I think Charles was taking a dig at my shifting speed. haha. Touche. He has the time slip to prove what hes taking about.

The only thing with launching hard is that horrible rear axle hop, which bushings will help with, I am yet to do them however. You will smoke your tires well before you smoke the trans. The stock clutch however, not so much. :tiphat:

I know what you meant, and I am saying it doesnt make a difference (in my head, at least). If you are no-lift shifting the car, are you going to push in the clutch and then sit there and wait for the engine speed to come all the way down to 5500? I'm not... defeats the entire purpose of no-lift shifting.

Unless you are granny shifting like that, engine speed probably would never have a chance to fall below 7000 before the clutch is reapplied and the engine is braked down for the next gear speed.

Sure anything can break, but all that you realistically need to worry about is the axles and differential mounts. Replace the diff mounts before the rear one busts open, and preload your axles before launching and you probably wont be unlucky.

Nah I have never seen you drive, I am just debating the purpose of even having a no-lift limiter unless its purpose is to ignition cut or retard and burn fuel in the exhaust for a couple pops of turbo spooling inbetween shifts... but I dont know that any of us are running enough turbo to need that.

Realistically what it's supposed to do is keep you from hitting the rev limiter between shifts. Maybe I'm misunderstanding that you're misunderstanding but, with it present when you push in the clutch the engine rev drop down to 5500 or 5600 almost immediately to keep the turbos spooling at optimum boost levels for the next gear (you want your revs to match where your torque is high and your next gear engages)

if you're at the rev limiter you're past peak torque for sure and most likely already out of the turbo's efficiency range.


I had this system set up on my wrx and you can feel each gear just pulling you harder...and harder...and harder

See I am on top of the theory of it all, but what I am trying to say is that: just because the no-lift shift box has cut fuel or spark doesnt mean the engine is immediately at the lower speed. It will still take a moment for the mass of the crank and flywheel to decelerate, and with the throttles wide open there isnt even any manifold vacuum to help. If you are shifting as fast as you are physically able, which I assume is pretty fast if you are experienced and confident, the engine isnt going to have enough time to decelerate to 5500rpm.

Of course, the way I am doing it, the engine is staying at redline the entire shift, working the synchros a little more, but my transmission does not complain, it shifts just fine and hasnt started to grind or anything and that is 60,000 miles on it and it is still on the factory fill trans fluid and all. I had the same experience with my 350z, however that car did break its transmission a couple months after I sold it (but it was 10 years old by then and been through hell, and a new trans isnt even expensive enough to worry about). To have it at redline as I release clutch in the next gear also gives me a nice little jerk of power as the inertial energy of the flywheel and crankshaft at 7500rpm gets blasted into the drivetrain to decelerate it to the next gears speed.

If you watch my in-car vids, you will notice that the car only taps the limiter the first time and you cant even hear it because the shift is already over. You use that first cut as your no-load chance to slam that shifter. Only on my slower/miss-timed shifts do you notice that it hit the limiter.

No ****? Wow. I'd love to see an analysis and see what weight it's sheared down to after the abuse you put it through. :rofl2:

my diff and trans fluids and coolant are factory fill, but my oil has been changed every so often :)

Oh I see what you're saying now. Well From my experience with it on a boosted engine, not the Z's, it has always fallen as fast, if not a tad faster, than the time it has taken me to push in the clutch shift to the next gear and release the clutch. Especially on 2-3 4-5 shifts. I may not be as fast as a DSG auto, but the .5 sec it takes me to shift is enough time for RPMs to fall enough to where it matters. And of course peak range for torque is more efficient this way.

EDIT: I'm sure a lightweight flywheel would also help it fall faster, when it's not holding the same intertia

whats it cost to do? ill send some out? i planned to change the trans fluid this winter LOL

peak torque and turbo efficiency and all that have nothing to do with it... gearing is gearing, and once the clutch is re-engaged the engine speed will match the wheel speed per the selected ratios and thats what you have to work with. the most a wot-box can do is help keep a big turbo spinning faster by burning the fuel in the exhaust mani, but we dont need that, turbos on Z's arent laggy anyway and the car has enough natural power to propel itself quickly even if it did loose boost for a split second.

my car has a twin disk clutch and light flywheel... it still isnt gonna fall quick enough that i want to wait for it!

