Bacon2002
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| posted on 4/6/07 at 08:58 PM |
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Zetec - Plenum / TBs - Emissions
Hi,
I am building a 7 clone and have a 2.0l Zetec engine (black top) which I intend to use.
I have also ordered a Megasquirt kit (V2)and ideally I'd like to use fuel injection rather than carbs.
Currently I'm reading the Megasquirt documentation which is helpfull but complex.
Having looked into this so far I am concerned about lots of things, two things in particular are:-
1) emissions in respect of the MOT test. Am I correct in thinking that the standard Zetec uses a plenum chamber and the plenum chamber is also used to
re-circulate some exhaust gasses in order to reduce emissions.
How will I be able to do this?
Will my engine fail emissions unless I use a plenum chamber?
2) It looks like I can use TPS (throttle position sensor) or/and MAP (Manifold absolute pressure) sensors to enable the Megasquirt to calulate what
fuel/mixture etc is required.
The TPS seems straight forward.
I think the MAP sensor will need to be connected to a plenum (via a tube to the Megasquirt), therefore would I still use TBs?
Where would I be able to get a plenum that will fit/work?
or
Can I get a manifold that will enable me to use a MAP sensor without using a plenum?
If anyone can help it would be appreciated.
Thanks,
David
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coozer
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| posted on 4/6/07 at 09:03 PM |
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My zetec engine doesn't have exhaust gas recircular. The plenums not connected in any way.
Best way forward would be a lambda sensor to control the fueling and emissions.
I'm pretty sure the Megasquirt can be adjusted easy to get the emissions down
1972 V8 Jago
1980 Z750
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Bacon2002
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| posted on 4/6/07 at 09:09 PM |
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Coozer,
Are you using TBs or carbs?
When you go for an MOT does the tester compare you cars emissions to a normal Zetec type engine (of a similar age) or to an older spec engine with
more relaxed emission rules, that is to say has the car always had the Zetec engine in it?
Also what ECU are you using.
Thanks,
David
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coozer
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| posted on 4/6/07 at 10:04 PM |
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I'm using ZZR1100 carbs and the engine is pre 95 so no cat. That means the emissions are not as tight as post 95 engines.
Dead easy to change the carbs off to get it through.
I'm using a Megajolt unit for the sparks.
Steve
1972 V8 Jago
1980 Z750
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tim windmill
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| posted on 5/6/07 at 06:20 AM |
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hi david,
i am in exactly the same position as you, have got a 2.0l blacktop and some r6 throttle bodies which i intend to fit, i have ordered a megasquirt kit
and then will get an inlet manifold made to suit. i intend to use a wide band lambda sensor and tps to srt out the emissions. i think that i could
still get the original black plastic inlet manifold under the bodywork if all else fails.
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Bacon2002
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| posted on 5/6/07 at 07:53 PM |
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Tim,
I have found a company (Griffin Power) who look like they can supply a plenum chamber that could solve the problem.
I have asked them a load of questions (as I am a bit clueless in this regard).
I'll let you know what they say.
Cheers,
David
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martyn_16v
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| posted on 5/6/07 at 09:50 PM |
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You won't need a plenum, or any of the EGR kit, to pass the emissions test. You'll need a catalytic converter in the exhaust to be able to
pass but other than that it's pretty easy.
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Bacon2002
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| posted on 6/6/07 at 06:07 AM |
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martyn_16v,
I was planning on using a cat anyway so thats handy.
Thanks for the note as I feel more confortable with the whole emissions issue now.
I will probably still go down the plenum route because I intend to use a MAP sensor with my ECU plus it will give me somewhere to vent the crankcase
gasses.
Thanks again,
David
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DIY Si
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| posted on 6/6/07 at 06:55 AM |
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Once you've passed the SVA the emissions test will go on the age of the number plate you are issued with. My Indy has a honda blackbird bike
engine in it, but come MOT time it's tested to the 1980 emission standards. Your main concern should be the SVA, where you get tested according
to the age of the engine. Even then, you won't need the EGR gear or a plenum. All you'd have to do is go to a friendly garage beforehand
and borrow there exhuast gas tester and fiddle with the mega squirt until you get the right readings. If the engine is post '95 you'll
almost certainly need a cat for the SVA.
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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martyn_16v
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| posted on 6/6/07 at 10:51 AM |
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If you are running individual throttles then you really don't want to use the MAP sensor as a primary load reference, there just isn't
enough vacuum to give sufficient resolution to provide any kind of part throttle control (trust me, I learned the hard way). Even if you did keep the
map sensor in there somewhere it will need to go between the throttles and the head, not out in the plenum. Other than for controlling noise there
really isn't a need for a plenum.
