Ceasars Chariot

iTrader: (16)

I have lots of questions. To be honest I don't know what im looking at when viewing dyno sheets. All I get out of it is that org member "such and such" has X amount of HP and Torque.

When I get the Chariot running again. Im going to head over to get a dyno done as well. Always wanted to do that. But I want to get everything I can out of each visit.

Is there a list for dyno newbies somewhere or can we make a list here of all the things to do to get the most of a dyno tune?

_____QUESTIONS_____

1. How do you find out what is the best rpm to shift at in each gear from a dyno tune ?

2. To actually tune your car (N/A) on a dyno do you need the Apex-i SAFC ? If so why ?

3. What gear should a 4th gen 5 speed manual and automatic dyno in ?

4. Whats the most you can get from a dyno?
4a. Can you walk away with charts (paper and cdrom format for using on the internet) , video, tuning, etc ?

5. What dyno (brand) should be used and why ?

6. What things should be done to the car to get the most out of the dyno? (examples: octane boost, rim size, tire pressure, fan blowing on engine or only dyno in low elevation, and cold temps, etc)

7. For comparision dynos for different mods what is the best way to get acurate results? such as ( intakes, ecus, ypipe, headers, etc)

8. How bad is it on the engine to do dyno runs ?

9. Why do you SAE correct your dyno charts?

SSR Engineering

1. It doesen't really matter, you just want to get to around 2000 in the ideal gear.

2. You need something similar to the AFC or an AFC because you can't change any settings without an air/fuel calibrator.

3. A 5 Speed Manual car will dyno in 3rd gear, a 6 speed will dyno in 4th, you want the gear that has the closest 1:1 ratio for the most accurate result.

4. You usually just get a chart, you can video tape it if you bring your own camera. Sometimes they burn CDs for you too.

5. Well for accurate tuning, especially on turbocharged or any F/I car you want to tune on a Load-based dyno, not some inertia dyno. So basically stay away from Dynojets.

6. Just take your car as it is, unless your car is turbocharged or f/i then you might want to use race gas especially if your going to be tuning for high boost settings.

7. Dyno stock, dyno with an intake, dyno with an intake and exhaust, etc. Thats how you do your comparison dynos.

8. No worse then driving it on the street.

9. SAE Corrections are there to correct for altitude, temperature etc. It basically simulates what you would be dynoing at sea level in a mild climate. Since every other place in the world is different it simplifies the results so you can compare to other vehicles. For example if you dyno a maxima in california at sea level in 60 degree weather and you get 160WHP then you take the same car and dyno it a mile-high in arizona in 100 degree weather and your only making 145WHP now.

JClaw

iTrader: (17)

Actually 4th gen 5-speeds should dyno in 4th gear. Gear ratios:

1st 3.28
2nd 1.85
3rd 1.25
4th 0.95
5th 0.77
Final Drive: 3.82:1

Autos should dyno in 3rd.

Ceasars Chariot

iTrader: (16)

i really do appreciate the feedback. regarding question #1:

1. How do you find out what is the best rpm to shift at in each gear from a dyno tune ?

im trying to describe something like from the information you get will it be possible to apply that information into shift points, so when you are racing the 1/4 mile track you know where the best shift points are in your car from the dyno ? make sense ? can this info be found from doing a dyno ?

NmexMAX

iTrader: (22)

"~500 rpm after peak hp" .. Credit I30MikeD,

makes perfect sense, you'll be in the "sweet spot" when in the next gear.

There's a threshold as to how far you want to take it, vs how much meat will be left in the powerband after the shift before it begins to drop off again. This is concerning more the 4g with the USIM.

cardana24

iTrader: (81)

unless you have a GXE with a speed limiter.....you will hit the speed limiter before redline in fourth gear ( I know). Therefore I have to dyno in third

Dave B

Calculating shift points is actually pretty complicated and is based on your torque, the rpm that it occurs at, the nature of your powerband, and your gearing. 500rpms past peak doesn't always apply, especially for the higher gears.

Here's the site I used to calculate my shift points:

http://www.bits.nl/re/shiftlight/sl-shiftpoint.htm

These were the points I calculated for my Maxima with the stock intake manifold:

1-2 ~6700rpms (can't do this without the JWT ECU)
2-3 ~6200rpms
3-4 ~5900rpms

These shift points landed me my best ETs and my MPHs went up by 1.5mph.

With the MEVI:

1-2 ~7200rpms
2-3 ~7000rpms
3-4 ~6800rpms

NmexMAX

iTrader: (22)

Whats the difference between the brake torque and the shaft torque?

steven88

iTrader: (28)

this is DEFINITELY worth a sticky....don't u agree mods?

