well the 4.2 starts with what? 200 hp? this thing adds 39 at the wheel, so thats probably about 50 hp at the fly, maybe a tad more. Thats 25% increase in hp, i think thats a pretty significant increase, of which the chip could easily account for 10% or so. I havent done work on the 4.2 but as i hear it they are easy to chip for more power, not seeing the article makes it hard to see what happened tho, i might have to pick it up.

 

oh yeah and jmc, you know those 6ers are gonna rev a lot higher than you are, just in the nature of the engine. Im with you on the 2500 rpm range, since gas has gone up i stay around there for the most part now. But for a v6, their gonna rev about 25% higher than us just because they have 6 cylinders.

 

The V6 is rated at 205 at the flywheel @ 4750 rpm. So if you take the higest stock RWHP of 165 @ 5000 rpm that is a 40 Hp loss through the drive train. The highest gain was 204 @ 5000 rpm. That calculates back to a 244 Hp at the flywheel. That is a 16% increase over stock. If you compare the last column to column next to it is is only increasing 21 HP or about 11 % The chip is supposed to give you 10% all by itself. So the pulleys, headers and thermostate only added 1%?

JMC

 

Well firstly, based on your calculations its about 20% increase over stock, which is still pretty impressive, you add 20% to 204 you get 244, you dont do it the other way.

Secondly, i really dont think you can calculate the hp loss the way you did. If you did that, you only gained 39 hp at the flywheel but that same 39 at the rear wheel? That doesnt make sense.

 

so what are you saying? are you saying the chip people are lying or are you saying pulleys, headers and thermostate are not adding anything.
the chip people (and every other aftermarket company)are probably showing a best case situation.

my guess
headers - 6 to 8 hp
pulley is 6 (that what it said somewhere in the article)
chip is 7 to 10

i found it interesting that in this article there was no testing where the chip or header where tested individualy.

 

so what are you saying? are you saying the chip people are lying or are you saying pulleys, headers and thermostate are not adding anything.
the chip people (and every other aftermarket company)are probably showing a best case situation.

my guess
headers - 6 to 8 hp
pulley is 6 (that what it said somewhere in the article)
chip is 7 to 10

i found it interesting that in this article there was no testing where the chip or header where tested individualy.

take a clue from the lightning guys, short headers are not worth the money. the chip for what it cost and the ease of installing is worth the money.

this is the kind of testing that probably answers a lot of questions here. i would have thought that some of the v-6 gurus would have had these number a year or 2 ago. do the above with some 4.10's in a regular cab and you would have a quick truck.

 

I think I will have to pick up that mag for a closer look. It would be nice to see the full dyno graph, especially as the stock motor makes peak hp at 4750 rpm, which is not included on Brotherdave's summary (thanks for posting that, BTW!).

RE: drivetrain loss, I am inclined to agree with JMC that it should be a fixed # at any engine speed rather than a % of the flywheel hp. Of course this loss will vary from vehicle to vehicle. I know it is convenient to use a %, but I fail to understand why it would be more accurate.

If I double the HP of my motor, has the HP it takes to spin my drivetrain and accessories doubled? If so, why?

On a stock vehicle that takes 30% of the stocker's power to spin the the drivetrain, it seems to me if I add 40 hp at the rearwheel, I have added 40 at the crank, not 40 + 12 (30% of 40).

 

Since we are talking mods and cumulative effects, I will summarize my experiences (no dyno or strip #'s, just seat of the pants). In order, my mods were:

1) Drop in K&N filter - no noticieable power or mileage increase.

2) Superchip - immediate, noticeable improvement at virtually all rpm. Added benefit of much improved shifting for automatic tranny. Good bang for the buck. Hard to tell if mileage improved as my mileage always varies alot.

3) Airaid Intake - noticieable power increase in power above 3,000 rpm, but did not seem to add as much as the chip. No noticieable change in power below 3000 rpm. Quiet at light throttle, much louder at full throttle.

4) Electric fan - could not really feel any power increase, but it must have reduced drag on the motor as spinning the stock fan has got to take some hp. Mileage seemed to increase some, but hard to verify. Added benefit of quieter motor except when fan is on. The stock fan is actually pretty loud.

Combined effect- the truck is noticeably better than stock, seems to make a little more high rpm power than my friend's stock '97 4.6, but not quite as much low end power.

I have avoided exhaust mods because I like my truck quiet at normal cruise. IMO, headers probably don't add much, and a cat back would probably only add at high rpm. Also, I like the fact my stock system is stainless steel. I would consider a catback system if it was shown to add power throughout the rpm range and did not add any noise at cruise (extra growl under full throttle is OK).

 

this is a manual, so it might be different, but i think on an auto, you will see some percentage loss, not saying it is gonna be consistent. On manuals im not sure if that applies or not, im used to looking at dynos for automatics so i might be really off. But i think if you have say a 800 hp engine running through an auto, your gonna see more hp loss through the tranny then, as opposed to running at 400 hp. Not positive tho.

In anycase, even taking it that way, those 4 mods still yeilded a 20% hp boost, which is quite a bit.

 

that is the numbers they show, no actual graph.