4.10 gears...not what I expected.
 

Picked up the car yesterday after having the stock 3.45 changed to 4.10 Danas. It appears that I am a victim of my own inflated expectations. After hearing the accolades and reading on this forum a post from a guy who literally said he practically had to "relearn to drive the car" after getting 4.10s, I guess I expected the car to take flight or something. Hmmm, not quite. Yeah, I can tell a small difference but I'd be willing to bet the car is no quicker to a stopwatch, which is kind of a bitter pill to swallow when I just spent $1500 to get "18% more torque to the rear wheels at all engine RPM", according to Marc.

Driving the 2 ratios back to back, I don't feel any 18% torque difference. Not even close. And yes, I did confirm that the stock 3.45s came out of the car. I can say this for sure: if your car is stock or near stock and you're thinking about new gears, DO NOT do anything less than 4.10s. You'd be flushing money down the toilet. Just my 2 cents. :)

Re: 4.10 gears...not what I expected.
 

I'm of the opinion that gears shouldn't be looked at as a power adder but rather as a tuning tool to get what you want out of the car. You really only get the extra torque in first gear (provided you have enough tire to hook it up), after that you are just changing shift points.

Re: 4.10 gears...not what I expected.
 

Obviously gears don't change the torque at the flywheel or affect the power of the engine at all, but what it does do is get you to the sweet spot a little sooner which would be more obvious during acceleration timing, quarter mile runs etc.

6th gear may actually be useful uphill no as well.

Re: 4.10 gears...not what I expected.
 

Marc says, "18% more torque to the wheels. All of the time!" Of course, gears don't change flywheel HP but gears, by definition, multiply torque and more gear is supposed to provide more torque at the end of the equation. Surprisingly, my car is not even any more tail-happy than before. Extremely disappointing for what's talked about as the "best upgrade ever."

Re: 4.10 gears...not what I expected.
 

Killshot you will feel more of a difference installing a Fidanza flywheel than gears. A light weight flywheel doesn't ad hp either but less rotating mass on the crank is very noticeable. RPM's rise very quickly.

Re: 4.10 gears...not what I expected.
 

With stock 3:45' I can spin the tires at will in first gear/ I cannot see how 4:10's would benefit me, it would only light up 2nd gear.

4.10 gears...Are NOT for everyone
 

That is a correct statement by Marc. At any specific engine rpm when compared to before and after differential gear change your wheel rpm has gone down and your wheel Torque has gone up (Same wheel Horsepower after drive train losses). This compares to the same engine horsepower output at any given engine RPM (flywheel horsepower) before and after differential gear change.

Now the reason you might not "feel it" is because you have altered your shift points when comparing before and after shift points at specific vehicle speeds. You now have a useful 4th, 5th and 6th gear. When before you could top out the quarter mile in 3rd gear.

Oh...and I can spin my tires in 1st, 2nd, and 3rd gears :D

See Tech Info - LT5 Horsepower and Torque Calculations

I happen to like stock rear end ratios as I can get that 28mpg cruising in sixth at 70 mph ;)

See rotating mass discussion and effects on Horsepower Tech Info - L98 Frisbee Horsepower

Hi rhipsher :handshak:

Re: 4.10 gears...Are NOT for everyone
 

Oh no, don't get me wrong: I do NOT doubt Marc. I fully understand the physics of his claim and I know it to be true. My issue is with the EFFECT of the "upgrade". So much was made of it by many that I think I just expected too much. However, going by just the numbers, I think you can understand why I expected a pretty drastic difference. I figured my car (Marc's chip, open exhaust) with stock gears was getting roughly 340 lb/ft of torque to the rear wheels at peak. Multiply that 1.18 and I'm over 400 lb/ft at peak. On paper, that is a DRASTIC difference in twist and I expected a big SOTP effect that I did not realize.

Re: 4.10 gears...not what I expected.
 

porting and exhaust are what I would always go after first....

porting 30-40hp
Exhaust 15-20hp
You could even run the stock exhaust if on a budget, put in an X-pipe and some decent mufflers....

$1000-1200 for 45-60hp and more RPM range

Headers would be next

Re: 4.10 gears...not what I expected.
 

Don yokums 91 made 365rwhp with porting(no port match) and an exhaust system(stock exhaust manifolds). That was not even tuned. So with headers and a tune....390+

Re: 4.10 gears...not what I expected.
 

