Mr_Q

iTrader: (1)

Okay, so I had baselined my 350z on a dynojet but now that shop is no more. So even if I went to another dynojet I'd not be getting anywhere near A/B results since my mods.

The dyno day that is coming up in SOCAL uses an engine dyno or dynopack I think they are called. It can spit out corrected numbers based on drivetrain loss with a drive train spin down. This number "usually" matches most normal dynojets if they are tuned and setup properly. (at least from other forums and poster's results)

So if I am starting from sractch....are there any 2003 350z owners out there, in the SW, who have had their stock Z dyno'd on an engine dyno? So that, plus or minus 5hp, I might get an idea if I have gained any power from my mods or lost? When I go to the engine dyno place next month.

Thanks.

THX723

iTrader: (3)

DynaPack is not an 'engine dyno' ... it is still a 'chassis dyno' like the DynoJet. However, unlike the Dynojet it measures torque/power from the rear-axle w.o. the wheels and tires. It is also a hydraulic load based dyno. The ramp-up time (load) will have an influence on effective drivetrain loss and consequently your final output number (as reported). Nearly all DynaPack operators do not use drivetrain correction factors, asi it adds an uncertainty that is likely to introduce more error than it corrects.

If you're attending the SoCal dynoday at Church Automotive this July ... a bone stock 287hp spec. 6mt 350Z measures on the average 258hp with their dynapack. That is using their standard ramp up time of 500rpm/sec.

Mr_Q

iTrader: (1)

Hmmm, okay cool. Well, as my sig says, I got 237 on a normal dynojet last year. Wonder of that number would have been anywhere near close 258 on Church's setup.

THX723

iTrader: (3)

It would have been very close indeed. I found the typical DynoJet number reads about 20hp less than Church's DynaPack.

nicolaycastro

iTrader: (3)

wonder which one is the right one...

Mr_Q

iTrader: (1)

Hmm, most folks have been telling me that dynojets generally give you 10% to 15% more HP.

Man I will never know if my mods hurt me or gave me gains! :\

I guess if my A/F looks square, I can safely say I gained, hmmm.

UnderPressure

iTrader: (4)

Church's has a nationwide reputation of reading very high numbers. Like +20% over what a dyno-pak normally reads elsewhere.

Key thing w/ dynos is to run pre-mod and post-mod on the same dyno. Not just the same brand but the very same dyno. (Well not w/ us, all of our dynos worldwide are within 1% of each other in Shootout mode)/sales mode off. Since the shop you went to before is no longer in business or is unreachable, I would suggest finding a local shop w/ a dyno and starting from scratch. Just remember numbers are just numbers. It's all about gains and losses.

I can provide a list of our dyno shops in CA if needed.

Z BOY

iTrader: (41)

so who bot the dyno of the shop that closed?

Mr_Q

iTrader: (1)

That would be cool, thanks! Yes I do want to run my Z on a dynojet again so I can at least see any gains or losses from my last dynojet. I figure I can safely use a 5hp +/- figure on whatever number I get when compared with my previous unmodded dynojet result..

Obviously I cannot remove my mods and return to stock and dyno again.

I will still do the Church run because I DO want an accurate reading for my car.

UnderPressure

iTrader: (4)

Autowave 714-841-2433 17122 Gothard Street Huntington Beach CA 92647 USA 2WD Dyno Chassis

Comptech 916-939-9118 4717 Golden Foothill Parkway El Dorado Hills CA 95762 USA 2WD Dyno Chassis

Force Fed Performance 530-755-0337 7333 Roseville Road Sacramento CA 95991 USA 2WD Dyno Chassis

JBA Racing 858-495-3395 5155 Convoy Street San Diego CA 92111 USA 2WD Dyno Chassis

Outback Motorsports 714-994-5222 8071 Commonwealth Ave Buena Park CA 90621 USA 2WD Dyno Chassis

Pann Auto Performance 858-278-7266 7960 Ronson Road San Diego CA 92111 USA 4WD Dyno Chassis

Saturn Motorsports 858-619-2954 4595 Convoy Street San Diego CA 92111 USA 2WD Dyno Chassis

Scott's Automotive 760-632-7096 1508 N. Coast Highway 101 Encinitas CA 92024 USA 2WD Dyno Chassis

The Dyno Shop 619-562-3960 10042 Prospect Ave Santee CA 92071 USA 4WD Dyno Chassis


Here is the list of our Dynos in CA. Hopefully someone is close to you. Let us know how it turns out.

Badmonkey

iTrader: (9)

There is a shop in Chatsworth that is a great shop with a Dynojet..
LAPD, Los Angeles Performance Design. That is where I got mine done and they are top notch. It was $75 for 3 runs.

Armitage

iTrader: (15)

Its not a matter of which one is right or wrong. They do things differently. Dynojet dynos with the rims on, while the dynopack bolts up to the hub.

UnderPressure

iTrader: (4)

Right = load brake dyno: eddy current, water brake, etc..

Wrong = inertia load dyno, ie. dynojet

nicolaycastro

iTrader: (3)

so about how much Hp difference is there?

UnderPressure

iTrader: (4)

Depends on the specific dyno and the operator.

See this thread for more details:
https://my350z.com/forum/forced-induction/123014-dyno-comparison-thread.html

Gruppe-S

iTrader: (66)

Underpressure has it exactly right - Dyno numbers are just numbers, there are FAR too many variables to be comparing dyno numbers against other dyno numbers.

