Dyno results the ultimate measurement tool ??

[wkautech]

Originally posted by ae92levin@Dec 23 2004, 18:21
ya but isnt dyno more effective? And i also heard a/f meter not so accurate if not connected to ecu wire properly, o2 sensor faulty etc...

although im in favour for dyno runs, im still gonna tune my SAFC with a/f meter. hope i dont get speeding ticket...

the word effective is not the for this topic, we r talking about feeling or maybe numbers. there is no effective word between this two thing.

i m using a very expensive a/f meter not apexi a/f timer or auto gauge a/f meter lah fren. If u cannot understand what i mean ' i smell a lot of smoke in dyno room', let me tell u there is no big deal for car below 200ps or maybe 300ps unless your car is under 800kg.

no offence :)

 

[cmng]

I believe Dyno tuning is for easier to tune

but on the road tuning is the best
since you have load. off load, traction
real atmosfere

 

[taqu]

Referring to lightweight engine components (eg flywheel, pistons etc) not showing improvement on dyno, I believe it's only true for convential brake dyno. For inertia dyno (eg Dynojet in N1), it's measuring acceleration rate of the drum roller. Since lighter engine components result in RPM moving faster, the acceleration should be faster, it should be visible to the dyno, since inertia dyno measures "acceleration rate", from the rate it computes horsepower & torque, not a problem since the weight of the drum roller is known & constant (remember F=ma).

Not promoting N1, just want to share my opinions on Dynojet that N1 is using :lol:

 

[Acoustic]

I thought all dyno machine measures torque then convert back to HP ???

actually KW right?

I don't know anything about dyno, please don't shoot me.

 

[taqu]

Almost all conventional, brake-based dynos measure torque except Dynojet that measures hp (from acceleration) only then convert to torque. Doesn't matter about the unit be it kw/hp/ps/Nm/kgm/lbft all can be converted using formulas.

Not related thing, but what I like about Dynojet is they provide a viewer so u if u do a dyno run on Dynojet, u can get the file (.drf) and later view it in your own PC. The software allows u to view in whatever unit u want, and view up to 4 graphs at one time, in short, manipulate the dyno chart as u wish. It even displays the actual measured gear ratio so u can also use the dyno to calibrate ur speedometer/tachometer. The best is the software is free :). Don't believe? This dyno graph is generated from my own laptop :lol:

http://img.photobucket.com/albums/v204/taquddin/dyno_18122004.gif

 

[GT20v]

tagu,

not bad the dynojet...emm

how much the run with AFR.and does they provide you with the graph in floppy or what..how many run they do??

can u explain bit ur graph??cant understand it

thnx

 

[yolk]

yeah how much does N1 charge for air fuel dyno tuning ? but i heard many many bad things about N1 .. especially on exploding engines ... scary shit man :ph34r:

 

[Battousai]

Sometimes the gains from mods are not tangible in power gains, because your mods must work in harmony with each other. Lightened internals don't really boost HP, but enable your engine to respond faster, and most importantly, REV higher.

For an NA engine, REVS = POWER. So at the same rpm as stock internals, you'd have little or no power gain, but now you can rev to 11,000 rpm which is 4,000 more than stock.

Also, the dyno only measures output at the wheels, so if you changed your final drive, bigger rims, etc that affects wheel output, but your engine output remains the same.

The most significant reading on the dyno i believe is torque. This is because hp is a function of torque x rpm.

So when ppl ask why this car got more hp, more torque, but still lose to this lesser powered car, you need to consider at what RPM they are making what hp/torque figures.

 

[taqu]

Gearing will not effect dyno reading (that's why dyno also measures actual gear ratio to be excluded from the graph), it comes into effect in real life eg 0-100, lap time, quarter mile etc.

If one can say hp is a function of torque, one can also say torque is a function of hp too. People telling torque matters, hp is irrelevant, or vice versa, is nonsense. In the end, is the horsepower that will tell u how fast the car will accelerate. No torque, no hp, no hp, no torque. Remember f=ma and hp=torque x rpm/5252.

