Why the 1/4 is useless for comparing engine power

[Sydneykid]

Absolute hogs-piss.  Take one Moroso calculator, apply it to ANY car at WSID and your results will probably surprise the hell out of you, Sydneykid.

Adrian

OK Adrian, let's do a few examples,

R33 GTST, lady driver, 11.9 at 119 mph. How much power does it have?

R32 GTR, male driver, 10.3 at 140 mph. How much power does it have?

R34 GTT, male driver, 11.6 at 120 mph. How much power does it have?

If you get within 10% on the three cars I will buy lunch next WSID major meeting. I have the time slips and the dyno sheets, all on the same dyno. You can inspect them if you want.

[BU5TER]

pretty hard to take a educated guess without full time slip details and what strip it was at and tyre details size etc

[2rismo]

What tyre sizes?

What diff ratios?

What were the race weights?

330ft times?

660ft times?

All these things are known and used in conjunction with the calculator. Not once have I suggested that using this tool BY ITSELF is what I was talking about.

Come on mate. Oh and btw, what the fark has the sex of the driver got to do with their power figure?

Adrian

[Sydneykid]

Easy............

R33 GTST, lady driver, 11.9 at 119 mph. Eastern Creek, nittos

R32 GTR, male driver, 10.3 at 140 mph. WSID, road tyres

R34 GTT, male driver, 11.6 at 120 mph. Heathcote, slicks

But remember this post....

Originally Posted by japsky33

What you can do is get each others REAL drag MPH from the track and match those up

all he needs is the MPH................. :confused:

[japsky33]

Agreed 2rismo..!

And I think by reading this people are getting confused with QUARTER TIMES AND MPH And the fact that people are bringing things like this into a discussion about power/mph "dynos for getting rid of problems and running in motors" well that’s stupid because who is going to go to the drag strip to get rid of problems and run there motor in??? Dahhhh :confused:

Your quarter times can vary a lot. Take my example with the 180sx for instance. But your MPH assuming you get a reasonable pass will stay with in an acceptable limit. I’ve seen this over and over again with my Car's and close friend’s cars where I have done a run after they have.

I’m not using theory and I don’t use other peoples examples or what I have watched to make my opinion on this matter IM using what I have seen over the years with my cars (SEVERAL OF THEM) and I consider myself a standard driver I mean how hard is it to take your car down the strip getting through all the gears where not talking about sub 10sec monsters. I’ve got a 355rwkw GTS-t R33 and I have no issues getting it down the strip time and time again.

==============================

With you guys breaking everything isn’t it better on the strip in a controlled environment where you can get a tow home easily instead of in the middle of a busy freeway (Sydney) or on a trip. We want to make this HP to use it not to wank over dyno graphs. And dont say "I dont like driving on the strip" ? Get off its bloody awesome.

==============================

I use dynos for all the normal uses as I tune and engine build, and I find it an excellent tool just not for the true performance 'of the most important word here' "CAR".

Also considering the differences between this 300KW @ 970NM and 325KW @ 938NM ? Which tune will be faster on the strip and produce a higher MPH? These are true dyno read outs.

With the engine dyno once again great tool for the engines HP but with this HP could you accurately assume what sort of performance you will get with this motor in the car? Of course NOT.

AS for the person who can’t stand their car on the dyno what mate? As long as she's tuned it will love it, I think your babying your car too much.

---Qoute SydneyKid

7,000 rpm for 6 seconds = 700 revolutions of the crankshaft

Time for a rebuild, new pistons, rings, rods, reseat the valves etc

7,000 rpm for 6 seconds = 700 revolutions of the crankshaft

Time for another rebuild, new pistons, rings , rods, reseat the valves etc

---

So your telling me that pac/gtr700 etc etc only get a pass or a few quarter pass' before engine rebuild? Hmmmmm... :confused:

BR,

JH

Absolute hogs-piss.  Take one Moroso calculator, apply it to ANY car at WSID and your results will probably surprise the hell out of you, Sydneykid.

It isn't just used for 6sec theorhettical pie in the sky dragsters that run sub 6's.

