Mike821

So, do you guys feel that we've been cheated by Nissan? I've dynoed my car this weekend and got no more than 230WHP from any of the runs I did.

It translates to about 270 at the crank - no way it's 287. I've seen other posts with similar results, and I know Nissan's done that before with the maximas which have 240 HP and not the advertised 255 and right now there is a lawsuit coming from the maxima owners.

What results did you guys get from your dynos (in 4th gear of course) and under what conditions? It was cold here in Massachusetts when I did mine, hood was open, fan was blowing right at the intake...

ares

iTrader: (2)

try 5th next time. 4th isnt 1:1, not that you gonne gain 15hp but just for futre reference.

it seems some people dyno low, some dont, I saw one guy that got 242 I thought...

is your car broken in? how many miles? which model? perhaps rim size could alter the drive train loss, but again, not by 15hp.

was it auto or manual, you could expect a higher loss from an automatic, but you said 4th, so unless you used tiptronic(in which case 4th is the correct gear) you were probably a manual.

anyway, just some ideas, I want to get mine on the dyno soon, just wanna finish the break in first.

deviousZ

Yeah I agree 30 hp is about normal to lose through the drive train but 57 is crazy I think they over rated the Z by alot!

Mr B

iTrader: (2)

Rare, but the drivetrain can have 20% power losses for your manuals. So 287 times 0.8 (80%) is 229.6hp...
Most of the time, people figure 15%, but it can be as much as 20%.

Mike821

Rim size is stock, car is not broken in, transmission is manual, 4th gear is almost 1:1, 5th is not.

20% loss is not normal for manual transmission...

SKiDaZZLe

'

you need to get back to breaking in the car, and not spouting off your incorrect information...

what does this mean to you: ?

ares

iTrader: (2)

not normal maybe not, but possible, supposedly the carbon fiber shaft was going to help, but it didnt... nothing you can do about it. but yeah 5th is the 1:1 gear.

Mike821

You're right I'm wrong... 5th is the 1:1...

Now I can't remember whether I dynoed in 4th or 5th.

If it's 5th then we're missing HP, if it's 4th then doesn't it mean we're missing even more HP?


Skidazzle, is there a post where you posted more information about your nav-tv mod and the rear view camera? I'm interested in something like that.

Let me know.

Michael

BigBadBuford

I wouldn't be surprised if the Z had 18-20% loss at the wheels, in fact I'd be VERY surprised if it only had 15%. Everyone seems to make a big deal of the carbon fiber driveshaft, but there are a lot of other factors that contribute to HP loss at the wheels. First, the Z is a rear wheel drive vehicle which inherently has more drivetrain loss. Second, it has a very stout transmission which I am sure contributes a bit to HP loss. Also, the Z has an independent rear which has more loss than a solid axle. The carbon fiber driveshaft will make some difference, but probably not more than 1%. Also, if you dynoed in 4th you will see some loss over dynoing in 5th. If you run your numbers using 18-20% loss, your car is making between 282 and 290 hp, which is pretty close to what Nissan says.

Mike821

How do you figure 282 - 290 hp?! Even with 20% loss, it's still below 280. I guess in 5th gear you'd get more HP but no more than like 4-5 more at the wheels.

So if you take 235 which is not likely, and take 20% loss which really sucks if it's true, then you get 282. It's not 287 and certainly not 290.

Where did you get those numbers?

Also, 20% loss i'd expect from an automatic Ford Taurus, not from 6-speed Nissan. I know Nissan is no Bimmer but 20% is huge.

cabalisticfire

It'a all in the math. Let's work with 20% loss just to keep things simple. To figure wheel HP based on crand HP you might subtract 20%. That 20% figure is Crank HP - (Crank HP * .20) as opposed to Wheel HP + (Wheel HP *.20). The 20% figure is based on the crank HP, no the wheel HP. Make sense?

So:
287 Crank HP - (287 * .20) = 229.6 Wheel HP
287 Crank HP - (287 * .15) = 243.95 Wheel HP

Since I'm not 100% sure that the % loss should be calculated based on Crank HP, here is the numbers based on Wheel HP.

230 Wheel HP + (230 * .20) = 276 Crank HP
230 Wheel HP + (230 * .15) = 264.5 Crank HP

I think the first set of numbers (calculated from Crank HP) make much more sense. But, since the dyno run was made before the end of the breakin period the numbers are not a valid assesment of the true HP of the engine.

myz350

230/(100%-20%)=287.5hp

SKiDaZZLe

do a search for "nav-tv". i did not post much except pics... internetabyss, and one oter guy posted all the information.

m

Mike821

My problem is 20% loss. That's unacceptable.

Manual should only loose 13-15% maybe a LITTLE more cuz of RWD

cabalisticfire

Right, but you're not broken in yet. Let the break in period pass and then go dyno again. Infact, it will be interesting to see just how much HP is gained at the end of the break in. In order to get to 287 Crank HP you'll need to dyno 243.95 at 15% driveline loss or 229.6 at 20% loss. Since you alread pulled 230 during the break in period it's probably safe to say that the loss is less than 20%. With enough cars and enough details we can probably pinpoint how much loss there is.

I'm thinking of starting a spreadsheet to keep track of all dyno runs. We can track the whole host of variables, temp, humidity, mileage, mods, type of dyno, etc. This could would be very usefull in determining which mods work, weather your car is tuned correctly, etc. If anyone is interested, send me you dyno info.

Mike821

I believe I saw a dyno somewhere here of 240 or 241 at the wheels buy mostly everyone got the same as me.

Also, on the same topic, how long does it take the ECU to learn and adapt to a new mod such as an intake? I know some cars it's instantaneous and others it takes a few days.

djbit

iTrader: (1)

My car is a totally diferent car at 2400 miles then it was at a few hundred miles. It feels plenty more powerful. I remember posting something that my 92 300ZX NA felt sronger (I had like 300 miles on my new baby) but now I take that back!

Fëanor

nevermind.

cabalisticfire

That's a good question for the ECU tuners out there. Either that or someone is going to have to do a little trial and error.

Mr B

iTrader: (2)

I'd like to know what car loses only 13 or 14% power from their driveline. 15% is already being optimistic for a fwd car...