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Krismc
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| posted on 6/6/07 at 05:02 PM |
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im using a black top, throttle boddies, and a mega squirt if that helps, with a 4 wire lambda
Built, Ivaed, Drove and now Sold - 2011 MNR VORTX RT+ 2000cc Zetec on R1 Throttle boddies.
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Krismc
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| posted on 6/6/07 at 05:02 PM |
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im using a black top, throttle boddies, and a mega squirt if that helps, with a 4 wire lambda
Built, Ivaed, Drove and now Sold - 2011 MNR VORTX RT+ 2000cc Zetec on R1 Throttle boddies.
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TangoMan
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| posted on 6/6/07 at 05:59 PM |
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quote:
Originally posted by martyn_16v
If you are running individual throttles then you really don't want to use the MAP sensor as a primary load reference, there just isn't
enough vacuum to give sufficient resolution to provide any kind of part throttle control (trust me, I learned the hard way). Even if you did keep the
map sensor in there somewhere it will need to go between the throttles and the head, not out in the plenum. Other than for controlling noise there
really isn't a need for a plenum.
I am using GSXR750 TB's on my 2.0 Zetec wit a flowed head and 270 cams. I am using MAP as a load reference and have no problems. It just takes a
bit of playing with BIN distribution to frame your general cruise area.
I have used most BINS in the upper region as I cruise around 88KPA and idle around 50-55. As MS interpolates this gives a consistent fueling increase
in the lower KPa areas but give greater scope in the more critical areas. Mine idles fine, even when the fan cuts in, and runs economically and
smoothly. There is a small fluctuation in the MAP signal most of the time but this is not that significant. When I get time I will try restrictors and
fuel filters in the MAP line to soften the pulses but it is such a small issue that I have not bothered yet.
I do run the Wideband permanently in closed loop though with an AFR target table.
I did find that TPS based acceleration enrichment was better though due to the small range of Map available.
I would personally start with MAP as it is easier to tune with Megalogviewer and then play with TPS once you have something to compare. If using TPS
as a load index, I would be tempted to go with Hybrid Alpha-N to keep MAP as part of the equation.
I am not trying to start a debate but just trying to give a balanced view. There is no right or wrong with this one, just individual preferences and
experiences. 
I am happy to send a copy of my map and latest datalogs for anyone who wants to use them as a guide.
Summer's here!!!!
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DIY Si
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| posted on 6/6/07 at 06:14 PM |
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If you can get megasquirt to accept an electrical input for the MAP then it gets a lot simpler. Just use one off a bike. My blackbird has ITBs, but
still has a MAP sensor on it. It takes a feed from each of the inlets and combines them in a common feed to the MAP, which then kicks out a signal. I
have no idea how much hassle this would be to accomdate though.
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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martyn_16v
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| posted on 6/6/07 at 06:56 PM |
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quote:
Originally posted by TangoMan
I am using GSXR750 TB's on my 2.0 Zetec wit a flowed head and 270 cams. I am using MAP as a load reference and have no problems. It just takes a
bit of playing with BIN distribution to frame your general cruise area.
I have used most BINS in the upper region as I cruise around 88KPA and idle around 50-55. As MS interpolates this gives a consistent fueling increase
in the lower KPa areas but give greater scope in the more critical areas.
I had a pretty similar setup on a VW 16v, whilst I got it driveable on speed-density control, it wasn't nice. The throttle pedal was basically
an on-off switch (mostly on, you just can't beat that noise bwaaAAAAAAAAAAAAAARP  ) Maybe you've just got more patience than me, I did
start out thinking 'how hard can it be to use MAP, just set the bins up to where the engine spends all it's time now' as you have,
but just didn't get it nailed down. My MAP went from about 65kPa at closed throttle straight to 80-85ish at even the slightest crack open, so
pretty much the entire operating range of the engine was compressed to about 10kPa or so, even if MS interpolates between bins (and i'm not sure
if it could over that range, it may only have a 1kPa resolution) that's a very small range. I often found that on one day I could get it going
reasonably well, but a change in weather the next day could throw it all off, a 1 or 2 kPa change in ambient when your operating range is so small is
a noticeable effect.
I'm interested that your idle pressure is that low, I didn't get much lower than that with the OEM plenum before i'd converted to
gsxr bodies. Probably has a lot to do with why you're having more success than most.
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chriscook
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| posted on 6/6/07 at 10:45 PM |
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MY Megasquirted XE with GSXR ITBS is using MAP for load and it seems to be going ok so far. Although the VE really starts ramping up above about
85kpa. My idle vacuum is similar to Tangoman's at about 50kPa. 60mph cruise in 5th is about 70kpa.
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