Power Gains

[bwenny247]

Here's the List of engine mods i've done:

Hypertech Power Programmer III
Low Temp Thermostat
Throttle Body Spacer
K&N FIPK
Underdrive Pulleys
2 1/2 inch Straight Pipe (Trick exhaust tip coming up soon hopefully)

I've also Herculinered the lower rocker panels and over the stock fender flares, no rust, chips, or rock dings.

The power difference is unreal. I put 33X12.50's on and i think i accelerate faster then stock....and i do have the 3.42 gears, but i think everyone greatly underestimates the power, or potential power, of our engines

anyways, like i posted on the Lift/Tires/Suspension forum, I'll get up a lot more pictures this next weekend. I've got 4 exams to deal with this week. But I LOVE MY CREW!
~Ben

[killian96ss]

The power difference is unreal. I put 33X12.50's on and i think i accelerate faster then stock....and i do have the 3.42 gears, but i think everyone greatly underestimates the power, or potential power, of our engines

I doubt your truck is faster than stock with 3.42 gears and 33's even with the power increase, but I reserve the right to be wrong. If I had to guess how much more power your getting with this setup I would say around 25-35 hp. If you like power gains try the CFM Tech throttle blade. It made the most noticeable power difference to me. I think headers, full roller rockers, and a nice port/polish job on the heads would also make a very nice power increase.

Steve

[bwenny247]

are you saying 25-35 at the rear wheels, or crank? My mechanic buddy figures about 40 HP increase at the crank. Especially with those underdrive pulleys. 40 horse on 190 stock is a big jump.
I'm out of cash for now. (crummy college tuition sucking my truck funds away )

[coreylubahn]

I must ask...what exactly is an underdrive pulley? I've seen them mentioned on other sites before and I still don't have any idea what they do both from an actual mechanical side as well as how they help performance, what they cost or if they're worth the money. Just curious, especially since I have almost everything mentioned except for the throttle body spacer (that everyone says does nothing anyway) and I would love 40 more horse and if underdrive pulleys were a way to get there I'd be interested if the price went in line with gains. I'll appreciate the education!!

[killian96ss]

The 25-30 hp would be at the crank. I think the mistake a lot of people make about hp increases come from thinking that every mod's hp adds up. For example underdrive pulleys typically gain 8-10 hp, K&N FIPK 5-10 hp, HPPIII 5-10 hp, TB spacer 3-8 hp, exhaust 10 hp. If you add evrything on the high side you would get 48 hp, and on the low side 33 hp. The problem is you can't just add the #'s together and get total hp gained because of the variety of components being mixed together. In real life you probably only gained 25 hp, and maybe, but not likely as high as 35 hp with those components. Of course the only way to know is to dyno your truck stock, and then again with all the components added. I'll bet you would be shocked or depressed about the results.

Steve

[killian96ss]

I must ask...what exactly is an underdrive pulley?

It's just a set of new pulleys in smaller sizes that usually slow down the water pump and PS pump to gain back some lost hp. Be careful which setup you use because a lot of them cause charging problems or overheating problems. A good set will include a matched underdrive (smaller) alternator pulley with the crank pulley. Don't get a set that doesn't include the alternator pulley! On a V-8 underdrive pulleys usually gain 10-15 hp, and on a V-6 maybe 8-10 hp. I have underdrive pulleys on my SS, but I only did that for high speed driving over 130 mph, and to prevent my PS pump from getting too hot on road coarses (I have seen melted reservoirs before). At slower speeds sometimes you will have problems with cooling on hot days (this can be fixed with electric fans like Brule has, or a higher flowing mechanical pump), and less responsive steering with some whining noise, because of the pump turning slower than it should. If you get a set without the alternator pulley you will also have low speed charging problems. IMOP I don't think underdrive pulleys are all that great for off roading because you want good cooling and good steering response which the pulleys will take away. If you want to go faster, then they are good for that.

Steve

[bwenny247]

the company i got my pulleys from was March Performance
http://www.marchperf.com/
something like a hundred bucks shipped i think

Another advantage that gains power is the weight reduction in the pulleys themselves. the March crankshaft pulley weighs about 5 pounds less then the stock pulley. taking less load for the engine to turn it. the kit comes with both a crank pulley and alternater pulley. they are powdercoated black and the only thing you also need to buy is a new belt. as the circumference of the belt is smaller becuase of the smaller pulleys.

getting to the crankshaft pulley is something fun though. i'm sure we've all dove into the engine compartment and seen how much room there is to work in there.

