Originally posted by dblissett
i have just purchased the whole kit of parts from bill shurvington for £38
dblissett - 7/12/04 at 02:41 PM
it took about a week but that included cashing my check
i have only the the complete parts for a board for megajolt running tps
the case is £25
i have read i practical performance car that you can buy a toothed wheel from a dohc ford for about £15 i will dig out the part number if you need
it
cheers dave
Volvorsport - 7/12/04 at 02:51 PM
ive got a BOM for the MS stuff - i think if you get stuff from bill shurvington , you wont be disappointed , hes a top bloke .
James - 7/12/04 at 03:24 PM
quote:
Originally posted by dblissett
i dident have a map sensor as i am going tps
Have to admit I don't fully understand the relative pros/cons of map or tps. Could you make it clearer for the more retarded please!
Thanks,
James
Volvorsport - 7/12/04 at 03:48 PM
the ecu decides what timing to put in via TPS , rather than a MAP sensor value .
both theoretically should work fine , altho there will be subtle differences .
some people can run without TPS since that only is used for accel enrichment
dblissett - 7/12/04 at 07:59 PM
hello james
i am just starting to learn about this stuff so if i am not spot on i am sure somone will take the piss
the timing of the sparks on a normal distributor car come from a combination of three inputs
input one static timing what we set with the timing light
input two timing advance from rpm (the bob weights in the distributor do this
input three the vacume advance this is the small pipe conected to the manifold that moves the plate the points sit on
with mapable you program what static and rpm advance you want this sorts out inputs one and two
for input three you can use a map sensor (it measures vacuume and converts this to a signal for the ecu to sort out the timing
or you can use a throtle postion sensor
this does the same thing as the map sensor but by calculation i think (this is the bit i am not sure about)
anyway my carbs already had a tps fitted so i am ussing it
as to the pros and cons i have no idea
which way is best
my feeling is which ever tps or map it must be eaisier to set up a modified engine with this system than a distributor
cheers dave
rich201283 - 7/12/04 at 08:57 PM
Has anyone got a contact number or contact for bill shurvington? so i can order the components off him
James - 8/12/04 at 10:43 AM
quote:
Originally posted by dblissett
hello james
i am just starting to learn about this stuff so if i am not spot on i am sure somone will take the piss
the timing of the sparks on a normal distributor car come from a combination of three inputs
input one static timing what we set with the timing light
input two timing advance from rpm (the bob weights in the distributor do this
input three the vacume advance this is the small pipe conected to the manifold that moves the plate the points sit on
with mapable you program what static and rpm advance you want this sorts out inputs one and two
for input three you can use a map sensor (it measures vacuume and converts this to a signal for the ecu to sort out the timing
or you can use a throtle postion sensor
this does the same thing as the map sensor but by calculation i think (this is the bit i am not sure about)
anyway my carbs already had a tps fitted so i am ussing it
as to the pros and cons i have no idea
which way is best
my feeling is which ever tps or map it must be eaisier to set up a modified engine with this system than a distributor
cheers dave
I know all that stuff!
My point, is which to use- TPS or MAP? TPS sounds easier to attach to any system so I'll probably go with that but I'd like to know the advantages of each- or whether they are the same!
Cheers,
James
wheelsinsteadofhooves - 8/12/04 at 11:02 AM
ditto james.
map seems more common but tps sounds easier. also map pulses on single branch of 4branch manifold, so they says. getting ready to build the thing, so
what inputs? anyone been there, one that?
bccox18 - 8/12/04 at 11:36 AM
I'm also at the stage where I'm about to start building and have decided to go the MAP route and see how I get on.
From what I have read., the MAP sensor is easier to install when you have a single carb setup where there is usually a vacumn takeoff on the manifold
which will give a good quality vacumn source.
The TPS route is more preferable for a multiple carb setup where it is more difficult to get a good vacumn source to drive the MAP. You can tap off
one of the inlets, but pulsing is a big problem which will give a poor MAP reading.
It also seems to be easier to mount the TPS on the Weber 40/45's than on the single downdraft types.(I found it difficult to mount it
effectively of my 38 DGAS)
For a good site on installing using TPS have a look here
http://www.cate1.co.uk/megajolt/index.php
Bob
PioneerX - 8/12/04 at 01:36 PM
Guys,
After 11 hours of wiring, braket making & generally looking for the tool I just put down I got my engine to fire for the first time (took it
from the scrap yard a year ago!). I have the MJLJ running on MAP on a four branch manifold for the Vx engine.
Basically to answer some of the questions, I personally believe that MAP gives you a better reading of actual engine load as the amount of vacum in
the manifold varies depending on engine load & butterfly position. TPS sensors can only do butterfly position, but still give a fair indication of
load.
The four branch thing can be a problem as ideally the MAP reading should be from all four intakes to maximise acuracy but most of all to minimise the
pulsing effect. I've solved this by using the vacum take off from Cyl1 (take-off on the carb) and connected this to the Cyl4, which has the prt
for the brake assist on it. I found that mondeos have a vacumn line to manifold connector that is excaly the right size to fit. These two points (Cyl1
& Cyl4) are connected together and then through an anti-pulse valve (also from the mondeo) before connecting to the MJLJ. This has given me a
pritty clean MAP single.
I will try and post pictures on my website over the next few days.
paulf : you are more that welcome to come and nose around the installation, just drop me a u2u.
PioneerX (Simon)
Chris Green - 8/12/04 at 01:50 PM
quote:
Originally posted by dblissett
it took about a week but that included cashing my check
i have only the the complete parts for a board for megajolt running tps
the case is £25
i have read i practical performance car that you can buy a toothed wheel from a dohc ford for about £15 i will dig out the part number if you need it
cheers dave
The part number for the toothed wheel is Ford 1078767.
This is taken from the PPC mag.
dblissett - 8/12/04 at 08:46 PM
i am using twin 40s and so with map i realy need to link all four inlet manifolds
to stop the pulsing if i did this i belive that it would be better because map measures what is happening in the intake
where as tps just calculates the engine load from throttle position and rpm
so its not quite as accurate but its a lot eaiser to fit and still alot better than a distributor
hope this helps you james
dave
garage19 - 9/12/04 at 04:05 PM
The other advantage of using MAP is that it is a direct measure of air preasure/vacum. If you used TPS and say, changed your cams you would need to remap to recalibrate the amount of air the engine is consuming for a given throttle opening. I realise this is more related to fuel mapping than ignition.
PioneerX - 10/12/04 at 01:14 PM
All,
Photos of my MegoJolt installation are now on my website PioneerX Web