[Kenso]

All automatics use the aluminum diff. housing, the manuals use the cast iron one. I think Dv8 weighed both and posted the results somewhere around here.

 

[hotlavaflow]

I'd also be very happy to hear if anyone has actually taken out their differential and counted the teeth on the gears.

I have both an auto and a manual diff. So I'll try and count those teeth this week coming. I have to open the manual to install an LSD anyway.

 

[Alperovich]

what are these gonna be made of, just wondering?

 

[mrkeith]

If it works with automatics, I'm in 100%.

k.

 

[Mikey851]

If it works with automatics, I'm in 100%.

k.

It will work with our automatics!

 

[kotetu]

Here's a quote from the manufacturer of the final drives: "Precision machined to exacting tolerances from high-tensile forged steel, heat treated and shot peened, you will not find a stronger, more reliable product on the market."

It will work with manual or automatic, no problem. I'm even considering getting the automatic differential or at least the differential case to save a bit of weight.

hotlava - while you are at it, weigh them both! Do you know which Type they are? (type 1, type 2) You need to count the teeth on each of the GREEN parts I highlighted in this picture:

http://www.kotetu.net/Legend/lsd-fd.jpg

Then divide the ring gear tooth count by the pinion gear tooth count. Thanks!

 

[ALoneR]

it's a tradeoff, unlike performance mods

1/lowers top-speed.
2/lowers fuel economy

it's good to change your gearing a lot when you're into racing on the track, but it isn't practical for daily driving.

granted, this is only the final gear. with a lot of cars, you can buy completely different gears so that the ratios are all different. in my friend's old school bimmer he's got 4-11 gears and the thing pulls like crazy 1st-3rd...except it tops out at like 90 or 100 mph =/

looking at the information presented so far, it looks like this wouldn't be a terrible mod. HOWEVER you really won't see a huge impact. it will be a SLIGHT improvement on acceleration. Highway cruising will be 100-300rpms higher, and you might lose 1 or 2 mpg. I don't know where theyre getting that 5-15% figure though.

I'm not denying it will improve performance, but personally I think there are more effective methods. The REAL best performance mod for the money is Nitrous.

 

[RangerJoe]

looking at the information presented so far, it looks like this wouldn't be a terrible mod. HOWEVER you really won't see a huge impact. it will be a SLIGHT improvement on acceleration. Highway cruising will be 100-300rpms higher, and you might lose 1 or 2 mpg. I don't know where theyre getting that 5-15% figure though.

I'm not denying it will improve performance, but personally I think there are more effective methods. The REAL best performance mod for the money is Nitrous.

I'm sure everyone has been waiting for my comments on this......

Anyway, the only difference in MPG you will see is the difference in how you drive a car after making the mods. (you will drive faster, therefore giving an inaccurate idea of how it's changing the mpg).

We are not talking about changing the top speed 25-40mph, this is going to make a very small difference in top speed. Although the six speeds are NOT geared for 200+ from the factory. They're geared for ~185. No one here could ever hope to go that fast.

Nitrous is NOT the best performance mod because it constantly requires you to keep a bottle filled (not that cheap), and you can't use it all the time. There is no real BEST performance mod for the money. And if there was on, gearing would be it. Intake doesn't come close, bayou chip doesn't do enough, exhaust barely does anything (even headers and all). And exhaust is expensive. It wouldn't be suspension (although decreasing the amount of body roll/dip/dive does significantly aid in increasing performance...it doesn't do enough). You could decrease weight, but in a legend, you're not going to take much out without really decreasing the quality of the car...which is not why you bought a LUXURY CAR in the first place. Gearing is about all that's left. Since changing aerodynamics won't do much at all for us.

If you change the mechanic aspect of the ratios between the engine speed and the wheels.....you see what I mean. Hell, we could put 6:1 gears for the final drive, and the car would scream...up to 90mph. This small change (from 4.491 to ~4.8, would maybe pull a couple mph from each gear. Of course changing more on the auto than the 5 speed, and more on the 5 speed than the 6 speed...)

I'm going out to party, but I will return and comment more on other posts. :hitit:

 

[tofusensei]

Nitrous is NOT the best performance mod because it constantly requires you to keep a bottle filled (not that cheap), and you can't use it all the time.

yah i agree. this on the other hand...

