Conflicting duno figures

[rjay]

ok guys, i'm really beggining to scratch my head with some dyno figures that have been posted on this site, heres why;

I have a R33 Gtst 4 door auto with:

3''Turbo back exhaust

hi flow cat

Profec B

Kn Panel filter

600X300 Fmic

T3/4 hybrid Turbo onto a rb30 exhaust manifold

Link E.C.U

I am only making 203rwkw on 1bar boost.

I've seen many people with less making similar power? its tuned by JPC, ive been to BGT, promaz, creatd, Nispro, Avo and they ALL say thats all i can get, also telling me not to believe power figures from magazines (which i dont). not too many places know how to tune Link E.C.U's but many agree that it is very good for skylines. This is my second R33 and power figures have been identical, i'll leave it to you guys to help me figure this out. Cheers!

[GTS-t VSPEC]

Not all t3/t4's can be easily compared, my mates car makes 360rwhp at 17psi with one, and similar other mods to you.

[meggala]

and not all dyno's read the same there are many differnt specs for t3/4 different wheel sizes. looks like you got a small one.

power comes from the amuont of air a turbo pushes through bigger wheels more air more power.

cheers

meggala

[rev210]

rjay,

don't get cut up about it mate. Quite possibly your car is still as quick or quicker than the others you have seen with higher readings. Take it for a go down the drags.

I'm sure the car is faster than when you had the old turbo? If so don't worry about it. Also the turbo's efficiency may be higher than 1 bar of boost.

[Gizmo73]

Hey rj...

Another thing to consider is the torque curve and power delivery low down, mid range and top end...

I would rather have more usable torque than a nice top end kw figure...

As rev said, you may find on the track you will be quicker than those with similar dyno figures..

[Jay95R33]

Yepp, don't be worried. As long as your happy with the way it drives.

One thing to consider is that your car is an auto, and auto's do tend to loose a bit more power than the manuals. Not a heap though.

I wouldn't be worried.

J

[R31Nismoid]

, ive been to BGT, promaz, creatd, Nispro, Avo and they ALL say thats all i can get

Some of those places dont know what they are talking aobut anyways i've found.

But as people have said, and will say for ever.

Every dyno is different, use them for tuning, not getting a 'power' figure.

If you wanna compare 'power' using a chassis dyno, have a dyno day and go to that. Everyone on the same dyno, on the same day.

Then compare mods vs what figure they get.

Best get it on a drag stip to be honest.

How is the auto holding up?

Stock or is it modded

[R31Nismoid]

One thing to consider is that your car is an auto, and auto's do tend to loose a bit more power than the manuals.  Not a heap though.

on a stock car, the Auto sucks approx 9kw out of the equation.

Not a lot really.

[rev210]

The auto soaks more power up as the power goes up, just like any transmisson does thanks to increased friction from the additional power. You will find quite a large loss if the trans cooler is not large enough to keep the oil in the right temp range. B&M make one that costs about $130 that will make a difference if you haven't got one already.

[Sydneykid]

Hi rjay, we find a standard R33 GTST auto makes around 105 to 110 rwkw. What if I add up the approximate power from your mods;

3''Turbo back exhaust = 15rwkw

hi flow cat = 5 rwkw

Profec B = 0 rwkw

1 Bar boost = 20 rwkw

Kn Panel filter = 5 rwkw

600X300 Fmic = 10 rwkw

T3/4 hybrid Turbo onto a rb30 exhaust manifold = 25 rwkw

Link E.C.U = 20 rwkw

Total = 205 to 210 rwkw

So your 203 rwkw is pretty much what I would expect from those mods. If you are looking for another 15 to 20 rwkw I would try a bit more boost, up to 1.2/1.3 bar. The GCG hi flows we use are extremely efficient up to 1.3/1.5 bar. Maybe check with your turbo supplier and confirm the efficiency limit of yours.

Hope that helps

[R31Nismoid]

The auto soaks more power up as the power goes up, just like any transmisson does thanks to increased friction from the additional power.

