Oops!!Just hit 6480rpm with the wagon in first gear!!

[StealthAu]

So whats wrong with dynos? It's not about the numbers they produce but they can be great tools for knowing the right shift points to improve your times.

[Stav]

Originally Posted by StealthAu

So whats wrong with dynos? It's not about the numbers they produce but they can be great tools for knowing the right shift points to improve your times.

Well...for one they are not accurate,secondly they have temp factors which still dont tell what power your car runs at the time.It cant tell you what your 1/4 mile time should be even though it claims to know your torque and mumbo jumbo.
I actually tested my theory.
I went to Blacktown on a dyno and got 117 rwkws.I then drove to Granville and scored 130 rwkws ,then to Sliverwater where I got 141 rwkws.I was too scared to drive farther east in case the power gain was too great for my old engine and transmission.Driving from Sydneys west to east netted me some impressive torque and power gains!!ll on the same day and ll on dyno dynamics dynos.

Also on the last dyno I went on cars scored 170 odd rwkws in the ba ranks and I got 141 rwkws . At the track I handed their butts back on plate. I am very anti dyno from these experiences.

[Stav]

Dynos cannot replicate real life.

[Sonik]

Originally Posted by Stav

Well...for one they are not accurate,secondly they have temp factors which still dont tell what power your car runs at the time.It cant tell you what your 1/4 mile time should be even though it claims to know your torque and mumbo jumbo.
I actually tested my theory.
I went to Blacktown on a dyno and got 117 rwkws.I then drove to Granville and scored 130 rwkws ,then to Sliverwater where I got 141 rwkws.I was too scared to drive farther east in case the power gain was too great for my old engine and transmission.Driving from Sydneys west to east netted me some impressive torque and power gains!!ll on the same day and ll on dyno dynamics dynos.

Also on the last dyno I went on cars scored 170 odd rwkws in the ba ranks and I got 141 rwkws . At the track I handed their butts back on plate. I am very anti dyno from these experiences.

Well generally speaking, 2 cars tested on the same dyno should be a 100% accurate in determining who has the most power. It's only when you start mixing dynos and comparing when things get inacurate. If you killed them on the QTR mile then it's a tyre/suspension difference or driving skill.

[DBourne]

Also on the last dyno I went on cars scored 170 odd rwkws in the ba ranks and I got 141 rwkws . At the track I handed their butts back on plate. I am very anti dyno from these experiences.

that's also because a dyno just measures power and torque, doesnt take into account diff gears, weight etc like a track run does. but they are good diagnostic tools...

ps. having the wagin near 6500rpm! you're crazy mate! haha love it

[Mechan1k]

Dynos are good tools ... especially when testing for problems as well ... I have found it useful over time (especially when using a gas analyser).

There's no way I'd push my 266,000-off kay vehicle that hard ... Ok it gets loaded up .... but i don't rev the guts out of her that hard.

[Stav]

Originally Posted by SgtBourne

that's also because a dyno just measures power and torque, doesnt take into account diff gears, weight etc like a track run does. but they are good diagnostic tools...

ps. having the wagin near 6500rpm! you're crazy mate! haha love it

Hehehh I am crazy... :

Sonik...its not about tyres ,stallies or diffs. Its about how much power you put to the ground.Its great that they get alot more power on the dyno but it seems the power magically dissapears at the track!!?
"Where is the power!!...i saw it at the kebab stand!!! it is certainly not making the car any faster!!"

heeh

[Sonik]

Originally Posted by Stav

Hehehh I am crazy... :

Sonik...its not about tyres ,stallies or diffs. Its about how much power you put to the ground.Its great that they get alot more power on the dyno but it seems the power magically dissapears at the track!!?
"Where is the power!!...i saw it at the kebab stand!!! it is certainly not making the car any faster!!"

heeh

But 30KW atw difference? Surely it must be their lack of driving skills.

[Stav]

Maybe.But even a monkey can press the acclerator and beat me if they had a genuine 30 rwkws more.
I dont like the dynos but if I had a 400rwkw xr6t then the safest place would be a dyno or track..

[Airmon]

Originally Posted by Sonik

But 30KW atw difference? Surely it must be their lack of driving skills.

I'm on Stavs side here, Same Dyno, same day, I made a fair few Kw more then Stav but his car will runs 14 all day whereas mine will run 15s, and it's got nothing to do with how it was driven, both are auto's driven in a straight line.
I rekon you'll be right with your bumometer Stav, I can;t wait to hear the wagon at 7000rpm at WSID though :

[DBourne]

I'm on Stavs side here, Same Dyno, same day, I made a fair few Kw more then Stav but his car will runs 14 all day whereas mine will run 15s, and it's got nothing to do with how it was driven, both are auto's driven in a straight line.

have you bothered to take into account the weight of the cars? also do you both have the same diff ratios?

