does "zetec" kick in at a certain rpm?

loydchristmas · May 17, 2003

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?

RainyZX3 · May 17, 2003

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 ]

Bmorezx3 · May 17, 2003

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

WayMag · May 17, 2003

The variable timing was on the exuast valves only
in the zx2. It gave no power value.

[ 05-16-2003, 11:47 PM: Message edited by: WayMag ]

TheReaper · May 17, 2003

Originally posted by WayMag:
The variable timing was on the exuast valves only in the zx2. It gave no power value.

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 ]

PhocusZX3 · May 17, 2003

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.

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.

TheReaper · May 17, 2003

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.

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.

thestiffmister · May 17, 2003

there is def. a gear ratio difference between the cars i do not know what they are exactly but they are very differant.

MichaelXi · May 17, 2003

When does "Cosworth" kick in??

TheReaper · May 18, 2003

Originally posted by MichaelXi:
When does "Cosworth" kick in??

When Ford decides to kick some across the pond

MichaelXi · May 18, 2003

Originally posted by TheReaper:
<blockquote>quote:<hr />Originally posted by MichaelXi:
When does "Cosworth" kick in??

When Ford decides to kick some across the pond

<hr /></blockquote>

I'm Waiting....

focus_on_speed · May 19, 2003

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?

Jon Sturgeon · May 19, 2003

Originally posted by focus_on_speed:
The intake and exhaust cams overlap between 6k and 7k...

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

Focusracer1 · May 19, 2003

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?

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.

2xZx3 · May 19, 2003

Originally posted by Jon Sturgeon:
<blockquote>quote:<hr />Originally posted by focus_on_speed:
The intake and exhaust cams overlap between 6k and 7k...

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<hr /></blockquote>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.

matthc33 · May 19, 2003

my cold air does the same thing. driving at high rpms through tunnels is probably one of my favorite things to do now.

JohnsZX2SR · May 20, 2003

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 ]

FociD00d02 · May 20, 2003

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

peak is 5500rpms

stealthturbofocus · May 20, 2003

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...

OmniFocus · May 20, 2003

Originally posted by stealthturbofocus:
Can someone please tell me what VCT means? None of these seem to fit...

Variable Cam Timing.

does "zetec" kick in at a certain rpm?

loydchristmas

RainyZX3

Bmorezx3

WayMag

TheReaper

PhocusZX3

TheReaper

thestiffmister

MichaelXi

TheReaper

MichaelXi

focus_on_speed

Jon Sturgeon

Focusracer1

2xZx3

matthc33

JohnsZX2SR

FociD00d02

stealthturbofocus

OmniFocus

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