Nissan 370Z Forum - Power loss

Nissan 370Z Forum (http://www.the370z.com/)

- Intake/Exhaust (http://www.the370z.com/intake-exhaust/)

- - Power loss (http://www.the370z.com/intake-exhaust/53120-power-loss.html)

Quote:

Originally Posted by chrischhorn (Post 1665249)

youre contradicting yourself......7k+ is top end...... mid range is 4.5kish. Not all cars pull all the way to redline. Its quite normal for a lot of cars to drop off before redline. Even hondas with their Vtec drop off before redline and 90% of factory turbo vehicles drop off before redline. Our cars, not so much but as everyone says, the manifold is why you're dropping off because thats the characteristics the manifold has. Now if you're making 5hp less then your baseline.....then you may want to start checkin things like spark plugs (which shouldnt be a problem if your under 75k miles) or in a bad case scenario, cylinder compression.

to put it simple, you're digging for an answer you want because you don't like the answer you're getting even with multiple people telling you what it is. Dont know where else to go from there.

its not that im digging for a certain answer, its that i know it isnt the manifold because the manifold on the other dynos ive seen it drops 3-5whp in the last 200ish rpm..my car makes good power til 6900-7000.stops making power(plateaus) til 7800-7900 then dips down...the dip isnt the issue..im trying to figure out whats causing the plateau from 7-7800rpm..which in any z i havent seen that happen lol...i guess its better to understand when i put up the dyno sheet...let me email it to myself and upload it

update on OP...that baseline is very old when i had i/testpipe/exhaust...but even there u can see it doesn't stop making power

Can anyone tell by the graph?

Looking at the graph I can definitely tell the old one did not have that intake manifold. Looking at your exhaust mods, nothing there will prevent you from making power all the way to 8k. I'm still unsure how dramatic of an effect the intake manifold has on full bolt on cars like mine and yours (yet to dyno under exact conditions). I would definitely check to make sure your filters are clean. It looks eerily similar to how the stock intakes choke up after 6500 rpm and flat line. Don't count out the M370 though. I have one on mine and I'm showing power loss up top, but not sure how much if I were to switch to 93 on the rollers.

Could it be the upRev tune? Was the dyno tune the last thing you had done?

does anybody else have dynos with the m370 installed? Maybe I am wrong but I was under the.impression that the m370 would cause the car to lose a few hp up top compared to baseline... I did not think it would actully cause the car to plateau and stop making power alltogether. Like OP suggested maybe it's not the m370 but I am curious to see other dynos with the m370

This is my dyno between the M370 and stock manifold. This is untuned and the M370 is running 91, the stock is 93. Those are the only differences.

http://www.the370z.com/attachments/i...ynocomparo.jpg

Idk how much being untuned and 91 octane are skewing the comparison, but your loss in top end looks like a lot more than "a few hp" like motordyne claims

U have to tune for the Mani when your full bolt ons. I lost the exact same as u on the baseline. 12 hp. But gained it back after tune and around 10-12 midrange above baseline

Quote:

Originally Posted by whoLEEoh (Post 1666816)

U have to tune for the Mani when your full bolt ons. I lost the exact same as u on the baseline. 12 hp. But gained it back after tune and around 10-12 midrange above baseline

That's why I'm reluctant to pass judgement on the M370 as of yet, especially with your issue as I don't know all the variables yet.

It's the manifold. It just makes peak torque lower in the rev range, which you can clearly see. A tune will only do so much.

Any other differences are as likely due to transient factors (e.g., intake temps) as not.

Also, see if you can get those results in SAE, DIN and STD tend to skew high on NA cars.

Quote:

Originally Posted by whoLEEoh (Post 1662971)

Hey guys I'm wondering why I'm losing power top end. Car builds good power til 6950-7000 rpm and then it plateaus til about 7500 then I lose 5hp til redline. Current mods.

Stillen g3
Motordyne manifold
Fi lth
Custom 2.5 exhaust h pipe with magnaflow muffler
4.08s
Uprev tune

Tuner says could be exhaust but I have no idea why it's happening. Any help will be appreciated.

http://farm8.staticflickr.com/7270/6...744df90b_b.jpg

I'd be more upset there are 370Z's that made like 20whp more on that dyno with just i/e and tune :)

TAKE THAT JULIO! JK of course..

It's weird though, didn't look like you LOST power, but it does flatten out. How does the car feel? I mean, you rev until 8k, you're going to fall more into your powerband and it should move nicely.

Quote:

Originally Posted by Jordo! (Post 1667055)

There is definitely at max a 10whp difference in correction types.
I have my drf run files so I can so adjustments, but I've posted strictly DIN on other threads so I use it incase anyone cross references.

Quote:

Originally Posted by gaveup (Post 1667140)

I'd be more upset there are 370Z's that made like 20whp more on that dyno with just i/e and tune :)

yeah I was about to say....those numbers look like they should be for a stock Z...how is he making so little power with all those mods?
But also going by the trend of the line before the plateau it looks like he would reach 300 if it did not level off like that. But still, 300 also seems low for those mods + tune.

Is that a low reading dyno?