: Abnormally large baseline HP spread between Golder and Wait4me?



Dave-V
01-03-09, 03:54 PM
Wait4me baselined around 430 and Golder baselined around 470, both on a Dynojet. I just found it peculiar and thought I would bring it up. I think after his tune wait4me is around 480. Did anyone else notice this? Does it matter? Does anyone else have a baseline dyno run?

GM-4-LIFE
01-03-09, 04:11 PM
Wait4me baselined around 430 and Golder baselined around 470, both on a Dynojet. I just found it peculiar and thought I would bring it up. I think after his tune wait4me is around 480. Did anyone else notice this? Does it matter? Does anyone else have a baseline dyno run?

I would say that the 470 baseline number is accurate. 470 RWHP with a 20% drivetrain loss for an automatic brings the total flywheel HP rating at closer to factory. Actually, 470 RWHP would yield in the 560 HP range at the crank so GM may have underated the LSA from the factory.

430 is way too low. 430 RWHP would yield roughly around 500 HP at the crank, so that engine is losing around 50 HP at the crank. Something is either wrong with the dyno or the car. At 430 RWHP, I would find another local dynojet dyno to baseline at. I am going to baseline dyno mine and see where it is on my local dynojet.

I will get mine custom dyno tuned when HP Tuner software is available and I will post before and after dyno numbers. I just hope mine baselines in the 470 range so I get a good starting point.

SG

jvp
01-03-09, 04:37 PM
470 RWHP with a 20% drivetrain loss for an automatic brings the total flywheel HP rating at closer to factory.

430 RWHP would yield roughly around 500 HP at the crank, so that engine is losing around 50 HP at the crank.

I've no dog in this fight as I don't know either tuner (nor care, really). But, you need to check your math. If you're going to stick with a 20% loss (which is HUGE and unbelievable), then your rear wheel and crank HP numbers will look like so:

470RWHP -- 588HP
430RWHP -- 538HP

jas

CadV
01-03-09, 04:45 PM
With jvp numbers 450ish seems like a more accurate baseline.

CIWS
01-03-09, 04:55 PM
I've no dog in this fight as I don't know either tuner (nor care, really). But, you need to check your math. If you're going to stick with a 20% loss (which is HUGE and unbelievable), then your rear wheel and crank HP numbers will look like so:

470RWHP -- 588HP
430RWHP -- 538HP

jas


My STS-V has been dyno'd several times and sees approx 21%, so believe it :D (autos should see a bit more than the sticks)

jvp
01-03-09, 05:04 PM
With jvp numbers 450ish seems like a more accurate baseline.

Very close. A 20% drivetrain loss (which I still DO NOT believe) from 556HP would yield 445RWHP.

The math is pretty easy. If you have a drivetrain loss percentage (XX%) and a flywheel HP number (HP), then it goes something like this:

RWHP = HP - (HP x .XX)

RWHP = 556 - (556 x .20)
RWHP = 556 - 111
RWHP = 445

Conversely, if you have a drivetrain loss and a real wheel HP (RWHP) number, you can easily calculate the flywheel number. It's here that most people make the cardinal mistake of just adding the percentage to the rear wheel number.

That's flat wrong.

The formula still stands, you just use a little algebra to reverse it:

RWHP = HP - (HP x .XX)
RWHP = HP - .XXHP
RWHP = (1 - .XX)HP

HP = RWHP / (1 - .XX)

So if we have a 20% loss and we're starting from 470RWHP:

HP = 470 / (1 - .20)
HP = 470 / .80
HP = 588

jas

jvp
01-03-09, 05:05 PM
My STS-V has been dyno'd several times and sees approx 21%, so believe it

I wouldn't. Not unless you've chassis dyno'd your car, then on the same day popped the engine out and engine dyno'd it right then and there. And I seriously doubt you've done that given the immense costs and time involved. :-)

jas

CIWS
01-03-09, 05:40 PM
I wouldn't. Not unless you've chassis dyno'd your car, then on the same day popped the engine out and engine dyno'd it right then and there. And I seriously doubt you've done that given the immense costs and time involved. :-)

jas


You're a funny guy :bouncy:


