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Author: Subject: Some ST170/Zetec engine questions
Jenko

posted on 12/3/14 at 02:52 PM Reply With Quote
I still stand by my previous comments - The On/Off comparission is not a true representation as the engine was not mapped accordingly around the function of the VVT solinoid.

So, at the moment, we can't really say if it works or not as no doubt the fuelling would be all over the place if using a standard ford ECU.

The utimate comparisson is using an after market ECU with your variable cam timing system - mapping it to it's full potential. then doing the same but just using the on/off - of course it would then need re mapping.

For what it's worth, I'm still sure the variable would be better, but at least we would know by how much.

all good though, and a great experiment.

[Edited on 12/3/14 by Jenko]





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mtechmatt

posted on 13/3/14 at 11:28 AM Reply With Quote
quote:
Originally posted by BaileyPerformance
quote:
Originally posted by mtechmatt
Hmm, IIRC Autodata liosts the St170 as around the 155 mark, certainly all we have ever seen anyway...

Our stock St170 focus we dynoed at the start made sub 150 And that is a normal car bought for testing, with no modifications at all

Matt


155bhp at the wheels would be correct, about 20bhp loss through transmission is normal.

The one we tested made close to 170bhp stock, we also tested a stock 2.0L focus mk1, was within 5bhp of what ford stated.

Same goes for my standard mk1 focus RS.

The point I'm making is Ford do not lie about power outputs, this is true right back to pinto powered escorts, we did a stock RS2000 and it make 105bhp, spot on.

We have stripped a couple of ST170 engines, looking at the ports compared to a black top you can see these engine will make power - if a stock blacktop will make 160 an ST should make 190 with decent induction and your VVT device.


A stock blacktop makes about 135. I honestly dont know how you are getting 170 from an OEM st170, the dont make it...

I think the fact the demo test car was a stock ST170 and it made what it made:

Here's the car:



And here's the graph...



What more can be said? Hang on.. our dyno is wrong

A blacktop on Jenvies makes 170bhp everytime, an ST170 in standard trim, does not.

I have dyno'd quite a few of them, and had this very argument with quite a few boy racers claiming they should have 200bhp as they had 170 and added a 30bhp air filter.

Again, not that it matters. We gained torque and power compared to how its usually done... that IS what matters, and what all the experimentation was about... As I said Dale, happy to send you a unit once stock lands in 3 weeks...

Dont get me wrong, I am happy to say to people, "Dont worry your car made 300bhp, BUT everyone on the internet says that an ST170 makes 170, and our dyno shows 20% losses, so really your car is 360bhp" - Its a shame, because those idiots would go away happy even if I did just talk compete sh*te to them...

I just prefer to look at before and after, thats all a Dyno is any good for, and failing that, does the car drive better sir? Wouldnt even need a dyno then.. well, just for mapping/steady state, but seat of pants and lap times would probably get you close enough, just would take longer...

Dont get me wrong, not having a dig, but a stock saxo VTS that is suppose to be 120bhp makes bang on 120bhp, an OMEx crate motor that ios sold as making 170bhp, makes 170bhp, an St170 is NOT 170bhp. (Now this in my experience, after mapping and running quite a few, and obviously I am not the only one out there.) If Dale has seen 170bhp, then I believe him, I dont think he would lie, nothing to gain, but I have not seen it myself, so if I am asked what power an St170 makes, I will tell you, sub 160...

