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Jason Moyle Racing
https://jasonmoyleracing.createaforum.com
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Return to: ROLLING ROAD & ENGINE DYNO RESULTS
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#Post#: 755--------------------------------------------------
Mk1 GTI DX SET UP
By: Markg Date: February 14, 2013, 3:16 am
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Hi, I'm new to the forum, my mate Tim Watson has just had his
16v head done with you and is very happy with the results, so
was i that thing a little rocket.
I have a mk1 gti dx which i have been doing a few mods on
lately: light diy port and polish, polished valve dishes, 3
angle valve seats, ashley 4 branch, 16v throttle body, 16 v WUR,
piper 270 cam, vernier pulley, minimal head skim. I have just a
few questions with regards to set up, the car is just for
enthusiatic road use on those infrequent sunny days and general
pottering:
1. Is there benefit from slight timing alterations or just a
trade off between top/bottom end (currently bang on tdc)
2. What is the optimal ignition timing for performance/ smooth
running with these mods ( currently 6 degrees btdc)
3. I have read a lot of controversial lit around air box
drilling/mods, in your experience are there any quantified gains
from some work to e airbox? Currently standards with a k&n panel
filter
Interested to hear anyones thoughts
Mark
#Post#: 756--------------------------------------------------
Re: Mk1 GTI DX SET UP
By: chrismc Date: February 14, 2013, 4:33 am
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Hi Mark.
Welcome along
With ignition timing, I'd suggest trying adding advance just
until it pinks then back it off slightly. You should get a wee
bit more if the head has only had a little skim. There is no
ideal setting for a particular set of mods, you just need to
experiment.
For the airbox, a few little holes really won't achieve
anything. If you open out the outer side & custom fab a decent
cold air feed you might gain 1 or 2hp & beefier induction note
(I did Tims airbox)
Cam timing I always used to set to give equal lift on overlap at
TDC as a starting point. Advancing it a degree or 2 from there
would stoke up the mid range. Ideally you want it on a dyno to
perfect that & also tweak the fuelling via the 16v WUR. My 8v
never ever benefitted from retarded cam timing
#Post#: 757--------------------------------------------------
Re: Mk1 GTI DX SET UP
By: Markg Date: February 14, 2013, 7:11 am
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Thanks Chris thats some good info, I've got a session on the
rollers booked at Clive Atthowe as am over in Norwich so will
have a play there, how can you tweak the WUR? Is there an
adjuster somewhere?
I might have a play with the air box :)
I have the stardard exhaust from manifold back, do younthink
this is too restrictive, i dont want to much noise and am trying
to keep the look standard?
#Post#: 758--------------------------------------------------
Re: Mk1 GTI DX SET UP
By: mitlom Date: February 14, 2013, 1:16 pm
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Hi Mark,
Welcome to the forum :)
There most certainly is an adjuster on the 16v WUR, if you
remove it from the alloy mounting on the block you will see a
brass cap on the back. What you need to do is clamp it in a
vice or even better in a pillar drill and very carefully drill a
hole in the centre of it.....I usually use a 7 or 8mm drill
(whichever is sharpest at the time) Behind this brass cap you
will find a screw that you can adjust with an allen key to alter
the control pressure.
The exact setting will be dependant on the tune of engine and
can be a little trial and error on the rollers. With the air
metering head that will have been standard on your car you will
typically find that the fuelling will start to run lean at the
top end....hence the need for adjusting it slightly, but adjust
too much and it will be too rich elsewhere!!
The Slick50 boys of old use to fit 1600 air metering heads as
the cone in these is significantly different to the 1800 items
and provides a better fueling profile for modified cars, however
these ran a far higher level of tune than yours and I'm not
certain what benefit it would give for you if any at all! I
have one of these fitted in mine but I am running a 1900 bottom
end with a big valve head, 11.5:1 CR and 300deg cam but it
certainly leveled out my fuelling ;D
Here's the two air metering heads side by side....the bigger dia
one is the 1600 one...
[IMG]
http://i149.photobucket.com/albums/s70/mitlom/Road%20Legal%20Track%20car/IMG-20…
And here is some AFR data from dyno runs with the two different
air metering heads to show the effect on fuelling profile and
also the effect of control pressure :)
[IMG]
http://i149.photobucket.com/albums/s70/mitlom/Road%20Legal%20Track%20car/AFRvsR…
Hope this gives you a little food for thought.
