think they'll be worth 15 rwhp??

10Hole - your reference sounds as if it's from a generic description of how feedback systems work. Let's get more specific. From Charles Probst' book "Ford Fuel Injection and Electronic Engine Control", pg. 86 in the Oxygen Sensor section --

"The ceramic sensor body is a solid electrolyte that generates a voltage only if the ambient air has a higher oxygen content thant the exhaust. The ceramic material must be hotter than about 300 degrees C (570F). On a cold engine, it may take 90 to 120 seconds for an unheated oxygen sensor to get hot enough to start generating voltage.

In most 1988-1993 EEC systems, and beginning with '93 MECS, you'll find electrically heated oxygen sensors to improve emission control. Durnig engine warm up, mixtures are rich because the system is operating open loop, not controlled closed loop. The sooner the oxygen sensor becomes hot enough to send proper signals, the sooner the engine can operate closed loop for better control. A heated sensor may be hot enough after 10-15 seconds. V-type engines usually two oxygen sensors, one for each bank."

Probst' book is considered the 'bible' when it comes to Ford's EEC systems. The engineers designed the system to get into closed loop as quickly as possible because cold start up is the dirtiest part of the engine's EPA running cycle. The last thing they wanted to do was wait until coolant temps had warmed to some predetermined temp -- they couldn't pass what were then becoming stricter and stricter emissions levels. The main reason heated O2 sensors were developed was so they could decrease the 90-120 second time interval to something much shorter - so the engine could get to closed loop much quicker - so they could better control emissions. There are coolant temperature dependant functions - but they pertain to primarily to how the thermactor diverter valves and egr systems operate.

The computer wants to get to closed loop asap - it's the most efficient mode of operation from an emissions and fuel economy perspective. It just needs the O2 sensors to warm up to do so.

....and we've got some semantics at works. Coolant temp has nothing to do with it. It's time and temperature based in that it takes a certain amount TIME for the O2's to reach operating TEMPERATURE. So it will take longer when the O2 sensor is colder to start with. But we're talking seconds, not minutes. It can take mine 10 minutes to reach t'stat open coolant temps; but it's in closed loop before I get out of the neighborhood.

electric fan...
I dyno'd before and after.
No other changes to the car, or it's tune.
gained 1hp, lost 3tq.
At the track,there was no gain what-so-ever... nor was there any loss.
It is a good mod for cooling purposes, or, if you're sick of the propelloer noise.

Intake spacer...
If you need valve cover clearence go for it, otherwise, send me the 40bux, I need it.

Mike - the problem is that neither the dyno or the track is repeatable enough to reliably quantify small incremental gains/losses. You definitely reduced parasitic losses by not twirling that heavy mass around - but it's gonna be REALLY hard to measure it.

Even if you removed the fan/belt while on the same strap down session at the dyno, the air pressure difference in rear tires that occurs after a run can alter the next run by 5HP. Virtually impossible to measure those small changes reliably. People put WAY too much emphasis on absolute dyno numbers.

Gearbanger 101 said:

Yeah, I'm with the majority on this one Grn92LX......you be wrong!

Good try though!

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I Be 100% right Read michaels post. I better get my 180* thermo out so my car gets into closed loop

Grn92LX said:

Open loop to closed loop transfunction is TIME based NOT temperature based

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My bad, I was always under the impression it was temperature related. Either way, an engine will run its best when it is running at normal operating temperature - which is at least what i'm getting at.

Anyway, more on the e-fan. It doesn't "add" horsepower, it just frees it up

Adaptive strategy needs 100* ACT to be enabled. Maybe that is what everyone is thinking about?

noslow5_0 said:

well from what ive been told by numerous people my current setup should be putting down a little more then what it did.... air fuel was at 12.3 i believe all the way across the board...

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Every engine is different. You can take 2 engines built with the same parts by the same guy using the same build techniques and get differences in power that you'll see on the dyno.

Michael Yount said:

Potential gains on tuning depend on the a/f ratio associated with your runs. For most of the naturally aspirated set ups I've seen, each point richer than safe optimum (around 13:1) gained about 8-10 HP. So, if you were around 11.5-12:1 a/f and you leaned it out to around 12.5-13:1, you'd likely pick up 8-10HP at peak.

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WOW!!! If this is true, I have a good 32-40rwhp in the tune!!! I was running 9:1 A/F and put down 223rwhp.

Matt