I have run different cars on the very same dyno and seen their losses (as measured) vary as well, all staying within the bounds of believability for the particular car. It measured my CTS-V at 17%. Now of course in all cases that's using the advertised HP rating at the crank, which we know will vary somewhat from engine to engine as built. But then so will their loss measurements from dyno to dyno even if every engine was built to exactly the same output. So being real world here and not working off an engineering room floor , when we're all posting various output numbers and measured losses it is based around accepted HP at the crank and not the engine on a test bed and the result taken from the very same dyno. Under your criteria all data posted here is worthless and unbelievable.

Dave Golder
01-03-09, 06:59 PM
Another stock one today dynoed at 465RWHP. But if you dyno at 430RWHP that 45HP you get from an airfilter or a tune is nice:)

jvp
01-03-09, 07:13 PM
You're a funny guy

Perhaps, but argue the point if you can...


Under your criteria all data posted here is worthless and unbelievable.

Not worthless at all, just useful only as a means of comparison. Using a rear wheel dyno to try and figure out what your flywheel numbers are is pointless. There's no hard and fast rule for drive train losses. Various tuners and folks that claim to be "in the know" will throw out all sorts of different percentage numbers.

The only way to be 100% certain is to measure them on the same day. Chassis dyno, then engine dyno. And the costs involved for that are ridiculous (just ask tuners like LPE that actually own an engine dyno how much it costs to run it...)

Use measured RWHP numbers as points of comparison. They're excellent tools for before-and-after measurements when you get an engine modification added. Test the car before the mod, mod the car, then test it afterward (in as close to identical conditions as possible). Or, you can use them to compare various cars on the same day at the same time (which is little more than measuring dicks).

Any use otherwise is just a waste, really. An example: Most Corvette Z06s with LS7s will chassis-dyno on the Dynojets at or near 450RWHP. The engines are SAE rated at 505HP. SAE ratings allow for very minor variances in HP. But, imagine that: 450 at the wheels, and 505 at the crank. That means the Corvette's drive train loss is a measly 11%. As Bill Cosby once said, "Riiiiiiiiiiight!"

jas

CIWS
01-03-09, 07:38 PM
Use measured RWHP numbers as points of comparison. They're excellent tools for before-and-after measurements when you get an engine modification added. Test the car before the mod, mod the car, then test it afterward (in as close to identical conditions as possible). Or, you can use them to compare various cars on the same day at the same time.

So any of the numbers posted really only come down to this one point. Anything else is really just extra data bits on the internet (or in the internet).:vulcan:

GM-4-LIFE
01-03-09, 08:53 PM
jvp,

According to the math I did, 430 baseline with a 20% drivetrain loss equals: 516 crank horsepower and 470 baseline with a 20% drivetrain loss equals: 564 crank horsepower.

Where did you get your numbers? I used a calculator with a simple percentage equation. I didn't use NASA calculations like it seems you used.

Furthermore, GM automatics have AT LEAST a 20% drivetrain loss, so believe it! I have had at least 25 new GM vehicles since 2000 (mainly autos) and I have had at least half of them dyno tuned and every single one that I did a baseline dyno test yielded AT LEAST a 20% drivetrain loss. GM manuals have a 15%-18% drivetrain loss between the crank and rear wheels. Again, believe it!

SG

jvp
01-03-09, 09:51 PM
According to the math I did, 430 baseline with a 20% drivetrain loss equals: 516 crank horsepower and 470 baseline with a 20% drivetrain loss equals: 564 crank horsepower.

Where did you get your numbers? I used a calculator with a simple percentage equation. I didn't use NASA calculations like it seems you used.

You've made the same mistake that many other folks have made: You added the (supposed) drive train loss to the rear wheel horsepower number. That is INCORRECT math. Plain and simple. Please go through my longer post in this thread. It explains the mathematics rather clearly. If it doesn't then ask specific questions on it and I'll try to explain.


