Dyno Run Results

[Al]

Isn't 3rd gear the power gear! (no runs are done in 2nd, also a power gear). I have taken my car up to 170-180km/h in third gear.

[NismoR34]

Al, your gearing must be different to mine [r34] or something, cause mine was hitting the rev limit at 150km in 3rd gear - no way I could get to 170k / 180k.

edit, oops here is my recent dyno sheet [just to stay on-topic ]

[Guest INASNT]

Originally posted by Al

Isn't 3rd gear the power gear! (no runs are done in 2nd, also a power gear).  I have taken my car up to 170-180km/h in third gear.

No way u can do 180km/h in 3rd gear, unless u r using a low ratio highway diff that is

[macka]

No the point of the matter is for a 1:1 gear ratio skyline gtsts must be done in 4th gear to acheive an accurate reading.

Dyno in 3rd will give a higher reading and will be less accurate.

Some cars it is better in 3rd gear...and so on

Get your skylines done in 4th gear and not 3rd

Im pushing 286hp but sure as hell i think im pushing more on the road with what i seem to wave goodbye to I thought mine was good for about 315@1Bar but not the case

[Rasi]

How is inaccurate in third? would the power curve be similar in all gears, just maybe more noticable in the third and fourth. As can be seen on the graph mine was done in third gear.

My dyno graph has a couple of flat spots that are noticable. Anyone want to speculate why and if they could have tuned it better or something. Just curious as I didn't notice any flat spots prior to the tune, and now they are very obvious even annoying.

Mike

[2fardown]

What mods do you have Rasi?

[whatsisname]

Mike,

Your A/FR curve on WOT is very very rich in the top end (above 100km/h on the dyno run)

I'm fairly sure the Dyno Dynamics A/FR software only reads to 10:1. So the flatline you see from 100km/h & above isn't a true reading. In other words something more like 9:1 A/FR. That's bloody rich! Bad for power, economy, health of engine internals (fuel washing oil off the bores), plug fouling, the list goes on.....

I'm guessing you don't have any form of ECU management. The dips in the power curve look like the factory ECU is pulling timing, & most probably causing the overly rich mixtures as well. You could advance the base timing as a slight work around, at least until you get some control over the ECU.

What mod's does the car have currently? I'm guessing it has FMIC?

Matt

[Guest SupraChigga]

rasi, your afr curve is in the too rich zone... get it dyno tuned with a pggyback fuel computer or a fullhouse aftermarket ecu and try and get leaner like into the 11.0 range... going leaner also gives you a heap of powa!

[Rasi]

The only mod is a bleed valve set to 9psi. I have been thinking about getting an aftermarket ECU but haven't persued it yet. Need the $$$

I don't want to sound like a cheapskate but a friend of mine had a wrx where he used a bleader on his fuel line?? Or something like that to lean out the mixtures. He warned that it can be dangerous as being too lean is not good, better to be too rich. Is that something to explore? I would only consider it if it can be done properly and not damage the engine, but that said a new ECU would be better by far.

[macka]

Hehe i guess that is possible Rasi, if you bleed the fuel rail pressure u can lean it out probably very effectively, But the cost of a new engine after u go too lean isnt worth it..

Take your time mate, all skys run rich, but as u boost her up more the fuel pressure rises as well keeping it mega rish and at some stage you will want some fuel management to fix it up and get some power back

[whatsisname]

You can actually buy mechanical fuel pressure bleed kits. See here - http://www.horsepowerinabox.com/mall/fs05.asp However this is very crude (yet effect) way to improve the A/FR's on boost. The system has no feedback. So a conservative approach is best. Mind you, considering your engine is running @ worse than 10:1 up top, there's plenty of room to move!

Much better to try & score a second hand Unichip or S-AFC (~$400-$500).

I'd also get a second opinion on the A/FR's. Just to make sure the dyno info is accurate.

[rev210]

try rest the ecu.

[whatsisname]

Yep, good call rev! Certainly won't hurt.

Just in case anyone was confused. rev means - "RESET". Although the ECU probably could do with a REST

[macka]

I didnt think the ecu reset had anything to do with the ecu altering the fuel map only ignition

But ill try to give mine a rest as well see what happens

[Sydneykid]

Hi Rasi, the first dip looks like a bit of wastegate creep, what sort of boost controller are you using? You will notice that Dremen's dyno graph shows the same first dip, this is typical and can be tuned out with judicious use of the boost controller and ignition timing (sometimes a little extra fuel helps as well).