[Stav]

I just went over the logged run .Rpm did not hit 6480 rpm..I made a mistake...it reached 6660 rpm!!!
I remember reading that the stock 4.1 litres sixes spun to 7500rpm I dont see why our destroked 4.0..

[Airmon]

Originally Posted by SgtBourne

have you bothered to take into account the weight of the cars? also do you both have the same diff ratios?

10-20rwkw would more then make up for 100-150kg difference, and this was on a night where it was either his Diff or Gearbox was playing up? He ran a 14.5 on the night I think and i ran a 15.3 best.
I am not saying that other factors don't come into play, but in terms of My Dyno sheet Vs Yours it means jack.

[Stav]

Originally Posted by Airmon

10-20rwkw would more then make up for 100-150kg difference, and this was on a night where it was either his Diff or Gearbox was playing up? He ran a 14.5 on the night I think and i ran a 15.3 best.
I am not saying that other factors don't come into play, but in terms of My Dyno sheet Vs Yours it means jack.

My car weighs 1720 kgs guys.It is about the same as the ba's.Please dont argue guys. It is my preference not to rely on dynos so the track is my dyno. If guys have the power then show me the slips.Et and mph means alot along with weight.Simple.

[5.0 ED]

4.0 isn't destroke'd it has a smaller bore, on the other side of things they do have very light weight pistons in them, and in my turbo engine i had federal moguls (rather heavy) standard rods/crank balanced and used to pull it to 7,000 all the time, my heavier pistons would make it much more likely to break than any unbalance standard 160,000km motor. also one of the motors i had used with turbo was stock and done 300,000km, and was pulling to 7,000 no probs.

[Stav]

Thanks for the info mate I am going to sleep easier.

[private9]

Originally Posted by Stav

I remember reading that the stock 4.1 litres sixes spun to 7500rpm I dont see why our destroked 4.0..

I would love to see a stock 250 that can even get to 7500rpm, let alone live to tell the story. Call me cynical if you will...

Stav, on another note, I don't really think 6.5k is really gonna kill it but boy your threads always seem to create alot of controversy....thanks for the entertainment!

[Sox]

Originally Posted by Stav

Sonik...its not about tyres ,stallies or diffs.

Umm, yes it is.

Its about how much power you put to the ground.

Exactly, and it's the tyres, stall converter, and diff which allow that to happen.
Gearing plays an enormous part in how ANY vehicle accelerates from the start.
A stall converter plays an enormous part in the launch of any vehicle.
Sticky tyres play an enormous part in how much wheel spin is had off the line.

If you think the time differences have nothing to do with those 3 items, then you need a refresher course. Sorry Stav, but you are so wrong, it's not funny.

Its great that they get alot more power on the dyno but it seems the power magically dissapears at the track!!?

It doesn't disappear.
The tyres, stall converter and diff gearing simply doesn't allow the vehicle to utilise it's power in an effective way to launch well.

Competitive drag racers go to great lengths to optimise these 3 units
Tyres need to have sufficient grip to allow no wheel spin.
Stall converters need to be selected to allow the engine to flash up to a high enough rpm so as not to 'load up' the engine on launch, whilst at the same time not slip to much at higher rpms.
Diff ratios are carefully selected to allow top gear to hit peak power across the finish line.

Any one of these items not optimised and you will be throwing away several tenths of a second. Throw away all 3 of these, and you will be more than a full second down on ET's. Guaranteed.

I won't even bring up driver skill, as I'm sure you feel that it also makes no difference.

"Where is the power!!...i saw it at the kebab stand!!! it is certainly not making the car any faster!!"

No offence mate, but you're just playing with yourself now.

What do you really expect to happen if you go to 3 different dynos, in 3 entirely different locations, and 3 different operators?

It's common knowledge that for dyno runs to be of any use, they must be done on the same dyno with the same operator.

Get with the program mate, all proffessional race teams spend countless hours on dynos perfecting things. Don't try and tell us that they aren't any good, you're only fooling yourself.

Rick.

[Stav]

Originally Posted by private9

I would love to see a stock 250 that can even get to 7500rpm, let alone live to tell the story. Call me cynical if you will...

Stav, on another note, I don't really think 6.5k is really gonna kill it but boy your threads always seem to create alot of controversy....thanks for the entertainment!

I like to get people thinking and provoke thought. I find it enjoyable and very interesting some of the stuff I get up to .
The 7500 rpm statement was made in a street machine magazine called six shooters from memory from the 1980's.

I love offering help to guys on the forum but I dont find threads like how to clean chocolate off my carpets as challenging .I am very inquisitive and like to shake the truth out by doing.

Rick. I just dont like em mate.Its just my preference.Drag racing teams do go to big lengths to perfect their setup Sox. So you would expect that by using the dyno they can tailor their stallies ,diffs and modifications correct?

