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Discussion Starter #1
I am starting this thread to get some feedback on gear ratio's. Gears are the next hot item on my list for performance and I am sure on allot of members to do list. Our factory gears are great if you plan on driving across the country but for performance (1/4 mile) they fall short.

I feel with the right set of gears along with the current mods out there, it will really make the package complete. I have PM some of you (and thank you for the feedback) but I though we should have a thread just for those that has changed gears.

So here is what I would like to see on replies.

What Ratio did you use and why ?

What is your opinion on your choice ?
 

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I am starting this thread to get some feedback on gear ratio's. Gears are the next hot item on my list for performance and I am sure on allot of members to do list. Our factory gears are great if you plan on driving across the country but for performance (1/4 mile) they fall short.

I feel with the right set of gears along with the current mods out there, it will really make the package complete. I have PM some of you (and thank you for the feedback) but I though we should have a thread just for those that has changed gears.

So here is what I would like to see on replies.

What Ratio did you use and why ?

What is your opinion on your choice ?
Although I have yet to make a purchase I intend to go with 3.73 as 4.11 would be a good choice for track only, 3.73's coupled with track radials, and an anti wheel hop mechanism should accomplish the desired times and all around perfomance I wish to achieve. Will post the results once installed. Hopefully in the spring I will be able to find a wheel and tire application which will not compromise the gear change.
 

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I am planning on 3.90s from Pro50.
 

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I am planning on 3.90s from Pro50.
I wish you luck in getting them to run quiet.

Anyone that thinks the 4:10s are not for street driving has not driven them. They make the car a pleasure to drive and with a double overdrive transmission, there is no negative on the top end. If I can cross the finish line in 4th gear at 6500rpm with my 4:10s, I'll be a very happy camper.:D
 

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I wish you luck in getting them to run quiet.

Anyone that thinks the 4:10s are not for street driving has not driven them. They make the car a pleasure to drive and with a double overdrive transmission, there is no negative on the top end. If I can cross the finish line in 4th gear at 6500rpm with my 4:10s, I'll be a very happy camper.:D
Why the comment about them not being quiet? Have you heard things about that ratio, or Pro 5.0? That ratio hasn't been around long for an 8.8 as far as I know. Is it the amount of teeth on each gear that makes it inherently noisy.

I also would be concerned about 4th gear through the traps. The more power you have, the faster you will need to go, and the taller the gears you will need in the 1320. Now you're making me consider 3.73s. I'd better do more research.

Another thing. I am hearing that high rpm is the achilles heel on these engines. I would not want to push it, or sustain high rpm for very long. Just my .02.
 

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Discussion Starter #7 (Edited)
Steeda told me that 4.11 or lower is great for a mustang without a supercharger...basically a GT, with the Shelby / Low first gear / and 18 inch tires in the back that the 3.73 let you travel some distance make use of the supercharger and boost and get some Momentum before hitting 2nd. I had 3.91 in my last toy with a 5 speed and I can tell you a couple of things that were true. 1st gear was good for about 10 feet and I was kissing redline and needed to shift to 2nd....also in that 10 feet I was spinning the whole time (yes needed slicks) in 5th at highway speeds it was taching around 2200 the best I can remember and that was with 17 inch tires. If you were going to run 19in or 20's than I would consider nothing but 4.11 or 4.10 which ever ford offers. 4.1x with our cars and a sixth speed well at highway speed should be no problem. I just worry about 1st and or 2nd being a waste, not that there is a huge difference but the 3.73 would probally be the best all around gear. Like I said in another post that normally in life you can't have the best of both worlds something has to give. If you were into the roll racing which is all over the internet where you are beside someone at 40 mph and you take off than the 4.11 or 4.33 would be the bomb but dead stop...I can see traction problems... I have it now with a tune and CAI 1st is a waste so more gear will only Multiply without some good tires.

With my new tune my redline is 6500 so I could go through the traps at that RPM but would like to know for sure the RPM with our factory rim size what the rpm is at the end of the quarter in 4th with 3.73 and 4.11. I would love to be around 5800 to 6200 I think that is a strong powerband for these cars. But only members that have done the gears can tell us for sure :(

Something else the Steeda Q525 comes with 3.73 I have been told now my thought is that Steeda could use what ever and they choose 3.73 and I am sure they tried other gears so there must be a good reason just not sure what it is. I have a video clip they sent me of there car doing the quarter..not the best quality but has 2 things.... 3.73 gears and the Ford Racing Exhaust (borla exhaust) if I can get it posted I will the file is only 5 meg.... If not maybe the admin of this board could let me upload it to some location... maybe we could have a section for members to upload movies etc :)
 

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Discussion Starter #8 (Edited)
Just uploaded video with 3.73 turn up the speakers and check it out.