The second dip is most likely a combination of the rich air fuel ratios (should be 11.5 or higher) and ignition timing. If you look at Benm's and Dale's dyno graphs the A/F ratio never goes as rich as 10. As you can see correcting the A/F ratio from 11.4 to 1 to 12 to 1 resulted in 13 rwkw more output.

As for the 3rd gear versus 4th gear, it may be to avoid the 180 kph speed limiter or keep the speed down on the dyno. It shows higher torque output but should show the same horsepower.

The question of kph or rpm on the graphs is simply a matter of selecting which you want displayed, provided the operator has hooked up the rpm sensor of course. Ditto, A/F ratios, torque etc

These 4 dyno graphs are a good reason why comparing power output from dyno to dyno and operator to operator is a very inaccurate measure. For example 2 of them indicate "shoot out mode" the other 2 don't.

When we are comparing one car to another on the same dyno (it's a Dyno Dynamics) we always use;

1. the gear that is closest to 1 to 1 (usually 4th)

2. conventional operation (non shootout mode)

3. ramp rate at 100

4. ambient correction at 1.00

5. xtra correction at 1.00

Let's say I am an unscrupulous dyno operator (not saying that any of the four examples are) and I have a customer come in and say something like "I need a better dyno tune, I took my car to XYZ and it only got 140 rwkw. I know, because of the cars that I drag off, it has really got 160 rwkw. They can't be very good, so I came to you cause I have been told that you will get the power." "I've done a few more mods since then and it should be up to 170 rwkw, if you can tune it right."

Now as the operator (and a business man) what am I going to do if I run the car up on the dyno it it has 140 rwkw? Simple I stick a 15% correction factor into it and it shows 161 rwkw. I then tune it and get an extra 10 rwkw, making 171 rwkw on the display.

I give a copy of the printout to my customer and he goes away happy. Now I feel OK, because I really did achieve a 10 rwkw power increase and I have a satisfied customer who will tell all of his friends that my dyno reads right.

The only problem is next time he comes back I have to remember to stick the 15% correction factor back in. Otherwise the power output will be lower, ever had that happen.................

Makes you go hmmmmmmmmmmmmmmm

[rob77]

The best use of the dyno is to gauge what HP gains you had from a certain mod and to diagnose/tune the car with a aftermarket ecu or a safc. If you use the same dyno everytime you get a good idea of how much HP that mod made. From my signature you can see I'm running around 235HP (or 175kw) at the wheels and I havent done a great deal. Using a electronic boost controller over a bleed valve will give you much better results, but will cost a lot more. Plus with the upped boost you really do need a fmic to keep intake temps down and it should give you a bit more HP as well. When I change my ecu to an autronics and add a dump+front pipe I'll be going back to the same dyno to see what real gains I had from those mods.

[crooser]

if you dont have an aftermarket ecu or a way to control fuel/ignition at given points, what could you actually do to the car on the dyno to "tune" it? (apart from altering base timing)

also, i've seen cars get higher readings by doing multiple power runs (like 3 in 5 mins) with nothing being touched by the mechanic.

this normal? are there really cobwebs in there?

[Sydneykid]

Hi Rob, let's try a question. Last time you took your car to the dyno (same one of course), when it made its 235 bhp, it was the middle of winter, say 14 degrees ambient temperature. This time it's the middle of summer and it's 30 degrees.

Now we know that for every 8 degrees of temperature you loose around 5% in horsepower.

Do you want the dyno operator to add 10% ambient correction? ie; the current dyno run shows 220 rwhp without correction but 242 rwhp with correction.

The answer is do you want to know how much horsepower it has today (that's 220) or how much compared to last time after allowing for that fact that it is hotter (that's 242)?

Tough call?

[rev210]

the dyno is a tuning aid (thats one more dollar closer to being a millionaire).

Do the dyno before and after the same day you put a mod on if you can and then you have a very relative guide to the improvement it made....on that day...wearing your lucky watch...and facing into the breeze.

[Sydneykid]

Hi Rev, somehow I just knew you'd be here for this one.