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GalantVR4.ORG Dyno Shootout

turbowop

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Joined
Apr 29, 2001
Messages
11,972
Location
Yakima, WA
So then I'm not smoking crack and we have one member that is inflating his torque numbers through some calculation that nobody else uses?
 

slugsgomoo

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Joined
Oct 16, 2003
Messages
3,776
Location
Tacoma, WA
it's also a dynapack, which are known to be the highest reading, and easiest to fudge, so it's not that surprising.

HP = (peak torque*RPM)/5252

i.e. 350ft/lb @ 7500 = 499hp


a 362 WHP skyline reading out 1259ft/lb is simply either an anomaly on the dyno, or it's dyno operator/configuration error. I lean towards the latter since it looks like the ratio is set wrong. I'd imagine that they're dynoing in as close a 1:1 gear as they have. in which case, if you divide the torque by 4, you come up with ~314 which with an RB @ 362hp would make a LOT of sense.
 

Polish

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Joined
Jan 10, 2005
Messages
8,936
Location
NE, IN
Quoting turbowop:
So then I'm not smoking crack and we have one member that is inflating his torque numbers through some calculation that nobody else uses?



No you're not. And I will rant a bit as well about it.

You know what makes 250hp and 600ft/lbs? A turbo diesel. Thats what, not a 4G63.

If a 4g63 makes 300whp, it makes somewhere between 250-400ft/lbs - depending on the setup. It could be a top end torqueless laggy sh*t box or a torque monster quick spooling murderball but falls off up top or it could be a normal car somewhere in between and make similar hp/torque numbers like most proper setup 4g cars should be. With the obvious exception of Rally cars which will always be the torque monsters with lesser top end and the drag cars that are torqueless laggy sh*t boxes (thus antilag/spray on drag cars) but have top end like mad.

No I am not saying your drag car is a torqueless laggy sh*t box, I am just speaking in general terms. (This is at everyone with a *drag car*, so no need to tell me it makes 400ft/lbs)...k

Anyway, sure you can use a wacky calculation to *prove* you make 600ft/lbs with a 250hp car but this isn't candy land. I could stick my crappy Honda on a dyno in 1st gear and probably register 400ft/lbs but the truth is it makes a whopping 105ft/lbs at the crank stock so breaking 3 digit torque numbers at the wheels in the real world will never happen, that is dynoing in a 1:1 gear or closest to it with the dyno calculations set properly.

There are standards when measuring horsepower/torque and this is what all manufacturers follow or should follow. This is also the same standards a dyno shop should follow, if it doesn't follow it then it will never be credible. I don't care if it's Wheel or Engine measured the only difference is that one number (the wheel reading) will always be a bit lower aside from that it's all the same. I don't know how it can't seem odd to someone that they make 2x as much torque as anyone else and think it's a correct reading. Something is missing or calculated wrong, that is all. Nothing more. Stick it on a properly setup dyno next time and get a real reading.
 

belize1334

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Joined
Nov 18, 2003
Messages
3,316
Location
Bozeman, MT
I've said it before and I'll say it again... torque_at_the_wheels has no meaning. It's totally dependent on gearing and in the end doesn't even affect anything since it has to be converted to thrust through the diameter of the wheel. And anyway, that's not how dynos measure stuff.

The dyno measures power output. It's simple and you don't have to know anything about the vehicle to measure it. Then you apply 5300/rpm to get torque. You call it wheel-torque when it's proportional to whp. You call it brake-torque when it's proportional to the corrected bhp. But in the end, knowing the torque tells you very little because you still need to know gearing and rpms in order to determine the thrust. On the otherhand, if you start with whp, you can get immediately to thrust simply by dividing by the speed... totally independent of the wheel diameter, the gearing, or whether it's green (cause they're faster).
 
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H05TYL

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Joined
Jun 9, 2007
Messages
752
Location
Wgtn, NZ
As you say wheel torque IS meaningless if it's based on applying 5252/rpm to wheel horsepower precisely because it is affected by gearing. However thrust IS important, because all else being equal a lower (higher numerically) geared car will accelerate faster.

It could equally be said that without knowing the weight and amount of grip a car has both thrust and horsepower are irrelevant because both those variables will affect how quickly a car accelerates.

At the end of the day a dyno gives you numbers that are only ever really relevant to other numbers from that same dyno run under the same conditions. Another dyno in my town is known to read 10% higher.

Some seriously bunched up panties over nothing in here...
 

Galantvr41062

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Joined
Aug 20, 2007
Messages
410
Location
plymouth, MN
click

For the cliff notes on that debate: It all comes down to doing a base line at a shop with a chassis dyno/ engine dyno, then going back to the same place and tuning the car to see your change. The start or end number is not important, you want to see the difference in the tune/parts on the car. If you see a change due to how the car was strapped down, or how the dyno was setup etc, well that can cost you a lot of cash to fix. Again we can not race dynos, so numbers are just that, numbers. What the car does at the track, auto cross, road race, etc or on a Friday night, that is what is important. Also watching your changes happen live is a huge plus to the Dyno Dynamics, as a former tunner I wish everyone knew how good the Dyno Dynamics is.

~John
 

Galantvr41062

Well-known member
Joined
Aug 20, 2007
Messages
410
Location
plymouth, MN
built 2.0, custom CP pistons, custom carrillo rods, the water jacket in the block is filled with hard block well most of it anyways, custom built everything, E98, aeromotive eliminator fuel pump base fuel pressure at 38psi, FIC blue max high z 2150 injectors, aem ems vs 2, MSD DIS2, MSD twin post GM coils, etc etc.

All the dyno tuning and runs were made at DB Performance on a Dyno Dynamics chassis dyno with the ramp rate at 100.

click 43psi, hit an ignition cutout at 9220rpm and caused the head to lift a little on this run.

click

click Here is were I want to start at going to the track this year, we are up 70hp from last year at only 1 more psi of boost.

click

If I want to make more then 800+ awhp I need to find a better ignition set up and I might have to o ring the block or the head.

I have video of the runs, I will get them posted to Youtube asap.

Also the 816 run in shootout mode on the Dyno Dynamics shows 976awhp, this is supposed to put the numbers close to a 2wd Dynoguess.

~John
 
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Nice work John. You don't need to O-ring the block & the head to get you where you want to be. As long as your tune is spot on & your not running some crazy timing, you'll be fine. Keep up the good work.
 

RedTwo

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Joined
Jul 16, 2008
Messages
1,917
Location
New Zealand
More work for me!

This would be so much cooler with a sticky... /ubbthreads/images/graemlins/laugh.gif
 
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