Furthermore, GM automatics have AT LEAST a 20% drivetrain loss, so believe it! I have had at least 25 new GM vehicles since 2000 (mainly autos)

Believe what you like, it doesn't make you an expert on the subject. That you've dyno-tuned a bunch of vehicles means absolutely nothing. Unless that dyno tuning includes running both a chassis dyno and an engine dyno.

jas

darjae
01-03-09, 11:57 PM
You added the (supposed) drive train loss to the rear wheel horsepower number.

I agree with this. you have to subtract the drive train loss from the spec'ed flywheel horsepower number to get in the ballpark. Assuming that 20% is at all accurate (and please remember that 20% is an arbitrary number) and 556 flywheel horsepower. 20% of this is 111.2 HP, giving us a net at the wheels (556 - 111.2) of 444.8.

Heavychevy1
01-04-09, 12:13 AM
I agree that unless you do an engine dyno you cannot determine drivetrain loss. We have one person claiming 21% for the manual and another 17%. And all are using external factors to come to said conclusion without proper testing to determine the numbers.

And dyno numbers are no better in trying to determine actual hp output unless measure across a broad spectrum of vehicles and their averages.

A better guage is trap speeds.

lawfive
01-04-09, 03:08 AM
Dang, from bench racing cars to bench racing benches...

CIWS
01-04-09, 08:57 AM
Dang, from bench racing cars to bench racing benches...

:rofl:

CIWS
01-04-09, 09:12 AM
I agree that unless you do an engine dyno you cannot determine drivetrain loss. We have one person claiming 21% for the manual and another 17%. And all are using external factors to come to said conclusion without proper testing to determine the numbers.

And dyno numbers are no better in trying to determine actual hp output unless measure across a broad spectrum of vehicles and their averages.

A better guage is trap speeds.


Yes yes, we all know what it would take to know the actual numbers for any car, this "proper testing" But can we please stay down here in the trenches and not in the labs please guys ? 99% of the people out here with cars do not possess the cash or access to facilities to do this so to continually bring it up is a moot point at this level of ownership. So there are certain factors we have to accept or take for granted when trying to discuss this at this level. One of them being the horsepower rating the manufacturer quotes us at the flywheel, although we know in real life it will vary. You're going to look like a nutjob to any salesman/dealership, even the owner of a performance shop, if you tell them to pull the engine from the car and run it on a stand before you buy it and prove to you what the actual flywheel horsepower is. Fracking get real here.


Trap Speeds ? You can keep the horsepower of a car at a constant and trap at a different speed, why is that ? Because there are other factors that come into play besides horsepower that determine the speed at which a car crosses the line at any given run. It is simply one tool in the box, just like a dyno. Neither of which is the only tool one should use.

CVP33
01-04-09, 09:18 AM
There's a really good article in the June 2008 issue of Motor Trend Magazine. The writer was trying to figure out how the Nissan GTR was hitting its performance numbers with relatively low (480HP/430TQ) numbers. After a few dyno pulls using an AWD dyno, rolling two 4,800 lb. drums and allowing for a 15% drivetrain loss they estimated that the actual crank numbers to be 507HP/500TQ. They also corrected using the SAE standards allowing for the .27 Cd, frontal area estimate of 22.5 sqft. and tire friction of .02. Lot's of math, but probably the only true way to know as already stated is to pull the motor.

***You may now resume your regularly scheduled argument already in progress.

atdeneve
01-04-09, 09:30 AM
And the 15% for the AWD is muy conservative. So it's probably puttin' even more out at the crank than that.

The drag coefficient on that monster is also much lower than you'd guess at first glance. That car is just an anomaly.

Heavychevy1
01-04-09, 12:30 PM
Yes yes, we all know what it would take to know the actual numbers for any car, this "proper testing" But can we please stay down here in the trenches and not in the labs please guys ? 99% of the people out here with cars do not possess the cash or access to facilities to do this so to continually bring it up is a moot point at this level of ownership. So there are certain factors we have to accept or take for granted when trying to discuss this at this level. One of them being the horsepower rating the manufacturer quotes us at the flywheel, although we know in real life it will vary. You're going to look like a nutjob to any salesman/dealership, even the owner of a performance shop, if you tell them to pull the engine from the car and run it on a stand before you buy it and prove to you what the actual flywheel horsepower is. Fracking get real here.


