Since i got my car tuned i always wondered if raising the rev limiter to 7100 rpm will make any difference in acceleration. Well yesterday i found out that it actually hurts the acceleration if u take all the gears to 7100 rpm (this applies to 6MTs only). Keep in mind that 7100rpm shows about 7400 rpm on the actual tachometer. My car makes peak power at ~6200 rpm.

After i got the tune i went to the drag strip months ago. My best time bone stock on that track was 14.6 @96 mph. Added kinetix plenum and catback exhaust and combined with better driving skills i got it down to 14.4 @ 97 mph. Added the tune and redlining at 7100rpm got it to 14.2 @ 96mph. Well yesterday i went to the track again and got one decent run (other ones I either missed 2nd or got 2.2-2.3 60ft time). With 2.172 60 ft time I did 14.127 @ 98.77 mph. This run was with redlining at 6700rpm showing on the tach on all the gears. The last time i went i was shifting 7400 on the tach. One of the runs I almost trapped 100mph with shifting 6500 rpm on the tach through all the gears but unfortunately i got 2.37 60ft time on that run.

BTW 14.1 @ 98 mph is my PB.

 

Vlad,

Where does your car peak in torque?

How much hp does your car lose after 6200 on the your dyno sheet.

I think 6500-6700 is a good number to shift for you.

I shift at 6500-6700 so that my rpms drop in between my peak torque and hp.

The power on my car before starts dropping off around 6200-6400.

The blue and yellow lines are 7.5psi with a different exhaust housing 0.63AR the red is 10psi with a 0.82 housing.

Hopefully the numbers will be different after my osiris tune.

 

I'm guessing it might be the case for you non-revups. Because at my 25-runs on a wednesday night at LACR (ignore the conditions, as that wasn't what I was there for), I tried a variety of shifting points/patterns to see what would yield the best trap speed & E.T. It turns out that, atleast for me (almost stock back then), shifting at 7100 RPM's yielded the best trap speed. (By 3rd gear, I believe the meter is 200 RPM's off...so I was shifting at 7300 RPM's which would be 7100 in reality.).

Cams would definately help the non-revups. But then again, that's a bit pricey.

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just maximize the area under the curve

 

here is the dyno sheet. It looks like im making peak tq at 4700-4800 RPM.
Looks like the dyno sheet doesn't show how much power im losing after 6200rpm but im guessing a lot because at higher speed i can feel the car run out of juice.

The only reason i would think it won't work for rev-ups because the tq curve is not as aggressive as non rev-ups. Later u shift better for u because u are going to need all the HP u can get under the curve. I am making a lot of tq down low so the car does not really need to see the HP decrease after 6200 rpm.

 

Shifts points are based on gearing and the shape of the power curve. I haven't sat down and calculated out the numbers, but I'd think shifting at ~7,000rpm on the 1-2 and then ~6,700rpm on the remaining gears would be close to ideal for a non-revup motor.

 

I am aware of that. The sad part is that no one has ever had the chance to figure out the shift points since 2003. I personally don't know how u would figure it out by looking at the gear ratios/dyno graph etc. For me it is still trial-n-error. Every time there is a discussion like this someone says I am going to figure it out and they disappear from that thread.

https://g35driver.com/forums/intake-exhaust/203555-how-much-horsepower.html

 

u know i noticed the same shyt a while back when i had mine bumped up with the utec. im gonna post up my graphs when i get home..

 

if you think about it logically, the first two gears need less torque to accelerate, and provide enough ratio that the drop in torque at the top end doesn't have as much effect, so you'll keep accelerating, and won't loose as much on the 1-2 shift, 2-3, with out knowing the ratios might be tricky, depending where it puts the revs, but it should still be shallow enough to be shifted into at a higher rpm, though from there on being closer to the torque peak at the shift into gear the better, since you need the torque to accellerate.

just theorizing, really, but seems logical. (old rule of thumb, torque accelerates, horsepower keeps you moving)

 

Do you have 100rpm (starting at 4000rpms) breakdown of your dyno numbers? I can do it off your graph, but it won't be as accurate.

 

^i am getting the car dynoed this weekend again. I will see if i can have the 100rpm lines shown on the graph.

 

Any update on this thread?

 

they fuked up the dyno graph when they dynoed my car, they had VDC on and did not get an accurate reading.

 

Oh yes, I forgot to mention in my other post. You raise your rev-limiter, especially on the non-revups, to avoid bouncing off of the redline. Raising the rev limiter doesn't mean you're going to get better peformance unless you have internal modifications that will allow you to have more power up top (ie. Cams).

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Why does 7100 rpm show as 7400 rpm on the tach? So, is it off from the beginning?