Underdrive pully kits

[doucebag]

I was wondering about the spark. With the altenator not charging the battery, would the spark be as "hot" or as high of voltage as it would be if the VAK wasn't hooked up? Just a ?

Kevin

 

[DavidT]

okay Mike,
I'll be your guinea pig. Send me a VAK. I will be going to the dyno in the next few weeks. I'll run with it in and with it out. Then I'll post the results thumbs_u
If I like... I buy.
BTW, there were 3 diff. ones to choose from... how do you know which one...
And what exactly do the wires hook to?

 

[Mike Kopstain]

doucebag:
I was wondering about the spark. With the altenator not charging the battery, would the spark be as "hot" or as high of voltage as it would be if the VAK wasn't hooked up? Just a ?

Kevin

Ok, well IE took a **** on me, so I lost my nice detailed response, but we'll try this again.

The ignition system is a high voltage, low amperage device. Spark is not affected with the VAK.

LB-SHO: The fans are a pretty high current draw, therefore shutting them off when there is no charge from the alternator frees the power to go where it is really needed.

The power output visually does not appear to be at a dangerous level, as the lights didn't seem to dim on the car that I installed it on tonight.

 

[LaTechSHO]

i will concede on the high current draw of the fans..... and truthfully if everything else was setup but the fans... you MIGHT run into a power problem...... of all of it that seems the most far-fetched.... but if you have tested it.... power to ya....good luck with the business venture

Louis

 

[SHOZ123]

bradman:
Mikey,
When are you going to answer doucebag's last question?? Does the accelerator have to be mashed to the floor for this thing to kick in? Can it be adjusted to kick in say at 3/4 throttle?

There is no adjustment. It does not need to be mashed to the floor. It depends on engine speed. The slower the engine speed the greater effect opening the throttle has on intake vacuum. You will love it.

 

[SHOZ123]

This works better with a good battery. Most auto start batteries are POS. Like Mikey said the coils are the least affected by the lower voltage. I also have a 14V mod that will switch a 2V cell in series with the normal 12V battery to maintain the 14V of a normally operating electrical system with the alternator running. It is not needed though if a good deep discharge battery is used. The VAK is only in operation for 15 to 30 seconds at a time.

 

[viperrt450]

So I am the proof that the Vak does work. Lets just say that I had 2 other people in the car which was around 400lbs, and it felt like it was just me in the car! When i was in the car by myself the car pulls so hard now it is so amazing!! So hard I broke my front motor mount! No BS

 

[Mike Kopstain]

Note to everyone: Craig bought a $29.99 motor mount, Which could have something to do with why it broke.

sorry bud.

 

[viperrt450]

Listen here you tool hehe. What's your point??? Had to try the aftermarket instead of buying Ford stuff. Damn Ford and overpriced stuff. So I learned my lesson and I ordered a Ford motor mount today

<small>[ January 09, 2003, 03:15 PM: Message edited by: viperrt450 ]</small>

 

[SHOZ123]

When figuring out the watts-hp computations you also need to figure in the efficiency of the alternator. I really don't know what it is but when the AC is converted to DC a good 4/5s of the AC current is wasted. Can't use any of the negative side of the sine wave and you need to chop the bottom of the positive wave off to.


Here is the three full AC sine waves produced by the alternator.



This is what's left after converting to DC.



<small>[ January 10, 2003, 11:16 PM: Message edited by: SHOZ123 ]</small>

 

[BlackOnBlackATX]

you know to go back to the actual underdrive pulley question, i was talking about this with a friend of mine who drives a trans am with an LT1 corvette engine in it, and the dyno he showed me says the pulleys only added less than 1hp and 5 ft-lbs of torque. and thats on an LT1!!!!! so its basically worthless except to save your accessories.

 

[SHOZ123]

Well it is very hard to measure small gains in HP on a dyno. Too many things change. But I feel a 1 hp gain is rather small and not accurate, 1% would be more in line with the V8 Chebby.

With any car the slowing of accessories will free up power. it does not make HP but allows more tot he wheels. The less gross HP the greater gain percentage wise. My guess WRT the VAK is close to 10hp with a full electrical load enabled.

