Hi everyone, I know the Z's have pretty short gearing which is awesome for fast acceleration, but ever since getting Turbos I've had one heck of a time hooking up in first. I can do it if I just ease on the gas but I can't do it hard AT ALL. Furthermore I have to shift very, very fast, the power comes on extremely quickly in every gear especially with the lightweight flywheel.

So I am thinking would a 3.3 FD swap help me? Would I put power down easier?

Or would this just slow my car down, because it seems so far only built motor guys are running the 3.3 FD.

Thanks, I want to start drag racing my Z as well and I want to be able to put more pow to the ground.

My Z is at around 430-440whp (depending on the dyno)

 

I know I'd probably go for a 3.3 final drive if I had a turbo and around your power level. It'll help traction and give you more time in each gear for the turbos to be running fully spooled up.

...though IMO I'd just give up on first gear. It's just too short in comparison to the other gears and the Z doesn't rev high enough to get any real speed out of first gear anyway.

You'd need something like a 2.5 final drive ratio to get it to really hook up in 1st gear. And if you could do a 2.5 FD, it'd just make your other 5 gears kinda suck, making the trade off probably not worth it

btw, what size/width and type of tires are you running?
can you get traction in 2nd and 3rd gears?

 

I'm running 285's on a 9.5" wheel. I'm gonna try some 295's, I know it's not a sound size for a 9.5" but I don't have he money to be swapping for larger wheels right now.

I plan on getting my rear fender's widened in the future, and getting some 18x11 or even 18x12 wheels with some 335's.

I can get traction in 2nd gear if I control my throttle. I absolutely CANNOT floor it in 2nd gear. In 3rd gear I will chirp, spin a bit and catch.

1st gear is ABSOLUTELY USELESS to me at the moment.

 

Also is there an overlay of 3.3 vs. 3.5? I found one of a 3.9 vs. 3.5 but can't find one for a 3.3 comparison.

 

Taken from: https://my350z.com/forum/showpost.ph...&postcount=115

I have a bit less than 450whp, so I'm assuming even though my 1st gear will be more useable, my car will feel noticeably slower in the higher gears?

Thanks. I know I will do this in a heartbeat with over 500whp with a built motor, but right now I'm still on stock block with a bit over 400whp.

Another thing is I have a 407whp map for daily driving. Don't wanna feel too slow in that map either.

 

You almost have to expect not to have 1st gear, I mean what your making close to 400whp....its a given.

 

Wish we had a huge first gear like Vettes. But then again our cars are never meant to be drag kings from factory IMHO, road racing we don't really need first gear.

 

your car will be fine, but you will notice it being a bit more doggy in the upper gears. When I was in the 400's 6th gear turned into a cruising gear. I felt like I had to downshift to 4th or 5th if I wanted to pass.

That said, 1st - 4th are much more usable, and your gas milage will increase. It is hard for me to say go for it based on the experience I have had. The only thing I can say is that the install is relatively easy, so keep your stocker and swap it back in if you aren't happy

 

this is the problem with the Z. At best you'll only be able to find a compromise. It's only a 3.5 liter engine and it only generates so much torque on it's own. To get the car moving from a stop in a brisk fashion, you need an aggressive 1st gear which doesn't work well with boost.

the cars that are in this same situation with a short 1st gear ratio, small engine, and lots of boost are pretty much all AWD and/or are rear engine. The 911 turbo is probably the closest thing to having similar gear ratios and similar power, similar engine size, and similar weight. It's AWD and rear engine in order to hook up in 1st gear. The new GTR is similar too and it also has AWD and is heavier which actually helps traction even though more weight slows acceleration. The pros outweigh the cons though and the car hooks and goes

The other approach is what if 1st gear wasn't so short? The cars that do that are big engine cars like the Z06 or viper or ford GT. Those engines generate huge torque right off the line without even having to get heavy on the throttle. If the Z had antilag and the turbos were constantly spooled even while at idle, then you could generate the bigger tq numbers right off the line to turn the driveshaft and diff easily from the start. A tall 1st gear would work out then in that case. ...But antilag is horrible on turbos for street driven cars and not many will run such a setup because of how impractical it is rebuilding the turbos every 1000 miles. So a really tall 1st gear probably isn't the answer for a turbo Z

the other cars out there with really aggressive 1st gears are high reving/low torque cars like the GT3, F430, S2000, elise, etc. Their engines don't make huge torque and need short gearing to get the car moving. They're able to accellerate fast though because those cars rev extremely high. Instead of having to shift around 6600-7000 rpms, they'll go to something like 8500 rpms where they can reach almost 50mph in 1st gear where they can hold onto their aggressive 1st gear ratio for a longer amount of time



so you're stuck trying to make a compromise because you have a high torque engine when under boost, but a low torque engine when not in boost when starting in 1st gear. You end up having to pick the lesser evil by going with taller gearing which has other benefits by keeping the turbo spooled for longer stretches of time between shifts and better highway gas mileage with less passing ability in 6th gear