Yeah i agree... stock i said 9kw is what you loose...

I wonder if there is any way of working out how much it is as power rises???

[whatsisname]

Auto GTS25t RB25DET's are rated 5ps lower to start with (245ps auto vs. 250ps manual).

rjay,

As a few others have mentioned, your dyno figure should only be used as a rough guide. A dyno figure (or even better a dyno power curve) is great if you want to compare before and after results.

Go hit the strip and see how you go? The time slip will give you a good indication as to how much power you're making.

[craz0]

I would be happy with that, that is about what I'm after.

Would like to know if the Auto box is stock or if it has had anything done to it.

Is that avatar a pic of your interior ? if so I would love to see a bigger one.

[RNS11Z]

have u taken it to the track??

our auto r33 with cat back and 9psi made 190rwhp

since then a front pipe has been installed, pod filter and 10psi. It goes down the 1/4 @ 14.1 @ 97mph

[benm]

Go hit the strip and see how you go? The time slip will give you a good indication as to how much power you're making.

I still disagree with this theory (to a certain degree).

Take my car for eg;

* Been on 4 different dyno's ranging from 180-203rwk (I believe its closer to the 180rwkw figure).

* My best 1/4 is 14.1 @ 99mph with a 2.1 60ft (which is about 0.4sec off what i'd be happy with for my current mods), I have done a 14.2 @ 100mph too.

Now using the data from my own "SAU 1/4 Mile List" (http://skylines.pnc.com.au) a 100mph pass is 'capable' of 13.5sec (thats a full 0.6sec quicker than what I am currently getting). So where is my 13.5sec? I'll tell you where, im not the worlds quickest driver and it shows in my time.

So if my car got ~180rwkw on a dyno does that mean that the other r33 owner has more power than me? Does it mean he knows how to drive the car much better than me (thats what I believe it is) or does it mean he was on a better prep'd track than me? (his 60ft was 0.1sec quicker than mine). What if he was using Nitto's or Drag Radials and got a further 0.5sec quicker.. that doesn't mean he has more power than me it just means he has better grip than what I do allowing him to put the available power down better, but it still could be the same amount of power. Their is heaps more to drag racing than just what is under your bonnet:

* Tyres

* Temperature

* Track Prep

* Track condition

* Driver

The list goes on and on....

I think the whole "if you wanna know how much power you have go drag race it" has just as many floors (if not more) than what a dyno does. I believe I have enough data (in the R33 GTS-t section of my website) to prove that whilst mph is good, its not 'everything' to a quick time.

Here's some more data:

#5 = 12.4sec @ 111mph

#8 = 12.6sec @ 120mph

So which car has more power? Well #8 does but why did it do a slower time than #5?

#21 = 13.5 @ 100mph

#37 = 14.2 @ 100mph

So which car has more power? Well they both crossed the line at the same speed but where did that extra 0.7sec go?

#5 = 12.4sec @ 111mph

#12 = 12.9sec @ 111mph

So which car has more power? Well they both crossed the line at the same speed but where did that extra 0.5sec go?

Now lets look at it the other way:

#13 = 12.98 @ 113mph

#14 = 12.99 @ 110mph

#24 = 13.7 @ 100mph

#25 = 13.7 @ 105mph

So as you can see their is a lot more than just 'having the power' in drag racing to get you to the other end in the quickest possible time. Whilst 18mths ago I used to think that Dyno's are the be all and end all I now love Drag Racing and thats what im working on to gauge my cars power. If I spend $500 on my car and get 0.3sec quicker I know that either a) I have more power/torque etc or B) I learnt something new behind the steering wheel.

NOTE: I'm not having a go at the people that say "Dyno's are a tuning tool, get on the drag strip" im simply stating that a drag strip is about as vague at measuring your engine power as what a dyno is; difference places will give different results.

[Sydneykid]

Hi benm, my sentiments exactly!

