Hey guys, a buddy of mine who works in a performance shop out in Cali has told me a few Z's have come in for Dyno's and that they were seriously undershooting their HP mark. He has had 5 Z's come in and the HP ratings have been between 226-234 HP @ the wheels. I was curious if anyone has heard similar rumors. I still love the Z and honestly it is an awesome performer one way or another. I've driven in one and it sure has some punch down there. But I want to know if it really is that over rated.


~Josh

 

The Z is rated for 287 HP at the flywheel. There is about a 15% loss through the drive train. This makes about 244 RWHP. I agree, 226-234 is low, but seriously low, not really. Are you sure you're not thinking it's rated for 287 at the rear wheels?

 

Nah dude I know the difference between flywheel and rear wheel but thanks anyhow. I agree it isn't a huge lack of power but still. That would kinda suck cause then you are looking at like about 265 at the flywheel I think? And that is similar to the other VQ engines that are out there. Not a big deal cause I know a lot can be done with this engine so I still love the car but I would sure like that 20 HP

~Josh

 

How many miles did these cars have? Auto or 6MT transmissions. The numbers look a little low for the 6MT, but are probably close for the Auto.

My car dyno'd at 241HP @ 6,000 miles.

 

While I'm kinda a noobie when it comes to understanding the world of dyno's, don't different models & styles come up with slightly different numbers, even on identical cars? Also, isn't a dyno supposed to be done in several runs, averaged w/hi & lo numbers (generally included in data). Can't outside air temp & amount of air volume entering the front of the car during the test also make a difference?

Just wondering. I haven't really heard numbers that low as a total - I've heard in the 230's for "low" dyno numbers, but usually the stock average seems to be upper 230's - mid 240's.

I am waiting for my 1st set of performance mods (probably intake & exhaust) before I spend time & $$$ on a dyno run.

 

Here we go again... do a search for "dyno", and you'll see further explanations on this topic.

But in short, most people who are pulling 225-230rwhp are dynoing in the wrong gear (3rd or 4th), while 5th is the gear with a 1:1 ratio in the 350Z. If you dyno in 5th, people are getting 238-245rwhp usually.

 

Thanks Hedonist. I am sending my buddy a email asking him that. Sounds like the right explination because he couldn't understand it either.

~Josh

 

Between 225-235 Horsepower is typical for an Automatic.
They lose between 18-20 percent through the drivetrain.

 

ya beat me to it Hedonist

Its best to run in 1:1 gear(5th on Z) but alot of shops dyno in 4th or even 3rd since it keeps the roller speeds down. Usually this doesnt matter since people normaly dyno to test or tune mods so whatever number they get in whatever gear they pull with are just used as a baseline to compare consecutive pulls in the same gear after mods/tuning. But if you are just doing pulls on a bone stock car for biggest number bragging rights or to satisfy your curiosity your going to be dissapointed with lower gear numbers

 

the difference in gears could not possibly be more than 2 or 3 hp.

with that said, 15% on 230 is about 271, not too bad, not too good either. at 240 your up to 282, a bit closer. might be slightly underrated, but I feel the better explanation would be greater than 15% loss. not all that unlikely on a RWD car. typical is 15-20. so the Z is falling most likely around 17. its impossible to say the car is underrated without dynoing it at the crank, instead all you can say is that it is losing power somewhere, be it at the engine, or the drive train.

 

Im not sure where you get the "2 or 3" hp difference, but on a Z there is a 21.4% difference in torque to the rear wheels between 4th and 5th gears on the Z at the its torque peak. Also, the Z is probably not losing more than 15% to the wheels, while its true, cars with large automatic transmissions like T-350s and R-400s lose close to 20% at the wheels, lighter manual tranies like in the Z are much more efficient, and the carbon composite driveshaft helps keep the drivetrain losses even lower, 15% is probably right on