Goto the forum of pics & videos
 

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It's not the 3.90 gear ratio that is inherently noisy, its the non-ford gear set. They are not ALL noisy but it is very difficult to get one set up to be quiet, if not impossible on many. Almost all of the Ford OEM gearsets will set up very easily and be quiet. They are just different in manufacture. Been there and done that and from talking with others that have tried recently, I'll stick with the Ford OEM gearsets.
 

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Discussion Starter #10

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Discussion Starter #11
Also not many people have added to this thread about how there car is with different gears... maybe not that many have change them but if you have please post up what you did and what the results are... everyone wants to know :)
 

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Here are the ones that I am getting Ford Racing Brand so should be 100%.
http://www.livernoismotorsports.com/product.phtml?p=167

Of course need to have my buddy 07 Shelby look into this as well he seems to always finds good prices and the right quality.

Looking at that web page, the part numbers, at least for the 410s are incomplete. THere is an M or an A on the end of that number which indicates the origin of the gears. M beign outsourced to Motive Technologies and A being OEM Ford. There is a very real difference. Judging from the pricing, I am pretty sure that those are the M gears, the cheapest I usually see in the A gears is in the $220 range and they come with the shims, pinion nut and crush sleeve, not as a seperate kit.

On install, you may also need differnt side shims to get the gear pattern optimum.


On another note, I have the 410s in my Shelby. Only for a few days now but REALLY like them. just day to day driving is MUCH easier. Clutch chatter from a standing start in traffic is gone. Whole car feels like it has lost hundreds of lbs. 5th gear is usable in traffic now and 6th on open surface roads with little traffic at 45 to 50. Cruise RPMs are still great with the double overdrive transmission. I am very happy.
 

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Discussion Starter #13
Thanks for the update... I will be getting the install kit for sure I don't want the installer using any used shims or try and use the bearing from the old. I was leaning strong toward the 3.73 but after talking to some people the 4.10 might be the way to go. I know people are happy with the 3.73 but the 4.10 which isn't a huge difference between 3.73 might be the better bang for the buck. Need to hear some more info and do some more calling but my installer things the 4.10 might be a better gear as well. He went from 3.08 to 3.73 on his turbo viper and said it made a world of difference but from 3.31 to 3.73 he said I might not feel it as much as I think... Decisions Decisions
 

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The pinion bearing is a good idea. They often get messed up being pressed off the old pinion shaft. The shims in the kit are for the pinion only. Side shims are ordered to exact size, they are not stacked. Many shops that do many gear changes will have some of the side shims from other cars on hand. Nothing wrong with reusing these as they are not wear parts. Mine needed one new shim and they had one on hand for the other side. Pinion shim ended up being exacty the same as on the old pinion which is always a good place to start.
 

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Discussion Starter #15
Well called Steeda today to get some advise from the experts on gears. Here is what was told to me... of course this is someones opinion but made good sense. You could call 10 other shops and maybe get 10 other opinions however if you do call and you should for piece of mind and the major of the shops tell you the same thing than you can feel pretty good about your decision.

My question to him was 4.11 or 3.73 with factory size tires and rims. Even if I change them in the future I will stick with 18in and the same tire size..bigger rim and or bigger tire means more weight and more power to turn them which I am not interested in adding weight to this car :)


His answer: If you not going to replace the pulley to a smaller one than 4.11 is a great strip / street gear. You will cross the quarter mile in 4th close to 6 grand on the tach.

If you replace the pulley than of course you will have more boost... and will rev quicker and with 4.11 with the pulley you will be up against the limiter at the quarter which is not a good thing. Of course if you put taller tires on the back than that changes your ratio and you will be back to okay again but remember I told him stock tire and wheel sizes.

On there Q525 which is supercharged and they have a smaller pulley on they ran it with 3.55 / 3.73 / 4.11 gears and the best results for them was 3.73. Like he said I can sell you and will sell you what ever you want this is just our findings. (I see no reason for him to lie to me so I have to take what he says as truth.)

So if no pulley change and factory tire size or taller than 4.11

If pulley change factory tire size than 3.73

If pulley change and taller tire than you could squeeze out the 4.11

I am not sure about the pulley change... I know it blows the warranty on the motor..and that is an expensive part to have to fix... Yes I know what your thinking what about gears...well that blows the rearend warranty but you can replace the rear or fix it for hundreds of dollars less than a thousand and even though it would suck we could all do it after paying what we did for this car. But the motor....well I need to see the pulley on more shelbys and see how it holds up for at least a year before I risk it for 40 more hp. And to add to the rear part.. the 8.8 is something like 90% as strong as a Ford 9 inch and unless your dumping the clutch at 5000 rpms every weekend at the dragstrip your be fine... gears don't stress the rearend it is the sudden force of torque that breaks parts..and if you think about you know what I mean how many axles get broke, or clutches get blown just driving....it is when you launch from a dead stop when parts a pushed to the test.