~t.s.

 

[Mikey851]

That's why I said it earlier. It may not be the best mod possible for the Legend, but it is definately the best mod for a relatively stock car if you're merely wanting to have a little more fun from light to light, or down the strip.

 

[hotlavaflow]

hotlava - while you are at it, weigh them both! Do you know which Type they are? (type 1, type 2) You need to count the teeth on each of the GREEN parts I highlighted in this picture:

http://www.kotetu.net/Legend/lsd-fd.jpg

Then divide the ring gear tooth count by the pinion gear tooth count. Thanks!

Auto is Type 1, Manual is Type 2. I'll get them weighed too.

 

[Geeque]

pm me if you need somebody to put the cash down to get things rolling.

 

[kotetu]

Thanks Geeque. It's not so much about cash as it is about interest. That's why I am holding back on talking about a group buy until there's been significant discussion - it looks like we are getting there.

Hotlavaflow - awesome. Also, can you compare the two differentials? I've heard they ARE interchangeable, and that they are not. I'd like to know the correct answer.

 

[ALoneR]

You can get a complete nitrous setup in your car for less than $1,000...most likely around 700-800 if you shop around and do the install yourself. Refilling the bottle isn't constant if you get a big one, and it's not like it's expensive...its anywhere from $10-60 to refill, thats pretty much the same price range as a tank of gas.

The fact that it's not always on is actually good. Because you only have to use it when you need it. 40-100whp boost at the push of a button for less than $1,000....how is that not the best bang for your buck? You're telling me that adding a final gear that makes the car accelerate slightly faster is a better investment? Sorry, I'm not sold.

You guys haven't even seen any dollar signs yet. First of all, the final gear itself will most likely not be less than $100. I'm guessing 200-350. Then....how many of you can honestly say you're capable of pulling your engine and transmission, taking the tranny apart, and then switching out the final gear and putting it all back together? I think theres maybe 2 or 3 people on this forum capable of doing that. Take it to a shop and it's going to be several hours of labor...at anywhere from $50-100 per hour. So realistically, you'll be spending between 500 and $1,000 for a slight increase in acceleration.

Notice I've been using the word acceleration because this does nothing for power. This changes the DISTRIBUTION of power. Yes, it improves performance. Yes, it improves acceleration. Yes, your car will be faster. But it won't be making more power and I'm still having a problem with this 5-15%
"increase" statistic.

Don't get me wrong, I'm not bashing gearing. It's definitely a vital part of any racecar and it can't be ignored when you're making plans to "go faster". The only reason I'm coming off so negatively is because it looks like the OP is sheperding forum members into believing this will make a significant difference on their cars. It will probably be noticeable. It will probably be a definite improvement.

But.

If you're looking for the best bang for your buck, this is not it. Labor to get a final gear installed will kill you.

One more thing, there are 300-400whp Turbo Hondas running around with STOCK transmissions. Do you think THEY have a problem running down the 1/4 mile in 11 or 12 seconds? Nope. The truth is, power is power. You can mess around with weight reduction, gearing, aerodynamics, whatever...but unless you go the EXTREME route on any of those, they will only be slight improvements. By extreme, I mean, running 4-10 gears in your car. You will accelerate like crazy and top out before 100mph and get terrible gas mileage. The same goes for weight reduction. You don't slap on a carbon fiber hood and expect to suddenly be a lot faster. You get half of your body panels replaced with carbon fiber counterparts and then strip out the entire interior...then you really start to move.

I'd like to end my post by saying that I'm not denying this is a good mod.
I'm not pretending there is no advantage to changing your final gear.
What I am doing, however, is making sure everyone realizes what they're getting themselves into, because this forum has a bad habit of one person saying "hey this is really cool" and then everyone jumps on the bandwagon.

 

[kotetu]

Thanks AloneR, I agree with some of what you've said. When I mentioned best mod for the money, I am talking about an all around mod - one you can use on the street and on the track. This will give you some pickup whereever you are driving, and the higher the final drive, the more the pickup. You're right about power, this doesn't add any. However, getting that 5-15% increase in acceleration is definitely possible, as my friend Al used to say "It's all math." (He was referring to billiards, but the same goes for gearing.)

