Ok thats nice but I guess their is no real solid advice on how to reach that goal??

 

These cars don't put out anywhere near their advertised crank numbers, so I'd stop shooting for that.

 

20hp from intake/exhaust??? wtf???

 

1/2'' plenum spacer is supposed to be pretty good.

 

md iso thermal spacer
z-tube
headers
hf cats/test pipes
exhaust

you'll be well past there

throw on lightened crank shaft pulley and grounding wires for more 'fun' (i.e., non-hp gaining stuff, but makes it funner to drive)

 

the difference b/w the 03 and 05 6mt engine is in the intake plenum, vvt on the exhaust side, and higher redline. for the plenum, you can get a 1/2" spacer and for the redline you can get a technosquare flash. I am not sure which other mods work. but one thing to remember, is that the 03 weighs less.

 

Here are my numbers for my 2003 G35C 5AT
Rated 280 Crank Horsepower
Dyno'd 221 Wheel Horsepower on a Dynoject
Drivetrain loss is roughly 21%

After all my mods (Stillen Airbox, Z-tube, 1/2" MD spacer with ISO Thermal Kit, Invidia G200, and KJR pulley)
Dyno's 250 Wheel Horsepower on a the same Dynoject
Estimated 316 Crank Horsepower

 

Could you elaborate?

 

Yea, I'm curious to......most dyno's are around the crank hp once converted from rear wheel.

 

My stock car on a dynojet put out about 238 whp.

My stock car on a mustang dyno put out 212 whp.

I then did extensive road dynoing on the street using the high resolution speed versus time datalog from Cipher and got a very repeatable 210-215 whp. Regardless of what any dyno said, my car was physically putting out this much power to the wheels during these runs. Can't really argue with that.

Given that the car actually accelerates at a higher rate on the dynojet than on the mustang, you'd expect it to put out lower numbers since more power is being consumed to more quickly accelerate the wheels / driveline / etc. But dynojets consistently put out much larger numbers than mustangs, and this was puzzling to me, so I did a little research and called mustang and dynojet. An engineer at mustang told me they knew exactly what I was talking about with the inertial losses, and said that dynojet actually includes a hidden fudge factor to try and account for this loss which is why their numbers are so inflated. I called dynojet and asked them about it and they basically told me that they couldn't comment on how their numbers are generated.

That being said, I'll trust the true power I'm putting out on the street any day over what some dyno operator set up on the dyno. But consisently mustang dynos put out very similar numbers to that which you put out on the street, specifically because they add a speed dependent load to simulate load on the street.

So at 210-215 whp for a stock '06 that is rated at 298 crank hp gives a driveline loss of nearly 30%. Do you really think that's how much power we're losing in the driveline? No way... in my opinion the crank numbers are just highly inflated.

 

I personally think that extra 7hp on Z come from carbon fiber driveshaft and not from the Z tube.

 

221*1.21=268hp at the crank
if the car really is putting out 280 crank it's ~26.7% loss

 

I guess it all comes down to preferences then.

Mustangs, Dynojets, DynoDynamics, Dynapaks, and all the rest, all have different methodologies used to measure and exatrapolate the collected metrics.

Some guys, like the tuners over at Dinan, prefer a load based dyno like Dynapaks. But guys like Doug Stewart obviously prefer dynojets. I understand where you're coming from, but to issue such a wholesale statement as you did earlier is patently false, in my opinion. Not calling you out on anything, just disagreeing.

Let's examine your reasoning. You reaffirm a mustang dyno's numbers based on numbers collected by your Cipher, correct? I'm not attacking your choice to road-dyno with the Cipher, just making sure I understand. You argue that your analysis of said numbers seem to confirm the mustang's numbers, thus you arrive at a drivetrain loss of roughly 30%. Do I believe a drivetrain loss of 30%? Absolutely, when examined in the context of how the numbers were collected. Obviously, if one chooses to collect the numbers by a different means, the numbers will be different. This little "alarming fact" apparently bothers many on these boards, but makes complete sense to me. But does this fact necessarily mean that the mustang "way of doing things" is indeed the *best*? Absolutely not.