Trap Speeds ? You can keep the horsepower of a car at a constant and trap at a different speed, why is that ? Because there are other factors that come into play besides horsepower that determine the speed at which a car crosses the line at any given run. It is simply one tool in the box, just like a dyno. Neither of which is the only tool one should use.

You missed the point, which is that we cant have guys using reverse numbers to come up with drivetrain loss numbers. And when I say reverse, they use their dyno's difference from the manufacturers claimed numbers to determine drivetrain loss numbers. That is absolutely rediculous because that means the drivetrain loss will be contingent on the dyno type, and in this case would be completely different on two of the same type of dyno.

Drivetrain loss cannot be determined that way, PERIOD.

Nor can they be determined by one dyno, unless it's for sure the same type of dyno the manufacturer uses and has been used for SAE certification.

Converting to crank hp is a joke nowadays with all the different corrections and dyno types, which is why it's better just to stick with the dyno as a baseline and use either comparative dynos or trap speeds to determine the cars hp.

Comparative dyno:

Let's say we have a dyno that the average of multiple Z06 dyno's 430-440 rwhp on a specific dynojet dyno location, then we know that the V should dyno 460-470 on that same dyno.

Comparative Trap Speed:

We know the average of many Z06 traps 125-127 at E-town or Atco, then we know that the average V should trap 118-120 at that same track.


People thinking everything is underrated these days has more to do with manufacturers using better than dyno-jet dynos to get their numbers which is why mustang dynos are considered better and more realistic.

GMX322V S/C
01-04-09, 01:11 PM
There's a really good article in the June 2008 issue of Motor Trend Magazine. The writer was trying to figure out how the Nissan GTR was hitting its performance numbers with relatively low (480HP/430TQ) numbers. After a few dyno pulls using an AWD dyno, rolling two 4,800 lb. drums and allowing for a 15% drivetrain loss they estimated that the actual crank numbers to be 507HP/500TQ. They also corrected using the SAE standards allowing for the .27 Cd, frontal area estimate of 22.5 sqft. and tire friction of .02. Lot's of math, but probably the only true way to know as already stated is to pull the motor.

***You may now resume your regularly scheduled argument already in progress.They amended their investigation in December; Hyper Power International has a dyno that can calculate parasitic loss by measuring how fast the rollers slow down when the tranny is placed in neutral; they went on to explain why using a flat percentage loss--of any arbitrary amount--is invalid; for one thing, the losses build exponentially with RPM; for another, increasing engine power output without making any changes to the drivetrain shouldn't increase the loss at any given RPM--it should remain the same.

http://www.motortrend.com/features/performance/112_0812_2009_nissan_gt_r_dyno_test/results_analysis.html

FreddyG
01-04-09, 01:17 PM
You Guys get caught up too much in dyno numbers! A dyno is a tool for tuning (and bragging rights for dyno queens) and nothing more! The only way to see which number is right is to put both cars on the same dyno and not change any calibration/input numbers. Just run them!

Dyno calibration could be different on the two dynos. Weather could make a difference (D/A aka air density). If it's colder out, the air has more oxygen molecules, thus making more power, and keeping the blower from heat soaking and the pcm from pulling timing because of high iat's, etc. There are lots of dyno tricks that can be done to fudge the numbers too. Please don't think that I'm saying that either tuner did those, just saying that they could be manipulated either way. I might not be telling you Guys something that you dont' already know, just stating my point of view.

If you want real world testing, put some drag radials on one of those Beasts and take it to the drag strip! Trap numbers will give you an idea as to the power output!

Oh, also, put that car on a Dyno Dynamics dyno and you'll take that tire slip number out the formula. They take the wheels/tires off and bolt the dyno to the hub! It makes lower numbers most of the time, but gives you a more realistic, truer reading.