I'm gonna' go the OTHER way here, after I get the pipes hung - 3.45 -> 3.07, since I've lost some top end with the 4L60e. Tach is just a little high @ 70, and it will add up to less wear on longer trips, and less fuel to boot.

I think that 3.07 is my only option here.

I found it interesting to learn that the original track car had a 3.07 installed...

Re: 4.10 gears...not what I expected.
 

My exhaust is wide open after the cats. Headers coming soon.

Re: 4.10 gears...not what I expected.
 

Gear to gear at any rpm yes more torque with the 4.10's but.... speed in gears is now different and at certain vehicle speeds the 3.45 car is going to be in a lower gear than the 4.10 car therefore the 3.45 will effectively have more torque in certain speed ranges. Numerically taller gears will not make every car faster in every circumstance, gears should be chosen based on the cars power output, traction, intended purpose and driving style.

Re: 4.10 gears...not what I expected.
 

Would of been nice to see before/after dyno sheets
I still think you made a good move and only will compliment the rest of your future mods
You should now be at aprox 2200RPM @ 75MPH

Re: 4.10 gears...Are NOT for everyone
 

I understand the expectation given all the talk. But for those that do not understand the physics/math I thought a good time to confuse them more :D

Like LGAFF suggests.....if you want real seat of the pants feel of accomplishment.....ADD HORSEPOWER which is pretty easy on the LT5 :thumbsup:

The 410s do let you get 6th gear into play more often.

Re: 4.10 gears...not what I expected.
 

I think it is all just a personal thing. I loved getting my 4:10s on my 93 early in its life with me. I felt it really improved my normal around town driving and cruising on the highway. Gears were also one of the first mods I did when I got my 95. To me the car feels quicker. Subjective I realize. I like the usefulness of sixth gear now. It does make the tires spin more but new tires recently helped a lot with that. WARP TEN ran a 12.4/116 at BG this week (admittedly with Marc H driving) and he wasn't power shifting. Overall I am happy with the mod; sorry you don't like them that much. Lots of folks are perfectly happy with stock gears but I am glad I switched. --Bob

Re: 4.10 gears...not what I expected.
 

If you got 340 rwtq on a dyno in 4th gear you will still get 340rwtq in 4th gear, but at a different speed (lower). There is a trade off- obviously free power isn't created, it is just shifted around by moving the torque curve left or right with respect to rpm, speed, time etc.

Re: 4.10 gears...not what I expected.
 

But how does that square with having "18% more torque to the rear wheels at all engine rpm?" That statement tells me that if I was putting down 340 lb/ft at 4800 rpm with stock gears, then I'm now putting down 401.2 lb/ft at 4800 rpm. Am I oversimplifying or misunderstanding the statement?

Re: 4.10 gears...not what I expected.
 

You traded wheel spin for wheel torque........same horsepower. Your wheel spin dropped 18%...the guy you were racing just out ran you ;)
18% more torque to the rear wheels at all engine rpm is a true statement. The wheel spin drop at all engine rpm was not mentioned :D

Re: 4.10 gears...not what I expected.
 

Just hung up with Psychic Hotline. They said heated discussion on the way yup...

http://www.zr1.net/forum/images/icons/icon10.gif

This statement needs quantification, for starters...
And I think a more judicious use of the term "multiply torque" is in order.

Re: 4.10 gears...not what I expected.
 

Chris,

Very interesting that you don't notice a difference with the 4:10's. Most notice a tremendous difference....

Can you get the model # of dana spicer they installed?

Also did they install a speedo correction gear? (did you get it from Marc?)

And if they did install the speedo gear, how accurate is it?

:cheers:

David

Re: 4.10 gears...not what I expected.
 

So, in reality, an identical car with 4.10 vs 3.45 gears does not necessarily accelerate quicker or harder...it actually accomplishes exactly the same thing, only requiring more engine RPM to do so? Honestly, not trying to be a smartazz here, just trying to understand. Has anybody ever timed a car to 60 or through the 1/4 before and after such a switch? I'd be interested to know because the car doesn't really "feel" any quicker. It definitely revs FASTER but doesn't feel quicker and most surprisingly, doesn't seem to spin the tires more easily. I was hoping to burn those masquerading-as-a-315 Sumitomos to the ground with one burnout!

