MikeRJ
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| posted on 21/9/11 at 01:37 PM |
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You are free to call it drivel but that doesn't stop it being true. Ask yourself why the solenoid valve is driven by a PWM signal if the phaser
is only supposed to work fully retarded or fully advanced? Also have a read of this, in particular the
following quote (my emphasis):
quote:
"The intake camshaft is equipped with an electro-mechanical control mechanism, which allows the cams maximum opening point, relative to
crankshaft degrees, to be varied between 85 and 145 degrees after top-dead-center on the intake stroke."
Considering none of the numbers add up on that dyno plot and the dyno operator hasn't even corrected for humidity or atmospheric pressure, I
don't see how you can put any faith in them.
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beaver34
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| posted on 21/9/11 at 04:25 PM |
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to be honest your attitude towards people trying to help your cause isnt great! why would they help you if your going to answer there replys like that
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coozer
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| posted on 22/9/11 at 11:28 AM |
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Sorry if it comes over like that, but it seems every time I post any questions about my engine it gets hijacked and turns into a argument about how
the vvt works.
I know how it works, I know how it works in my car and I'm quite happy with it.. I'm perplexed by the low comp figures and looking for a
bit more power....
1972 V8 Jago
1980 Z750
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Rob Allison
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| posted on 25/9/11 at 10:10 AM |
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Done a bit on the ST170 with a mate who has one in a mk1 escort on bike carbs with megajolt.
When setup at motorscope without vvt it made almost 170bhp. Then they tried just switching the vvt on (5Volt) it was a bit hit and miss but had a big
spick in torque at 2500 rpm. but due to the bodge trying to get it on the results were not realy usable.
But the VVT is not just a turn on at a set rpm. It has a map of its own through the rev range and it is a vairable signal to the solenoid as said.
Just putting 5 Volts on will just move the cam to its max setting.
But caution. The VVT should not be switch below 2000rpm. This is something to do with the cam timing causing piston to valve contact. I'm not
too sure on the exact point in the rev range that the max cam timing will cause this just i know it will happen. So it is possible that your
compression loss could be due to this ??
I'm trying to find the cam timing map for an ST170 in my mk2 escort. Below is the plot from the mk1 escort. The spike at the 2500rpm point is
the use of the vvt.
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Rob Allison
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| posted on 25/9/11 at 12:16 PM |
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Heres some ST info copied
The 170PS 2.0-litre Duratec ST engine has been developed from the standard 130PS 2.0-litre Ford Focus (Zetec)engine with several new features,
including:
· New, high-flow aluminium cylinder head with larger inlet valves and higher lift intake and exhaust camshafts for higher peak rpm levels
· Continuously variable intake valve timing
· High compression, cast-aluminium pistons and forged steel connecting rods
· Dual mass flywheel
· New dual state intake (DSI) manifold, using long runners for low-end torque and shorter runners for higher peak power outputs
· Larger bore free-flowing stainless steel exhaust system, tuned for enhanced performance sound.
Duratec ST’s new aluminium cylinder head features enlarged intake ports to increase its flow potential. It is fitted with larger intake valves (33.5
mm) to further Duratec ST’s free-breathing character. Stiffer springs on both the intake and exhaust valves help to facilitate a higher red-line.
Focus ST170 has an indicated red line of 7,200 rpm on the tachometer and rev-limiter intervention beginning at 7,350 rpm.
Fuel is delivered to the cylinders via an electronically controlled, high-output fuel pump. With precise electronic control of the fuel delivery to
the injectors, no return fuel loop is required. The system contributes to ST170’s Euro Stage IV emissions capability.
Variable valve timing technology gives Duratec ST combustion efficiency that eliminates the need for a close-coupled catalyst in the exhaust system.
This enhances its flow characteristics and performance capabilities further.
Duratec’s intake camshaft is equipped with an electro-mechanical control mechanism that allows the cam’s maximum opening point, relative to crankshaft
degrees, to be varied between 85 and 145 degrees after top dead centre. Variability is calibrated according to engine speed, load and operating
temperature. It is accomplished by changing oil pressure on either side of a piston in a helix between the cam and its drive pulley.
On cold start-up, VVT helps to provide a precise combustion calibration that facilitates quick light up of the underbody exhaust catalyst before
adjusting to a profile for high combustion efficiency. As a result, SVE could position the catalyst unit – incorporating premium metallic elements –
approximately 900 mm away from the cylinder head face to give Duratec ST its free exhaust flow with reduced back pressure. A second catalyst unit is
located downstream in the exhaust.
