 3.27 - Success!
I pulled out the differential last night and everything looks fine. I guess the noise it coming from somewhere else. 
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Re: New gearing in my SRT6 - from 3.07 to 3.27 - Success!
wt
Your complaint has been echo'd on this forum since its inception. Probably happened the first time somebody pulled up along side a Camary, and had their doors blown off by the Toyota.
Or by nearly every other car built that had a lower gear ratio than the Crossfire. (Which includes every other sports car that was considered direct "competition" for the XF.
The only reason the NA, and the SRT's are saddled with such ridiculously high gears is because of Benz's obsession for long high speed crusing on the Autobahn.
To answer your question, yes a 3.46 would be an excellent gear ratio for an NA Crossfire......Automatic. For a 6 spd. it would make the already very low 1st. gear, even lower. Normal everyday driveability would be effected, in most situations you would probably start off in 2nd. But if you're proficient with a manual, and have good biting tires, then you will out accelerate a Crossfire that has a 3.27 gear.
The same is true for any other "lower" gear ratio somebody wants to use.
A stock SRT with DR's and a 3.46 gear will beat a matching SRT with a 3.27 gear.
AN SRT with a 3.73 differential will out run an identical one with a 3.46, and so forth and so on. (as long as traction remains a constant). That's the trick.
But maybe somday, "Wheelie Bars" on 9 and 10 sec. Crossfires will be the norm. Rudy's going to be very busy.
Your complaint has been echo'd on this forum since its inception. Probably happened the first time somebody pulled up along side a Camary, and had their doors blown off by the Toyota.
Or by nearly every other car built that had a lower gear ratio than the Crossfire. (Which includes every other sports car that was considered direct "competition" for the XF.The only reason the NA, and the SRT's are saddled with such ridiculously high gears is because of Benz's obsession for long high speed crusing on the Autobahn.
To answer your question, yes a 3.46 would be an excellent gear ratio for an NA Crossfire......Automatic. For a 6 spd. it would make the already very low 1st. gear, even lower. Normal everyday driveability would be effected, in most situations you would probably start off in 2nd. But if you're proficient with a manual, and have good biting tires, then you will out accelerate a Crossfire that has a 3.27 gear.
The same is true for any other "lower" gear ratio somebody wants to use.
A stock SRT with DR's and a 3.46 gear will beat a matching SRT with a 3.27 gear.
AN SRT with a 3.73 differential will out run an identical one with a 3.46, and so forth and so on. (as long as traction remains a constant). That's the trick.
But maybe somday, "Wheelie Bars" on 9 and 10 sec. Crossfires will be the norm. Rudy's going to be very busy.
Last edited by srt6Master; 03-27-2019 at 08:40 PM. Reason: Word correction
Re: New gearing in my SRT6 - from 3.07 to 3.27 - Success!
Swapped stock gears to 3.27, added killer chiller kit, got tcu tune and my 60 foot sling with quarter mile times are the worst they have every been. Either TCU is just horrible and/or 3.27 gets on the srt6 just straight suck. I have the wavtrav diff as well and just like everyone states with 3.27 gears have less wheel spin but that only because it puts down less power!. I'm st 5600 feet DA today was best out of the entire season. I ran a 13.87, 13.92, 13.91, and two 13.6s at 13.64 and 13.62. 60 foots varied between 2.145 being the best and 2.48 being the worst. Before 3.27 gears and TCU tune in was running 12.7-12.9s all day not problem with 1.8 average 60 foots. 3.27 gears can blow donkey kind D. I'm going back to stock gears and stock tcu tune and I bet my times will be right back in high 12s. Remember I'm at 5600 feet elevation about a full second difference from sea level. I do not suggest 3.27 gears unless your running nitrous out the whole as top end is pretty nice which seems weird. Only positive is crossing the quarter mile while still in 3rd before shifting. Bah humbug 3.27 gears. Sorry
Re: New gearing in my SRT6 - from 3.07 to 3.27 - Success!