The only real way to compete with AWD is with huge extremely sticky tires. A widebody kit or extending the fenders would work so you can maybe get some 345mm R-compound tires in there. Drag radials might also work for your power levels if you're willing to trade off handling.

An extremely tall 1st gear just isn't going to go well with starting the car from a stop. Try starting your car in 2nd gear and see how that goes, because that's what a tall 1st gear would feel like

going with a 3.3 FD is only a 6% change and probably about as much adjustment as you'd want to make to your gearing with a turbo unless you increase your displacement or get into expensive custom gear ratios



On my car, I've taken a different approach. I can actually start my car in 2nd gear just fine depending on how warmed up the car/clutch is. Sometimes there's a delay and sometimes it's fairly brisk. I still mostly use 1st gear though especially when on a hill or if there's a car in front of me that isn't going to accelerate from a stop as fast as me. I'm running a carbonetics twin disk clutch, 3.9 FD, vortech, etc. Because superchargers are always running, even at idle, they effectively make the engine "bigger" by having more air/power available since the blower is constantly turning. The 3.9 FD shortens my 2nd gear. Going with a stroker kit I think would push 2nd gear starts over the edge and make them more of a regular thing for me. Then if I raise my redline to 7000 rpms, I can hit 60mph in my new "1st" (2nd) gear and save time having one less shift

 

Wouldn't another alternative be to have a boost controller (like the HKS EVC6, for example) that has gear based or speed based boost??? That way you can just run lower boost in first and second gears, or until a certain speed. It seems like progressive boost control might be an optimal solution to the traction problem.

I think I would want to try something like that first before messing with the gear ratios. Has anyone tried these features in the higher end boost controllers? I haven't really seen any threads about it with guys posting reviews (although I have to admit that I haven't searched much for it either).

 

How expensive are progressive boost controllers? Sounds likes something in the $1k+ range.

And about Sentry stating that the Vortech is making your engine "bigger", not sure what you mean. You are probably losing a good amount of HP just turning the blower in the low rpms.

 

After doing more research I think I will stay with the 3.5 FD and just learn to drive the car better and hook up better.

Thanks everyone.

 

even though a supercharger has parasitic loss, the whole point is that regardless of that, it still creates a gain. The blower is constantly turning so it's constantly blowing air even at idle. My idle is 1200 rpms and with the 2.87 pulley which turns the blower even more. That's a decent amount of extra air on tap right off of idle

By making the engine "bigger" I mean it gains power through all the rpms which is as if the engine itself became bigger. Even the smallest turbo isn't going to be partially spooled up at idle to generate more power than NA, so it's not gaining any power at idle to be able to use dramatically taller gearing

 

I dynoed 426whp, I have a 3,3 diff and 295 tires and spin all of 2nd. I would say yea its a good upgrade but not having 6th gear cruise control sucks

 

+1 good thinking . Haltech is working on something along these lines for its built in boost controller and I eagerly await it. However, with internal wastegates with a spring pressure of 9.3 psi, I cannot go lower than 400 whp (unless I figure out a way to de-tune based on gear) so first gear still tough to use .

 

Have you had a chance to overlay NA graphs with a Vortech graph? Is there actually a gain over NA say under 3k?

 

yes I have

My car gained exactly 40 tq at 2500 rpms with the vortech vs when I was NA. This was on a dyno dynamics.

I'm not just saying that, I can also feel it.
I can show you the overlay graphs, but I don't have my original NA dyno, just a tracing I did of it in photoshop then deleted the original scan

 

I will be going the opposite direction and getting a 3.9 when my project is all said and done. From the research I have done on this subject I would say that a 3.3 is going to be best utilized with a turbo of sorts where the stock will work great for higher WHP SC'd cars and the 3.9 works goog for about 400whp an under. That is what I have come across so far but I have never actually had the chance to drive a car with these setups so I can't justify them other than hearsay.