The gearing determines how many turns of the wheel you get per turn of the engine. If you get 15% more turns of the wheel, does that mean you get 15% more acceleration? Yes and no.

These are 'perfect' situations. In perfect situations, you don't lose anything due to aerodynamic drag, tire slippage, or other factors. I am sure there are loss factors involved that I know nothing about, but there is merit to my statement about gearing and acceleration. So, not knowing what all the loss factors may be, let's assume there would be as much as 20-25% loss of the expected gain (similar to HP drivetrain loss) - that is to say, a 5% increase in the final drive ratio might result in 3 or 4% increase in acceleration. A 15% boost to the final drive might see as high as 12% increase in acceleration. Gearing is the reason why 1st, 2nd, 3rd, etc accelerate differently.

Now, a 10% increase in your final drive will NOT make your 4th gear accelerate like a 3rd gear. Your 3rd gear is about 33% shorter than your 4th (on a 6 speed). But, that is 1/3rd of the way there.

Here's another site with some interesting info:
http://www.chevyhiperformance.com/techarticles/148_0208_gear/

This site points out that in fact, (and I have mentioned it before, but not in so many words), you can get this gearing change by changing to smaller wheels/tires. This would be far cheaper than nitrous OR a final drive, and accomplishes what the FD swap would do.

Oh yeah, and removing the differential is not as bad as all that. Take a look at the differential rebuild DIY. It's not easy, by any means, but no removing of the tranny or engine! thank goodness.

Anyway, thanks for taking the time to post your thoughts! It really helps. I don't want ANYONE "jumping on the band wagon". This is a mod that should be well thought out decided on knowing as much as possible. It would be GREAT to get some guys in here to post about their experiences installing the upsized JDM final drives in their integras.

 

[RangerJoe]

You can get a complete nitrous setup in your car for less than $1,000...most likely around 700-800 if you shop around and do the install yourself. Refilling the bottle isn't constant if you get a big one, and it's not like it's expensive...its anywhere from $10-60 to refill, thats pretty much the same price range as a tank of gas.

However, the thing about gas, you have to have it to drive a car anytime. Nitrous kits should cost around 500for a wet kit and then maybe another 50 worth of jets. Depending on how you want to run it. Installation is easy anyway. It can be completed with a minimal number of tools or experience. It is not difficult to do either. In fact, I helped install a wet kit on tnelson's sedan a few years back. Therefore, you think it makes sense to spend $100+ to fill a 40lb tank. Who the HELL wants a shit ton of nitrous in the back of their car anyway (especially on a street car)

The fact that it's not always on is actually good. Because you only have to use it when you need it. 40-100whp boost at the push of a button for less than $1,000....how is that not the best bang for your buck? You're telling me that adding a final gear that makes the car accelerate slightly faster is a better investment? Sorry, I'm not sold.

The thing about a performance mod, just because you have it in does not mean you have to drive the car like a bat out of hell. You do not have to drive as if you are on an autox course just because you have a strut tower brace. I am not adding anything; I do not think you know what we are talking about in the first place. We are changing the final gear ratio.

You guys haven't even seen any dollar signs yet. First of all, the final gear itself will most likely not be less than $100. I'm guessing 200-350. Then....how many of you can honestly say you're capable of pulling your engine and transmission, taking the tranny apart, and then switching out the final gear and putting it all back together? I think theres maybe 2 or 3 people on this forum capable of doing that. Take it to a shop and it's going to be several hours of labor...at anywhere from $50-100 per hour. So realistically, you'll be spending between 500 and $1,000 for a slight increase in acceleration.

The final drive ratio is in the differential, which can be removed directly off the engine and transmission; please figure out what we are talking about before we have to deal with your ridicule and bullshit.

Notice I've been using the word acceleration because this does nothing for power. This changes the DISTRIBUTION of power. Yes, it improves performance. Yes, it improves acceleration. Yes, your car will be faster. But it won't be making more power and I'm still having a problem with this 5-15%
"increase" statistic.

