Good rpm to shift at?

[anthonysmithr33gtr]

Hey guys I was just wondering what rpm you guys think is best to shift at and also what is best to take off from a stop at?

[Daryl @ RightDrive]

It all depends on how your car is set up. Best idea is to get a dyno done with a printout, and see where your powerband is. Then you can time your shifts to maximize the powerband.

[anthonysmithr33gtr]

That's a great idea! But I meant for daily driving, the car is bone stock nothing done enginewise!

[steveo1502]

I'd say about 8000 depending on who's beside you, lol

[anthonysmithr33gtr]

Heh yeah the cops dont really like that xD or my gas tank, completely blew the doors off a brand new mustang gt on the way home from the city today, like 50$ worth of gas by the time I got back home !

[steveo1502]

Bahahahaha, ya mines not good on gas either, especially with the boost cranked up, Boost controler helps a lot, if I turn it down to 12 psi, it's not as bad, 18 shes a real pig.is yours still stock boost? With the restrictor pill in the line ? If it is ya should have removed that already. way more fun.... And more gas, but I'm guess in you weren't goin for fuel economy when u picked up this beast right.

[Skym]

With GTS-R (Group-A racecar with RB20DET) they had to drop down a gear before a corner to keep rpm needle in the 4800rpm-7500rpm area (powerband). If drops below 4800rpm it makes the car slower to accelerate, then sudden rush of hp. Stock is around 4800-6400rpm.

Stock RB26 is 3800-6400rpm and transistion response has been softened (using a twin turbo setup) and has a linear power delivery (not a sudden rush of hp) when exiting corners and mix with smooth delivery of torque to front wheels via 4wd it helps to pull out of corners quickly. That's what made the Group-A GTR's fun to drive, as they accelerate quickly out of lower speed corners with the help of 4wd. At high rpm, speeds they should be close to rwd, but R33 GTR has preload to front wheels, so is always slightly 4wd.

The peak rpm I mentioned at lower rpm is usually peak boost if you look on a dynochart.

[anthonysmithr33gtr]

Fuel economy? I certainly wasn't looking for a smart car xD It's still stock boost, no idea what a "Restrictor Pill" is. (First turboed car that I have ever owned)

[steveo1502]

Look it up, it's in one of the vac lines by the factory boost solenoid, limits the boost to7 or 10 psi, something like that , remove it and it's 14 I think. Big improvement. Its prob already removed. And if u find it still in place, means your car has never been over stock boost, be nice to know, I guess....... But then I'd still take it out haha. Should be a little yellow band on the line where the pill is

[Skym]

That restrictor is said to help the stock boost control solenoid control boost level and it shouldn't be removed (boost level is raised on ECU side via boost duty maps). If remove restrictor, should put a adjustable valve in it's place.

[NismoS-tune]

7800 for me. power was dropping off above it.

[steveo1502]

U should prob listen to skym, lol, I've never heard of this valve in it's place. ? Sounds like basically a manual boost controler ? Where the pill would be? Idk, this is also my first turbo car , but I think an electronic boost controler was the first thing I did, the pill was already gone when I got the car, but would still only go up to .7-.8 bar. . I was kinda kidding about the 8000, lol, not sure if I've ever been that high.it should have a rev limiter , I have an aftermarket ecu(impul) its up around 8000 i think, ive hit if a few times, but really,Anything over 6k and your haulin axx, I usually just grandma it around though, 3-4000.

[Skym]

It's mentioned in a build thread on SAU and was with a aftermarket stock like solenoid setup (he had removed the hose with boost restrictor in it when replumbed). He fitted a adjustable valve from US? (to act as a restrictor) and was able to control boost level better (from what I can remember, boost built quicker and held boost level above 1 bar). Most upgrade to top of the line Blitz or HKS boost controller with better solenoid when running above 1 bar (most tuners know about this problem, as was mentioned on here as well). The factory had a good reason to put the restrictor there (probably due to solenoid they fitted).

Also someone with Nistune has experimented with different restrictor sizes, stock boost control solenoid and I posted a link to that thread in the past.

[MarusGTR]

The factory had a good reason to put the restrictor there (probably due to solenoid they fitted).

Some also say that it could be a power restrictor for the gentleman's agreement... all I know from my end is that I raised my AFR by removing the restrictor for (what I think) is the vacuum signal. The other restrictor (what I think) is the pressure feed from the plenum remains.

Both restrictors are located in hoses with a very noticable thick yellow stripe. Press the stripe to feel for the restrictor.

[Skym]

Since without restrictor, it allows boost level to rise, it probably also helps stock boost control solenoid prevent boost spikes (since wastegate port is said to be small on back / exhaust housing of stock turbo's), as stock boost control doesn't have map sensor like aftermarket Japanese made boost controllers do. The MAP sensor helps controller to prevent overboost (on some boost controllers it can drop boost level if car wheel spins, etc).