I think the car likes the 3.27. This was done today on street tires with no nitrous. I'm very surprised the lower gearing didn't cause a lack of traction. It actually feels like the car is hooking better now than with the 3.07's, and I know that makes no sense. I can floor it a little sooner now than I could before (it seems). My first 0-60 today was an easy 4.2 with me slowing rolling into the throttle. Next I got into it a little sooner and pulled a 4.1. A little more got me the 3.9. Strange but true.
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Re: New gearing in my SRT6 - from 3.07 to 3.27 - Success!
Maybe TCU tune but I have failed to see anyone show proof that 3.27 gears made there car faster except for Jim who was running a v8. Can you show me proof or link to proof that 3.27 helped some with actual times?
Re: New gearing in my SRT6 - from 3.07 to 3.27 - Success!
maybe this will help
not me found on the net
A lot of people don't understand the importance of rear-end gearing, or what kind of gears to choose for their particular vehicle, so I thought I'd take some time to try to simplify it so you can understand it better.
First off, regardless of what kind of engine you have or how much power it makes, gearing can make or break your car. In other words, having the wrong gear ratio can turn your car into a complete and utter turd, or it can make it lightning quick off the line but no with top-end speed what so ever.
"Tall" gears and "short" gears are referring to the gear ratios. Tall (high) gears have LOWER numerical numbers such as 2.79, 2.90, 3.00, 3.25. Short (low) gears have HIGHER numerical numbers, such as 4.11, 4.30, 4.56, 4.88, 5.13, 5.36, etc. In simple terms, the numbers mean how many turns of the drive shaft to one turn of the rear wheel. If you are cruising down the freeway at 60 MPH with 3.00 gears, in a typical high gear with a 1:1 output ratio, it simply means that the drive shaft (engine) is spinning 3 times for every 1 rotation of your tire. If you had something like 4.88's, then your drive shaft (engine) would need to spin almost 5 times for every one rotation of the tire.
So think of it like this, ride a 10 speed bike. Take off in 1st gear. That's a low gear ratio. You can go from 0 - about 5 MPH in a split second, do wheelies, ride up hills, etc quite easily. Now try to do the same thing in a taller gear, like 6th or 7th. Now you can't take off the line very fast, you can't do a wheelie, and you'll fall on your face trying to ride up a hill. It takes much more leg power to "pull" that taller gear, just like taller gears in a car need engines with more power (TORQUE, not "horsepower"), to pull those taller gears. If you want to cruse down the highway on your 10 speed bike, can you leave it in 1st gear? No, because your legs can't go fast enough to keep up as the bike goes faster. Short (low) gears work the same way. They require less power, and accelerate from a dead stop much quicker than taller gears, but you can't cruise very fast down the road without running out of leg RPM. Well, if you plan on doing a lot of freeway driving, you don't want to choose a gear that's too low for your car because you'll be going down the freeway at too high of an RPM.
Rear end gears (2.79’s, 3.00’s, 3.25's, etc) are great for freeway driving, bit not good for 0-60 MPH or accelerating from a dead stop. Shorter gears (higher numbers) are much better suited for accelerating, such as 3.55, 3.73, 3.91’s, 4.11’s etc. Always remember, for very “give” there is a “take”. If you take lower gears to accelerate quickly from 0-60, you will give top-end speed.
Think of it like this; let's say you could only have 1 gear on a 10 speed bike. If you rode around town a lot, then something equivalent to 2nd or 3rd gear would be good to have so you can take-off from stop signs and accelerate quickly through traffic, but if you are going to be riding long distances along the highway, then something like 6th or 7th gear would be a better choice. You won’t be able to get-up and go from a dead stop very quickly, but you will be able to cruise along at 30 MPH pretty easily along the highway without your feet going round and round at 10 million miles per hour. Think of your feet as your engine and the bike’s gears as your car's rear-end gearing. Low gears like 1st, 2nd and 3rd will give you the gitty-up and go from a dead stop, and higher gears will allow you to cruise better at fast speeds.
