NZ's Fastest Road legal subaru?

[Guest]

4th gear dyno run

[GC8E2DD]

So how do the 4th gear and final drives compare on the two cars you are comparing?

[funkytown]

I can tell you on my vf23 to gt30 swap my axle torque almost doubled while KW's increased by abotu 40wkw. Due in part to the swap from a long 5mt to the super close 6mt.

[Guest]

 funkytown said:

I can tell you on my vf23 to gt30 swap my axle torque almost doubled while KW's increased by abotu 40wkw. Due in part to the swap from a long 5mt to the super close 6mt.

shiiiit .lol have you got any pics of your dyno sheets with the gt30 turbo?

[WRXONP]

Yeah mine was around 1050 NM if I remember correctly . . Was over 1000 though

[R8TD_R]

for a 2.2l that car got shit all torque then as far as i know the more cc you got the easier to make more torque and brad you making 150nm more on bolt ons shows how much was done to that GT ay

[WRXONP]

Yeah man my old ver 2 wrx only had 600nm and 185 kw lol

[Guest vf20/21bg5]

 sti8u']

[quote name='funkytown said:

I can tell you on my vf23 to gt30 swap my axle torque almost doubled while KW's increased by abotu 40wkw. Due in part to the swap from a long 5mt to the super close 6mt.

/quote]

shiiiit .lol have you got any pics of your dyno sheets with the gt30 turbo?

............?

[R8TD_R]

i ask SKRMER once what kind of torque he got out of the 2.5l man was somthing crazy like 4000nm soo impressed

[Koom]

You guys need to learn the correlation between torque and power. And that half the time the torque shown on dyno plots is the torque the dyno sees and needs to be calculated to what your engine is actually producing as your gearbox and diffs are torque multipliers.

i.e.

So if you turn that equation around, and plug some numbers in to calculate torque for a certain power level (@xxxx rpm) you can see how far off some dyno charts are when they are shown uncorrected.

Using the last dyno chart on the Dyno Leaderboard 2011 thread as an example;

Peak torque occurs @4600rpm.

Power at that rpm point is ~195kw.

So Actual Engine Torque = (Power [kW] x 9549)/(Revs[RPM])

= (195 x 9549)/4600

= 404.79 Nm

Which is pretty close to what that chart shows (and there will be a bit of variation due to my accuracy in reading the chart).

Now take the first chart on that thread;

And using peak torque @ 4000rpm

Actual Torque = (150 x 9549)/4000

= 358 Nm

But the graph shows 2080 Nm!!

Its because of this;

And specifically Torque (Out) = Torque (In) x Gear Ratio

Read this for a bit more information;

http://wotid.com/dyno/content/view/18/37/

[Koom]

 CP93MM']

[quote name='funkytown said:

I can tell you on my vf23 to gt30 swap my axle torque almost doubled while KW's increased by abotu 40wkw. Due in part to the swap from a long 5mt to the super close 6mt.

/quote]

shiiiit .lol have you got any pics of your dyno sheets with the gt30 turbo?

............?

How much did your mid-range power increase by? Have a look and before and after graphs and compare the power levels at peak torque on both. I bet if you've actually doubled torque then you must be making peak torque earlier and have a heap more power at that point in the rev range.

[R8TD_R]

u can also just divide the ATW max torque by the ratio that the dyno reads and that comes close too but thats only if u want to know what kind of torque your motor is putting out not the torque that u got at the wheels which is what u going to be using thats what i think but i could be wrong

[R8TD_R]

koom you seem very on to it kinda guy

[GC8E2DD]

Hah, nice one Koom. I didn't put much effort into it.

[Koom]

;D Thought it was about time for a mathsdebate as there is no way in hell our puny little 2.0L engines are going to be putting out the same amount of torques as one of these;

(no matter how much we dream)

http://www.dragtimes.com/Mercedes-Benz-CL65-AMG-Timeslip-15116.html

http://www.rsportscars.com/mercedes-benz/2008-mercedes-benz-cl65-amg/

[R8TD_R]

but this says its making 724nm at the wheels ??? ???

[Koom]

The CL65 AMG makes 1000Nm which is 724 ft-lbs and is a hell of alot more than our 2.0L engines will make (and the 2.5L ones for that matter).

Even if we were making 600hp, the peak torque would be way the hell off to the right of the graph (and definately not anywhere near ~4k rpm) so the torque would be a heap lower.

The big 6.0L Bi-Turbo V12 makes huge torque down low, if it made its torque up high like our motors then it would be making 800-900+ hp.

What I am trying to get across is that anything over 400-500 Nm is fu***ng heaps for our motors and anyone who thinks they are making more than that needs to look at what they are actually reading on their dyno plots. The uncorrected torque shown on alot of dyno plots will vary wildly depending on what gear you are in (i.e. Torque Out = Torque In x Gear Ratio). Should do a dyno run in first gear to get a 9000 Nm plot

Using Borg Warner's Matchbot to calculate the theoretical boost needed to make ~720 ft-lbs of torque @ 6000 rpm on a 2.0L engine (with all other inputs left as standard for Matchbot), gives a required boost pressure of 65psi in the manifold. Although if you have a 2.5L then you only need 50psi

[rex-leggy]

wow and thats a truckload of boost!! i would have big smiles/very scared

[Koom]

I hypothesize that at 65psi you would have a truckload of parts spread across the road.......

[R8TD_R]

sorry mate just trying to get my head around this

so what matters more the torque at the wheels or the flywheel?

am making 3215nm at 6100rpm what does that make it?

[Koom]

 R8TD_R said:

sorry mate just trying to get my head around this

so what matters more the torque at the wheels or the flywheel?

am making 3215nm at 6100rpm what does that make it?

Torque at the wheels means nothing at all (unless you have the power at that rpm point too). It can vary due to gear ratios and diff ratios, tyre circumference etc.

For your figures to mean anything, how much power are you making at 6100 rpm?

[R8TD_R]

 Koom']

[quote name='R8TD_R said:

sorry mate just trying to get my head around this

so what matters more the torque at the wheels or the flywheel?

am making 3215nm at 6100rpm what does that make it?

/quote]

Torque at the wheels means nothing at all (unless you have the power at that rpm point too). It can vary due to gear ratios and diff ratios, tyre circumference etc.

For your figures to mean anything, how much power are you making at 6100 rpm?

a bit over 400kw cuz at 6700 i make my full power

[R8TD_R]

http://www.clubsub.org.nz/forum/index.php/topic,1835.210.html

its the last dyno sheet on page 15

[Koom]

So Actual Engine Torque = (Power [kW] x 9549)/(Revs[RPM])

= (400 x 9549)/6100

= 626 Nm

Which is a really impressive number ;D

626Nm to me makes me think that you make huuuge power, where 3215 Nm just makes me think that something needs to be corrected to give a realistic number. Kinda like when shops sell stereos with 2400 W pmpo written on them

[R8TD_R]

 Koom said:

So Actual Engine Torque = (Power [kW] x 9549)/(Revs[RPM])

= (400 x 9549)/6100

= 626 Nm

Which is a really impressive number ;D

626Nm to me makes me think that you make huuuge power, where 3215 Nm just makes me think that something needs to be corrected to give a realistic number. Kinda like when shops sell stereos with 2400 W pmpo written on them

not bad for a boxer?

i think this number going to jump even more once we stroke it mite go for the 2.35l next year

and once i go bigger turbo exhaust hosing the torque should carry on and not drop off after 6800 because now am maxing out the 35/40 at .82 hosing

what you think? any thoughts