Re: Power mods for the I-5
 

HP is not the limiting factor, unless you are talking about heat rejection due to internal friction, or a design limit for maximum internal rotating speed.

Most engines do not produce their peak torque at maximum RPM as you are implying here.

Check the manufacturers specifications for drivetrain components. They do not list horsepower. They do list torque.

Michael

Re: Power mods for the I-5
 

Over 20%???!!! Not any SAE certified test, with all emission equipment functioning and within spec. Maybe on some bogus inertial dyno.

Michael

Re: Power mods for the I-5
 

Come on...... do you even know what HP is? HP IS a measure of torque. :rolleyes:

Re: Power mods for the I-5
 

Mikey, I think you are quickly losing some of the information you learned during the school year in your high school shop class.

Re: Power mods for the I-5
 

No, it is not. It is a measure of power.

I bet you are one of these uninformed people who thinks the faster car always has an engine which produces more torque.

Michael

Re: Power mods for the I-5
 

brain trust going at it! I like it!

Re: Power mods for the I-5
 

Mostly useless info, still no proof of significant power increase to the I5 without s/c or turbos.

S.

Re: Power mods for the I-5
 

stupid speaks

Re: Power mods for the I-5
 

Where did you hear that? From a horse? :rolleyes:

Ok, sport. Here's a little lesson for ya'

Torque is tangential force TIMES the distance from the fulcrum or a measure of force at a single moment in time. HorsePower can be defined as work (force over distance) per unit time.

Applying 1 lb of force 1 ft from the fulcrum for a complete revolution will lead to;
W = F*2*Pi*r = 1 lb * 2*Pi * 1 ft = 2*Pi lb-ft = 6.283 lb-ft

If it takes one minute to complete this revolution, then the power is;
P = W / time = 6.283 lb-ft/min
1 HP is defined as 550 lb-ft/s or 33,000 lb-ft/min

Therefore, applying 1 lb-ft of torque in one minute (1 rpm) = [6.283 lb-ft/min] / [33,000 lb-ft/min] = 1/5252 of 1 hp.
From this you can then calculate the number of hp from any given torque and rpm:
HP = Torque * RPM/5252 or
HP = Torque measured over time and distance.

Therefore, HP is a measurement of Torque over a given time and given distance.

Re: Power mods for the I-5
 

First off, I don't need your lesson.

Second, that's not what you said. You said it was a "measure of torque", not a "measure of torque over time". You've just proven my point that horsepower is a measure of power, not a torque measurement. If horsepower was purely a measure of torque, then how is it that 1 horsepower = 745 watts? Just because torque is one variable in the equation of horsepower, doesn't mean it's a measure of torque. That's like saying wattage is a measure of volts.

Michael

Re: Power mods for the I-5
 

Ok,

do you attempt to think with that thing you call a brain or does it just occupy space. Go the fck back up and look at my posts. My first post in this thread where you have spat your ignorance contained this little gem "Since HP is the measure of torque over time, HP is just as limiting a factor as torque. You can't have HP without torque."

To which you disagreed.

Care to try some more?

Re: Power mods for the I-5
 

Hope that is not from the southwest and some "GM engineer." Just a note, I can take any dyno graph and change it the way I like it. Not saying this is what happened, but, if GM could raise the HP (safely) with a tune, and a new cat back system and airbox, they would have already done it. I say safely, but I also mean legally.

Re: Power mods for the I-5
 

I see about 3.5 block increase for which each block is 5 hp about a 17 - 18 HP gain at the wheels. This is the power measured at the wheels. The drivetrain has an efficiency. The power loss is mostly converted to heat and absorbed in inertial loads. The drivetrain loss is dependent on the drivetrain loading. On a dynojet, the stock peak power might be 165 hp at the wheels.

Re: Power mods for the I-5
 

I don't think it was raised by that much.

There is no 100HP difference between BHP and rear wheel HP, which is what is being shown. Stock listed BHP for the H3 is what? somewhere around 220BHP and the stock rear wheel HP listed on the graph is about 138 HP. The coefficient for friction doesn't increase as the HP increases so one could naturally assume a 80HP difference. 153 + 80 = 233 or a net gain of about 13 BHP or somewhere around a 6% gain.

Re: Power mods for the I-5
 

I'll give you a 20 BHP gain and it's still less than 10%. Driveline has nothing to do with this since you are looking at the actual before/after.

Again, whatever driveline loss occurs at the stock level will occur at the higher level, you don't arbitrarily just throw in some additional ponies.:rolleyes:

Re: Power mods for the I-5
 

dummy, the new SAE tests have shown to INCREASE stated BHP on many domestic engines.

Re: Power mods for the I-5
 

This is not my dyno graph. This is from another post from another H3 forum. I was just providing it as an example. You can look in Colordao/Canyon forums for other dynos. Here is a dyno on a dynojet by K&N for an H3. In stock form the drivetrain efficiency (on this inertial dyno) was 75% or 25% loss (0.25 * 220 HP = 55 hp loss)

http://www.kandn.com/dynocharts/77-3044.pdf

I'm not surprised by the 65% drivetrain efficiency with dyno that properly loads down a 4WD vehicle like a Mustang dyno. Here is another dyno from K&N for a colorado same 3.5 L engine but 2WD and the stock HP is 180 hp (compare to 165 hp for the H3).

http://www.kandn.com/dynocharts/63-1095.pdf

The difference peak HP is due to the drivetrain efficiency ~82% for the 2WD colorado and 75% for the H3 on an inertial dyno.

GM has to tune for the masses. Because of production tolerances, different environments, different local fuel, etc. GM can't tune to the performance edge. GM uses a consevative ~11.9:1 A/F at WOT when most tuners bump that to 12.8:1 or so for more power.

GM has noise goals to meet. In the past, GM would ship a Z28 to SLP to have and intake, exhaust, etc. put on and SLP would not have to meet the noise requirements that GM had to meet. A new H3 airbox that eliminates the resonator will have more noise as well as a free flowing exhaust. For the new Z06, GM designed a cutout, so when you went to WOT (which does not have noise requirements) the cutouts opened for more power and substanially more noise.

Re: Power mods for the I-5
 

The drivetrain has an efficiency (percentage loss) not a fixed HP loss.

Re: Power mods for the I-5
 

It depends on the manufacturer. Some rating stayed the same, some went up (some GM) , and some went down (some Toyotas). In fact, GM underrates their engines so that their expected worst engine meets the advertised ratings.

Re: Power mods for the I-5
 

My reply was toward power mods for the H3 and having the ability to gain over 20% with bolt-ons. Based on personally observed data, I said that you can. I presented someone elses dyno graph that shows a 15% increase with only an airbox, exhaust, and tuning.

Here are bolt-on mods that if all done, that will increase the HP by more than 20%

1) Well designed cold air intake
2) Ported throttle body
3) Under drive pulley
4) Electric fan(s)
5) Header
6) High flow cat and piping that doesn have the two crush locations like the stock piece
7) Cat back exhaust
8) Custom PCM tuning
9) Electric water pump

If properly done, there will be no change in emissions, more HP, and better fuel econony.

If you have a different opinion that's fine.