CVP33
01-04-09, 02:22 PM
They amended their investigation in December; Hyper Power International has a dyno that can calculate parasitic loss by measuring how fast the rollers slow down when the tranny is placed in neutral; they went on to explain why using a flat percentage loss--of any arbitrary amount--is invalid; for one thing, the losses build exponentially with RPM; for another, increasing engine power output without making any changes to the drivetrain shouldn't increase the loss at any given RPM--it should remain the same.

http://www.motortrend.com/features/performance/112_0812_2009_nissan_gt_r_dyno_test/results_analysis.html

It make sense that parasitic loss increases exponentially with rpm/speed. That explains a car's top speed being drag limited. Without drag, which increases with speed, cars would be able to achieve higher speeds. Without friction, even higher. I'm waiting for a MagLev car. No friction, just drag.

trukk
01-04-09, 02:28 PM
You Guys get caught up too much in dyno numbers! A dyno is a tool for tuning (and bragging rights for dyno queens) and nothing more! The only way to see which number is right is to put both cars on the same dyno and not change any calibration/input numbers. Just run them!

Dyno calibration could be different on the two dynos. Weather could make a difference (D/A aka air density). If it's colder out, the air has more oxygen molecules, thus making more power, and keeping the blower from heat soaking and the pcm from pulling timing because of high iat's, etc. There are lots of dyno tricks that can be done to fudge the numbers too. Please don't think that I'm saying that either tuner did those, just saying that they could be manipulated either way. I might not be telling you Guys something that you dont' already know, just stating my point of view.

If you want real world testing, put some drag radials on one of those Beasts and take it to the drag strip! Trap numbers will give you an idea as to the power output!

Oh, also, put that car on a Dyno Dynamics dyno and you'll take that tire slip number out the formula. They take the wheels/tires off and bolt the dyno to the hub! It makes lower numbers most of the time, but gives you a more realistic, truer reading.


I agree with most of this. Best thing to use a dyno for is to trck the progress of your mods.

I also agree with the trap time to show how much the car is making. That can also be adjusted based on the temp, dynamic altitude, etc, to get a more 'true' and realistic idea of what the power car actually makes.

I don't like the dyno dynamics dyno's. While tire slip can be an issue, last time I checked most pople run 4 wheels on the street. Finally, the reduction in rotational mass makes a big difference. Removing the two rear tires can free up at least 60 lbs or rotational mass from the car.

I think we agree in general that dyno's are just a tool to track mod progression.

-Chris

Razorecko
01-04-09, 02:36 PM
Did you guys forget that the cts-v / ZR1 motor is hand built ? - There is usually a much larger discrepency in power by hand built engines. Like the blow E55 amg motors. Hand built blown v8's they've had a large discrepency in 1/4 times and dyno'd power. Its just the luck of the draw.

CIWS
01-04-09, 03:58 PM
Drivetrain loss cannot be determined that way, PERIOD.

Nor can they be determined by one dyno, unless it's for sure the same type of dyno the manufacturer uses and has been used for SAE certification.

No two automobiles are the same. No two engines, transmissions, rearends, etc.

The only way to be really truthful is to test each individual car, each engine, each chassis and drivetrain on the same piece of equipment. But that's just not going to happen, PERIOD.

So what's left at the street level is the information we're given and the information we can realistically acquire. A lot of that info is rough numbers, but that's what there is to work with. Even if a single owner spent the cash to have their car completely tested those numbers will still only reflect that individual machine and their relevance to other vehicles would be general. So we can sit here all day long and spout what it takes to do things scientifically, but it's not realistic.

trukk
01-04-09, 03:59 PM
Did you guys forget that the cts-v / ZR1 motor is hand built ? - There is usually a much larger discrepency in power by hand built engines. Like the blow E55 amg motors. Hand built blown v8's they've had a large discrepency in 1/4 times and dyno'd power. Its just the luck of the draw.

ZR1's (LS9) are hand built at Wixom.

CTS-V's (LSA) are rolled off the factory line in Mexico.