Tim
#Post#: 759--------------------------------------------------
Re: Mk1 GTI DX SET UP
By: Markg Date: February 14, 2013, 3:20 pm
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Cheers tim, i had read about the 1600 metering heads providing
better fuelling, and thanks for the tip on the WUR adjustment,i
shall prep that For the rollers. The 16v WUR was a bit of a
fluke really as i had fuelling issues on my first run prior to
the mods, I had 5 bar control pressure! Popped on the 16v WUR
and control pressure is know around 3.75 when warm and drops
with the vacuum advance as you throttle hard so will be
interesting to see if this will suffice.
What sort of power are you getting out out yours Tim I bet its a
bit of a rocket :)
On another subject I have just done an oil and filter change,
started and have low oil pressure and oil is not getting around
the engine, tried giving a little rev and no joy so switch off
sharpish, i thought is may have been a dodgy filter so i put
some fresh in the old one and started her up and still the same
issue, i have never had this on any car, possible hydraulic
lock? Or feed pipe blocked??? Typical!
#Post#: 760--------------------------------------------------
Re: Mk1 GTI DX SET UP
By: mitlom Date: February 14, 2013, 3:36 pm
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Hi Mark,
Yeah mine goes pretty well ;) There's a build thread on here
http://jasonmoyleracing.createaforum.com/customer-cars/tim-moll's-red-mk1-track…
/> It's producing 155bhp so a fair bit of fun ;D
I don't tend to bother with the vacuum connection on the 16v WUR
TBH I just leave the outlets on the WUR open to atmosphere as
with them connected I have found previously it overfuels at top
end!
With regards to the oil pressure problem I have had this before
with an old engine.....but only when I have drained and left
engine for a little while before filling it up! I'm not sure
what causes this but suspect it's either a worn pump or worn
main bearings but not certain....what I do know is whenever I
build a new engine I fill the pump with grease and this prevents
this issue on initial startup...however this doesn't help you
much unless you feel like whipping the sump off!
I actually made a tool up that attaches to an electric drill,
you pull the dizzy out and drop this in the hole where dizzy
normally lives and it slips over the drive on the oil pump and a
quick spin of the drill and hey presto......the other solution
which might get it sorted is whip the plugs out and disconnect
the DIS plug to the dizzy and crank away until you get pressure,
ideally do this while jumping from another car so you have
plenty of cranking speed and don't flatten the battery ;)
[IMG]
http://i149.photobucket.com/albums/s70/mitlom/DSC01970-1280.jpg[/img]
[IMG]
http://i149.photobucket.com/albums/s70/mitlom/DSC01973-1280.jpg[/img]
[IMG]
http://i149.photobucket.com/albums/s70/mitlom/DSC01971-1280.jpg[/img]
Hope this helps a little.
Tim
#Post#: 761--------------------------------------------------
Re: Mk1 GTI DX SET UP
By: Markg Date: February 14, 2013, 4:58 pm
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Nice tool ;) thanks again tim, i might whip of the sump to check
pick up gauze anyhow I've heard these can clog sometimes, I'm
hoping its a simple fix, the engine was still hot at this point
and no previous issues so should be mechanically sound, i might
even pinch your tool idea!
155bhp too, wow thats awesome, mine was 102 at flywheel pre
works, we will see how my handy work bears up
#Post#: 762--------------------------------------------------
Re: Mk1 GTI DX SET UP
By: mitlom Date: February 15, 2013, 6:07 am
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Mark if you are struggling let me know and I can always stick
the tool in the post to you if you need to borrow it.
Cheers,
Tim
#Post#: 763--------------------------------------------------
Re: Mk1 GTI DX SET UP
By: Stooza Date: February 15, 2013, 6:32 am
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And this is why this place is so great! Welcome Markg, get some
pics up buddy 8)
#Post#: 764--------------------------------------------------
Re: Mk1 GTI DX SET UP
By: Markg Date: February 15, 2013, 6:34 am
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Cheers Tim, thats very helpfull, i will have a play today, i
will get some pics up later, i have baby duties to attend to :)
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