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does "zetec" kick in at a certain rpm?

8.3K views 24 replies 17 participants last post by  JohnsZX2SR  
#1 ·
i was driving my fiances zx2 with the zetec engine like mine, hers is a 2002. when i got at about 4000rpm i could hear something in the engine, like a little angry animal that just got kicked in the butt and the car suddenly has more hp. i have never noticed this in my zx3. am i just crazy?
 
#2 ·
The engine in the ZX2, as well as the SVT has varriable came timing on the intake side for the SVT, and Exhaust for ZX2. The regular Zetec engine does not. Other than that, there is no such thing as Zetec in the manner that Honda drivers "Hit VTEC"

[ 05-17-2003, 03:50 AM: Message edited by: RainyZX3 ]
 
#5 ·
Originally posted by WayMag:
The variable timing was on the exuast valves only in the zx2. It gave no power value.
<font size="2" face="Verdana, Arial">Actually it does, when cruising around in the lower rpms, the zx2 has noticably more torque. In my zx2 I can go up any hill at 40mph in 4th with no problem, I can't in my zx3.

To answer Nickzx3's original question, you are not crazy. In the zx2, somewhere between 3500 -> 4000 rpm, the vct stops retarding the exhaust cam, and you get a little kick in the pants.

[ 05-17-2003, 05:45 AM: Message edited by: TheReaper ]
 
#6 ·
Originally posted by TheReaper:
Actually it does, when cruising around in the lower rpms, the zx2 has noticably more torque. In my zx2 I can go up any hill at 40mph in 4th with no problem, I can't in my zx3.

<font size="2" face="Verdana, Arial">Actually that is due to the superior transmission gearing in the ZX2. I think they have somewhere around a 4.08 final drive.

VCT is truely an emissions tool, and does hinder performance. We have seen a couple ZX2's on a local dyno lean-out and run like ass in the upper RPM range...not a good thing. ZX3's do not suffer from the same condition. Of course this could be a couple isolated cases on two seperate cars, but if I had a ZX2 the first thing I'd do is scrap the VCT.
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#7 ·
Originally posted by PhocusZX3:
Actually that is due to the superior transmission gearing in the ZX2. I think they have somewhere around a 4.08 final drive.

VCT is truely an emissions tool, and does hinder performance. We have seen a couple ZX2's on a local dyno lean-out and run like ass in the upper RPM range...not a good thing. ZX3's do not suffer from the same condition. Of course this could be a couple isolated cases on two seperate cars, but if I had a ZX2 the first thing I'd do is scrap the VCT.
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<font size="2" face="Verdana, Arial">1st gear in the ZX2 is definately lower than the ZX3. But in 4th gear the rpms to mph match pretty close between both.

As for scrapping the VCT, just like an EGR valve, neither is actively recirculating the exhaust when you are accelerating in the high rpms. But in normal driving, VCT is superior to an EGR valve.
 
#11 ·
Originally posted by TheReaper:
</font><blockquote><font size="1" face="Verdana, Arial">quote:</font><hr /><font size="2" face="Verdana, Arial">Originally posted by MichaelXi:
When does "Cosworth" kick in??
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<font size="2" face="Verdana, Arial">When Ford decides to kick some across the pond
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</font><hr /></blockquote><font size="2" face="Verdana, Arial">
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I'm Waiting....
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#12 ·
I don't know about all of you, but my ZETEC kicks in at 6k rpm. HAHA. Just kidding! At 6k it does sound like VTEC with my CAI & TB. The intake and exhaust cams overlap between 6k and 7k, and therefore I get the exhaust sound unmuffled out of my intake. It sounds cool as hell, and if I recochet it off of a bus or something, it is ear splitting. I know others have this as well, but do all CAI do this to a focus?
 
#14 ·
Originally posted by focus_on_speed:
I don't know about all of you, but my ZETEC kicks in at 6k rpm. HAHA. Just kidding! At 6k it does sound like VTEC with my CAI & TB. The intake and exhaust cams overlap between 6k and 7k, and therefore I get the exhaust sound unmuffled out of my intake. It sounds cool as hell, and if I recochet it off of a bus or something, it is ear splitting. I know others have this as well, but do all CAI do this to a focus?
<font size="2" face="Verdana, Arial">Funny you mention this. I've had the FS Cool Flo for a long time, but recently switched to a CAI and after 6k it changes tone just like you said. I was trying to figure out why.
 
#15 ·
Originally posted by Jon Sturgeon:
</font><blockquote><font size="1" face="Verdana, Arial">quote:</font><hr /><font size="2" face="Verdana, Arial">Originally posted by focus_on_speed:
The intake and exhaust cams overlap between 6k and 7k...
<font size="2" face="Verdana, Arial">Can you explain what you mean by this? Since there is not variable valve timing on the Zetec, I don't see how the speed of the engine would make the cams overlap at a particular engine speed.

Confused.

Jon
</font><hr /></blockquote><font size="2" face="Verdana, Arial">It takes a small amount of time for the spring to close the exhaust valve, and at 6 to 7 k, the cam is opening the intake valves faster than the spring can pull the exhaust valve. Stiffer valve springs can eliminate this.

With softer valve springs, at high rpms, you can get valve float, where the spring never fully closes the valve before the cam comes around and pushes it open again. If you have ever driven an old chevy s10 with the 2.5, you will feel this. Those had slinkys for valve springs.
 