With cars you need to pick a happy gear that works with your engine and driving needs. Smaller, high winding engines that make good “peak” power need lower gears or they will fall on their face. Big, torquey engines can “pull” taller gears easier and don’t need short (low) gears as much as a smaller engine does. No matter how powerful the engine is, if the gearing isn't low enough, it won't accelerate. Arnold Schwarzenegger couldn't do a wheelie on a 10 speed bike if it was in 10th gear, but an 8 year old kid can if it's in 1st gear. Cars and engines are no different. Just because you may have a powerful engine doesn't mean you'll be "quick" or will accelerate quickly if you don't have gears low enough. Race cars don't run super low gears for no reason. Even with VERY powerful engines, without the gearing, an 8 second drag car can instantly become an 11 second car.
Aside from engine size and power, you also have to take into consideration your tire diameter, transmission type and final drive ratio, the speed you’ll mostly be driving at (town or highway), and calculate the gearing from there. It may sound complicated but it isn’t really. On a 10 speed bike, do you have troubles figuring out which gear to change to as you go faster or slower? Car gearing is no different once you know the info and what to take into consideration. This is why good car builders always have quicker / faster cars than the average guy. They take the whole picture, (the car, engine, gearing, driving style, etc) into consideration so the car can perform as it is intended.
To make a point, if you took a bone stock V-8 car with say, 275 - 300 HP and put 4.88's in the rear-end and ran it against a car with a 750 HP race engine that has 3.00 gears in the rear-end, I guarantee you the bone stock car WILL out accelerate the race car from 0 - 60 MPH, just like an 8 year old kid on a 10 speed taking off in 1st gear will get-up and go to about 5 MPH or so quicker than a bike ridden by someone like Arnold Schwarzenegger could in 10th gear. A car's performance isn't solely related to just the engine's power. Gearing is every bit as important if you want it to go like it's supposed to.
When I was younger and was the "John Milner" of my town with the quickest car in the valley, a lot of people thought it was because I had such a bad *** engine in my car. Indeed for a small block it WAS a bad *** little engine, BUT what most people didn't know was hiding in my rear-end was a set of 4.88 gears. Without those I wouldn't have had a 10 second street car, it probably would have been more like a 12 or 13 second car.
not me found on the net
Rear-End Gearing Simplified
A lot of people don't understand the importance of rear-end gearing, or what kind of gears to choose for their particular vehicle, so I thought I'd take some time to try to simplify it so you can understand it better.
First off, regardless of what kind of engine you have or how much power it makes, gearing can make or break your car. In other words, having the wrong gear ratio can turn your car into a complete and utter turd, or it can make it lightning quick off the line but no with top-end speed what so ever.
"Tall" gears and "short" gears are referring to the gear ratios. Tall (high) gears have LOWER numerical numbers such as 2.79, 2.90, 3.00, 3.25. Short (low) gears have HIGHER numerical numbers, such as 4.11, 4.30, 4.56, 4.88, 5.13, 5.36, etc. In simple terms, the numbers mean how many turns of the drive shaft to one turn of the rear wheel. If you are cruising down the freeway at 60 MPH with 3.00 gears, in a typical high gear with a 1:1 output ratio, it simply means that the drive shaft (engine) is spinning 3 times for every 1 rotation of your tire. If you had something like 4.88's, then your drive shaft (engine) would need to spin almost 5 times for every one rotation of the tire.
So think of it like this, ride a 10 speed bike. Take off in 1st gear. That's a low gear ratio. You can go from 0 - about 5 MPH in a split second, do wheelies, ride up hills, etc quite easily. Now try to do the same thing in a taller gear, like 6th or 7th. Now you can't take off the line very fast, you can't do a wheelie, and you'll fall on your face trying to ride up a hill. It takes much more leg power to "pull" that taller gear, just like taller gears in a car need engines with more power (TORQUE, not "horsepower"), to pull those taller gears. If you want to cruse down the highway on your 10 speed bike, can you leave it in 1st gear? No, because your legs can't go fast enough to keep up as the bike goes faster. Short (low) gears work the same way. They require less power, and accelerate from a dead stop much quicker than taller gears, but you can't cruise very fast down the road without running out of leg RPM. Well, if you plan on doing a lot of freeway driving, you don't want to choose a gear that's too low for your car because you'll be going down the freeway at too high of an RPM.