[Jay95R33]

I'm with you on this one Ben, way too many variables with the cars/track/driver/weather conditions.....

Plus I know for a fact that I'm a 16 second driver in a high 13 second car

J

[whatsisname]

Ben and SK, the one fundamental flaw (or floor if that's your bag ) in the proven examples, is that they don't include ALL the timeslip data. Nor do they have additional info on how the car went on the pass.

Of course if you isolate the ET and TS it's going to be a poor indication.

Look at your own results Ben. You've run as fast as 100mph yet your best ET is a 14.1. You know that your car is good for 13.5, and others (with quicker 60's) have reached that 13.5 @ 100mph. If you were to compare both timeslips you'd see why the 13.5 car ran the quicker ET. My guess is... both your car and the 13.5 @ 100mph car would be making very similar power.

A perfect example, as you've given above, is the following:

12.4 @ 111mph

12.6 @ 120mph

These two sets of figures on their own tell us very little. The 12.4sec car may have got off it well before the traps? Hence the lower trap speed. But if you add the 60ft, 330ft, 660ft, 660ft mph, 1000ft and so on and so on... and THEN you include the drivers comments on top of that, such as "had a lot of wheel spin in 2nd and 3rd, missed a gear, backed out of it ~50m before the line etc... You can piece the whole picture together.

A timeslip with "ALL" details, a driver that can feel what the car is doing on the strip (i.e amount of wheel spin past the 60ft mark - which obviously the slip won't show) and a bit of a clue on how to interpret that information will give a "reasonable" idea as to the potential horsepower. I believe it's a better one than any dyno figure, or dyno power curve for that matter, will give.

It's not a new theory you know. Take a look at the various drag racing calculators out there. Look at the Americans, they've been using these drag racing calculators for YEARS! And they are often pretty damn close, provided ALL data is included.

As with any figures, the more sets of data you have to base your info on the more accurate the result. If you take one single 1/4 pass and use that as your basis (for power potential) you "may" well be a bit off. But if you use 10-15 or more passes you'll start to get a bit more of an idea.

I have a shite load of timeslips from 4yrs of drag racing my car and I can see the mph has gone up steadly with each power increase. The average mph gain at each level of modifications is very obvious. Has my ET improved? Yeah a little bit. So why only a modest improvement in ET? Because my 60ft, 330ft, 660ft and so on... have only improved a little. in other words "I" need to improve my driving skills. But by looking at the mph readings in conjunction with the ET figures, and recalling how the car was hooking up throughout the pass, I can see how the extra horsepower has gained me mph.

It goes without saying that big mph doesn't necessarily equal a quick ET. But I said it anyway.

Having said all that, yes I do agree that both the dyno AND drag racing calculators are at best a rough guide to estimating horsepower.

Hey one things for sure, it's damn hard to fudge a 0-400m pass! Short of the timing gear faulting, the car lining up on the rears (and the officals not picking it up) or an act of god, 400m in a straight line is 400m.

At the end of the day as long as you're having fun, be it on the drag strip or the dyno

[rev210]

benm,

All the examples you mentioned are easily explained by the difference in 60ft (launch times) and in the case of those who had a little extra wheel spin the 330ft time's if you got hold of those.

by my calculations ,using a peice of stale bread and an arc welder, you have about 150 (rev210)rwkw based on your 1/4 mile data. Since I had only 170rwkw odd when I did a 13.3 @ 106mph and a slower 60ft time.

[whatsisname]

Dave your just making this even more confusing now!!! I just about had it all figured out and my head was getting around this whole issue... And now you bring in this new information!

Was the stale piece of bread recently calibrated? Are we using the hubs of the welder, or the wheels? It the welder a US model or Aussie made? What is the loss ratio between the welder and the bread? How stale does the bread need to be? I've seen Tip Top bread show higher numbers, but only on US made welders.

Sorry I couldn't help myself. I'm very bad, I know! But I did post a very long and completely serious post above