This is all a matter of your own personal preference, and how you plan to use the car. As is normal around here...people tend to post up quickly "get 410 gears they are great" , and only a few have posted pros vs cons. At your power level, you would probably be just fine, but if you ever add more power, you will have traction issues..which some people don't mind, others do. I personally think its stupid not to be able to use 1, 2nd and part of 3rd gear...all that power, wasted, no way to plant it to the ground (unlesss you wanna drive around on drag radials all day)
I have almost the exact power level you do... I was very close to doing 410 gears, took a ride in a friends car, YES it pulled great, but cruising 75-80 mph , I prefer to turn lower RPM's. I choose 390 gears and I could not be happier,. .. A significant improvment over 342's.,, they dont pull quite as much as 410...but a lot of my driving is on the highway at higher speeds. and I like keeping the RPM down a bit. JMO. and how I drive my car.

Good luck

 

Thank you frank,thats what i was looking for.

 

I use to have 4.10 gears - great for daily driving, running from light to light or the ocassional drag racing on the strip. However, if you EVER plan to do an HPDE on a road course - you won't want the 4.10. I finally went with 3.73 because I do a lot of HPDE and will eventually move into road racing. The 3.90 is a great trade-off between the two. Just my .02 Mike

 

Ok guys, heres a new spin on my driving style..

all my races are usually highway pulls.. Ive had people comment to me about how those gears arnt too great for the highway pulls.. I do not plan on staying at this power level much longer. By the end of the summer I wanted to add heads, nitrous, anf a Fast 90 90.

Ive been advised to skip over the diff, keep my 342's and put the money in a 175 shot..?

I Thought about doing the gear swap because my T56 is shot, and its being rebuilt to withstand about 700 HP i thought it would be a good time to do a diff.. But I dont want traction issues and other issues that will make the car harder to race..

Im really looking for some definitive answers as I could invest this money into a nitrous setup?

 

Well, I love my 4.10's at HPDEs, so it may depend on track layout. I love them because third gear is much more usuable (on my tracks) although that does mean I see higher RPMs more often. Then again, my redline has been bumped up a lot too

The only thing we have noticed is that throttle application must be regulated more closely exiting a turn.

The wide open, 4th gear pull-away from an 08 Z51 on the front stretch of Texas World (I have less power) is worth the extra attention in the turns...

 

The 410's will still pull good on HWY races..but just depends on what speed you are starting at.. obviously , the lower the speed you start the better wtih 410's..

For the mods you have planned, Nitrous, Fast 90, heads etc... I would stick with your 342's for now.. but you do make a good point about the fact that you would save on labor if you had the Gear swapped at the same time the tranny is out. I would tend to stay with the 342 if I were you, but again that is me.

 

Well, I have 410whp and 4.10s and with KDW II's the top of first got loose and a hard 1-2 or 2-3 shift would cause a slight traction loss, but you could mitigate that with good throttle control... you don't have to leave it mashed to the floor all the time... thats an amateur mistake...

Once I moved to Nitto 555 RII Extreme DOT Radials (They're not Drag Radials, they're Road Race DOT Radials, made for things like HPDE... with a 100 Tread Rating) I no longer have any Traction loss through 1st, and only a little on a hard 1-2 shift... It is GLORIOUS!!!!

Freeway, is also not a problem - I don't see why people say they're not good on the freeway. I can use 3rd and 4th more than someone with 3.42s unless they wanna race to 150-170 all the time... then i'll just get into 5th sooner, which doesn't really help, but pulling through 3rd and 4th will be easier. Most "Racing" on the freeways is done from 60 to 130ish anyways, and 4.10s with a 6500 Redline is PERFECT for that range.

On the freeway - at 75 I turn 1900 RPMs... not a big deal. Only 300 higher than the 3.42s... and it had no adverse effect on gas mileage Besides, I'm cammed... so at 65 with 4.10s i turn 1700 instead of 1400 - which my Cam is much happier with. Otherwise I'd have to use 5th around 60, because 1300 and below would be gutless. If you've got a cam, decent tires, and ~400whp - 4.10s are fine, freeway, strip, street whatever.

If you add more HP, get better tires... You people whine about "I don't understand people who add all that power and can't put it to the ground... blah blah blah" What I don't understand is people who PAY for so much power, and don't MAN UP for a set of decent rubber to hook with!

Got 500hp+? Get GOOD rubber! The end! Regardless of gears...

-Dan

 

Like I said before, it's all personal prefrence , to each his own, and each person has their own use for the car. 410's are not for everyone. I am sick of everyone saying "410 are great man up" You yourself switched to better tires due to some traction issues, you went to Nittos. My point in case.

There are pros and cons to every mod depending on driving style and use for the car. What works for you might or might not work for everyone else.

 

I switched to Nitto's because they're freaking SICK in the twisties. I ran on KDW II's for over a year, and the traction issues were minimal, seriously... Running PS2's you won't have any more traction issues than a Stock Z06...

I'm SICK of telling people 4.10s and 400whp is not some magical Driving on ICE experience. The traction is there! You can't pretend like it's not.

Personal Preference (like track days, RPMs, engine temps etc) aside, whenever someone mentions 4.10s its ALWAYS "Oh you won't be able to hook, waaa, cry... blah blah blah" But if someone mentions a P1SC or Maggie, or STS nobody says "Don't do it, you won't have traction..." Why, Because Increasing power means some other sacrifices, it's expected. But in the case of 4.10s around 400hp, which sacrifice a LITTLE bit of traction, I promise you, unless you're running GY Run Craps the car is perfectly drivable, and you'll just have a little extra wheel spin, and it won't be any worse than a Z06 with a set of long tubes...