-Chris

CIWS
01-04-09, 03:59 PM
Did you guys forget that the cts-v / ZR1 motor is hand built ? - There is usually a much larger discrepency in power by hand built engines. Like the blow E55 amg motors. Hand built blown v8's they've had a large discrepency in 1/4 times and dyno'd power. Its just the luck of the draw.

No sir, it is the same with the motors in the STS-V and XLR-V, and you are correct because they are hand built their output as built is going to certainly vary. Their degree of what is "hand built" will vary by engine type.

CIWS
01-04-09, 04:01 PM
I agree with most of this. Best thing to use a dyno for is to trck the progress of your mods.

I think we agree in general that dyno's are just a tool to track mod progression.

:yeah:

Heavychevy1
01-04-09, 07:55 PM
No two automobiles are the same. No two engines, transmissions, rearends, etc.

The only way to be really truthful is to test each individual car, each engine, each chassis and drivetrain on the same piece of equipment. But that's just not going to happen, PERIOD.

So what's left at the street level is the information we're given and the information we can realistically acquire. A lot of that info is rough numbers, but that's what there is to work with. Even if a single owner spent the cash to have their car completely tested those numbers will still only reflect that individual machine and their relevance to other vehicles would be general. So we can sit here all day long and spout what it takes to do things scientifically, but it's not realistic.


LOL, you have to be kidding if you think one manual V2 loses 17% through the drivetrain and another 21 %. That is laughable. I'd bet there isnt 1% variance across the model line from any one V2 to another (assuming same tranny).

If you test on a dyno dynamics your car will be losing 30% through the drivetrain. How realistic is that????

No one is saying to open a lab for verification, I'm only saying what everyone else is and that is to use dyno's for baseline's only to determine differences when mods are added. Or if you have several examples of a car on one dyno to determine if one is running extraordinarily low on power.

You seem to only disagree with what I'm saying though, go figure.

FreddyG
01-04-09, 08:03 PM
I agree with most of this. Best thing to use a dyno for is to trck the progress of your mods.

I also agree with the trap time to show how much the car is making. That can also be adjusted based on the temp, dynamic altitude, etc, to get a more 'true' and realistic idea of what the power car actually makes.

I don't like the dyno dynamics dyno's. While tire slip can be an issue, last time I checked most pople run 4 wheels on the street. Finally, the reduction in rotational mass makes a big difference. Removing the two rear tires can free up at least 60 lbs or rotational mass from the car.

I think we agree in general that dyno's are just a tool to track mod progression.

-Chris

Hi Chris!

I think that the wheel weight does play a little part in the equation, but to take away frictional forces or tire slippage is more important than the weight of the wheels (at least I think so, but that doesn't mean that I'm right).

I actually like Mustang dynos the best because you can load them up to simulate driving on the road, plus the quarter mile simulation is pretty cool too! :yup: The ones that I've used seem to give more "Real World" results too! Once again, just my take on it!

Now, as far as handling, the unsprung weight of the rims/tires Definitely makes a difference. Taking weight off for that reason plays a HUGE part!

CIWS
01-04-09, 08:07 PM
LOL, you have to be kidding if you think one manual V2 loses 17% through the drivetrain and another 21 %. That is laughable. I'd bet there isnt 1% variance across the model line from any one V2 to another (assuming same tranny).


I never said this dude. Go back and reread the posts. Go figure . . .

trukk
01-05-09, 10:33 AM
Hi Chris!

I think that the wheel weight does play a little part in the equation, but to take away frictional forces or tire slippage is more important than the weight of the wheels (at least I think so, but that doesn't mean that I'm right).

I actually like Mustang dynos the best because you can load them up to simulate driving on the road, plus the quarter mile simulation is pretty cool too! :yup: The ones that I've used seem to give more "Real World" results too! Once again, just my take on it!

Now, as far as handling, the unsprung weight of the rims/tires Definitely makes a difference. Taking weight off for that reason plays a HUGE part!