Further reading:
http://passionford.com/forum/technical-help-q-and -a/337589-st170-poor-dyno-run.html#post4695583


And yes, I expected an ST24 to be referring to the vales, I was just seeing who would actually point out my obvious, sarcastic mistake

[Edited on 13/3/14 by mtechmatt]

[Edited on 13/3/14 by mtechmatt]

[Edited on 13/3/14 by mtechmatt]

[Edited on 13/3/14 by mtechmatt]






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Dusty

posted on 15/3/14 at 10:47 PM Reply With Quote
Interesting point on comparison of ST and blacktop heads the exhaust valves and ports are the same sizes. Considering the inlets are very different I suspect this limits power on the ST and is part of why both engines need a good exhaust system.
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mtechmatt

posted on 29/4/14 at 01:43 PM Reply With Quote
Here is a quick video on how VVT works...

https://www.youtube.com/watch?v=O5qkdFk50Zg&feature=youtu.be[/youtube]






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Rob Allison

posted on 15/6/14 at 11:19 AM Reply With Quote
For those interested i have some information on the differences with the zetec and the ST170 duratec(zetec)

Engine
The 2.0L Duratec ST engine is based on the 2.0L Zetec-E engine. In comparison to the 2.0L Zetec-E engine the modifications are:

Cylinder Block
part modified to include piston spray jets. (Some zetecs have these)

Cylinder Head
Inlet Port: - High flow design with new manifold break-out.

Exhaust Port: - Standard port but with secondary air feed to the back of the exhaust valve.

Water Jacket: - Revised flow around ports.

Oil feed arrangement for variable valve timing installation.

Incorporation of VCT (variable camshaft timing) solenoid in front camshaft bearing cap.

Inlet Valves
33.5 mm diameter with revised spacing to maintain bridge material and longer length for new port.

Exhaust Valves
Standard diameter but longer to commonise tappet with the inlet side. sodium-filled exhaust valves

Inlet Camshaft
Increased lift and duration with variable timing. 277/265 lift 10.95mm

Trigger wheel fitted to indicate cam position.

Exhaust Camshaft
Increased lift and duration. 230/220 lift 9.85mm

Tappet
Series of sizes commencing with unique graded part to suit new length valve and revised cam profile.

Valve Springs
Inlet and Exhaust unique parts to suit new valve lengths and revised cam profiles.

Power Cell Assembly
Piston with 20 mm diameter gudgeon pin.

Connecting Rod (139.19mm) - Forged fracture-split design.

Top piston ring Internal bevel to reduce blow-by of combustion gasses and negative ovality of the ring ends to reduce wear.

Cam Cover Assembly
Re-styled and revised to suit new VCT solenoid installation. Cam Cover and Gasket Assembly.

Upper Timing Belt Cover Assembly
Re-styled to include VCT pulley.

Front Engine Mount
Mounting studs moved to clear VCT pulley.

Alternator Bracket
Modified to accommodate revised engine mount.

Intake Manifold
Made up of two assemblies replacing the single piece manifold with fixed length tracts.

Plenum Assembly
Housing Assembly-Manifold-Injectors
Variable-length intake runner design.
The unit is in the short runner position with the engine off and then switches to the long runner position when the engine starts. The runners then switch to short runner position above 6000 rpm.

Throttle Body
Modified 63 mm diameter part.

Injectors
Increased flow items specified as 224.8 g/min at 2.7 bar (normal fuel rail pressure)

Fuel Rail
Redesigned part with integral damper and no fuel return connection. The fuel inlet to the rail has been repositioned requiring a new fuel feed hose assembly.

Flywheel Assembly
Dual mass flywheel.

Clutch Assembly
Friction plate increased diameter.

Pressure plate increased diameter. 228mm

Oil Cooler
Modine type.

Variable Cam Timing System

Variable Timing Unit Assembly
Solenoid Assembly
Oil Separator Assembly
Internal changes to improve performance under high cornering loads to be introduced onto base engine.

Exhaust System
Tuned 4-2-1 system with the catalyst located under the oil pan.






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Jenko

posted on 16/6/14 at 07:35 AM Reply With Quote
Quite a bit changed on the st170 engine then...more than I thought...great info.

I was just reading back through the thread, and the real conclusion to the on / off function of VCT, is it seems to work fine as on / off, as long as your ecu has the function of turning it off again at higher revs, else, as per the findings, you loose lots of peak power.