#17 ·
The ZX2 is 200-250 lbs. lighter than the ZX3 and the MTX has slightly better gearing for acceleration. The exhaust VCT in the ZX2, Cougar and '99-'00 Contour Zetec engines is primarily for emissions and for economy. It does, however, allow the use of longer duration cams in a stock emissions legal engine.

ZX2 intake: 214 deg @ 0.050", 0.366" lift
ZX3 intake: 206 deg @ 0.050", 0.353" lift

ZX2 exhaust 211 deg @ 0.050", 0.338" lift
ZX3 exhaust 205 deg @ 0.050", 0.342" lift

The VCT is under PCM control, advancing the exhaust cam up to 60 deg. anytime the throttle is opened wider than idle and the engine is above idle. At some points the cam is fully advanced allowing exhaust gases to mix with the intake charge. At other points, the cam is partially advanced increasing power at high rpm.

The improvement in midband is partly due to the longer duration and higher lift of the intake cam, and partly due to more aggressive (relative to the non-VCT Zetec) fuel and ignition maps from 2000-4000 rpm. The changeover in the 3500-4000 rpm range is real as the engine shifts from emissions/economy mode to power mode if the engine is revved at WOT.

In general, the non-VCT Zetec in the Focus makes more torque in the 3000-5000 rpm range than the ZX2 engine. With cams, head work and exhaust the Focus Zetec is easier to work on and is a screamer.

The one exception is the engine in the federal ZX2 S/R with the federal PCM code, CWQ3. The S/R used a stock ZX2 engine but equipped with an Iceman intake, Borla muffler and the Ford racing PCM.

This S/R engine was rated at 146 HP and 140 ft-lb of torque and makes consdirably nmore torque from 2000-4000 rpm than any of the other 2.0 liter Zetecs, except for the SVT engine (170 HP, 145 ft-lb torque)

Interesting that the CWQ3 engine does not show the switchover at 4000 rpm, mostly because it is making more torque in the 2200-4000 rpm band, and keeps making torque up to 5000 rpm where the stock engine starts to roll off.

[ 05-20-2003, 07:29 AM: Message edited by: JohnsZX2SR ]
 
#18 ·
Originally posted by Bmorezx3:
although the variable timing on the ZX2 is for emmissions only. the focus zetec does, however, seems to meet it's powerband peak around 4000rpm, which is where my car really gets going.

Nate
<font size="2" face="Verdana, Arial">peak is 5500rpms
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#19 ·
VCT Value Chain Transformation
VCT Venture Capital Trust (UK fiscal status)
VCT Versatile Card Technologies, Inc.
VCT Vibronic Coupling Theory
VCT Victims of Crime Trust (United Kingdom)
VCT Victoria, TX, USA (Airport Code)
VCT Vinyl Composition Tile
VCT Virtual Connection Tree
VCT Visual Communication Technology
VCT Vitrified Clay Tile
VCT Voluntary Correction of Tax-Sheltered Annuity Failures (IRS)
VCT Voluntary Counseling and Testing

Can someone please tell me what VCT means? None of these seem to fit...
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#21 ·
Originally posted by OmniFocus:
</font><blockquote><font size="1" face="Verdana, Arial">quote:</font><hr /><font size="2" face="Verdana, Arial">Originally posted by stealthturbofocus:
Can someone please tell me what VCT means? None of these seem to fit...
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<font size="2" face="Verdana, Arial">Variable Cam Timing.</font><hr /></blockquote><font size="2" face="Verdana, Arial">Surely he was Joking......
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"The one exception is the engine in the federal ZX2 S/R with the federal PCM code, CWQ3. The S/R used a stock ZX2 engine but equipped with an Iceman intake, Borla muffler and the Ford racing PCM."

This Brings about a BIG Question...
Could you change to that PCM on a Focus Zetec w/ the same Mods (Or Similar) and see the same results?
Would a Chip achieve the same end result if it's the correct program for your Mods and goals?
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[ 05-20-2003, 01:28 AM: Message edited by: MichaelXi ]
 
#25 ·
Originally posted by MichaelXi:
"The one exception is the engine in the federal ZX2 S/R with the federal PCM code, CWQ3. The S/R used a stock ZX2 engine but equipped with an Iceman intake, Borla muffler and the Ford racing PCM."

This brings about a BIG Question...
Could you change to that PCM on a Focus Zetec w/ the same Mods (Or Similar) and see the same results? Would a Chip achieve the same end result if it's the correct program for your Mods and goals?
<font size="2" face="Verdana, Arial">The CWQ3 code has an aggressive fuel and ignition advance map and better control over the VCT. It is aggressive to the point that Ford had to issue a different PCM codes (XHG3, NGP0) to be smog legal in CA and the Northeast states.

One other advantage of all 3 Performance PCM codes is that they adapt and learn within a +/-30% variance compared to the +/-16% allowed by most Ford OBD-II PCM codes.

Ford Performance missed an opportunity by not releasing a performance PCM for the Focus Zetec !!

It doesn't make sense to try to adapt the S/R PCM to a Focus. Without the VCT active you will get a CEL and interfacing the PCM to the instrument panel would be a headache.

One big advanatage the Focus Zetec has is better exhaust flow over the VCT Zetec in stock form. The stock focus tubular manifold and cat flows better than the ZX2 exhaust. Header upgrades even with the cat are easier on the Focus. The Focus also has a wider range of cams available. Try to maximize what you have with the Focus Zetec.

A good Superchip program will give similar improvements to the fuel map and ignition advance. Get one of the better Focus Zetec PCM codes and add a Superchip. I would recommend going this route.

[ 05-20-2003, 12:01 PM: Message edited by: JohnsZX2SR ]