Haha, fair enough. The whole process is more useful on 4cyl cars by far, and especially for awd where gear to engine speed management is important to not break things. If you're not spinning you wheels every shift, not experiencing an absurd shock, and shifting before your rev limiter you're most likely good to go anyway

What is important, i believe (im not a transmission expert) in the quick-shift is that power is momentarily cut. For me, that is happening when I hit the factory rev limiter. I dont try to hit the limiter before I begin the shift, but when I push the clutch in the engine flys to the limiter because I am still at full throttle, hits the limiter, and this factory cut is my moment to perform the shift and drop the clutch.

my slower shifts, if you watch the vids, you can tell what happened was that I accidentally hit the limiter before initiating the shift, screwing up my whole timing.

I would suspect, tell me if I am wrong, that the reason you felt the difference with your no-lift shift module is possibly because you were not no-lift shifting until you had the module. Am I right? Because trying to shift at that engine speed without being on the down-slope of a cut, it doesnt really want to shift fast and it will grind if i release the clutch too soon in the process. What I am basically saying is, I feel like my transmission lets me shift it faster if i bang the rev limiter, than it will if I try and slam a gear hard without hitting the limiter... and I dont think it would let me into the next gear as quickly if I didnt keep the throttle down so that I tap the limiter.

Perhaps its time for me to study my transmission a little bit more.

Blackstone Labs

$25 or so.

I did it a few times in my wrx before actually having the ecu tuned for no-lift (on the wrx they call it flat foot shifting)...basically I could feel the transmission jerk quite hard, and twice the driveshaft actually slipped! It scared the piss out of me the first time it happened...

with the flat-foot programmed in the engine would quite rapidly drop back down to the appropriate rpm as fast as i was on and off the clutch so that the next gear lunged me forward rather than feeling like i ripped something apart.

Then again with AWD there are a lot more moving pieces and there's less room for error/slop between shifts. Get it wrong and you'll feel the clunk and chunk of all four wheels, get it right and you'll feel all the wheels grip

I think your onto something there. Shifting once you just tap the rev limiter takes all the stress away from the drivetrain and gives you a nice window to shift in. I personally run the Racelogic for day to day driving because A. it sounds awesome, and B it does work very well. Launcing with it I still have not perfected and to be honest I only do it for the sound, lol. It does manage to build 2-4psi of boost though. Although as we know with this car traction is already an issue and boost at 0mph is sorta useless. lol

I played with using map switching in the UpRev for a 2-step, and it didnt work out... but I need to double check my settings.

What I did was copy over my map to the second position, then just pull a bunch of timing out and set a rev limiter at 4500 to start. Then I would go to that map, and do the sequence to switch back to the first map, only keep holding the button down because it doesnt make the change until you let the button up.

While sitting there holding it, i would also build some boost and it seemed to work well, cept when I performed the launch, as soon as I got up to somewhere around 60mph, the car hit a momentary speed limiter... and i had to let off then get back on it to get past it.

Was confusing me... but thinking back i believe i put that speed limiter there in the 2nd map pretending it was liek a valet mode, and perhaps for some reason the speed limiter takes a few seconds to switch? wierd either way... thus i didnt make any attempts with it at the track.

BTW I am not against RaceLogic, I have used it in other cars and like it a lot. I was just arguing about needing it for the no-lift shifting stuff.

From St Pete, says it all... :rofl2: {JK}

Welcome to the forum.

the way it worked on my car was through an ecu mod for the actual code level. While below 10km/h and clutch in the rev limit was 4500 rpm. while above 10km/h and clutch in the rev limit was 5500 rpm...clutch out there was obviously no limit. Not sure if you can set up something like that...

If you want to PM me, I might be able to look at it code level and figure out what might work on this ecu compared to my old ecu. Coding is still coding, and that's partly my profession. Who knows, could find a whole new way of doing things...

If you know IDA and your way around a BIN file there is a large potential to make some $$ with these cars. Everyone has been promised all these features by ECUTEK with 0 to show for it. But if you have the skills to get into it that level (I started to, but to be honest I just dont have the time) then there is a large service that you could offer.

As far as adding these features through existing tuning platforms its just not going to happen, not soon anyways. Ive tried to get a stock dump file out of my ECU awhile back without much success, albeit I didn't spend all that much time on it.

I use the UpRev software and there is no 2-step option, that is why I tried using the map switching for it. You would want to talk to UpRev about it if you know how to add functions to the stock ECU.

For me personally, its not a big deal. I only race the clock when I am at the track, so the R/T doesnt matter to me. I will sit there on the green until I am happy with where my RPM is and then launch. On the street, the Z does not hook well enough to do anything other than roll out and mash the gas. If the software I already had could be made to do with with the map switching technique, then sure why not... thus I tried. Others have had it work for them so I am going to eliminate the speed limiter in my second map and try it again next time and it should work for me.

So did old boy go over to MY350 or Zilvia, lol?

You are so funnnnnny!!!

:happydance: