16 psi Pulley


ByeEnzo

ByeEnzo

GT
Mark IV Lifetime
Le Mans 2010 Supporter
Dec 10, 2005
2,326
Fort Worth, TX
Just got my Ida exhaust and cold air kit. Since they were back ordered for a while, he threw in the 16 lb. pulley for free. I had no intent of increasing boost. My question is... do you have to reprogram the computer if you increase boost from 12.5 to 16? Won't the ECU reprogram to prevent detonation etc? Ida says you can swap the pulley without changing the belt, but he recommended a dyno tune. I'm in TX and don't want to send the car to NJ. There are local tuners that I could investigate if necessary.
 
1) you will definitely need a tune. PCM does not have detonation/knock sensors, so you need to tune before you drive
2) You will get some belt slippage unless you figure out a way to pick up the slack of the smaller pulley (larger idler, power steering spacer, etc..)
3) It's a huge difference in power!
 
centerpunch said:
There is a spring-loaded tensioner on an idler pulley that compensates for variations in belt lengths, etc. This is probably adequate to compensate for small changes in the diameter of the supercharger pulley.
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I dunno. The terminators would go for the stock belt down to a certain pulley size. After that you needed rollers near the blower to wrap the belt around the pulley for more contact area. Your pulley supplier should know and have idlers for it.
 
ByeEnzo said:
Just got my Ida exhaust and cold air kit.
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Who is Ida? I such a newbe!
 
Ida is just one of the very nice "tuners" on this site that is more than willing to take our hard earned dollers to turn your "very fast GT" into a "stupid fast GT". :thumbsup
 
On any pulley less than 3" you will start to get some belt slippage. Since every tuner sells a pulley less than 3" diameter, you will need something to ensure max tension. People sell larger idler pulleys (easiest to install) and power steering pump spacers. The spring tensioner tension is not linear. When you go to a smaller pulley there will be less tension/pressure to keep the belt from slipping. Usually, it only happens on the top end 5800rpms and up, but it will happen depending on the conditions.
-W
 
With a 16 psi Pulley, you "DO NOT" need a TUNE, unless you peg the MAF; BUT; A tune will give you MORE HP etc. The COMPUTER will COMPANSATE for it. The Ford GT STOCK TUNE is VERY "conserveative".

AMB
 
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SteveA said:
Ida is just one of the very nice "tuners" on this site that is more than willing to take our hard earned dollers to turn your "very fast GT" into a "stupid fast GT". :thumbsup
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OK, I've poked around a bit (to no avail), where can I find Mr. Ida?
 
 
Ford has a ton of timing advance to compensate for the ridiculous amount of fuel the PCM program dumps. When you add 3-4lbs of boost, the car will not compensate and will lean out with the added air and the timing will not retard.
Personally, I would not add 100hp to a $35k engine and not tune the car for the power, but to each his own.
 
It was annouced at the Rally that Ford Racing should soon have a smaller pulley and a tune. Keep watching their site.
 
Ida does not sponsor the site, and you will definitely want a tune with 16psi!
 
ByeEnzo,

Engine management and programming is one of my favorite topics and we could (and happily!) go on and on about it. I'll give the 30-second summary. All OBDII cars (1996+) have an ECU that runs in closed-loop or open-loop mode. (There are other modes like warm-up, etc, but we'll ignore for now.)

In "normal" driving a car is in closed-loop, applying fuel injector pulse durations and then checking the O2 sensors to achieve an ideal 14.7:1 A/F ratio (stoichiometric). It does this many times per second and IT WILL rapidly achieve stoich. BTW, if the ECU cannot achieve stoich it will very rapidly issue a Check Engine Light.

BUT.... modern fuel injected cars ar not designed to run at stoich ALL of the time. Under load (quick acceleration, steep hills, etc.) engines need to run richer (more fuel) to prevent detonation. The problem is that O2 sensors (despite common belief) can only tell the computer if the A/F is above or below stoich. In the closed-loop scenario above, the ECU is fiddling around "walking the fence" of above/below/above/below stoich. As the O2's ARE COMPLETELY USELESS for anything other than reporting on stoich, manufacturers must have other means. This is open-loop mode. So, as you depress that gas pedal, at some point the ECU will seamlessly jump out of closed-loop in favor of open loop (running richer). It achieves the "running richer" by looking at the quantity of air being ingested through the mass air and using internal, factory-programmed values to hit these richer values. The trouble is that it has no feedback loop (hence the name of "open loop"), to know if it achieved the value or not. It could easily run either rich or lean and not know it.