[Edited on 16/6/14 by Jenko]





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Andy S

posted on 16/6/14 at 05:29 PM Reply With Quote
Interesting that it was chosen to present the 10 degree fixed advance graph here and not the 30/40 graph.



It would have also been more representative of comparison if you had taken a run of the Escort at a fixed 30/40 - i.e. the 100+ fixed mechanical option against the benefit of your box at 240+ As you had already proven that the max advance provides rubbish results.

Hopefully 30/40 fixed V the PWM would have shown that you could offer a real world benefit in the 2000- 4000 RPM range as well as the pub bragging rights of keeping the maximum power capability for the extra cash and complication.

Mate is working on a turbo ST170 and has the lock out kit to fit but I have given him your company detail to discuss the box with you.

Cheers

Andrew






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Rob Allison

posted on 16/6/14 at 05:46 PM Reply With Quote
You don't get any extra power by running the vct but you gain a little extra torque at 3 to 3.5k revs. For me the extra torque is not worth the price. Yo may as well put the cash towards a set of cams and got for over 200 bhp which you'll not get even with the box of tricks.

With the vct just switched on you advancing the cam 9 deg past the point ford control it to and about 30deg past the best power point.
There is a massive difference with the cam locked at the right point.






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Andy S

posted on 16/6/14 at 06:33 PM Reply With Quote
You "may" not get any extra top end but it is quite clear that you will get a great deal of extra power (torque is the best sort of power - ask F1) - the area between the two graphs is where you should be focused, and you have to go through every RPM from Idle to get to that magic maximum and the less there is on the way the slower you will get there. That's why those that appreciate it do not dismiss that area.

If you leave you your driveway with clutch dumped at 5000 rpm and your box ratios never drop below that then fair play - lock and enjoy.

A lock out kit is 100 + the hassle of fitting it and finding that sweet spot for your set up - good luck with that . To plug in a box for a 150 more and potentially (yet to see proof mind) get all that available power in that 2000-4000 area that could be worth every penny. I would rather have a simple map change on the box to re-timing cams any day of the week.

There is only a massive difference between locked (at the correct point for your car) and uncontrolled. You would need a PWM input to find that control point to lock it at. and if you have fitted Verniers to make the job easier you have already spent far in excess of the box and for ultimately less power ......

The only option that is better value than the box is the fixed "if" there is a cam timing at 38.678 degrees that magically works for every installation providing more power at all RPM.

If going for power then you could argue then dont use an ST170 with cams - just fit a Duratec and go from there - but the point being made is that there is a nice little box that appears to solve the issue of good power from the ST as standard with a lowish cost and real world use.

Hopefully a better Dyno back to back will emerge.



quote:
Originally posted by Rob Allison
You don't get any extra power by running the vct but you gain a little extra torque at 3 to 3.5k revs. For me the extra torque is not worth the price. Yo may as well put the cash towards a set of cams and got for over 200 bhp which you'll not get even with the box of tricks.

With the vct just switched on you advancing the cam 9 deg past the point ford control it to and about 30deg past the best power point.
There is a massive difference with the cam locked at the right point.







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Rob Allison

posted on 16/6/14 at 06:57 PM Reply With Quote
Locking kit is 35 not 100+ and you don't pass 3500rpm more than once accelerating from a stand still. Unless you short shift






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Jenko

posted on 16/6/14 at 07:53 PM Reply With Quote
Just by running on/off you get a big gain in power right from 2000rpm up until 5500rpm, right where you want it.....this can be done with most aftermarket ecu's.





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Rob Allison

posted on 16/6/14 at 08:04 PM Reply With Quote
The cam advances too far by turning it on. It moves 60 degs, 30degs too advanced. You loose out on power and torque.






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Jenko

posted on 16/6/14 at 08:32 PM Reply With Quote
Hence why it needs turning off again at 5800rpm, you then get another kick in power at the top end of the rev range.





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