if i was broke, the pulley.

if i had some flow to blow, the headers.

you'll see more power with the headers, but the pulley is damn cheap.

 

I made 10whp more with cp and test-pipes at the same time over my baseline. Take it for what its worth, I know the tp didnt provide all the gains...

 

See you really don't know because you dynoed the CP with the TP. For all we know the CP could have only put out 1-2 HP out of the total 10HP. We all know that Test Pipes can be could for 8Hp.

 

If you understand dynos then you know why some dynos will show no gain in horsepower. That is because there is no true gain. The engine produces no more torque, so no more hp. What happens is the same thing as runing very light wheel/tire combos - they are easier to spin so the car accelerates faster - with the same horsepower. Lightweight driveline parts are worth increases in acceleration, this is why the move to aluminum or carbon fiber driveshafts in HiPo vehicles - less rotating weight.

Dynos like the DynoJet will show hp increases because they measure acceleration and convert that to horsepower. Because the drive wheels accelerate faster, the dyno thinks there is more horsepower.

Dynos like the Mustang run in a loading mode and will not show gains because at a steady rpm there is no acceleration, just torque. This is why dyno racing is so pointless - your car can accelerate faster with the same horsepower as another guy's....just by removing rotating mass.

BTW, I've seen DynoJet dyno sheets showing a hp increase from pulleys. All ya gotta do is search a few forums......

 

I would ditch the cats before getting headers...

 

Diesel he gained 10 peak hp.. light wieght pulley would bump hp up 3-4hp everywhere on the dyno..not like a breather mod... it frees up power so ull gain atleast 3-4 hp at idle and 3-4 hp at peak.

 

Oh the myths will NEVER die. It's so annoying that people will believe what the aftermarket will tell them.

Kolia is the only one with a clue and what he says is correct. The stock pulley is in fact a harmonic damper. It's a two peice pulley with a sandwiched elastomer ring inside. The elastomer ring quells crank vibration/resonnance when the pistons are firing. The fact that the VQ is internally balanced HAS ABSOLUTELY NOTHING TO DO WITH THE OPERATION OF THE CRANK PULLEY/DAMPER!!!!!!!!!! When the pistons are firing, first and second order vibrations are occuring. The dual mass flywheel or torque converter act as a damper on one end of the crank and the OEM crank pulley acts as the damper on the other end. Remove the damper from the crank pulley and there will be uncontrolled resonance in the crank. That's a fact. Will the VQ fail? Very unlikely because the lower end of the block is very stout as is the crank. Gains? No.

I had a UR pulley on my 96 Maxima VQ30 (1.5lbs vs 6.5lbs). The car felt more lively, but was more prone to bogging off the line and on part throttle shifts. I also noticed a grainy vibration through the pedals and shifter that wasn't there before. Over the span of 1.5 years and 40 passes and one dyno, the UDP gained me absolutely nothing. It was a waste of time and money. I put the stock pulley back on and the grainy vibration disappeared and the car felt better.

The facts are UDP on the VQ show minimal to zero gains. And fellas, don't be dumb. Reducing rotational weight will be seen on the dyno. If you remove 15lbs of rotational weight from your wheels, you'll see it in HP/TQ on the dyno. Why don't the UDP pullies see any real gains?

1) They're connected DIRECTLY to the f-ing crank. The further away the rotational device, the harder it is to accelerate (ie wheels/tires). The pulley is mounted directly to the power source. Think about it.

2) The pulley diameter is supper tiny and the weight is nothing. The larger the diameter of the rotational device, the harder it is to spin. A 7" 8lb pulley is going to be far easier to accelerate than a two 26" 50lb wheels.

Removing 10lbs from each wheel (20lbs less rotational inertia, less 40lbs static weight) will net almost .1 seconds and 1mph. Why in the world do people believe that removing 6lbs from a single pulley mounted directly to the crank is going to do much of anything.

People, this isn't your brother's 5.0 Mustang and the VQ isn't going to make the same gains. Yes, a 5.0 Stang with an UDP set (crank and water pump pulley) will see a solid 8-10whp gain. Guess what though? The VQ has a timing chain driven water pump and the UDP of the 5.0 water pump pulley is what nets most of the gains.

Don't believe the hype or the myths. Research it for yourself and get a better grasp of late model engine design before believing the aftermarket nonsense.

 

ok ok so whats up about headers not making power.
I have them and they have more punch all the way to redline.
but.......................................................
I'm using the stock cats.

Could it be true that the test pipes free up so much flow that at that point you would not feel a gain from headers if you already have test pipes installed?????????

So now i am starting to understand this a little.

I made power from headers with stock cats, but others have had no gain because of already havin test pipes and then adding headers and seeing no gain!!!!

So I'm guessing that if you dont want to mess with the cats or the smog issue go for the headers for a gain. and if you go test pipes dont get headers because its a waste of money at that point??

alberto can you explain a little more on this please. Thanks.

 

Crank pulley is much cheaper and easier to install

Headers are expensive and pain to install, plus they dont give expected HP's

 

I have megan headers that i payed 175 shipped.
good quality, bends ect.
the first pics below are stock.

 

comparison of stock to new

 

restrictive cats

 

last one.

you can save alot of money doing the install you're self but it is a PITA

 

Not starting conteversy, but just wanted to post up pics for discussion.

everyones stock headers may not be as bad as mine, i just think i had the absolute worst set of stock headers ever i mean look at those ports.

but the cats look really restrictive.

 

Nice pics !

 

thanks

 

Very interesting stuff guys.

I agree with the chap that mentioned not trusting information from the aftermarket, I definately do not take information from tuning companies as gospel and always do my own research but then at the end of the day you have to believe someone lol.

 

Your guys are comparing apples to oranges...

Headers deals with exhaust, a/f, ect ect ect
Pully deals with drivetrain, unsprung weight, ect ect ect..

Hell get a lightweight flywheel it will do more than the pully w/o the possible nasty side effects

 

Your guys are comparing apples to oranges...

Headers deals with exhaust, a/f, ect ect ect
Pully deals with drivetrain, unsprung weight, ect ect ect..

Hell get a lightweight flywheel it will do more than the pully w/o the possible nasty side effects

 

The Grassroots Mag has a great article on trying to get more performance on an old Nissan. They actually got more gains from changing the old fuel filter ($2 part) than they did by putting a light weight pully on (NO GAIN)!! Funny thing is that the more expensive the aftermarket part was, the less gain they got on the dyno.

This just confirms what someone said before - don't believe what the aftermarket part dealers tell you!

Also, someone said it above too - lightening up your Tire/Wheel will give you a good hp/torque gain (less rotating mass) and will help you corner better (less unsprung weight). And this is probably the easiest thing to do to your car!