Rear end gears (2.79’s, 3.00’s, 3.25's, etc) are great for freeway driving, bit not good for 0-60 MPH or accelerating from a dead stop. Shorter gears (higher numbers) are much better suited for accelerating, such as 3.55, 3.73, 3.91’s, 4.11’s etc. Always remember, for very “give” there is a “take”. If you take lower gears to accelerate quickly from 0-60, you will give top-end speed.
Think of it like this; let's say you could only have 1 gear on a 10 speed bike. If you rode around town a lot, then something equivalent to 2nd or 3rd gear would be good to have so you can take-off from stop signs and accelerate quickly through traffic, but if you are going to be riding long distances along the highway, then something like 6th or 7th gear would be a better choice. You won’t be able to get-up and go from a dead stop very quickly, but you will be able to cruise along at 30 MPH pretty easily along the highway without your feet going round and round at 10 million miles per hour. Think of your feet as your engine and the bike’s gears as your car's rear-end gearing. Low gears like 1st, 2nd and 3rd will give you the gitty-up and go from a dead stop, and higher gears will allow you to cruise better at fast speeds.
With cars you need to pick a happy gear that works with your engine and driving needs. Smaller, high winding engines that make good “peak” power need lower gears or they will fall on their face. Big, torquey engines can “pull” taller gears easier and don’t need short (low) gears as much as a smaller engine does. No matter how powerful the engine is, if the gearing isn't low enough, it won't accelerate. Arnold Schwarzenegger couldn't do a wheelie on a 10 speed bike if it was in 10th gear, but an 8 year old kid can if it's in 1st gear. Cars and engines are no different. Just because you may have a powerful engine doesn't mean you'll be "quick" or will accelerate quickly if you don't have gears low enough. Race cars don't run super low gears for no reason. Even with VERY powerful engines, without the gearing, an 8 second drag car can instantly become an 11 second car.
Aside from engine size and power, you also have to take into consideration your tire diameter, transmission type and final drive ratio, the speed you’ll mostly be driving at (town or highway), and calculate the gearing from there. It may sound complicated but it isn’t really. On a 10 speed bike, do you have troubles figuring out which gear to change to as you go faster or slower? Car gearing is no different once you know the info and what to take into consideration. This is why good car builders always have quicker / faster cars than the average guy. They take the whole picture, (the car, engine, gearing, driving style, etc) into consideration so the car can perform as it is intended.
To make a point, if you took a bone stock V-8 car with say, 275 - 300 HP and put 4.88's in the rear-end and ran it against a car with a 750 HP race engine that has 3.00 gears in the rear-end, I guarantee you the bone stock car WILL out accelerate the race car from 0 - 60 MPH, just like an 8 year old kid on a 10 speed taking off in 1st gear will get-up and go to about 5 MPH or so quicker than a bike ridden by someone like Arnold Schwarzenegger could in 10th gear. A car's performance isn't solely related to just the engine's power. Gearing is every bit as important if you want it to go like it's supposed to.
When I was younger and was the "John Milner" of my town with the quickest car in the valley, a lot of people thought it was because I had such a bad *** engine in my car. Indeed for a small block it WAS a bad *** little engine, BUT what most people didn't know was hiding in my rear-end was a set of 4.88 gears. Without those I wouldn't have had a 10 second street car, it probably would have been more like a 12 or 13 second car.
Last edited by amx1397; 10-23-2019 at 02:08 PM.
Re: New gearing in my SRT6 - from 3.07 to 3.27 - Success!
Where is proof 3.27 gears helped anyone(real proof) for a better time besides the v8 crossfire. Have a few things we can try and tweak that to Jim. Tha kķ Jim for always eing there.
Re: New gearing in my SRT6 - from 3.07 to 3.27 - Success!
Rudy supplied the reprogrammed TCU, and it's functioned perfectly so far. Will this make the car any faster, I don't know. I think it will. At a minimum, I can now get inexpensive ring and pinions from a NA Crossfire for cheap whenever I kill another one. This alone will pay for the swap in a year or two if I keep destroying them.
Last edited by Toolman; 02-20-2021 at 10:17 AM.
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