The exhaust system is constructed entirely of stainless steel, tuned for its throaty performance sound. Its exhaust manifold, cleverly designed for
package efficiency in the Focus engine bay, is created of equal-length tubular headers in a four-to-two-to-one configuration. The design combines the
first and fourth cylinder exhaust tubes and the second and third cylinder exhausts, respectively, before the resultant two pipes are combined into one
to enter the catalyst. The exhaust pipe diameter is 65 mm.
Robust elements were incorporated in Duratec ST’s top end to reflect the additional performance demands being placed on the engine. These include
stronger, lightweight, cast aluminium pistons with larger, 20 mm wrist pins and robust, sinter-forged connecting rods.
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ss1turbo
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| posted on 25/9/11 at 01:14 PM |
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I suspect that the VVT would work in conjunction with the dual length runners in order to improve the torque curve to be honest - any talk regarding
emissions is, at the end of the day, all about efficiency and not always about lean running.
If you're running throttle bodies/carbs/whatever isn't as it came from Ford, then you have already changed the inlet system - and its not
all about cam timing as thats only part of the story.
IIRC (and i'm not an expert on it) the early VVT systems (Honda? Toyota? Rover?) were not much more than an on/off system whereas now its become
a totally variable system allowing tuning as the engine passes up the rev range (and this is where the OE dual runner system would come in). On OE
power curves, you tended to see almost a "double dip" torque curve as one cam timing profile ran out and the other kicked in. The dual
length runners would possibly switch in and out as this change occured to again change the torque figure - and all of this only applies to full
throttle! What it may be used for at cruise and 50% throttle may be completely different.
If an ignition advance curve was just two settings, you'd have a very strange torque curve as well..and that tends to look like a map of the
Alps when viewed in 3D. Why should the cam advance/retard map be any different?
I think it was the Rover VVC engine that for more power, you just junked the VVC system and fitted a different (fixed) cam...
Long live RWD...
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Rob Allison
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| posted on 25/9/11 at 01:45 PM |
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The above was a quote for the standard ST170 as fitted into the Focus. So standard inlet, exhaust etc
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DixieTheKid
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| posted on 25/9/11 at 02:30 PM |
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The easy answer is to throw it in the bin and start again, listen to what people are telling you. You need a NASA engineer and lots of cash to see any
big BHP gain. If your worried about compession, go back to basics as i said before. Pull the head off, check the rings and valves. Simple!........
COS IT'S Worth IT
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Rob Allison
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| posted on 25/9/11 at 05:47 PM |
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Don't know where you get that idea. ST vvt is fine, you just need to run it right. Over 200bhp has been seen without opening up the st.
Or fit delete vvt cams and there good for 206bhp.
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DixieTheKid
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| posted on 25/9/11 at 06:59 PM |
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quote:
Originally posted by Rob Allison
Don't know where you get that idea. ST vvt is fine, you just need to run it right. Over 200bhp has been seen without opening up the st.
Or fit delete vvt cams and there good for 206bhp.
I would like to see that!
COS IT'S Worth IT
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Rob Allison
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| posted on 25/9/11 at 07:12 PM |
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One version http://www.catcams.co.uk/acatalog/Latest_News.html
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DixieTheKid
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| posted on 25/9/11 at 08:00 PM |
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LOL! Yeah without opening up the engine!
quote:
New Cat Cams Ford Duratec ST170 VVT delete profiles deliver impressive gains New Cat Cams non-VVT cam profiles for track day / rally use
High lift / short duration format to maximise torque and power Precision CNC ground from new steel billets Designed to work with original
Ford mechanical valve gear Original front camshaft seals (which is normally fitted around the VVT sprocket) can be maintained thanks to a
clever billet design Drop in profile with no piston to valve clearance issues Cat Cams adjustable pulleys required due to VVT deletion
Designed to work with carburettors or independent throttle bodies Dyno proven to produce 207 bhp / 177 lb.ft of torque Ideal for track day
and kit car applications Priced at £643.81 including VAT @ 17.5%, part number 2301013 Contact Cat Cams UK on 0845 51 95 720
Let me tell you that you will spend more getting to 200bhp then it will cost you to buy a MK1 Focus RS engine package.... So why do it?
[Edited on 25/9/11 by DixieTheKid]
COS IT'S Worth IT
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coozer
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| posted on 25/9/11 at 08:28 PM |
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Somebody PLEASE delete this thread....