Finally, to your question of the smaller (more boost) pulley. You'll be fine in closed-loop (light to mid throttle applications.) However, you will go into the danger zone when your car jumps to open-loop. The internal algos are now out of whack, and despite the car "sees" the amount of incoming air, the slopes of the computations have changed and your engine COULD be running lean. A lean supercharged motor = "Boom!"

In summary, 16psi pulley and drive like Grandma = OK.
16psi pulley and drive GT as you should = potential disaster.

Get a tune.
 
The Ford Racing guy at the rally would not confirm or deny that you would void your warranty by using his parts. Curious.
 
Believe me, using a pulley or tune, no matter who makes it will immediately void your powertrain warranty. Until they write it in big bold red letters on the box, don't take anyone's word for it. Of course, you could run 16-17 psi on these things forever, and nothing is going to happen...

fjpikul said:
The Ford Racing guy at the rally would not confirm or deny that you would void your warranty by using his parts. Curious.
Click to expand...
 
nota4re said:
ByeEnzo,

Engine management and programming is one of my favorite topics and we could (and happily!) go on and on about it. I'll give the 30-second summary. All OBDII cars (1996+) have an ECU that runs in closed-loop or open-loop mode. (There are other modes like warm-up, etc, but we'll ignore for now.)

In "normal" driving a car is in closed-loop, applying fuel injector pulse durations and then checking the O2 sensors to achieve an ideal 14.7:1 A/F ratio (stoichiometric). It does this many times per second and IT WILL rapidly achieve stoich. BTW, if the ECU cannot achieve stoich it will very rapidly issue a Check Engine Light.

BUT.... modern fuel injected cars ar not designed to run at stoich ALL of the time. Under load (quick acceleration, steep hills, etc.) engines need to run richer (more fuel) to prevent detonation. The problem is that O2 sensors (despite common belief) can only tell the computer if the A/F is above or below stoich. In the closed-loop scenario above, the ECU is fiddling around "walking the fence" of above/below/above/below stoich. As the O2's ARE COMPLETELY USELESS for anything other than reporting on stoich, manufacturers must have other means. This is open-loop mode. So, as you depress that gas pedal, at some point the ECU will seamlessly jump out of closed-loop in favor of open loop (running richer). It achieves the "running richer" by looking at the quantity of air being ingested through the mass air and using internal, factory-programmed values to hit these richer values. The trouble is that it has no feedback loop (hence the name of "open loop"), to know if it achieved the value or not. It could easily run either rich or lean and not know it.

Finally, to your question of the smaller (more boost) pulley. You'll be fine in closed-loop (light to mid throttle applications.) However, you will go into the danger zone when your car jumps to open-loop. The internal algos are now out of whack, and despite the car "sees" the amount of incoming air, the slopes of the computations have changed and your engine COULD be running lean. A lean supercharged motor = "Boom!"

In summary, 16psi pulley and drive like Grandma = OK.
16psi pulley and drive GT as you should = potential disaster.

Get a tune.
Click to expand...


I have not seen this explained so succinctly. Thanks. :thumbsup
 
pleaese TUNE YOUR CAR WITH NEW 16 PSI Pulley...


JOE
 
Byeenzo, call John Hennessey in Houston! Good guy and reliable company. He did a blue '05 GT and that car sounds and performs fantastic. Here's the site:
www.hennesseyperformance.com Good luck, BD40
 
AJ just go to Dallas Mustang if you need the tune done..they are local and an advertiser on the site.

I would not WOULD NOT got to HENNESSEY...if you want some insight go to the viperclub sight and read some of the post on what he has done over there...after some of the stories I don't care if he has turned around he will never see one of my cars.

Matt
 
Thanks for all the input, especially nota's explanation of how this all works. Matt, good idea to use the guys in Dallas. AC
 
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