OMG, you are not even worth replying to if you think trap speed has NOTHING to do with HP, it does. So do shift points, your launch, weather conditions etc etc. Many people feel like there's something wrong with my car because they cant possibly swallow the idea that the pulley that they have on their car is worthless. I'm glad you felt a difference, so did I, but my car didnt dyno any higher. Have you dyno tested your mods? Do you track test all your mods? If not, just live with the idea that your pulley may not be doing $hit, until you prove yourself right think what you want. I proved that the pulley on MY CAR did nothing. When I dynoed my car a second time, my car felt much stronger than stock, guess what it only dyno'd 6whp higher. Dont go by feelings, dont even go by dyno numbers, I go by what works @ the track, and I do better than any Z I've seen at Capitol or Ive come across on the street. End of story. So what if I'm the first person not gaining anything on the dyno, show me some non-biased dyno's of people that have done a before and after pulley dyno like I did that showed gains. The opnly gains I have seen are coming from magazines and such, I'm sure those numbers arent messed with to sell products All you guys with pullies claiming better throttle response or a more power, I ask you, where are your track slips and dyno sheets? If you have them post them, if not, stop trying to make it seem like I'm full of $hit, I post my info to help those considering doing a pulley...take it for what it's worth.

 

Thanks

**ZXSaint I am at work right now, I will email you those dynos when I get home later tonight**

 

trap speed has more to do with how long you burnout and where you make power, shift, and weather conditions. it is not a good indicator of hp bc a car that has 300 hp but weighs 3500 lbs will have the same or similar trap as a car with 250 hp and 3000lbs.

i didnt jump on your case so plz dont jump on mine i was stating what i know.

yes i have dynoed my car but i dont bother testing them individually its a waste of money in my opinion i subscribe to the theory that the end results are more important than the individual parts that make it up.

i do track test my mods and picked up about .2 in the 1/8th with the mods that i have equipped, enough of a diff to let me know that what i have done is doing something jsut not as much as i would like. there are lots of dynos floating around showing 3-8 hp gains with the ur pulleys all across the rpm range, there are very few mods that provide those kinds of gains across the board. if it was even 3hp across the range id take that over the 8hp up top from my exhaust.

 

Not jumping on your case just defending my point of view....I know that a 2500 lb car with less hp will trap close to a 3200lb Z wih more hp, but that has nothing to do with what I said. If I would have increased a few hp, 5-7whp, I would have trapped slighlty higher, maybe .5-1mph. I compared my average trap speeds with the pulley compared to without it, that is afair comparison. If I look at my time slips and find 2 slips one pre pulley and one after, both with similar 60ft's I can see that my trap stayed very similar along with my times. If thats not enough proof for you, then I dont know what to say. You say you dont care about individually testing parts, but individual testing can lead people to find out crazy results...like when I switched from an AEM to a Pop-charger and gained 11whp! That happend because the long tube intakes dont work well with the Crawford plenum. I would have never found out if I hadnt tested my plenum and intake combo. The end result is a stronger running car, with more hp, less TQ loss and all with a minimal $100 investment. And as far as the power across the range, I LOST power everywhere from the beginning of the dyno at 2000 rpm to 6000 rpm, where I gained .5-1 hp to redline. My pulley didnt make any more whp at any point in the dyno under 6000rpm. IMO, on my car it's junk...BTW how much has your trap speed increased from stock to where you are now? I went from consistent 100-101 to consistent 103 with a few runs netting me 104 mph trap. I'd say that pretty decent for a Z with no cams or headers, and guess what I never hit 104mph with the pulley on, I did that before the pulley. I have more than enough reason to take it off of my car, feel free to leave yours on, just dont come at me with "I felt gains" what you feel doesnt mean $hit...prove to me that just your pulley increased your whp or helped you @ the track, I dont think you can...

 

Have you checked your Voltage reading after installing the pulley? I think these pulley mods are just fine, but I'm so far less than impressed with little things on the Z like the alternator output. There is a possibility that if the alternator output drops, the vehicle voltage could drop, and the fuel pump output could then also drop causing a lean condition. Of course, that's a lot of "coulds" in a string -- a bad dyno AF sensor is much more likely. But do check the voltmeter -- it's right there on the tripple guage....

-frank

 

i went from averaging about a 9.5-9.6 @77(only intake) to a 9.3-9.4@80 with the mods in my list. though this is on avg. there is no 1/4 closeby so i dont do it often. im hoping to get it closer to a 9.0 this summer but the track is a very slow one. its not kept up well and its only paved on the track itself and some of the waiting lane so we get lots of dirt all over the place. for a comparison i ran a 9.1 @78 gainesville in the 1/8 the one time i ran the quarter there with only an intake and the pulleys

 

As promised...

 

Not all performance mods increase your HP and show up on a dyno. You felt a difference? Could you describe it?

Using the logic of a lighter flywheel. It doesnt give you MORE hp; that is, there will be no gain on the dyno. However, it does give you your existing hp quicker... car should pull better.

imo at least

 

This has been an interesting thread only because universal mis-understanding of the difference between HP and T.. HP is a unitless # derived from an even less meaningless origin..The capacity of a horse to pull..You can't even measure HP directly it is derived and in the case of I.C. engines from the Torque (which is measurable ) and developed by the engine. Any rotating mass reduction attached to the engine and driven by the engine will result in an increase in the engines T output.. Higher T = greater HP..However you dont feel HP you only feel Acceleration (G's) which results from the T increase with the lighter Pulley.

The underdrive function of the Pulley also lessens the demand on the engines (T) thererby freeing it up for the wheels since less energy is needed due to the lower angular velocity of the attached pulleys (A/C, Alt) .

Not to sound to parochial but Dyno's do not measure HP. They measure T and then calculate the meaningless HP #..