Dynos are useful tools if you stick to the same dyno.I am just a bit over them for now.Dynos do not tell you how much torque you produce at takeoff or how your power curve looks before the dyno operator fully loads the tyres to the rollers.The car therefore travels around 80 to 100kmph before proper measurement are taken. This is another reason why they dont indicate true performance for our cars.
Dynos are great for tuning but dont give the full performance picture which is critical for our sixes as we dont have 400rwkws to pull the cars weight at high engine speed.

It is this grey area under the dynos radar which decides who is the quickest.

[Laminge]

Stav

Why do tuners, like bluepower use Dyno's?

Are they missing something?

[StealthAu]

Stav, have you still got the dyno sheets that you ran on the same day with different results? The numbers on them may differ, but I'd be guessing that peak power/torque would still be shown at the same rpm.

[Sox]

Originally Posted by Stav

Rick. I just dont like em mate.Its just my preference.

It's a preference brought on by your own lack of knowledge on what a dyno is actually used for.

Drag racing teams do go to big lengths to perfect their setup Sox. So you would expect that by using the dyno they can tailor their stallies ,diffs and modifications correct?

To a degree, yes.
Diff ratios can be calculated by knowing the tyre diameter, RPM at peak power, and a couple of other items. That's not rocket science.
Stall converters can also be chosen by knowing when an engine 'is on it's cam', so to speak. A dyno will show this.

Dynos are useful tools if you stick to the same dyno.I am just a bit over them for now.Dynos do not tell you how much torque you produce at takeoff

Of course they do.

or how your power curve looks before the dyno operator fully loads the tyres to the rollers.The car therefore travels around 80 to 100kmph before proper measurement are taken.

I'm not quite sure what you're saying here?
A dyno can read power at whatever point the operator wants to.

This is another reason why they dont indicate true performance for our cars.
Dynos are great for tuning but dont give the full performance picture which is critical for our sixes.

Of course they can, if you also take all other aspects into consideration.
Such as weight, gearing, traction, driver skill, air temp, and a pile of other variables.

A dyno is a seriously good tuning tool, sorry mate, but you're delusional if you think otherwise.

Rick.

[Stav]

Originally Posted by Laminge

Stav

Why do tuners, like bluepower use Dyno's?

Are they missing something?

You are missing something champ.
As I have mentioned .They are a safe tool for tuning high speeds provided you stick to the same dyno. If bluepower who I think is highly likely the best in the business only used a dyno then their results would be suboptimal.The cars would not be as fast. Without their work at the track and off the dyno they would not be able to get their na sixes as quick as they have gone.

The best tuners may tune on their dynos but then go to the track to see if what they have done really works. I am talking strictly na sixes here Gary. Thats why the development of a car on a dyno proves nothing in terms of tuning or modifications until they hit the track.

I did my headwork..got gret flow figures.Installed a bigger cam and gained 29rwkws on the same dyno I have used since starting my project. I went from 141 to 170.1 rwkws. At the track the car was hard pressed to beat its oold time with a cam only.Finally I cracked a few 14.5's.This what 0.2 seconds faster. A 14.5 is not reflective of the power gain.This is what prompted me to get a haltech interceptor and fix the off idle tune to full throttle. Ironically I went in summer at 25 degrees as opposed to my 14.7 run in 7 degress. I ripped 3 14.3's back to back and earlier when it was 28 degrees ran 2 14.5's.

My last tuning was with my bumometer and data logging equipment.

I hope this has made it clearer.I hope it has illustrated why I have come to not be a big fan of the dyno.

[Stav]

If dynos are used to see the effectiveness of stallies and diff gears then what effect does this have on the dyno power curve or torque curve? I would think that you get a fatter dyno power curve? Correct?

For an automatic car the dyno operator steadily raises the speed of the car so it doesnt kick down gear and spoil the dyno run.The car must reach 80 to 100kmph before the dyno operator hits full throttle so it stays in gear.This has the effect of readings below 80 to 100kmph as being useless and not an indicator of true power potential below these speeds.
I am not delusional mate.You are wrong.

[ratter]

Stav not trying to take from anything you are doing but you are pretty wrong about dynos.

A dyno used properly is not just about doing a full throttle (ramp) test.
First off the ramp test can be started at any speed you like that the car will run at which in a manual will be anything above idle although it is not normally done that low, with an auto it will only go down to as low as the torque convertor stall speed which is what would happen on the road also

They can be held at any RPM and any load point so the tuner can tune that load point which is very hard to do on the road and also give you power readings at all these points no matter how small the motor is.