In my personal experience Dynojets seem to be a bit more consistant across the board, albeit reading higher. Mustangs seem to vary greatly, and seem to depend on how well and often they've been calibrated. I've taken my car to 3 local Mystangs (one 1750, and two 1100's), and they are definately NOT consistant between the 3.

Don't get me started about superflow's and thier 'Dynojet' corrected numbers. I wend to a mustang 1750, and got a mostly stock reading of 291 (obviously very low), and then went to a superflow, and in DynoJet corrected output, it read 391. :hurl:

-Chris

FreddyG
01-05-09, 01:12 PM
In my personal experience Dynojets seem to be a bit more consistant across the board, albeit reading higher. Mustangs seem to vary greatly, and seem to depend on how well and often they've been calibrated. I've taken my car to 3 local Mystangs (one 1750, and two 1100's), and they are definately NOT consistant between the 3.

Don't get me started about superflow's and thier 'Dynojet' corrected numbers. I wend to a mustang 1750, and got a mostly stock reading of 291 (obviously very low), and then went to a superflow, and in DynoJet corrected output, it read 391. :hurl:

-Chris

That's kind of like the person who's on a diet and stepping on five different scales and each one giving a different reading. I've only been on Mustangs, because of it being able to load up the motor for tuning (F/I motor), and the only numbers that I cared about were the numbers starting and the finishing numbers (to see if I made a gain or not on the same day).

I guess the thing is, that if you ask ten people which they like better, you'll get ten different answers. I can respect that! We'll just have to agree to disagree! :cheers:

trukk
01-05-09, 01:37 PM
That's kind of like the person who's on a diet and stepping on five different scales and each one giving a different reading. I've only been on Mustangs, because of it being able to load up the motor for tuning (F/I motor), and the only numbers that I cared about were the numbers starting and the finishing numbers (to see if I made a gain or not on the same day).

I guess the thing is, that if you ask ten people which they like better, you'll get ten different answers. I can respect that! We'll just have to agree to disagree! :cheers:


I don't think we are disagreeing actually. I prefer the Mustang as well as a tuning tool. If you are internet bench racing however, Dynojet's seem to be more consistent (albeit high), from dyno to dyno.

-Chris

thebigjimsho
01-05-09, 11:51 PM
This thread is teh ghey...

trukk
01-06-09, 10:22 AM
This thread is teh ghey...


It wasn't untill you showed up and said gay.

:thepan:

-Chris

Hogg
01-06-09, 01:29 PM
It was mentioned earlier that someone thought that the LSA is underrated by GM.
With the new SAE Certified Power/Torque this doesnt happen anymore. The LS7 was teh 1st GM engine to use the new SAE spec of power measurement.

There is no more under/over rating of powerplants. Each model and even engine option is rated independantly.

A vivid example of this is the 4.4L Supercharged Northstar(LC3) that is used in the STSV and the XLRV.
STSV 469 hp @ 6400 rpm 439 lb-ft @ 3900 rpm
XLRV 443 hp @ 6400 rpm 414 lb-ft @ 3900 rpm

Same engine, but intake and exhaust differences due to differences in packaging, force the differnces in ratings between the 2 cars.

there is no more rounding up or down to the nearest 5 or 10 hp.

Some of the Asian cars were hit HARD with the new SAE ratings, the Domestics werent affected as much.

peace
Hog

FreddyG
01-06-09, 02:28 PM
I don't think we are disagreeing actually. I prefer the Mustang as well as a tuning tool. If you are internet bench racing however, Dynojet's seem to be more consistent (albeit high), from dyno to dyno.

-Chris

I do agree that for bench racing puroses, you can't beat a dynojet! :cheers:

gotapex
01-06-09, 02:51 PM
In my personal experience Dynojets seem to be a bit more consistant across the board, albeit reading higher. Mustangs seem to vary greatly, and seem to depend on how well and often they've been calibrated. I've taken my car to 3 local Mystangs (one 1750, and two 1100's), and they are definately NOT consistant between the 3.