Now let me ask you another question: exactly what number are you attempting to reach when you are deriving "crank hp"? Again, different methods of measuring crank hp will yield different numbers. The Nissan/Infiniti numbers are *certified* against the SAE standard(can't remember the revision number). Those numbers no longer apply in light of the new standard, hence the numbers will be different. Likewise, the numbers would be different than those collected 20-30 years ago.

Again, maybe I'm just confused, but I just can't understand how the fact that you choose to exclaim that the crank numbers are nowhere near published when examined through a very narrow set of filters. Choose another means of measurement, and of course the numbers will change. What's the big deal?

Let me elaborate through an example. My company measures media consumption, for the use of advertisers. One of the numbers we publish is Reach, which is basically the number of people exposed meeting certain criteria. We collect our data through various means, from interviewing respondents over the phone, to having panelists track media consumption. We also have multiple Reach Models to calculate the reach numbers. Certain models better fit with certain data(meaning the way the data were collected), and don't make much sense with other data. Does this fact invalidate the models? Absolutely not. It's a bit like economics. The mere fact that the entire media and advertising industry "believes" in these disparate models validates them, giving them "currency". The same can be said of the various forms of dynos.

Saying the mustang dyno is superior to others is like claiming that the Baptist church is a better denomination than Methodist.

And by the way. Have you ever operated a dynojet? I'm pretty sure that when the dyno is first installed and setup, some calibration is performed, and some "magical fudge factor" may be setup in the system(basically a weight factor), but that is a one-time deal. At most, it may be updated from time to time to calibrate the roller. But a dynojet operator does not augment the measured numbers. If you've experienced otherwise, first hand, I'd like to know the model number of the dynojet.

 

The dynojet just measures the drum acceleration in 1/100 second increments and use math to reverse engineer a torque number that would be necessary to accelerate the drum.

The problem is the drum weighs less than the car so they fudge up a correction factor. Also the drum diameter is small than the road so tires are stressed and get hotter [changing friction coefficient] than on a level road

Many newer ecu do not like the more rapid than physically possible acceleration [on road wind resistance] at speed in direct gear.......thus tuning can be problematic. Dyno tuning can be wrong [not necessarily ideal]for real world on road acceleration in direct gear.

Obviously the piston [combustion chamber] gets warmer in 25 seconds than it does in a 10 second dyno burst............say from 100 mph to 140 mph.

Many ignition advance parameters vary in ecu depending upon the gear you are in to reflect the possibility of long term WOT creating knock.

 

Not necessarily true. Dyno numbers are not absolute. Dyno numbers can and will change from run to run, especially with dynojets. Numbers will also differ based on environmental conditions. The dyno software attempts to correct for these conditions, but it's a best guess and not necessarily accurate. For example, if you dyno in the middle of the summer, your ECU might be pulling timing, something the SAE lookup tables cannot account for. Numbers will also vary on location.

So his baseline dyno is 221 is within reason, but should not be taken as his exact rwhp.

Doug Stewart at Crawford claims that the drivetrain loss for a 6 speed 350z is 17%. My baseline dyno(stock) resulted in a peak of 242/211. At 17%, that equates to 291.56hp and 254.21 torque at the crank. The published numbers for my car(05 6MT sedan) are 298/260. The dyno was performed in August, and temps in the garage were in the high nineties. The car was also running extremely rich, so I can guarantee you the ECU was pulling timing. Even so, my peak hp was within 2% of crank, as was torque. 2%, considering variations from car to car off the same assembly line, variations of the individual dynos, variations of the "fudge factor" to which MechEE refers(which, btw, on a dynojet will apply to all cars dyno'd there, each with different drivetrain losses), and even taking into account variations such as tire pressure, toe, and camber(all of which affects a roller-based dyno) is pretty damned accurate when you think about it.