-Dan

 

Here - I have some examples of "Omgz0rs no traction!!!11!!" lol

Granit - i didn't "Launch" any of these... your Launch RPM will be effected by the gears - but your overall 1/4 will only get better...

330whp 335 tq - 4.10s - Damp Conditions - A little slipping on a hard shift at WOT.
http://www.youtube.com/watch?v=l8moLY0dPWo

Same config (~330hp) - Dry Conditions - No Wheel Spin
http://www.youtube.com/watch?v=J-yOO...eature=related

Now - with 400whp - Dry Conditions - Hard shift, a little slipping... not much. Anybody seeing any HORRIBLE Traction loss?
http://i34.photobucket.com/albums/d1...t=MOV00097.flv

All these videos were shot on KDW II's. (320 Tread Rating)


You be the judge.

I'm in the works for a romp on the Nittos - hard shift, no slipping at all, even more glorious!


Now, for anyone who makes the "Heat, RPMS, Gear Positions" arguments for things like AutoX, or Track Days, that's fine, those are arguments I can accept. But Severe Traction Loss is simply not a reality.



-Dan

 

That's all good and I agree with most of what you are saying...I just wanted to point out the pros and cons. Now at least you have listed some of the cons as well as pros by talking about Track events and Higher RPMs, temp etc...
I'm not trying to hate on 410's, its just good to think through everything, use of the car, driver style, etc...

Btw- I happen to agree on your point about Turbo and Blower cars etc...I've seen 400WHP cars smoke 600WHP cars due to traction issues (on stock gears)

There is a lot of subjectivity still in these discussions...my own included.

 

one thing to consider is that it cost more to buy one pre-built because most of the time the rear has been upgraded with stronger clutch packs. all HD stuff in there so its bullet proof. ECS and DTE all use beefed up parts inside. find out if your tranny shop is putting in HD stuff in it or if its just all oem stuff.

yes 4.10s will make your car feel like a new animal. go for it

 

that means theres more teeth on the ring and pinion allowing the car to accelerate quicker. you will see that it will put the car in a powerband quicker in low gears. but even higher gears you will see the difference too. ever nride a 10 spd bike? from a stop, you want to make sure its in 1st or 2nd gear to ge tthe bike moving faster. why coz theres alot of teeth on the ring gear. try to accelerate fast with the speed set on 6th. you will go nowhere fast. but will be so tired of pedaling

another way to look at it is on the highway youd normally have to downshift to 4th gear to pass someone. well with 4.10s you can pass in 5th gear easily.

 

juice is fun but is a never ending money pit coz you have to keep the bottle filled to go fast. with gears, you willalways have that extra punch. long term its a cheaper mod.

I have no traction issues, coz I just lean into the throttle to ge tthe same affect of smacking it down with 3.42s

 

Yeah - There's definitely pros and cons for this mod depending on what you use the car for. I just wanted to clear up any undue fear mongering over traction issues that may not really be there. Of course - as you add power, traction issues crop up, no matter what gear you choose. The only real solution for traction limitation is... well... more traction! (Better Tires)

I've seen plenty of guys go w/ 4.10s, then decide they want 500whp, and all of a sudden, 4.10s are not so great! Just like any mod (Cam, gears, clutch, et al) you should really consider where you are, and where your going with your car.

As far as Top speed goes - that really depends on your tire and rev limiter.

If you're ~400whp, i'm assuming your cammed and probably have a 6500+ Red line. In that case, at 6500RPM in 5th gear, with 4.10s and a 275/40/18 (stock C5 rear tire) you'll turn about 167 max. Which isn't bad. (Not like you'll ever use that though...)

Here's a good tool to play with gearing, speeds, RPM, etc...
http://www.xse.com/leres/bin/gearrat...mference=79.20

Set your Redline to the correct value - and then swap Axle Ratio back and forth between 3.42 and 4.10 to see how it will effect your top speed in each gear.

-Dan

 

wow you are the first person that I have heard of that likes 4.10s for HPDEs. I do roughly 15-20 track days per year and after 6 track days I took the 4.10s out and went down to 3.73s because there was way too many shifts with the 4.10s causing more wear and tear on the driveline and also my engine temps were higher since I was running in the higher rpms more often. At the time I had 460 rwhp/ 401 rwtq. Now its a different game for me with much more RWHP / RWTQ that I might even step down to 3.42s, but I am now waiting for VIR with NCM before making final decision.

I also know of some MN12 guys with stock 3.42s that took out the MN12 because they said that 3rd gear was not usable with their power since the gears were acting like 3.90s.

I have a couple of questions for you if you dont mind answering. I am asking not to question your choice (you are happy and that is what matters), but more so I can support customers better and so I understand.

1. Your RWHP / RWTQ
2. How many RR events do you do on average
3. How many different tracks do you go to
4. Which tracks


My thinking is that the combination above will help dictate gears that you should run.

any feedback is appreciated.

Thanks

Bob

Oh and for people thinking I am not endorsing 4.10s that is not correct. I had 4.10s on my car when it was mainly street and 1/4 mile. It was my first mod and I would have kept them if it wasnt for me getting into RR.

 

Iraq and Iran love you for this thread.

 

Drove to Maine and back (to TX) last summer with my 4.10s and averaged almost 27 mpg. Also includes my 224 cam.

Maybe I should be driving a Suburban with boxes stacked on the roof racks!! Or an H2??

For my driving style I noticed very little difference in MPG

 

 

I am curious, where did you get the 27mpg from, your DIC reading? Because it is calibrated (and someone correct me if I am wrong) to your stock gears, unless there is some way to adjust the computer to account for 410 gears. When I went to cruise-inn this year, I manually calculated my MPG by the number of miles driven, by how many gallons of gas I used.. my DIC said I was getting 28mpg , by my calculations I was really getting 25.6 MPG (with 390 gears btw).
?????