I've gotten a little more used to it over the weekend and frankly, I sort of like the new "personality" of the car. The upper gears are more usable and the car moves away from a stop more easily, which is great. Again, this has to do with having unrealistic expections, more than anything else. Overall, I'm more surprised with the result than disappointed.

Re: 4.10 gears...not what I expected.
 

Hey bro!

Yep, I could get you the number of the gearset, I still have the box at home. I also had Marc's correction gears installed. It's different, there's no doubt. It does rev quicker and the upper gears are more useful. As I've said in other replies, I really think this has more to do with unrealistic expectations than anything else. It accelerated hard before and I expected this to increase that sensation but it didn't. It really just feels more high-strung, if that makes sense.

Re: 4.10 gears...not what I expected.
 

You should be running out of rpms in 3rd around 100+mph vs 120+mph with 3.45s, I'm around 115mph with 3.73s

Re: 4.10 gears...not what I expected.
 

http://www.carcraft.com/techarticles...s/viewall.html






Geared Up For Speed
Hot Rod did a test of gear ratios and converter sizes (smaller equals higher stall speed) versus engine rpm and quarter-mile times for their June '95 issue. We helped with the testing, so we don't feel too bad about ripping them off and reprinting the numbers here. The car used was a small-block Nova with 26-inch-tall tires. We tried four gear ratios with two TCI converters, and here's what we found:

Same Car....
3.50 gear 13.40@102.59
4.11 gear 13.18@102.81

Read more: http://www.carcraft.com/techarticles...#ixzz32C7fPvaZ

Re: 4.10 gears...not what I expected.
 

First let me say, I could take or leave the 4.10s....I would rather have $1500 in motor mods. That being said the 4.10s have:
*Less Bog on the launch
*Better accel from a roll...

I was in my 92 Zr-1(4:09) when two guys in Ducatis kept flying up on the back of the car, then backing down(we were out in the country)....after about 3 three times, the one went to haul *** past me, and when he got up close to the car I punched it....the car pulled with the bike.(it was a smaller Ducati) When we got to a stop they said they were surprised at how well the car pulled compared to the bike....to me with the 3.45 there would have been a "lag"...with the 4.09 its immediate kick in the pants throttle response.

Re: 4.10 gears...not what I expected.
 

Thanks for this. Yeah, looking at these numbers, I think that this is about the actual performance gain that I would have reasonably expected. But as I've said, in my head, I think I just blew right past expectations that were reasonable. Nobody's fault but mine.

Re: 4.10 gears...not what I expected.
 

I had a guy do a 2.59 to a 3.45 swap on an LT-1 I did head work on...after driving my 3.45 and 4.11 cars and then into the LT-1 it seemed slow....however when he got in it....he was amazed. You are right sometimes its just perspective and in your mind/expectations.

Re: 4.10 gears...not what I expected.
 

A chassis dyno won't take the gear ratio into account except that some gear selections may have more friction than others. Lets say your engine makes 300 lb/ft of torque and you run it through a 3.08 diff. The axle will see over 900 lb/ft of torque (and of course 3 times slower rpm for a conservation of energy). The chassis dyno won't read 900 lb/ft, it's a separate system with its own diameter and speed calculation. All you get is the engine torque minus the frictional losses (and whatever other fudge factors are in the mix for the dyno).

I always felt individual trans gearing would always be more useful than just the final drive, but that is not too practical in production transmissions. Take a look at the MT-82 trans in the new mustangs... 1st gear is nearly 4:1 and the 1:1 gear is actually 5th (not 4th). That's about 1/2 the reason those new Mustangs scoot so well in the 1/4. I wish the ZF had tighter ratios sometimes.

It is a time-to-distance mod, not so much a seat-of-the-pants mod. I'f I had the budget, I'd do 3.73's myself.

Re: 4.10 gears...not what I expected.
 

.22 @ 1/4 mile, I like it

Re: 4.10 gears...not what I expected.
 

Stock gearing 3.45

385 lb/ft engine torque/2.66:1 1st gear ratio/3.45:1 rear gear'

385x 2.66x3.45=3533 lb/ft torque at the rear at the halfshafts

4.10 gearing
385 lb/ft torque/2.66:1 1st gear/4.10 ratio

385x2.66x4.10=4198 lb/ft @ the rear halfshafts.

