blowers - multi question post

The first step in getting a blower is deciding what kind you want, centrifical or positive displacement style. Do you want the stump pulling low end of a positive displacement or the top end rush of a centrifical?

I have a P1sc Procharger which is a centrifical style which I like cause it is semi soft off idle so it gives me a chance to hookup and not blow off the tires. But you can't go wrong with the big block torque a positive displacement provides. I will say the P1sc is LOUD. Drive throughs suck, especially if there are walls on both sides.

For gauges I would get a boost gauge and either a fuel pressure gauge or if you have the cash get a wide band O2 sensor and gauge.

Your compression is actually lower then stock because they made the chamber larger by removing the bump.

The Saleen blower from a 4.6l 2v motor would work, just make sure it isn't from a 05 or newer with the 3v. And no I don't believe a 4.6l positive displacement blower will fit a 5.4 without some adapter plates to make it fit on the wider 5.4.

And don't for a second believe this is your last mod. A blower is just a whole new, exponentially more expensive begining.

High compression itself is not really the enemy, it's just not good for a street driven daily driver supercharged engine running on pump gas. Detonation is the enemy. If the shop that worked your heads altered the size of your combustion chamber, or decked your block, then your compression ratio will be different. Try to find out exactly what they did.

Hood clearance should not be a problem. Your choice of superchargers depends on preference between centrifugal vs roots style. You can find some good complete used centrifugal kits online for $1500-$2000 and a lot of companies sell new kits for around $3500. I personally would stay away from a Saleen supercharger kit unless it came complete. I wouldn't spend more than $1200 for one. The important gauges are boost/vacuum gauges, and a wideband AFR gauge.

centrifugal examples- vortech, procharger
positive displacement examples- eaton/tork tech, kenne bell

Supercharger basics:
Supercharger specifies simply that it is a belt driven turbocharger. For both kinds as the RPMs rise, obviously the accessory belt spins faster and will spin the supercharger faster. How fast the supercharger spins is also determined by how big of a pulley is being run by this accessory belt. In general the smaller the pulley, the faster the supercharger spins, thus (hopefully) additional psi or "boost" over STP (standard temperature and pressure) which more air means more power.

Centrifugal vs. positive displacement:
The difference is that centrifugal superchargers have centrally mounted fan blades that increase their compression of air as the RPMs rise. At lower RPMs this type of supercharger is providing additional boost but is not spinning at enough RPMs to produce the maximum capable. Thus while your are making more power than if you were NA, it feels as if you have "turbo lag" because you have a larger disparity between your power in the low RPM vs. the higher RPM. Because of the higher power up top, it will feel like you have a rush of power up top. Centrifugal tend to be easier to install for the do it yourself person from what I have read, and overall tend to be cheaper initially.
Now positive displacement superchargers are different in that they have screw type mechanisms that compress the air at near maximum pressure (for the pulley size) any time you floor the accelerator. HP is related to RPM so you still get the most power up high but there is less of a disparity in power down low in the RPM range. Thus a positive displacement supercharger will act similar to your NA mustang but with a bump in power across the RPM band. Once again, typically a little bit more involved on the install and you have to pay a little more to play.

Whether one will make more hp than the other turns into a pissing contest because it depends on if they are intercooled, what psi, your tune, what other mods, etc. etc.

With all that said I think you should look at several options (in no particular order: tork tech, kenne bell, vortech, procharger. All are good options, weight it out and get what you like, and it sounds like a basic kit with any of those companies would work well for you.

Even though the name is tempting I would stray away from saleen superchargers. Unless you are happy with low to mid 300 hp they are notoriously inefficient and I have heard they may require some special components.

Disclaimer: I don't have a super charger but I have spent an abnormal amount of time looking at the options.

screamin gt said:

and whats the diff between wide band and narrow band A/F gauge?

Click to expand...

It's not so much the gauge as it is the sensor.

As you probably know, the PCM uses the O2 sensor during closed loop fuel operation to regulate the fuel mixture. It constantly monitors the O2 sensor and adjusts the fuel injector pulse width to try to attain a "stoich" AFR. An AFR gauge looks at the signals from the O2 sensor and displays them on LEDs or some other sort of display.

There are two types of O2 sensors; wideband and narrow band.

Narrow band O2 sensors pre-date the wideband variety and were used for years and years on computer-controlled engines as feedback sensors. They produce an output voltage ranging from ~100mV to ~1000mV, where 100mV is lean and 1000mV is rich. The thing with narrow band sensors is that they're not very accurate, if you like, about just how rich or how lean. The "switch" point of NB sensors ~450mV which roughly corresponds to 14.7:1. A voltage less than this is interpreted as "lean", a voltage higher as "rich." However, the transfer function is very steep around stoich and flat in the rich/lean regions:

View attachment 211295

so it's impossible to say what the mixture actually is. This is fine for PCMs designed to use them. These systems simply continually adjust the mixture so the O2 sensor reflects the system as operating as much in the "rich" zone as in the "lean" zone. This is why traditional AFR gauges with NB sensors just use LEDs (or something similar) and swing back and forth rapidly when in closed loop mode.

Wideband (WB) sensors use a very sophisticated control system, using current and temperature control, to produce a linear output representing mixture:



You can see that there's a definite mapping between AFR and voltage output and that the scale is linear. A PCM designed to use this type of sensor can actually specify an AFR rather than just time-averaging fuel delivery to net 14.7:1. In some ways, a WB system should never really ever have to leave closed-loop operation, even at full-power. All the PCM needs to do is specify, say, 12.5:1 AFR and adjust the fuel delivery to get the correct voltage back from the sensor(s). An AFR gauge using a WB sensor is much more accurate than a NB sensor. As long as the transfer function is correct, the WB AFR gauge can show the actual air fuel ratio, usually expressed on 7-segment LEDs (or something similar) rather than dancing LEDs.

The Innovate LC-1 sensor and controller:

LC-1 Lambda Cable with 02 Sensor : Wideband Controller Cable for Dyno, ECU, Data Acquisition, or Gauge Applications

can actually be used in place of a narrow-band sensor because it can produce an output signal to "simulate" a narrow band signal that is sent to the PCM while the linear output can be sent to the AFR gauge.

I had some questions too on the same subject i'm new into prochargers so i don't know much about them. I have a 2001 Roush Stage 2 with 30,XXX miles on it and I found a p1sc for a good price.I was wanting to put the procharger in myself but if it will be to difficult to do so let me know and.I was wondering if anyone knew of a place in oklahoma close to tulsa that could do tunes and actually put the procharger. Everything on this roush is stock so far. please let me know through a PM or on here! thanks!