Don't get me started about superflow's and thier 'Dynojet' corrected numbers. I wend to a mustang 1750, and got a mostly stock reading of 291 (obviously very low), and then went to a superflow, and in DynoJet corrected output, it read 391. :hurl:

-Chris

Yeah, there's definitely a huge difference between dynos.

Direct comparison of a few:

http://www.turbomagazine.com/tech/0306tur_turbo_magazine_dyno_dash/index.html

GNSCOTT
01-06-09, 04:11 PM
The only thing a dyno should be used for is tuning the same car on the same day.Comparing 2 different cars on 2 different dynos is a waste. There are too many variables. Altitude, engine temps, air temps, and humidity to name just a few. Oh and I did not even mention the variables on the dyno itself (even made by the same co.) one could be using correction software and one not, could be 2 different programs in the different dynos ( one dyno may be a different model from a different year) etc

thedead
01-06-09, 07:24 PM
I dont understand how you can get HP from the qtr mile time... wouldnt the gear ratios mess everything up?

jvp
01-06-09, 08:00 PM
I dont understand how you can get HP from the qtr mile time... wouldnt the gear ratios mess everything up?

You get it from trap speed, not ET.

http://www.ajdesigner.com/fl_horsepower_trap_speed/horsepower_trap_speed.php

jas

thebigjimsho
01-06-09, 09:50 PM
It wasn't untill you showed up and said gay.

:thepan:

-Chris
U sed it, not me...

thedead
01-07-09, 07:05 PM
You get it from trap speed, not ET.

URL

jas

But what if you miss a gear? Your trap speed would be lower? or if you start in 3rd instead of 1st...

I know I am wrong, but I dont understand yet how the gear ratio of the car doesnt affect this formula.

FreddyG
01-08-09, 11:44 AM
But what if you miss a gear? Your trap speed would be lower? or if you start in 3rd instead of 1st...

I know I am wrong, but I dont understand yet how the gear ratio of the car doesnt affect this formula.

From your scenario, I'd say that you should've bought the automatic!:histeric:

That's what's nice about the trap speed formula, is that it doesn't care what gear ratio is in the car, whereas the dyno numbers will be lower with more gear in the car, or a stall speed, tire pressures can change a dyno reading, even where you place the car on the rollers. There are so many more variables that can effect a dyno, but trap speeds are trap speeds, as long as you have a good run!

CIWS
01-08-09, 11:49 AM
as long as you have a good run!

..and that's part of it. There are variables that also come in on a track and can affect trap speed. It's no more the end all of HP numbers than a dyno alone is.

CTSV_510
01-08-09, 10:42 PM
jvp,

According to the math I did, 430 baseline with a 20% drivetrain loss equals: 516 crank horsepower and 470 baseline with a 20% drivetrain loss equals: 564 crank horsepower.

Where did you get your numbers? I used a calculator with a simple percentage equation. I didn't use NASA calculations like it seems you used.



:histeric: :histeric::histeric: :histeric::histeric: :histeric::histeric: :histeric:

forumsid987
01-09-09, 11:41 PM
I've no dog in this fight as I don't know either tuner (nor care, really). But, you need to check your math. If you're going to stick with a 20% loss (which is HUGE and unbelievable), then your rear wheel and crank HP numbers will look like so:

470RWHP -- 588HP
430RWHP -- 538HP

jas

haha thanks for correcting him, i love it when people use math but have no clue what they're doing. so sad that at this stage in his life he doesn't understand the concept of percentages.

and to you douche, you dont need a nasa calculator...you use a regular calculator + a brain. WHAT A CONCEPT.

if you are LOSING 20% of 588 , then you have 80% of 588 left, .8 x 588 = 470.4.

You SEE?

If you lose 50% of 100 dollars, you are left with 50 dollars.

If you gain 50% of 50 dollars, you only have 75 dollars.

Man, elementary school sure scammed you.

(P.S. Because I'm sure you wont figure this out on your own, if you want to work ass backwards from RWHP to HP, take your dyno # and DIVIDE by 1-% loss you believe. For example, 20% loss at 430 RWHP means you take 430 DIVIDED BY .8)