1972 V8 Jago
1980 Z750
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scutter
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| posted on 25/9/11 at 10:27 PM |
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Coozer, give me a week whilst I do a stint on nights and I'll compression test my St170 lump in the Locost, I should be good as it made 188
earlier this year without the VVC even being switched on
I'll get back to you. Dan.
The less I worked, the more i liked it.
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silky16v
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| posted on 3/8/12 at 12:14 PM |
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Not wanting to stir all this up again but i've brought Coozer's old MNR Vortx
I'm having the car mapped in the next week and having spoken to my tuner he suggests that switching the VVT on around 2250rpm and then off again
around 5600rpm will give 180BHP+ on Throttle Bodies & this is possible on Omex 600 ECU
But he also said ideally i just install the DTA Pro 60 ecu that has full variable cam control, but at the moment i can't justify the cost of
this.
So we will have a play around with the VVT and try some different setting and i will report back my finding
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MikeRJ
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| posted on 3/8/12 at 01:40 PM |
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quote:
Originally posted by Cornishman
Just worth pointing out that MikeRJ has accidentally used the wrong RPM figures in his calculations thus causing some confusion. He has substituted
the RPM for peak torque into the peak power calculation therefore giving the false impression that a practically impossible set of figures have been
produced.
If you look at the print out CAREFULLY and run the figures as I have just done then they seem fine mathematically.
Not wishing to cause offence to anyone but thought it worth pointing out as I am following the thread with interest to help decide what engine to run
for the 2013 season (1.3 xflow for 2012!).
Steve
I know this was a long time back, but I hadn't noticed your post before. You are absolutely right, I did accidentally swap the peak and power
RPM figures. However, even with the correct numbers the results still make no sense even allowing for my cock up.
code:
RPM Claimed Power(bhp) Claimed Torque (nm) Claimed Torque(lbft) Calc power from claimed torque(bhp) Calc torque from claimed power(lbft)
4419 174.861 241.12 177.84 149.63 207.82
4711 178.36 235.13 173.423 155.59 198.84
Not only do the claimed power and torque not match up at the given RPM, a 2.0L normally aspirated production engine running on pump fuel simply can
not make 175bhp at just 4419RPM. That equates to a BMEP of over 15bar, beyond the capability of e.g. a normally aspirated Formula 1 engine, or a
NASCAR V8 and makes something like a BMW M3 CSL look pretty pathetic with it's 13.7bar
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coozer
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| posted on 3/8/12 at 07:17 PM |
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For gods sake dont start this off all over again...
1972 V8 Jago
1980 Z750
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mtechmatt
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| posted on 13/2/14 at 07:34 PM |
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I thought I would jump in for 2 reasons:
A) I have mapped several ST170s.
Those of you whom are under the impressions that a standard Focus St170 strapped down to a dyno makes 170bhp are wrong, they make usually around
155bhp. Our particularly nackared test car (see point B) makes 135bhp. Fact, pure and simple.
If you fit throttle bodies (and I mean good ones) and map it properly, and just do the old 'switch on the solenoid trick (which is NOT how Ford
do it, as stated by Mike, closed loop PWM) you will get crica 195 with a lumpy map and poor bottom end torque. My personal best is 197.4. headwork
(which you cant do much of, better off building from a blacktop) will take you to maybe 220bhp.
The second reason:
B)We are in the process of finishing the design of this little product which gives full VVT control on the ST170, mappable and accurate cam
positioning using closed loop cam/crank angle tracking, that will work with ANY engine management system, and thought it may be of interest to some of
you 
http://motorsport-electronics.co.uk/index.php/vvtpro.html
Cheers,
Matt
V4 Engine Management System | Online Shop |
Rolling Road Tuning | Motorsport
Preparation | Engine Packages | Throttle
Bodies
Check out what's happening in the workshop via our Facebook Page:
The Workshop
MEGASQUIRT ROLLING ROAD & BIKE CARB TUNING SPECIALISTS
www.mtechautomotive.co.uk
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Xtreme Kermit
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| posted on 13/2/14 at 08:23 PM |
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Holy thread resurrection!!!
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mtechmatt
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| posted on 13/2/14 at 08:47 PM |
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hehe I just couldnt let these dreams of 200+bhp, from an ST170 go by un-corrected lol
V4 Engine Management System | Online Shop |
Rolling Road Tuning | Motorsport
Preparation | Engine Packages | Throttle
Bodies
Check out what's happening in the workshop via our Facebook Page:
The Workshop
MEGASQUIRT ROLLING ROAD & BIKE CARB TUNING SPECIALISTS
www.mtechautomotive.co.uk
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