Last time I checked Sharif has a DD and does all his pulls in 1-1 ratio which is 5th gear.He also starts at 2000rpms, and full bost hit at 4500rpms.
How ofted on the street do you do a run from 2000rpms?

 

My greddy kit full boost around 4500rpm. But its boosting 19psi and not 7.5

 

my greddy kit full boost is around 3600 rpm.. But its boosting 17psi and not 19

 

Not starting anything, or trying to single YOU out and correct you, but these 6mt transmisions in these cars do not have a true 1:1 ratio (direct drive) gear.
Although 5th gear is the closest gear to 1:1. I don't know the exact ratio off the top of my head of all the gears, but I know that 5th is a slight underdrive at just a little inder 1:1, with obviously 6th being overdrive.

 

What? The gear ratios for the 6MT of all MY's of the 350Z and G35 have been

1st - 3.794
2nd - 2.324
3rd - 1.624
4th - 1.271
5th - 1.000
6th - 0.794
Rev - 3.446

5th is 1:1.

 

obviously no one would race from 2000 rpms, and no would would start a race from 3500 rpms either, but sharif apparently started this dyno at 2500 rpms:


seems to me, we'd all be more interested in how fast a turbo will spool up in an actual racing rpm like if the run started at 4500

if you brake boost, it's not going to matter anyway, so therefore it'd seem that people might race from a stop in 1st gear if they're to ever see 2000-2500 rpms

on top of that, who starts a race in 5th gear? By the time any normal person will hit 5th gear, the turbo is damn near spooled up anyway



I swear, someone needs to someday take a turbo car, do a 5th gear pull starting at 2000 rpms taken to redline, then another run starting at 2500 rpms, then another run starting at 3000 rpms, etc all the way up to starting at like 5000 rpms and compare the graphs to each other. That'll show you what sort of lag you're dealing with at different rpm ranges. You could compare hp/tq as well as the boost charts. It's not like it'd be hard to do, but no one ever does anything like that.

You'd have to start the run and then stomp on the gas at pretty much the same time so you can see the lag taking place since the turbo won't be already spooled up. Of course all setups/exhausts/boost controllers will be set up differently, but you could show a better idea of what the setup does other than "look at my 5th gear run from 2500 rpms that no one would actually drive like this in real life"

 

As per the Nissan service manual for 2003-2005 non rev up:
1st - 3.794
2nd - 2.324
3rd - 1.624
4th - 1.271
5th - 1.000
6th - 0.794
Rev - 3.446

5th is 1:1.
The rear end ratio for 5 A/T is 3.3 the rear end ratio for 6MT is 3.53

As usual Scott, YOU are incorrect. Surely someone of your caliber who has built some of the worlds fastest cars, would have known this and was just testing me, right?

 

The problem when dyno tuning a car is that first -4th gears are usually way to short, and have traction issues,making a clean pull impossible. 5th gear is the most load you will put on the car and get the highest stable boost readings on a 6MT VQ.

 

As far as the different turbo spool up times, it realy does all depend alot on the suporting mods as to what the ramp up time each turboed car will have.

IMO, one of the biggest overlooked factors is cams. Cams play a pretty big role in getting the turbos spooled up faster. I was already awarwe of this before, but here recently it became even MORE aparent when we installed our new (one off) prototype custom made JWT MONSTER cams (we call them N9's). After installing these cams (with everything else unchanged) on our Time Attack car and I immediately noticed the boost came in, and up to peak boost quite a bit sooner than it did with the previous S2 JWT cams. We went from a decent amount of lag with the JWT 850BB kit, at about 4100ish rpm, to about 3800 rpm's with the new cams. This is a big help on getting these turbo's to come in sooner and make alot more usable power for us on the huge JWT 850 TT kit.

 

Interesting, can you post up a DYNO for us to see??So that we may discuss..

 

Oh, I agree. You are 100% correct, there is no better gear than 5th to dyno a 6mt in, that's the gear we use. I was just clarifying that there is no direct drive gear in these trannies.

 

Here is a dyno of my car on low boost DYno Dynamics uncorrected with the BC stage 2 cams..Were upgrading to the stage 3 soon. Notice how the TQ comes in fully by 4400rpms, that the boost peaking as the turbos fully spool.



Now lets see yours with the JWT monster cams.

 

Yeah nevermind I got confused. I just looked at it and it is at full boost by 4000.

 

that's interesteing, but just because you're cruising at 3800 rpms and then suddenly put your foot down to go WOT doesn't mean you have instant full boost. To get full boost at 3800 rpms, you probably had to have your foot planted since like 2500 rpms and waited until you reached 3800 rpms - of course depending on what gear you were in which would dictate how much total time you'd spend holding the gas pedal at WOT

 

You mean the 284 cams? That is really odd, since I was always aware that big cams like 272+ will make the car boost later.

 

And move the power band to the right of the Dyno Graph, and extend the RPM range higher up..Usually..

 

perhaps Scot overlloked this post.Il repost for his convieninece,Please post up a dyno sheet of those monster cams for all to see and discuss.Were all interested and hanging on the edge of our seats..

 

+1

Intense Motorsports installed Tomei 280 cams on their G. They told me that it moves the power curve to the right and is made for top end power.

 

The chirp starts here.

 

I hope I am not being bated here ...... but
It wasn't a dyno session to brag about and we were in a hurry to get out of there and loaded up for the Laguna Seca Time Attack the very next day, so I didn't get a copy of it and I am not sure if any of the pulls from that session were even saved. The car actually ended up loseing a bit of peak power compared to the previous sessions, do to these new cams uncovering even more breathing restrictions do to us still running the original JWT FMIC and pipeing that was designed for the standard 530BB kit. This last time the car made 680ish whp at 20 psi. We found that 20 psi is all the standard JWT TT kit pipeing and FMIC wanted to handle eficiently. But the cams did help to reduce the lag by quite a bit and we noticed it even more at Cal. Spdwy. at the last track day we were at.

Our next step will be a bigger FMIC and bigger IC plumbing.