4198/lb/ft3533lb/ft=18.84% increase in torque

We are measuring the actual torque or twist that is seen at the rear wheels, not calculating the torque of the engine.

There would be a measureable difference if before and after 1/4 mile runs were done.

I went from a 3.08 gear to a 4.10 gear and was unimpressed in gains in acceleration during WOT SOTP testing.

Re: 4.10 gears...not what I expected.
 

SOPT = butt dyno

Re: 4.10 gears...not what I expected.
 

I recall when I went to 4:10's in my 91 ZR-1, I shaved .3 tenths off my quarter mile times and the fact that 6th gear could be used more often without downshifting was priceless, before that 6th gear was pretty much worthless unless you were going 70mph on a flat road.

I felt it was a worthwhile change and cheap $ to get there a little faster, I guess I'm one of the few that did notice a big difference with the gear change.

Gibby

Re: 4.10 gears...not what I expected.
 

A bit difference with our manual 6 speed Z's.

I agree money would've been spend better in other mods.

My Z has run 11.04, 11.09, 11.06 with 3.45 gears I install 4.10's thinking I will get a 10 sec pass well that did not work as I thought I got a killer 60ft time and thought h@ll yeah this is it picked up my timeslip 11.10's well anybody wanna guess why, ok i'll tell you had an extra shift.

4.10's are lame and loose big end that's what our cars were made for,top end.
With 3.45 gears I top out 4th at 155-160mph with 4.10's 135mph
and if anyone has shifted into 5th would also know she falls flat on her face in 5th.

4.10's will get you better 60ft times over the 3.45's but with the extra shift takes it right back.

Reinstalled 3.45 back in her and happy again.
Pete

Re: 4.10 gears...not what I expected.
 

So Pete, how much better did your 60ft. times get with the 4.10's?

The combination of a better 60ft. time, combined with the advantage of being able to stay in a, (higher), more powerful RPM range throughout the run should add up to a better e.t.
It doesn't seem possible that the brief power shift from 3rd to 4th costs you THAT much.

Is it a possibility that with your high power output, (550+?), and the 4.10 gears, you may need more tire to see the full advantage of this gear ratio?

Your times are phenomenal. But its just hard for me to believe that the best 1/4 mi. e.t. for a high power, high rpm ZR-1 is with a three speed with no torque converter. :confused:

Re: 4.10 gears...not what I expected.
 

Shifting into 6th from 5th @ 7200RPM with 4.10's & 422RWHP car really noses over, fighting wind resistance

Re: 4.10 gears...not what I expected.
 

If your car is trapping at 129mph and 4.10's are good for 135mph in 4th gear,why are you having to shift into 5th?

Re: 4.10 gears...not what I expected.
 

It really noses over from 5th to 6th,with 3.45's also. I really liked the 155mph 4th gear w/3.45's but I find the 4.10's are a much more useful ratio,overall.
Our car will see a bunch more 0-120mph blasts than it ever will to 150+. If top end blasts are your thing,3.45's or even 3.07's are the way to go.

Re: 4.10 gears...not what I expected.
 

Here's what i think.
That auto car for example, lets say peak power is at 5500 rpm with the 3.50 gears it would finish the 1/4 at 4700 rpm with the 4.11 it would finish at 5500 this is the reason for the much better ET's.

My Z peak power 6900rpm with 3.45 i finish in 3rd gear at about 7400 rpm
With 4.10's i finish in 4th at 6800 below my power peak so either i god with 4.33's or 4.50's
My Z looses about 15hp from peak (6900) to 7400rpm so not much loss.

Also i did not mean going into 6th i meant going into 5th i know you don't feel it much but trust me car does not pull as hard in 5th if you shift her at 7k rpm it drops way below peak power down to 5200 rpm what you have to do is run her to 74-7500rpm just to get her closer to peak power going into 5th.

I went from 1.74 60ft to 1.59 you would think 1.5 at 60 foot would get me 2-3 tenths i can't shift that fast so i loose it at the extra shift even if i got 11.00 it still did nothing for me.

Pete

Re: 4.10 gears...not what I expected.
 

So,you're going through the lights in 3rd gear,not 4th? If your stock displacement LT5 makes peak at 6,900,I agree a 4.30 cog might work better than a 4.10 for your combo. A 4.56 would probably be too much gear.