E55AMG2

iTrader: (4)

1. You note where peak power occurs, then shift enough after it so that you land in the powerband just before the sweet spot in the next gear. For most manual maximas its ~5-700 past peak power. In an auto, you will have to shift at 6600 frim 1-2 then you can put it in D and let the car do the shifting for you (typically programmed to shift at 6250 which is ~750 past peak, but that is to overcome the slightly taller overall gearing)

2) Yes, or something equivalent

3) 6MT = 4th gear
5 MT = 4th gear
4AT = 3rd gear

4) A very well tuned and fast car

4a) you should be able to take vids/pics of your run and the dyno screen. Also, they should be able to print off a run sheet and/or give you a runfile on some form of electronic media

5) For tuning, eddy current or load dynos should be used due to the fact that you can hold the car at any RPM and tune on the fly. For peak power, Inertia dynos should be used. For load dynos, you will want to use a Mustang, and for Inertia the Dynojet 248c should be used.

6) There should be a fan blowing into the radiator. Everything else should be left in the state that the car is going to run in. SAE corrections will take care of the other stuff mentioned.

7) For comparisons, you should dyno each mod one by one. That is, install an intake, go dyno. Exhaust, go dyno, etc..... If you want to compare 2 products, you should install one then dyno. Let the car cool for 15-20 min Install the next one and dyno again.

8) No worse than driving it everyday

9) SAE corrections are used so that there is no "cheating" when you go dyno. IE, if you go to a dyno below sea level the #s will be higher than one at sea level. Or if you go dyno in 100 degree weather, its gonna be lower than one done at 50 degrees. Basically, it levels the playing field.

smotz

iTrader: (3)

How much does a dyno cost?

cardana24

iTrader: (81)

It depends....

where I go its $65/3 pulls with a/f, and its $125/hr with a/f

NmexMAX

iTrader: (22)

What A/F method do you use for best results, and by "best" I mean, how much better/accurate are they.

Wide band before main cat, or tail-pipe sniffer ...

I've read on here as well as a few other boards that the sniffer givesvery similar results as the widband upstream does ... so which is actually better, and by how much.

E55AMG2

iTrader: (4)

Tailpipe....mostly because I dont have a wideband installed

nismology

iTrader: (8)

How would tuning with a WB02 on a quick highway 3rd gear run compare to tuning on a load dyno?

E55AMG2

iTrader: (4)

If you had that kind of open road, and someone driving the car, it should be similar to an eddy current dyno holding the car at a certain rpm. However, the chances of it happening, and you not being pulled over are slim to none

nismology

iTrader: (8)

Haha. My 3rd maxes out at just below 100 MPH so that's nothing too major. But would you agree that tuning on the fly as such is better than tuning on an inertial dyno? I figure that tuning with not only real-world load but with realistic airflow would prove more beneficial than having a car running in artificial conditions on a dyno, no?

E55AMG2

iTrader: (4)

I honestly couldnt say, as Ive never tuned my car on the fly.

NmexMAX

iTrader: (22)

I was bored, here you go.


This is all with respect to using a Dynojet


Dyno run data files.

These data files give very helpful insight on the data and also help the user determine exactly what they're looking at. Many conditions can be changed. Such as the X axis(horizontal) variable can be toggled from time, speed or RPM. Obviously we like to see RPM in order to level the field to compare since most cars if not the same year/transmission type etc will have different power at different speeds(MPH) due to different gear ratios, hence the above statement about RPM. The Y axis can also be changed, from A/F, WHP, and/or WTQ. Also, it can be toggled in 3 different windows to view each component (WHP/TQ/AF) in separate windows all with a common X axis.

So, essentially, you can view AF/TQ/HP all with a common data point, whether it be speed, time, or RPM.


The reason who some dyno runfiles do not have an a/f readout is typically because the owner or shop has used an upstream wb and have the data recorded on a laptop or similar device using the wb's own supported software. That's what i do anyhow. Some if not most shops use a 'tailsniffer' o2 sensor. Tailsniffers have been known to read a bit leaner than that of an upstream WB02 (wideband o2) sensor. By upstream I mean closer to the engine and before the main cat. An upstream (WB02) gives a more accurate reading.


Always take your car to its rev limit so you get the most out of your experience. Even if you're not making power at your limit, at least you have something to compare to and improve on at the same time.

Again, for you A34 people w/ AT's, you need to hold the shifter down in order to hold the gear longer. This may also eliminate the torque converter lock-up 'blip'.



When tapping in for the RPM signal, use the small clip and take the signal from the primary wire only. Do NOT loop the entire cable going to the coil. This means you'll need to peel back the cover for the three wires. If you do not do this, you will see missing hp data and torque spikes.

abustiffy

iTrader: (1)

The problem with street vs load bearing dyno is that you use the dyno to tune. Your target a/f may not produce best torque. To truly tune, you need to adjust timing, as those changes are where the power are. Tuning steadystate on a load bearing dyno will tell you in real time if the change you are making is helping or hurting you.