You are also wrong about how gearing and convertors will influence times at the 1/4.
Try this for an excercise
get a 21 speed push bike, measure a distance say 30 metres, put the bike in top gear, go from a standing start and pedal as quick as you can and time it, then do the same but in maybe 2nd or 3rd gear, same bike, same rider, same distance which do you think would be quicker?

[Stav]

You have more torque multiplication in lower gears ratter.The gear ratio will push the weight off the line and it will accelerate.This also is not represented in a 3rd gear dyno pull.I never said histall or diff gears wont make the car faster its just that the dyno is not able to show the results accurately below the stall lockup speed.The converter has more torque multiplication until it locks up .

You are actually agreeing with me here. The dyno cannot measure wot throttle runs properly before the converter locks up.Converters lockup at say 2000 rpm? 1800? 2500rpm?Right? So that means my 2500 stallie will be pulling 100 odd kmph before we get an accurate picture under full throttle dyno runs. Will we ever know what power is below these speeds on a dyno? A standard car would probably lockup at 80 kmph roughly before true power measurements can be taken? Am I wrong or right and if so please help me understand.

[Stav]

Even Doogstar some time ago said that he lost power with his stall converter but went faster.Casper was the same. On face value that statement is not logical.You cannot go faster without more power/torque churning out of the rear wheels it is not scientifically possible. The dyno should show a much fatter curve. The stall converters hidden increase in the dyno power curve isnt represented in the runs.
Still in any case I do agree that dynos do have their place.

[5.0 ED]

Still stav is partially correct, dyno's have trouble holding any car with decent power in first, and engines all create power differently, 2 motors can be run up on a dyno, and yet have exactly the same power curb, yet on the track be completely different, because an engine's rpm excellerating at 2000rpm/sec won't have the power of one held down at a constant, and cam/heads/rotating enertia etc. effect how different that is engine to engine.

A stall converter lowers the rear wheel kw readings because there is more slip in them up in rev's therefore maximum speed at say 5500 was 80kph will now be 75 and so on depending on stally of course. Dyno's purely measure speed vs, weight on the load cell to give kw calculations.

Now in previous thread by stav i noticed that he said his car prefered richer fuel mix than i wont go into this deeply but thats because he is driving the car doing the testing, when an engine is excellerating in first gear it'll actually make more power quicker with a slightly richer mix, than it will if it is just held down.

Im not against dyno's they have there place, but best results will always been attained with a combination of dyno and track.

[ratter]

yes stav I do agree with some of the things you said but clearing up some wrong info in other things you have said.

I'm sure there are lots of members who will look at what you have done and achieved and then everything that you type as gospel.

road testing the car below the stall speed will not do anything different to what would be acheived on the dyno.

As I mentioned earlier there is more to a dyno than just a ramp test. The car could be driven at any speed at any gear and at any measured load point to get a power reading.
But yes you are correct that if your auto with its hi stall will flare to it's stall speed and affect the power levels below that point.
But it will be measuring what your car is actually making at the wheels under those conditions no matter what is influencing the result.

Some of the hi stalls these days do not alter the figures very much under a wot test (above the stall point) as opposed to the standard convertor as some manufacturers are making more efficient convertors

As mentioned the combination of a dyno and track useage will give you your best results and keep you licence safe
Keep up the good work

[mcflux]

Originally Posted by Stav

Even Doogstar some time ago said that he lost power with his stall converter but went faster.Casper was the same. On face value that statement is not logical.You cannot go faster without more power/torque churning out of the rear wheels it is not scientifically possible. The dyno should show a much fatter curve. The stall converters hidden increase in the dyno power curve isnt represented in the runs.
Still in any case I do agree that dynos do have their place.

I managed just that? It's not about PEAK power, it's about the entire area under the power & torque curves. BTR + std stall + 3.27 diff gears would make for a sloooooow launch. BTR + 3000rpm stall + 4.11 diff gears effectively gave me a slingshot launch as I was taking off at a point where a heap of torque was instantly available, rather than having a doughy launch & waiting for the power/torque curves to do their thing once the revs built up.

It's awesome (stally, short gears) for around town but you lose oomph at highway speeds. The tradeoff worked fine for me because I'm not interested in oomph at highway speeds.

I raced a mate at Heathcote a while back. I had 12rwkw less than him but beat him by nearly 0.5 seconds, and he's not a **** driver. I'd say our cars are about the same weight too (EB Ghia 5.0 auto vs EL XR8 5.0 auto). As mentioned in the 1st paragraph, my stally gave me a wicked launch, and I was even jumping on LS1s & XR6Ts (these guys would reel me in after half track though & walk all over me down the 2nd half).

I wouldn't be too concerned about peak power differences on various dynos, I'd use it for improving the AFRs through the rev range and for optimising the area under the power/torque curves.

I've "slowed" by 0.15 seconds since removing my stally, despite having my RWKW increasing to around 150 now.