I do know that with a good battery or the 14V mod going I can get an extra .1 to .2 in the 1/4 taken off my time with the VAK. And this is over what the single crank UDP on the '97 produces.

 

[BlackOnBlackATX]

even so, 1% of 280hp is only 2.8hp, so its pretty worthless. youre not going to feel the 3hp on a car like that. although i will say yes i do not know if the dyno's were taken with consistent conditions.

 

[SHOZ123]

So basically you are saying that the UDP mod which so many have used to gain HP for the last 30 years is worthless? And that the accessories on a car today do not draw any HP to drive? And that all the power consumed by the accessories is because of bearing load? Where does this magical power come from? Why does it take such a large gas motor to generate electricity? Why not use a crank and your arm?
HORSEPOWER

 

[AutoSHO]

I think that the VAK system and the UDP's were designed with a different mindset. Yes, they both want to increase power, but the pullies, especially with a SHO, are marketed to increase the life of the accessory bearings, along with slowing them down to decrease draw. The VAK system, on the other hand, was designed much more like a nitrous system (just for the sake of comparison, bear with me) where it only engages at WOT and is not meant to be used constantly, or at least not without losing some efficiency (Air Conditioning, etc...) Am I correct? In this case, I also ask why we wouldn't use both? Being able to turn off the alternator and spin it slower will both lower the load on the engine, making it much easier to rev to high rpms. Maybe I'll do some testing on my new SHO. I appreciate the information from both sides, and I think both have a good, marketable product. There's no reason to attack one or the other. They aren't so much competing products, as some which work well individually or great as a combo.

EDIT: Also, in response to the LT-1 post. They do not rev to 7000+ like our cars, where loads become much greater, especially the centrifugal weight involved. I think that a SHO will gain more from pullies than the LT-1, and gain yet more from not having the accessories, especially the alternator, draw any power aside from spinning them.

<small>[ January 11, 2003, 06:07 PM: Message edited by: AutoSHO ]</small>

 

[Big SHO Davo]

As I mentioned in the performance section Underdrive pullies are not all created equal. They very in size (from application to application) as well as material. For example a set of pulluies that are 15% bigger and made of steel will not give you the same gains as a set of pullies 15% larger but are made of Aluminium. Some of the gains from the pullies can be attributed to the weight loss.

 

[BlackOnBlackATX]

shoz123, you wouldnt use a crank and your arm because you would get tired quickly wink but yes, im saying if you look at the dyno and what the other sho owners here (majority, not all though) are saying, its more or less not worth doing until you have nothing else to throw your money at. search the threads and see for yourself. which gas motor are you talking about? like a home generator? because i think you and i both know that it doesnt take the 220hp to make 140 amps, if it did you wouldnt have any power left to move anywhere, so thats kind of a silly remark. keep in mind i said most not all people who have done this. im sure there are people with a grand national lets say for ***** and giggles who have gotten 10hp from these, at the wheel, but it does not hold true on the sho's from what the owners are saying. i think alot of it is having the right combination of mods with it. im not saying it doesnt take energy to drive pulleys and im not saying you will NEVER get hp from them, but what i am saying is if you guys think a new pulley is the magic cure youre incorrect. what did the pulleys dyno on your sho? why take a crapshoot on a possible 5hp when you could pony up an extra hundred or whatever for cams and get 15?

AutoSHO, you are truly right, the dyno only goes to about 6k rpms on the LT1, not 7k like ours do. but they also have less alternator load than ours, they dont require a huge amount of current, which if we follow mikeystaurus since everyone backs him, is where a majority of the load comes from. and this guy doesnt have his a/c either. so thats something more to think about.

bottom line, if money was not an issue would i get them? shit yeah i would. if i was looking for more horsepower would i get them first? not at all. now im not trying to **** you all off or start a flamewar or nothing like that. im just relaying what ive seen from my experience and on the forum. like i said before, if im wrong im wrong, thats fine and ill live, but this is what ive seen the trend moving towards and thats all im saying.

<small>[ January 12, 2003, 12:39 AM: Message edited by: BlackOnBlackATX ]</small>