Some of the fastest Super Sedan teams in this country and the states use it almost exclusively to estimate the horsepower their engines makes.  Dyno's are just an estimate as well.  Lets not forget that.

At the end of the day, usable, real world hp is what interests most people (leaving out the obvious dyno queens) and MPH is a fantastic and vastly underated measure of power.

Adrian

[ferni]

Reading the topic... "why the 1/4 is useless for comparing engine power"...

I'd say an engine dyno would be the best tool to compare engine power....

if you were asking whats the best way to compare how much power/fast a car is, then i'd say 1/4 mile strip, MPH is a good way...

I went to the drag strip for the first time last sunday... my MPH were pretty consistent considering i was a first timer, started off about 109mph, then think a few runs later was running high 110/low 111mph... until i broke my gearbox farken...

i guess it depends on what you are trying to compare...

how powerful your ENGINE is... engine dyno sure... i'd probably go with a (normal?) dyno as well over drag... but if you want to compare how powerful your whole car is or how fast it is, then the drag strip....

you're both right maybe just misunderstanding each other?

[2rismo]

What tyre sizes?

What diff ratios?

What were the race weights?

330ft times?

660ft times?

Easy............

R33 GTST, lady driver, 11.9 at 119 mph. Eastern Creek, nittos

R32 GTR, male driver, 10.3 at 140 mph. WSID, road tyres

R34 GTT, male driver, 11.6 at 120 mph. Heathcote, slicks

Errrr.... You're not paying attention are ya?!?!?

If you are gonna argue your point, (and I believe you're wrong in your statement, "The 1/4 is useless for comparing engine power"), at least try.

Adrian

[japsky33]

======================

QUOTE : SYDNEYKID

But remember this post....

Quote:

Originally Posted by japsky33

What you can do is get each others REAL drag MPH from the track and match those up

===========================

WHAT DOES THE 'REAL' MEAN IN THAT DUDE ? Thats the part where you both get accurate MPH of your car's and compare it.

BR,

JH

Easy............

R33 GTST, lady driver, 11.9 at 119 mph.  Eastern Creek, nittos

R32 GTR, male driver, 10.3 at 140 mph.  WSID, road tyres

R34 GTT, male driver, 11.6 at 120 mph.  Heathcote, slicks

But remember this post....

all he needs is the MPH................. :confused:

[2rismo]

Oh and while we're at it, do your 'examples' run that mph + or - 3mph?

Come on mate, give us the info we need to shut you down hard! ;)

Adrian

[czy18e]

A road tune shits on a dyno tune anyway doesnt it?

I only go on a dyno if i got a problem.

[RB20LagWagon]

How do you tune for 400 rwhp++ on the street?

[Sydneykid]

If you are gonna argue your point, (and I believe you're wrong in your statement, "The 1/4 is useless for comparing engine power"), at least try.

Adrian

Hi Adrian, my reply was to BU5TER's questions, regardless of what you think, other people have the right to ask questions. And he asked before you, so wait your turn.

You posted, tell you the MPH and you would calculate the power. Now your telling me you can't calculate the power without a whole pile of other data. Make up your mind. :headspin:

Oh Ok, I'll help you out.......

The MPH is accurate via the track's sensor, the timeslips read to 0.1 mph.

RE; The sex of the driver, I was helping you out (before you even asked), she weighs <60 kgs and the guys driving the other 2 cars weigh 100+.

All the cars had standard diff ratios and all were at their usual road weights (ie; not lightenend).

The GTST had 245/40/17

The GTR had 275/40/17

The GTT had, I can't remember, whatever Goodyear drag slick fits on 16 X 7's

Errrr.... You're not paying attention are ya?!?!?

Nope, I was puting a race gearbox together, sorry I couldn't drop everything and answer your questions.

[DoughBoy]

Actually, to be pedantic, SK is right. Because you can always argue the complete opposite ends of the scale to exaggerate the other factors involved in drag racing (or any form of racing really).

But you can also argue the same about engine dynos, and how they are useless for comparing engine power as there are too many variables (even though alot less than in drag racing) that can affect the printout by a massive scale.