That being said I would continue to encourage Z owners to avoid non-loading dynos. Tuning on a non-loading dyno on a high-power Z can be disastrous as loading (or the lack thereof), for the lack of a better description, completely changes the operating characteristics of the vehicle.

On a particular Greddy T/T 350Z we saw ~1.5 AFR points and 35whp differences with loading turned off (ooops) and loading turned on.

Cheers,

Gary
Gruppe-S

nicolaycastro

iTrader: (3)

you are totaly right thanks for the info

xNeo

Hey, I'm new to the Z and Dyno's in general, why would it dyno so low when it supposed to have 287hp? A budy of mine has a SRT-4 and it dynoed at over 250hp (254), when Dodge says it has 230...why would a Z dyno so much less?

phunk

iTrader: (21)

Who makes a dyno with no load? How would you ever build boost without load?

I have seen you say this before... but the problem here is that its completely WRONG.. hah. I tuned my Z on an intertia dyno and my logs show no difference at all on the street.... sorry but 5 psi at 5000rpm, 6 psi at 5000, etc, is the same engine load regardless of what dyno your on. Sounds like you ran into problems with your tuner, not the dyno.

A dyno with an eddy current brake allows for less time spent to map a car to precision... but the load applied to the engine is no more realistic then the load of inertia... all the engine see is resistence to accelerate and that is that. A brake dyno allows you to hold a load point... thats it... Think this one thru now... what load is there on the street? Do you have your brakes on when your racing full throttle? I certainly hope not... see there we have it, the street is not a BRAKE load. On the street you are fighting INERTIA to accelerate the car. A BRAKE LOAD is used for TUNING by holding a load point to allow you to accurately tune it. The same thing could be done by using you brakes to hold the car on the street or on an inertia dyno (which would ruin your brakes right away, hence why you dont do it for more than a second or two).

But in all reality, what most likely happened between your load on/off comparison is that you hit slightly different boost, as engine load will change the boost curve. This is why one particular boost controller setting will make different boost between the street and an inertia dyno... after tuning on an inertia dyno you will need to recalibrate the boost controller to run the boost you just tuned for.

From your website " With a non-load based dyno (ie Dynojet) you are only spinning a heavy drum - similar (although not as bad) to accelerating with your tires off the ground"

Easily the most ignorant comment about a dynojet i have ever seen. Because spinning 4' diameter rollers that weigh about 5000lbs is SIMILAR to running the car with the tires off the ground... hahaha. Have you ever used a dynojet before? If there was NO LOAD like your claiming, why do the runs take so long? How does the turbocharged engine generate boost... or even better yet... why does the boost come on so fast... as fast as it does on the street? Because most brake dynos are setup incorrectly by people who have no idea how to use the machine of their investment, and on a non-tuning full throttle power measurement run the load is not correctly configured and the turbochargers response is not accurate to real world. I have seen some of the dyno graphs of turbocharged Zs on load dynos and their boost curve is WAY off because whoever setup the dyno didnt have it calibrated to properly simulate the road. A dynojet 248, depending on actual weight of the car, gearing, and whta gear its run in, will generate similiar enough load to the street to spool the turbos with a boost profile within a few hundred RPM (or better) as it performs on the street.

Your mustang dyno is a great tool, in the hands of someone who read and fully understands the manual... but, preach it for what it is, and dont make incorrect comments based on some sort of phenomena that you experienced on a car you worked on. There is a reason for everything.

phunk

iTrader: (21)

Mr Q: You can get a good comparison if you do use another dynojet. The dynojets may make it more difficult to accurately tune a car... but you can be assured that another dynojet of the same model you ran on before (most likely the 248) will be a very fair comparison.

Most Dynojets use inertia as their load (only brand new one are available with eddy current), there are no user defined settings... The inertial mass between one dynojet 248 to another is EXTREMELY close, and it will be very accurate comparison. What you need to find out about your previous runs is if they were done CORRECTED or UNCORRECTED and what type of correction was used. If they WERE in fact corrected numbers then you need to make sure they are accurate corrected numbers... for example some dyno shops will leave their air temp sensors in a poor spot that gets a lot of heat from the car, which will INCREASE the corrected output numbers. The CORRECTED readings are to compensate for baro pressure, air temp, etc. Also for fair comparison you need to be on the same wheel/tire combo with the same tire pressure.

Basically what I am getting at is if you meet the proper conditions, you can get an extremely accurate comparison on another dynojet that is the same model... this way you can see your gains or losses... not to mention the dynojet 248 is the most common dyno in the US... you can find one anywhere.

Brake dynos are very configurable (which is great for tuning) but unfortunatly you might not even get consistent readings on the SAME dyno from one day to another as they might not be running the same settings as the last time you were on it... if you start using a dyno like that.. make sure and take a note of all the configured settings on the day that you use it... so that when you return (or use another identical dyno somewhere else) you can make sure to have them run it the same way it was before.

There is nothing wrong with choosing to use a different dyno now... as like I said before the dynojets that are inertia only (almost all of them) make it more difficult to tune. However, dont believe the ******** from the people posting who have no idea what they are talking about, or no experience with the dynojet, or especially someone who SELLS other dynos, haha. The dynojet 248 is pretty old and obsolete now, but there is certainly nothing wrong with its intended functions.