goaway

dose anyone know anything about central 20's 3.9 gears? I want to know what the quality of the gears are. To anyone that has them or knows about them input would be appreciated. are they manufactured well? has anyone had problems with them? are they nosey? I want to get gears but im tring to avoid paying crazy $$ for the 350evo ones. is the quality between the two any different? i called 350evo they told me the specs on the steel and such for there gears right off hand. i called two other places about the central 20's gears and they couldn't tell me anything. i don't know what to do ..help please!

Kwame

iTrader: (78)

The central 20 gears are as good or better than any other gears on the market. They have been manufacturing parts for around 30 years now and their quality is top notch. As far as noise goes that is strictly dependant upon your installer. You can read more here...
http://www.z1auto.com/prodmore.asp?m...ne&prodid=1726

roast

iTrader: (2)

I wouldn't question the quality of the gears.... but I would question the point of putting gears in the Z when it's already geared perfectly as it is... all a FD is, is a torque multiplier... it's not like it helps your lbs:hp... first gear is already short enough as it is... making it shorter will just make launching more difficult.. it also only stands to increase the amount of time you spend shifting in a given distance... in the quarter mile they can hurt you just as much as they can help... and then your cruising rpm on the highway will go up which puts more revolutions on your motor and wastes gas... it would also significantly reduce your top speed(even though it would still be above the limiter)

Personally I would take 10hp over gears in a heartbeat... but that's just me.

Let's hear a differing opinion.

Armitage

iTrader: (15)

Do you auto-cross or track (track != drag) your Z?

goaway

i havent gone to the track yet not that i wouldn't .my Z is not my daily driver so i just want the car to be more fun with out spending major $$.

zachcrosen

iTrader: (23)

Roast, I did a pumpkin swap(running 3.5 now) on my Vortech Supercharged 5AT several months ago. After doing this, I shaved roughly .3 sec off my 1/4 mile time as well as upped my trap speed to around 108 and some change. My cruising RPMs at around 80MPH only increased by 200-300RPMs and my fuel consumption decreased by about .5MPG. Granted this is not apples to apples, but it is a somewhat differing opinion. Overall, I am happy with the change in gearing on my Z. I have thought about going with the 3.9s on my current setup, but want to see someone else doing it before I do it!

roast

iTrader: (2)

Yes. I understand that the corner before the longest straight is generally the most important corner. You make the most time by being fast in the fast parts, rather than being fast in the slow sections. As a general rule of thumb you want to be at maximum power upon exiting the most important turn. Changing the FD can help that or upset that, and it depends mostly on the state of tune and the individual track. This is a big thing with motorcycle racing since they can easily change their gears to suit the track.

I was mainly only considering the manual. Between the two, they are geared completely different. The auto as you know is geared taller to begin with and has less gears. I can see a shorter FD benefitting the auto before it will the manual because of that, but there would still be a point of diminishing returns. What were your traps before the gears? I can't really see gears having much of an effect on your traps because your hp:weight ratio isn't changing and it's hp that gets you across the line at a given speed. The gas consumption must be a difference in the way you drive now. Maybe you aren't as apt to floor it since you have more torque multiplication for each gear? As you noted your cruisng rpm still go up regardless, so apples to apples as you said, you can't run more efficiently unless you change your inputs. If you ran more fuel efficient with shorter gears I think the manufacturers would have already taken advantage of that.

I don't think this mod is necessarily a bad one, I just think it takes a little more consideration than some people give it. Then again I am certainly no expert and I could be terribly wrong!! lol...

zachcrosen

iTrader: (23)

My best trap before the gear swap was 104 and some change!

roast

iTrader: (2)

Not according to your cardomain page????

I'm confused.....

zachcrosen

iTrader: (23)

My bad dude! I forgot that I hit 106. That is accurate and not my brain! Either way, I still trapped around 2 MPH faster.