My point of believe is since Dynojet directly measures acceleration, lighter engine components that contribute faster increase of RPM result in faster acceleration, therefore the computed horsepower will be higher. Plz correct me if I got wrong understanding on Dynojet.

FYI N1 charges RM100 for both dyno & air-fuel ratio reading, can do 1 run or 3 run. Just give the guy a floppy disc and he will copy the graph into ur floppy. No dyno tuning is done (mine runs on Mikuni only :P)

 

[GT20v]

thnx dude..what car u drive?

 

[Battousai]

Gearing will not effect dyno reading (that's why dyno also measures actual gear ratio to be excluded from the graph), it comes into effect in real life eg 0-100, lap time, quarter mile etc.

Gearing does affect dyno readings, by a few hp. That's why you try to dyno the car in the gear that's as close to 1:1 as possible.

If one can say hp is a function of torque, one can also say torque is a function of hp too. People telling torque matters, hp is irrelevant, or vice versa, is nonsense. In the end, is the horsepower that will tell u how fast the car will accelerate. No torque, no hp, no hp, no torque. Remember f=ma and hp=torque x rpm/5252.

HP is a straightline measurement, but engines can only spin. So the true measurement of output is an engine's torque rating. In other words, HP is the end product of an engine's torque output, because an engine cannot produce HP.


My point of believe is since Dynojet directly measures acceleration, lighter engine components that contribute faster increase of RPM result in faster acceleration, therefore the computed horsepower will be higher. Plz correct me if I got wrong understanding on Dynojet.

The dynojet measures via a brake attached to the drum. It is my guess that this brake measures torque by loading the engine. If it were a measure of acceleration or horsepower, no brake would be required.

 

[taqu]

1. I mean torque is not multiplied with the gearing during calculation.
2. Battousai, I don't understand what u mean engine cannot produce horsepower, if no horsepower, how can the car moves from stop to 100kmh, this is what Newton discovered centuries ago :blink: When the engine spins the tyres, they convert the rotation to straightline movement. That's where the classic hp=torque*rpm/5252 formula comes from. Both torque & hp matters.
3. Dynojet is well known around the world as inertia dyno. I guess N1 is using http://www.dynojet.com/automotive_dyno/424x_dyno/index.php . It's an inertia dyno but also has a brake-loading devide for tuning purposes, since inertia dyno, unlike regular brake dyno, CANNOT measure torque when the car is not under full-throttle (eg part-throttle).

GT20v, I drive a puny Iswara :(

 

[GT20v]

ok..guess we both have a puny car lar..hahahhaha

 

[Acoustic]

Originally posted by taqu@Feb 8 2005, 14:50
2. Battousai, I don't understand what u mean engine cannot produce horsepower, if no horsepower, how can the car moves from stop to 100kmh, this is what Newton discovered centuries ago :blink: When the engine spins the tyres, they convert the rotation to straightline movement. That's where the classic hp=torque*rpm/5252 formula comes from. Both torque & hp matters.

I think in order to understand what Battausai is talking about you'll need to refer to references from: -

AUTOMOTIVE Engines

by Crouse & Anglin

(8th Edition)

published by (GLENCOE) McGRAW-HILL International Editions

under Automotive Technology Series

ISBN 0-07-113884-6

Chapter 11



This is not an offence, please don't misunderstand.

I'm not automotive engineer, I also don't have good command of english to describe as well as textbooks. But after you read it you'll know immediately.

 

[taqu]

I don't know how to get that book, plus currently I don't have much free time to read books. Well I'll no longer ask "engines don't produce horsepower" anymore, doesn't matter much for me anyway as long as both hp and torque graph can be drawn :)

If we're so afraid of dyno operators deliberately "cheating" the dyno output, what if we dyno ourselves? Plenty of on-the-road DIY horsepower measurement methods out there eg G-Tech Pro or Apexi RSM or Home Dyno.