3,0" Pulley Technology pulley, Dyno results !

[jmc007]

Today I got my Pulley Technology 3,0" pulley installed on my 2005 Victory Red Cobalt SS / SC ... (We measured it and it measures 2,95" instead of the stock 3,35").

Here is the data we measured: HP, torque, air / fuel ratio, timing and boost. Remember it's was a Mustang dyno ! All test are in 4th gear. Each pull reached the cut-off (6500 RPM on the tachometer; 6300 RPM on the dyno !). Air temp was 65 farenheit degrees; pretty good.

At this very moment, I am only able to post these quick results. All my dyno graphs (HP, torque, air / fuel) will be posted next monday, since I haven't any scanner at my house but at work.

Bone stock : 191 WHP, 170 ft-lb torque, air / fuel ratio varies slightly from 10.9 to 11.4 between 3500 and 6300 RPM.

Magnaflow 2,5" exhaust + 2,25" rear section replaced to 2,5": 200 WHP, 174 ft-lb torque, air / fuel ratio varies slightly from 10.5 to 10.9 between 3500 and 6300 RPM.

Magnaflow + 3" pulley : 215 WHP, 187 ft-lb torque, air / fuel ratio varies slightly from 11.3 to 11.5 between 3500 and 5200, then is rising in straigth line from 11.3 to max at 12.8 at 6300 RPM.

Magnaflow + 3" pulley + one range colder BKR7E plug: 213 WHP, 185 ft-lb torque, air / fuel ratio varies slightly from 11.1 to 11.3 between 3500 and 5200, then is rising in straigth line from 11.1 to max at 12.45 at 6300 RPM. The goal of the colder plugs was to get the air / fuel ratio richer a little bit, and it worked for a 0.2 to 0.35 air / fuel ratio rise.

(One comment: I think the stock injectors are giving their max flow at 5200 RPM.)

About the timing, we recorded 0 knock, but last 100 to 150 RPM before redline were between 0.5 and 1.5 degrees of knock.

General comments: The very first dyno run after the 3" pully has been installed, the following thing happened: The max boost achieved 14 PSI near 5500 RPM, then drop at 10 PSI the reach 12 PSI for the last RPM's. As we all know, it has been caused by the signal the PCM give to the selenoid that control the max boost.

So I had to disconnect the vaccuum hose between the selenoid and the by-pass valve actuator. This way the maximum boost has been reached.

My bone stock max boost have always been 12 PSI on the stock gauge, and with the 3" pulley we recorded a max of 15,2 PSI on a mechanical gauge and 14,5 PSI on the stock gauge. At this very moment, my vaccuum hose is unpluged from the actuator, and the hose's tip is plugged with a screw. I installed a little filter on the "now opened to air" by-pass valve actuator's nipple.

To conclude, I gain roughly 25 WHP and 17 ft-lb torque from the 2,5" catback and the 3" pully. (The 3" pully itself gives roughly 15 WHP and 13 to 15 ft-lbs torque.)

Remember that a Mustang dyno is usually 10-12 % lower than a Dynojet. Making the calculation (3" pulley and catback) gives 238 WHP and 207 ft-lbs torque. Plus the 16% drivetrain lost, it gives roughly 275 BHP (at the motor).

I am very proud of the result, the boost is achieved sooner also; it gives 13 PSI at 5000 RPM and 15 PSI near redline !

Have a nice weekend and have good kills !

[jmc007]

The custom made Magnaflow 2,5" catback (including labour) cost me roughly 400 $ US.

The 3,0" pulley have been purchased on E-Bay and cost me (including labour) roughly 225 $ US.

I also received yesterday a Cold Fusion Nitrous Wet kit (tunable from 35 to 100 HP), which cost me (includind 10 lb bottle, heater and shipping, excluding labour) 508 $ US. Installation of the nitrous kit very soon ... it has also been purchased on E-Bay.

Added on October 16, 2005. "I am selling the kit now ... Since the long Canadian winter is coming, I decided to replace it by a CAI and a header ..."

[jmc007]

59$ US for the pulley only, yes I paid for the install LOL.

[RL-2005]

jmc007, are you suggesting that any intake modification would hurt hp? As I understand it you modified the stock box and put a KN cone on but, are you considering installing a k&n typhoon, weapon R, or similar intake kit?

[jmc007]

RL-2005; On the CobaltSS, the Mass Air FLOW sensor is very close of the filter. I think that replacing the stock filter with a less restrictive filter (and probably causing more turbulency) can affect performance if the air fuel ratio is untuned. Personnaly, I am waiting to see if a good company (Injen, AEM, K&N) decide to make, test and sell a CAI which is tested for a TRUE HP gain.

[jmc007]

http://stuff.urbanghetto.net/Jmc007_Dyno_Runs.pdf

Thanks to nka for the hosting !

[Mike@Psi-Fi]

Originally Posted by ChrgdUp

Sorry to throw in a stupid question here...but I want to get a new puley for a decent horsepower gain with the easiest install...I think I remember reading that you have to get the ECU or whatever it is adjusted if you get a pulley, can someone explain this to me. true not true?

Well, I think I can answer two questions by answering this one.

At the top of WOT, the cars factory bypass opens and bleeds boost down to almost 10psi. Since the car knows this is going to happen, it pulls fuel to compensate for the decrease in boost. When you put a pully on the car, and then bypass the bypass (no pun intended) you are keeping the boost at peak pressure all the way to redline. If you do nothing to compensate, you are going to be pushing 16-17psi when the car wants to see 10psi. Thats a 60-70% increase in pressure without any change in fuel.

So what is the answer? You have to pay to play. You can spend $140 and a couple hundred to have the pully installed and the car will run okay for a little while. Then it will start throwing codes the more you drive it and it will run fairly lean at redline when you get on it. Or for $550 you can do it right, save yourself the headache, and beat the hell out of the car on a daily basis.

I don't want to disuade those that are doing thier own thing because I started out as a grassroots guy myself, but for those that don't have the time to design thier own parts, I don't want to see you do damage because you want to save a couple bucks in the short term.

[jmc007]

Originally Posted by Sp00ner

If you're running the pulley with the bypass still hooked up though, you should still have the A/Fs in the right general range though, no?

Yes, but I notice that the HP drop when the selenoid open (the boost drop to 10 PSI), then at redline the HP raise to about the same number as stock, so there isn't any advantage to run a smaller pulley without doing the by-pass mod, but the fact that the boost come sooner ...

[Sp00ner]

The boost coming sooner is a big plus to me...

[WopOnTour]

Originally Posted by Sp00ner

Well, one thing that I notice when I watch the fuel trims on the car during WOT runs, is that it seems to have a standard WOT fuel setup.

Fuel trims are not functional at WOT. At WOT you are in "Power Enrichment" mode and fuel delivery is pretty much based on air mass and the VE constants. Whatever you show as fuel trim, would be whatever value was stored in the highest closed loop cell (15) where the fueling would be based on exhaust oxygen.

Originally Posted by Sp00ner

I tried to sit down and run the math on the injectors last night... my head hurts now and I did something very wrong. Since by my calcs, my car should have leaned out and blew up near 3,000 rpms... so that's not right...

Formula for injector duty is base pulse width (in mS) x engine RPM / 1200 Normally you would use the scanned BPW from a 3rd or 4th gear pull just before it hit the rev limter

HTH
WopOnTour