March claims about 12.5 horse at the real wheels (i'm sure on a small block) so, i think 5-10 is reasonable with our 4.3
overall power to price ratio is pretty good.

[killian96ss]

the company i got my pulleys from was March Performance
http://www.marchperf.com/
something like a hundred bucks shipped i think. Another advantage that gains power is the weight reduction in the pulleys themselves. the March crankshaft pulley weighs about 5 pounds less then the stock pulley. taking less load for the engine to turn it.

Did March tell you that their pulley weighs 5 lbs. less? A stock pulley only weighs about 5 lbs. If their pulley was 5 lbs. less it would weigh nothing.

The kit comes with both a crank pulley and alternater pulley. they are powdercoated black and the only thing you also need to buy is a new belt. as the circumference of the belt is smaller becuase of the smaller pulleys.

If you got the black ones they are probably steel not aluminum, which is ok since they will be a little stronger and will last longer. I have the aluminum ones on my SS and had them on another car and they are clear coated.

March claims about 12.5 horse at the real wheels (i'm sure on a small block) so, i think 5-10 is reasonable with our 4.3
overall power to price ratio is pretty good.

12.5 hp would be a best case scenario, and is probably the most they have seen on a dyno with their pulleys, and yes it was most likely a small block chevy or something similar. The only thing you are slowing down are the PS pump and water pump. These accessories don't draw as much hp as some people think. I have seen the old trick at the drags where people take off their belt to get better 1/4 mile times and some gain a little, and some are actually slower. The pulleys I have on my SS are also from March, and I have used their pulleys on 1968 Impala drag car that I used to have. March does make quality products, and if I were to put underdrive pulleys on the CC I would most likely use theirs.

Steve

[HenryJ]

It is awfully easy to predict, or boast huge gains in horsepower with lots of mods, but the only way to easily tell is to get it on a dyno. You could also calculate the drag coefficient, weigh it and make some runs at the drag strip to come up with a pretty good estimation.

A 10% increase in horsepower is darned significant, 40% will require boost or major internal modifications.

The main thing here is that you are happy with the performance.

I am happy with the performance that I have and I'd be hard pressed to think that I have much more than a 10% increase over stock.


Give all the changes time to sink in. The "new mod effect" will wear off and the performance reality will surface. We all like to have a new mod add power. Sometimes they do and sometimes they don't. Half of it may indeed be the psychological effect of our desire to have positive results.

Some mods do change the powerband, or throttle response, which you might interpret as an increase, when in reality you gain little or nothing.
Without an unbiased, scientific method of measurement there is no real way to tell.

Enjoy the ride, and look for that next mod

[bwenny247]

well put HJ
most likely i'm just an excited little boy with his new toy and EVERYTHING seems to be unrealisticly impressive. lol

I've got the balck powder coated power and amp series set#4460
it's an alluminum crank pulley and steel alternater pulley. my 5 pound estimate was obviously off it was late (1:00 AM) when we pulled off the stock pulleys and it seemed like a hundred pound difference to tired hands, lol, we'd been going since 8:00 the previous morning with a BL and other complications.

I'll let you know what realistic gains where made when this great big smile comes off my face but it's been on there since friday at 4:00 and i don't think it's leaving anytime soon!!!!

[jeff024]

the new hypertech has a built in Dyno list prices are around $799.00

[F9K9]

HJ, I have to believe you have gained over 10 HP with your mods. I realize that you're the expert in this area. Just the intake, exhaust and LS1 fan would surpass 10 HP, not to mention the HPPIII. I could be very wrong on this but, do not see it now.

I was going to do my transmission cooler install today but, after searching the threads and posts, I have postponed it. I want to do it right the first time and the mod section is a little misleading on how simple it is to do. Metal tubing is the only way to go.

I then drifted off into the radiator upgrade thing and before it knew it, I was looking at electric fans

To bring this full circle, I started thinking HP increases and know that the LS1 fan gives a boost in HP but, has an electric water pump crossed your mind

[HenryJ]

...has an electric water pump crossed your mind

Only for a brief moment.
Electric water pumps can not move enough water to cool consistently, and their lifespan is not acceptable for a daily driver.
Those that do offer the volume needed pose a clearance issue. I would also be concerned with the additional load being placed on the charging system. This would not be an intermittent load, it would be there all the time.

I have not yet solved the "bigger alternator" , and I am starting to wonder if it too will require some compromise, or just staying with the stock unit.

I think that perhaps the gains in this instance would not out weigh the reduction in efficiency and longevity.