One more thing and I will shut up... using ford gears FRPP gives you a better chance against no noise than using non standard gears... I mention to him the 3.90 he said will work... will fit fine, BUT very go chance of whinning because not FRPP. So I am back now leaning hard toward 3.73. Next month Mustang and fast ford is going to put gears in the shelby and beat on it at the strip I am guessing they will use 4.11 since they put a taller tire on but maybe they will have some words of wisdom for all us.

Okay I am done typing...
 

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Here's a few charts for y'all. These are MPH in each gear.

Engine RPMS 6500
Rear Gear 3.31 3.55 3.73 3.9 4.11
1st Gear 53.1 50 44 37 30
2nd Gear 88.6 83 73 62 50
3rd Gear 121.3 113 100 85 69
4th Gear 157.7 147 131 111 89
5th Gear 197.2 184 163 138 112
6th Gear 250.4 233 207 176 142


Engine RPMS 2000
Rear Gear 3.31 3.55 3.73 3.9 4.11
1st Gear 16 15 14 11 9
2nd Gear 27 25 23 19 15
3rd Gear 37 35 31 26 21
4th Gear 49 45 40 34 27
5th Gear 61 57 50 43 34
6th Gear 77 72 64 54 44


Just a little math, boys. As you can see, the 4.11 rear cuts the top end to pieces. Oh, I know it's fun... I've got one in my '65 but 1st gear is REAL short! and cruising speed goes up in RPMs too.

My pick is the 3.5? to 3.7? especially with the amount of torque we're seeing and the 4th gear top for 1/4 mile. Any higher than 3.7 rear and you are having to use 5th for the 1320ft. I know it's a little extreme but, the Evolution Shelby is running 4.10's. I can't help but think that it's all about launch(That's why 2 cajuns, Boudreaux and Thibodeaux, lost their job at NASA... they thought launch was time to eat!).

Anyway, hope the charts help.
 

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Sorry about the alignment of my charts. They came out bad.

Engine RPMS 2000
Rear Gear 3.31 3.55 3.73 3.9 4.11
1st Gear 16 15 14 11 9
2nd Gear 27 25 23 19 15
3rd Gear 37 35 31 26 21
4th Gear 49 45 40 34 27
5th Gear 61 57 50 43 34
6th Gear 77 72 64 54 44
 

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Sorry about the alignment of my charts. They came out bad. I'm not sure how to upload an Excel in the correct format. Anyway, there it is using the transmission data that is in our owners manual.
 

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Discussion Starter #19
Very nice thank you for the info, anyone else put gears in their Shelby if so what is the 411 on the results.
 

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Very nice thank you for the info, anyone else put gears in their Shelby if so what is the 411 on the results.
Busa,

I may have missed this point through your thread, but please refresh my memory....what are you wanting to accomplish?

Mine are 3:73 for 2 reasons-
a) Because I thought it would result in slightly better every day driving from a dead stop. I was right.

b) I did the same ratio graph as the other poster and did so because my goal was to get 65 mph up to 2,000 to get my Ford Racing axle backs out of the drone zone. It did. In 6th, it makes about a 275 rpm difference at 65mph. Perfect. There is little to no difference in economy at those speeds. It's above 2,200 that the economy begins to suffer.

Someone else mentioned high rpms as the Achilles to these motors and they're exactly correct. But, it's HIGH rpms (above 6,500) that grenade these things. So far, SVT has only two cases of complete failures due to high rpms. A few hundred rpms at cruise isn't going to cause premature wear.

That said, you mention the pulleys voiding your warranty. They don't. Nothing voids your warranty unless it's explicitly named as such (ie "the installation of this supercharger will void your factory warranty". This verbiage is all over the FRPP catalogue). Now, IF you had a failure that could be directly linked to the increased pressures, heat, etc then you're screwed.
Same goes for the swap of a gearset. IF they proved that a failure was dueto increased rpms....installation problems...increased NVH due to an aftermarket gearset, you're screwed.

So, in a nutshell, ANY aftermarket part COULD result in a refused warranty claim, but unless it is specifically stated, this is NOT automatic and has to be proven that the part or service is a direct or indirect culprit. For the record, they'll probably win, but that's the risk you take.

Want some REAL risks? Watch what happens when a handling related accident occurs on a car that's been lowered....is shod with aftermarket wheels and tires, etc.

Hope this helps.


BTW- Mine has the Evolution Ultimate Handling package installed and I have the Metco 2.6 and idler sitting here to be installed in a week. As you know, I have a JLT and an Evo tune. Am I screwed? Only if something breaks ;)

bj
 
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