Yeah I might have backflipped on my previous posts, but this is degenerating to specific examples that have too many outrageous factors. It's fine if you want to compare serious, competitive cars but if you go throwing granny-shifting, 205 compliance tyred cars up against proper race cars you might as well talk about dyno operaters with the temp sensor jacked up their ass, or spiked wank factor readings from mass dyno comps.

[Roy]

My car is quicker then your...FULLSTOP:)

[Sydneykid]

Actually, to be pedantic, SK is right. Because you can always argue the complete opposite ends of the scale to exaggerate the other factors involved in drag racing (or any form of racing really).

But you can also argue the same about engine dynos, and how they are useless for comparing engine power as there are too many variables (even though alot less than in drag racing) that can affect the printout by a massive scale.

Yeah I might have backflipped on my previous posts, but this is degenerating to specific examples that have too many outrageous factors. It's fine if you want to compare serious, competitive cars but if you go throwing granny-shifting, 205 compliance tyred cars up against proper race cars you might as well talk about dyno operaters with the temp sensor jacked up their ass, or spiked wank factor readings from mass dyno comps.

I agree, but I chose examples where the drivers where trying as hard as they could. I know because I did data logging for 2 of the cars personally and I can see from the logs how quick the gearchanges where, how much throttle was applied, the longitudinal G forces, I can even see how much steering was used to correct any slides.

The big factors here were, one of the cars was an auto, one had a dog box and one a standard synchro box. Just changing to the dog box lower the ET's by 3/10th and increased the TS by 7mph. Same engine power, same dif ratio, same weight, same tyres etc.

If I plug the numbers into one of the basic drag horsepower calculators, I end up with this for the R34 GTT;

120 mph = 508 bhp

11.9 secs = 441 bhp

If our engine dyno was that inaccurate or inconsistent I would be in deep touble, 10 bhp is enough to win or loose a race, 67 bhp is unthinkable.

So yes DB, you are correct. :cooldance

[dangerous_daveo]

.........

The big factors here were, one of the cars was an auto, one had a dog box and one a standard synchro box.  Just changing to the dog box lower the ET's by 3/10th and increased the TS by 7mph.  Same engine power, same dif ratio, same weight, same tyres etc.

If I plug the numbers into one of the basic drag horsepower calculators, I end up with this for the R34 GTT;

120 mph = 508 bhp

11.9 secs = 441 bhp

.........

Two questions.

First off topic, how does the dogbox make you go faster??? Less drive train loss or something???

2nd, what was the power of the r34 GTT? Just so we can get a rough idea.

[DoughBoy]

Quicker shifts and closer gear ratios.

Edit: An example of two people trying as hard as possible to get a decent time in the same car... Wreckedhead + Alex(?) from C&V. Same car, same track, same nearly everything.... 2 seconds difference? At the pointy level of competition ( your 6 second example) you're not going to get such differences in driver ability, car setup, gearboxes, tyres etc so it's more consistent to compare times/power.

[Sydneykid]

Quicker shifts and closer gear ratios.

DB is right, plus you don't have to lift off when you up change, if you have the right ECU of course. It just cuts the ignition for around 10 milliseconds, which is plenty of time to change gear with a dog box.

Plus the straight cut gears soak up a bit less horsepower than hellicals. The Hollingers we use are also very carefully assembled with minute tolerances to further reduce loses. :cooldance

[low747]

SK,

i've had really good results over the years using a drag calculators, always racing back to back after a dyno result, and mph's and et's were fairly spot on, providing the weight figures were correct.

[R33vit]

An so the saga which is day's of our life continues...

Chris. I think when Wreckhead run he had a leak from the NAWS system, then fixed it and Alex tried his hand at it..

I know it still will not give you an exact HP reading, there is some truth in the drag racing method. Although I do believe that it takes more than just 1 run down the 1/4 mile to get a good idea. On a dyno you have more than 1 run and then the output changes at a different dyno.

At the end of the day who care as long as I leave the dyno with more HP than when I arrived.