Apparently, you are the only one that does not know what we are talking about. You never saw me say it will give your car more power. Alternatively, any of the other well-known or knowledgeable people that have posted on this thread

Don't get me wrong, I'm not bashing gearing. It's definitely a vital part of any racecar and it can't be ignored when you're making plans to "go faster". The only reason I'm coming off so negatively is because it looks like the OP is sheperding forum members into believing this will make a significant difference on their cars. It will probably be noticeable. It will probably be a definite improvement. If you're looking for the best bang for your buck, this is not it. Labor to get a final gear installed will kill you.

Do not assume he is trying to push anything onto us; he is simply giving us another idea and giving us another chance to upgrade our car. You are not a leading expert. What made you think you are the person members come to when they want to upgrade?

One more thing, there are 300-400whp Turbo Hondas running around with STOCK transmissions. Do you think THEY have a problem running down the 1/4 mile in 11 or 12 seconds? Nope. The truth is, power is power. You can mess around with weight reduction, gearing, aerodynamics, whatever...but unless you go the EXTREME route on any of those, they will only be slight improvements. By extreme, I mean, running 4-10 gears in your car. You will accelerate like crazy and top out before 100mph and get terrible gas mileage. The same goes for weight reduction. You don't slap on a carbon fiber hood and expect to suddenly be a lot faster. You get half of your body panels replaced with carbon fiber counterparts and then strip out the entire interior...then you really start to move.

WE are geared slightly different than a civic, since when do we have turbo systems that are bought as kits, or reasonably priced ECU that allows you to work on mappings or whatever. I can guarantee they aren't running stock transmissions with 400hp. If the legend's 2 piece clutch can't even take 220hp/tq from Dv8's 3.5 swap, what makes you think a much more economically produced car can take 2x the power? And they are definitely not running 11-12 second 1/4s with those stock transmissions. We're not talking about extreme modification to the final ratio either. How about you figure out a reasonably priced way to ALWAYS give the same results as gearing. Nitrous is not the end all be all of mods. Personally, I think it's a cheap cop out when you can't figure out what else to do...but you NEED your car to be faster.

I'd like to end my post by saying that I'm not denying this is a good mod.
I'm not pretending there is no advantage to changing your final gear.
What I am doing, however, is making sure everyone realizes what they're getting themselves into, because this forum has a bad habit of one person saying "hey this is really cool" and then everyone jumps on the bandwagon.

Dude, you've only been here for SEVEN months. Since when do new guys understand how the forum as a whole works? Next time you try and gain support for your side, PLEASE figure out what the hell you're talking about. Because the quotes of you saying the FINAL RATIO gets ADDED to the transmission doesn't help your case.

 

[1_Hot_Legend_LS]

Hey Aloner, You obviously haven't messed with the final drive on our cars. Why pull the engine or transmission? It's not needed, 1 1/2 hours tops and you can have the diff out of the car. It's not hard at all. I'm sure my little brother could do it. But for someone like me that wants to add the LSD to the car also this is perfect. A lil more ecceleration and a Limited Slip.

 

[Mikey851]

AloneR,

Ask anyones grandpa or father what they did to their Camaro or their Mustang back in the day to make it faster if they just wanted to have some street fun without major mods. They will tell you they changed the ratio in the rear diff. It's a very proven modification that is not necessarily an all race modification. If the change is mild enough it will help acceleration and really won't change gas mileage or top speed all that much unless we plan on testing it's upper limits.

Don't worry, we're not getting "talked into" a modification here. This is a modification that alot of people have probably thought would be good but didn't have a clue who would make such a thing for us. As long as we all come to a consensus of what the final ratio should be and the product is of high quality we will all be happy.

Edit: Just as an example. My grandpa had this extreme final drive ratio (I can't remember the exact numbers) in his Chevy Custom 10 pickup which had a rare Chevrolet 302 block transplanted in it. The diff was so extreme that at 80 mph the truck was pulling 4000 rpms, but that was probably also due to the Hi/Lo powerglide tranny it had. Anyways, yes that's a little too much for a street car but one thing is for sure, that truck wanted to get up and go.

 

[1_Hot_Legend_LS]

I only have one question......where do I get the LSD? Cause I went and picked up a junkyard Differential from a manual to do this work on. I'm gonna change the final drive ratio and install the LSD.

 

[Mikey851]

A guy named Hondaman used to make LSDs. I believe someone is trying to see if he will still make them. I believe they were in the neighborhood of about $400.00 which is a damn good deal.