Okay... everyone can breath easy, I got the runt of the litter... not you.

Seriously, tho... I went to have my Z dyno-ed today and must say I'm a little disappointed with the results. Let me give the facts first, then I want to ask a few questions of others who have had dynos done. I have done zero modifications to my car at this point. These dyno runs were for me to set up a base number to measure future mods. Car currently has 4750 miles on it and has had two services including oil changes (at 1000 miles and 4200 miles). All runs were done on dynajet dyno, but I don't know the model number

Here are the conditions during the 3 runs...

Absolute Barometric Pressure = 28.86 in.Hg.
Vapor Pressure = 0.056 in.Hg.
Intake air pressure = 59.5 to 60.5 degrees
Correction Factor = 1.00 SAE

(For those using a dyno correction tool, those numbers yield a near perfect 0.998 correction factor)

Run #1 was done in 5th gear and yielded...
Max Power = 216.1rwhp
Max Torque = 215.7ftlbs

WTF????? That's 25 hp and 20 ftlbs torque lower than what most have seen...

The mechanic helping me said the pull was taking to long in 5th and that could be the problem. He suggested we probably should run it in 4th.

So, run #2 was a repeat of the first except in 4th gear. The results...
Max Power = 223.1rwhp
Max Torque = 217.7ftlbs

A little better, but still... WTF???

For the last run, I had decided to run without the air filter to emulate a high flow filter in place of the paper filter. ACK!

When we opened the filter case, we found all manner of crap clogging my intake tube!!!! Jesus, there was newspaper, whole candy wrappers, leaves... I'm surprised I was getting any air!

In light of this, we decided I still did not have an accurate normal run. We put the factory filter back, minus all the excess garbage blocking the intake, for the third run. Third run numbers...

Max Power = 226.6 rwhp
Max Torque = 221.6 ftlbs

Okay, that's a little better. Still, this seems very low compared to what others have been pulling on dynos.

Here are my questions for those who have had more favorable dynos... please respond with relevant, helpful information if you have it...

1. Has everyone been posting SAE hp ratings here? I did a quick search and only found one graph that listed the HP as SAE and the max Power there was mid-230's. Those pulling 240+, were your pulls SAE or STD??? How much difference would there be between the two?

2. How much difference would it make if the car was not perfectly aligned on the rollers? I noted that the right front tire was a little further forward on its roller than the left... maybe 2-3 inches (meaning car was not pulled in straight onto the dyno). Would this skew the numbers alot???

3. Did you others who got higher numbers do any modifications to your Z prior to the dyno? even if it was only changing spark plugs, putting on a ground kit, changing wheels/tires...

4. Is there anything simple that maybe would have caused hp loss that I could be overlooking? (BTW, VDC was turned off for all three runs and car was allowed to cool approximate 10 minutes between each run)

Please share any insights you may think of, and let me go on record to say... I am very disappointed with the dyno runs, but I'm still not disappointed at all with my Z.

Driving it is a blast, and I feel like it pulls pretty strong. Based on the fact that I have been on the winning end of encounters with a Boxster S and Bullitt GT, I think there is a fair amount of power there. I guess I'm wondering if these dyno figures are indictative of what I have been experiencing in day-to-day driving.

The only other thing I thought of is possibly dyno-ing a different machine somewhere.

Thanks in advance for you responses!

 

something sounds funky, he shouldnt have gotten better numbers in 4th, not by a huge margin, so Id imagine there was something wrong with his technique.

 

Try a different shop and dyno, get a second opinion, so to speak.

 

When letting it cool off, did you have a fan blowing on the engine compartment? Only ten minutes with no fan would heat soak the engine bad, but even still I wouldn't think the numbers would be that low. I'd say try another dyno shop if so, or ask if other cars are dyno'ing what they expect. I have a very hard time believing your car is just weak.

Dan

 

McDan... I agree... driving my Z seems to indicate, to me, more power than the dyno run shows... and I seriously doubt that production tolerances are so off in Japan that any new Zs would dyno more than 5% different than others (mine was almost 8% off average!).

Yes, we had a fan on the Z the entire time of the runs.

I'm seriously beginning to wonder if the wheels being slightly out of alignment could have thrown the number approximately 10hp or so.

I'm no expert on dynos, but had my fair share of Physics in college (almost came out with a Physics degree). I'm thinking if one wheel is further forward noticeably, the car is skewed. That means the majority of the driving force on the dyno drum is going in the correct direction for the dyno, but a smaller portion would be pushing the drum to the side... it wouldn't be a huge amount, but I don't think 10-20hp would be out of the question. Any thoughts on this from someone who is dyno-savvy???

 

its the front wheels that are out of alignment, not the backs. of course you should be sure that you back tires are full on pressure, that would hurt your results, but still, not that much.

 

What kind of dyno was this done on? There are several different kinds; Dynojet, Mustang, and Super Flow are a few of the more popular ones. I know for instance, that a Super Flow will typically show results 15% lower than a Dynojet, but it is better for tuning specific load values.

