So I guess autos just see a 7500 redline, but is for show? or are you trying to rev to it while not moving? Because my last car could only rev to 5.5k rpm when not in motion, but once I am rolling, I could rev to redline.

 

If 2007 automatics also came with the 306hp HR engine, why would they limit it to 6600rpm?

https://my350z.com/nissan-350z/2007-...ine-part-5.php

 

My only guess would be cause of the auto tranny, damn u nissan lol.

 

Not only is that article wrong, but they also contradict themselves. First they say that all models have 306hp, but then they say that the autos only rev to 6600 rpms. If that were true, then there is no way that the engine would have the same output.

Also, another member on the forum posted a vid of his auto hr, and it definitely has a 7500 rpm redline.

https://my350z.com/forum/maintenance...ns-issues.html

 

Check under your hood...do you have one or two intakes?

 

Okay- and in any of the stock dyno sheets you're looking at, do you see an increase in HP past 6600 rpm by any chance?

Spec sheet says 306HP at 6800rpm- which fits with the stock dyno sheets I'm looking at (mind you- they are mostly in the 260s as expected).

I had my rev limiter bumped up during my first tune (though I'm a DE- but the trend seems to hold) but never got anything out of it... in fact I just lost power for longer. On most of the dyno sheets- you don't lose much but you certainly don't gain anything.

 

Pre-UpRev Tuned, my power drops around the 6800 range. After the tune, it was more of a steady increase all the way up then stabilizes at a HP till redline instead of dropping.

 

are we talking about peak hp or redline? no cars that i know of makes peak hp at redline...redline is setting you up for the next shift so you are in your powerband:

hypothetical example quoted from elsewhere:

"Coming out of first gear 6500 redline is when you switch to 2nd. Say peak hp was at 6200 which is 400HP now if you were to switch at 6200, although you have peak hp, when you switch you will be at say 3800 rpm which will give you 350 torque.. now if you switch at 6500, although you dont have peak hp and you only have 380 hp, you will be at 4200 rpm which will give you your peak tq of 405."

 

I'll pass that one off to Peter who seems to believe vq engine that redlines at 7500 MUST have more power than one that does at 66/6800.

 

What I am confused about is why ashram is setting his rev limit at 6600rpm? if peak is at 6800 rpm why not allow it to shift at stock redline, 7500rpm, at the very least?

 

The car and driver article claims that both cars have the same engine. An engine which makes its peak hp at 6800 rpm. If the article was correct (it's not) and the autos were only limited to 6600 rpms then there is no way they would have the same output as the manual transmission cars.

Not sure how you interpreted what I wrote to mean ANY engine

 

If his tach says his redline is 6600, then he doesn't have an HR (unless someone swapped the dash out with a DE dash before he bought it, which seems pretty unlikely).

 

ashram, can you take a pic of your guage? are you sure you don't have a late model 06 auto which has the de?

 

Lol guys i have an hr. The car has the hood bulge , with twin intakes. I had the rev limit increased to 7500 rpm and then lowered it back to 6600 rpm. Which i believe is correct fore an auto hr. Ive been searching all day trying to find nissan literature that shows what an auto hr revs to but have still not been successful. Its like nissan doesn't want us to know . Im thinking about just calling a local dealer and seeing if a tech can confirm what the car revs to and the redline.

 

If you have an HR then set the revlimit to 7500 rpms as that is the correct redline regardless of whether it's auto or manual.

I'd be interested to see a picture of your engine bay and gauges to verify what you're seeing.

 

ok so i think i figured it out, the car makes 306 bhp at 6800 rpm and redlines at 7500 rpm . so increased the rev limit from 6600 rpm to 6800 rpm looks like lowered my rev limit 300 rpms below the factory specs. took the car fore a drive and it does feel more responsive or maybe it was just the cool night air. using osiris rom edit i went into section that says rev range limit. so im not able to change the redline only the rev limit ? so i think im back to factory specs. i just wanna make sure that the range rev limit is referring to the rev limit and not the redline. im confused as hell lol.

 

Increase the rev limit all the way to 7500 rpms. The car might make peak power at 6800 (stock) but consider the following:

1) You are tuned, and seem to be making power past 6800
2) You want to stay in a lower gear as long as possible in order to take advantage of the additional torque the lower gear provides. Eventually there is a point where it's more advantageous to shift (you run well out of your powerband basically), but often times it is after you've made peak power and are starting to lose a significant amount of power as you keep revving. Eventually the loss of power counteracts the advantage you get from being in the lower gear, and that's when you want to shift. For stock cars, this point happens to be at around 7500 which is why the "redline" is there. You are only hurting yourself power wise by setting the rev limiter lower than that.

Also, don't have so much faith in how the car "feels" with your butt dyno. That's very unscientific and it's a bad way to determine the optimal tune / shift point.

 

Ok i took your advise and set the rev limit back to 7500 rpms, that car and driver article confused the heck out me and i thought my rev limit was to high lol. Thanks fore the info

 

http://www.datsuns.com/Tech/whentoshift.htm

Cool article explaining how to calculate the optimal shift point.

To add to what Peter said, the car is making more horsepower @6800rpms than it is @7500. However, you'll obviously need to shift to the next gear at some point. That *next* gear is going to have a lot less mechanical leverage.

The real question is...how does 7500rpms in 1st gear compare to X rpm in 2nd?*** I think you'll find that 7500rpms in 1st is still putting more torque to the ground than ANY rpm in 2nd gear -- so if you shift before 7500, you're leaving something on the table.

***Of course, this is taking the torque multiplication of each gear into effect.

 

People are overlooking that you need the torque for the next gear. Once you pass the peak power point, the acceleration slows down, so you'll be slower shifting past that point. You want the revs to drop down back into the torque again.

****EDIT - So glancing at that article seems to confirm what i just said Basically, setting an auto (of all things) to shift that high, is pointless.