-Jeremy

 

ares,

when I referred to alignment, I did not mean the mechanical soundness of the car's alignment. I meant if you were looking down on the car from the top and the dyno was perfectly aligned along a north/south axis, the car physically being parked 10 degrees or so off that axis (just like when a car is parked crooked in a lined parking space)

Monkey Man...
the dyno was a Dynajet, but I do not know the model number. I've found a second shop in town with a dyno, so I may try a second run their as long as I can get runs without the air/fuel mixture test. Also, will make a point to ask for printouts of SAE and STD graphs. I think the big discrepancy between my 226 and the 240's most others have been pulling could be because we are looking at a different set of graphs

 

ah ok, well, they should have made sure not to do that, cause your car would have slid around, very dangerous. but it is possible. if it was the case, I woudnt go back to that shop ever again.

 

mcduck,

My graphs are in SAE. But my numbers varied 5hp based on what level of smoothing was used on the graph. Smoothing essentially samples points along the graph and averages peaks and valley all along the range, to smooth out the curve. On a setting of 5 (the most aggressive), my hp was 236.66. On a setting of 1 (the least aggressive), my hp was 241.05. On 1, you can also see the extreme jaggedness of my dyno pulls.

This brings up another issue. Did your ABS and dash lights come on? Mine did so I brought this up with my Service Advisor at the dealership. He, in turn, discussed it with Nissan Tech, when they were diagnosing my tranny. The guy from Nissan Tech confirmed that it was the computer (didn't specify which computer) noticing the front wheels were stationary while the rears were spinning. He also mentioned that the systems would go into a safe mode when this happens. I don't know if this safe mode is doing anything to the performance or not. I have asked him to speak to Nissan Tech to help us find a way to not set off the computer when we are dynoing the cars. It will probably be Monday or Tuesday before I have an answer.

As for the wheels not being lined up properly on the dyno, I don't know enough to say for sure that this would cause your low numbers. I definitely would seem like the wheels would not be providing the force in the correct direction, which would logically show lower numbers.

JD

 

I did verify the dash warning lights phenomena with the techs. It is exactly as you describe... on the first run, with the rear wheels turning and the front wheels stationary, the system does not know what to do with it and goes to safe mode.

Until the vehicle physically moves 1/4 mile or more those systems remain inactive. ABS does not know what to with rear wheels slipping/front standing still. VDC does not work since the ABS is deactivated at that point.

So... in short, the safe mode should not affect numbers unless it also sets the ECU into safe mode.

 

McDuck,

Which dyno did ya go to,..here in Charlotte???
Sounds kinda Fishy,...hp#'s are kinda low,...I should have been there w/ ya,.I only have like 2000miles on mine, no mods ,still on Factory oil,..would have liked to see if Mine was different,...

How much did it set you back per run or how long,...

Still getten together for the Z RUn on the 19th?

 

mine was sae with smoothness of 3. what gear was your 3rd run made in? If it was in 4th, your numbers aren't too far off. I think I got 228 in 4th and hen 242 in 5th. I had a K&N panel filter but no other mods.


Mike

 

Mr Fairlady...

I went to Dave Brown Motorsports off of Albemarle Rd. for my dyno. Nice folks, I'm just not sure everything was set up properly... and, as I said in my original post, I had some serious clogs in my intake tube. I got 3 pulls for $50.

I may take to Lee's Performance and re-verify things... if I get the same figures, I'm basically out $50, but I'd rather be sure of the numbers before I make any mods. I really think have the car parked a little crooked on the dyno drums has to throw off the numbers a little.

We are still doing the run on Sunday (unless we get a lot of snow on Friday ). Planning to meet at Reedy Creek Park around 3pm, then drive over to Macaroni Grille off of Harris around 4pm. If you send my you're email address, I'll include you on the updates... mine is mcduck@earthlink.net

2003z....
Last two runs were in 4th. The first run was in 5th and produced numbers around 216hp, 220 ftlbs torque if I remember correctly. We kept with 4th because the pull "took to long" in 5th. Those are the techs words, not mine.

 

Not feeling so bad about my dyno numbers now... it seems the Injen Technologies test car pulled about the same HP and torque figures as I did. Here's a link to their dyno chart for the 350Z.

I think I'm going to chalk up the discrepancy to the fact my figures we're given in SAE HP and, probably, those hitting 240ish are using STD HP figures.

 

Does anyone think that maybe having the car not aligned proberly on the roller might have cause more drag through the LSD and the tires?

 

I agree, Zeeee... now my mod-quest begins. Considering the Injen CAI and a Y-pipe + flowmaster 80s. Hoping at worst they will net a zero.

although, I did see where someone actually hit close to 260... see this thread ... while I'm sure has to STD instead of SAE, it still sounds like a net of around 15hp with Injen + exhaust. Figure I'll pick up another 4 to 5 by dropping the heeeeavy 18" performance wheels in favor of some light weight SSRs (16lb total difference in unsprung weight!)

Possibility of 245-250 SAE HP with those mods? not holding my breath, but we'll see. Regardless, I'll just have to wait for the bigger gains of a SC or Turbo until someone cranks out a good kit...

 

my 242 was SAE corrected, so was dougraceszs 244, as for that guy claiming 260, personally I don't believe it,as he hasn't posted graphs, and knowing what my injen/exhaust before after numbers and another before after injen that only netted 1 hp.