nige
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| posted on 16/8/06 at 07:00 AM |
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bike carbs on an " xe "
my mate rash has got himself some bike carbs for his pinto and while listening to
a conversation he had at harrogate
with a guy running bike carbs , its got me
thinking ??????????
has anyone run them on an xe 16v red top
i like a bit of a challenge and its seems not insamountable to make a manifold
any comments , idea,s please
what carbs to use ???????
if this works i will have a set of 40,s on a xe manifold for sale
when you start this journey
you think it will be done in " no " time but then " no " turns into a " bloody " long time
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the_fbi
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| posted on 16/8/06 at 07:19 AM |
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If you can afford it, go with bike throttle bodies.
Same principal but you'll also need megaquirt (at the least) and GSX-R (more commonly) throttle bodies.
The alternative is R1 carbs and a cav dizzy with the advance curve modified, although you may already have all this for your 40's?
You'd probably break even with selling your 40's/manifold and getting www.boggbros.co.uk to make up the manifold and supply suitable
carbs/filter.
May only cost £150-200 more to go the throttle body route, but its just slightly more complex. Definately better economy and power though.
A few people on http://www.migweb.co.uk/forums/ and on here are running both setups, just can't remember their names.
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ned
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| posted on 16/8/06 at 08:01 AM |
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mnr had bike carbs on an ecotec demonstrator a while back.
I have also seen a few bike carb pics on xe's on migweb.
Ned.
beware, I've got yellow skin
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nige
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| posted on 16/8/06 at 11:02 AM |
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xe bike carbs
the throttle body route is more than i want to spend
i would like to think i could fabricate my own manifold
the bit about
"cav dizzy with the advance curve modified "
tell me more about this please
when you start this journey
you think it will be done in " no " time but then " no " turns into a " bloody " long time
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MikeRJ
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| posted on 16/8/06 at 11:43 AM |
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The standard XE distributor contains only a cam phase sensor for the sequential injection, not very useful to run a stand alone igntion system. There
are three ways to get around this:
1) Buy an aftermarket ignition ECU that uses the standard 60-2 timing wheel built into the XE's crank.
2) Fix a 36-1 wheel to the crank pulley and use a Megajolt ignition system
3) Replace the XE distributor with one from a early 2.0L 8v carburettored Cavalier that contains a mechanical advance system and electronic igntion
module. The advance curve will be incorrect, so this will need fixing.
You might want to nick the Cavaliers steel sump while you are at it!
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NS Dev
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| posted on 16/8/06 at 11:44 AM |
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You can go for the bike carbs but as pointed out, you have to step back to the dark ages of clockwork ignition timing, which will pretty much destroy
the advantages of using the bike carbs to start with comapred to the std vauxhall injection!!!!
You really need mapped ignition to actually make any use of the carbs, in which case you need to buy megajolt anyway at least, and then injection
costs nothing extra really!!!
Bike throttle bodies are as cheap if not cheaper than carbs, need the same manifold, it just makes no sense to me using the carbs when you have to
sort the ignition anyway!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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nige
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| posted on 16/8/06 at 11:55 AM |
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carbs
so basicaly you say the carbs wont run with the cav dissy
i dont really understand the megajolt
ecu system enough to go that route.
it may be an antiquated system useing a dissy but thats my chosen path , im not looking to go racing , the car will just be for fun
when you start this journey
you think it will be done in " no " time but then " no " turns into a " bloody " long time
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MikeRJ
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| posted on 16/8/06 at 12:06 PM |
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quote:
Originally posted by nige
so basicaly you say the carbs wont run with the cav dissy
They would run, but as Nat quite rightly points out, meachanical advance system are crude and give only a rough approximation of the timing the engine
realy needs at any given point. With individual carbs, quite often using the vacuum advance is awkward, so many people don't bother which makes
things even worse as part throttle driveability and economy is destroyed.
If you really want to stick with carbs then Megajolt system is really not very complex and you can buy it ready built. The only real work is
mounting a trigger wheel and sensor to the front of the engine. The Megajolt can then use a throttle position sensor mounted onto the carbs (bike
carbs may already have one) to sense engine load instead of manifold vacuum.
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NS Dev
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| posted on 16/8/06 at 12:07 PM |
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carbs will "run" with the cav dizzy but you'd be better off with the std vauxhall/bosch injection/igniton if you are doing that
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gregf27
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| posted on 16/8/06 at 12:32 PM |
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H & H ignitions do a dizzy ignition set up Nige , that are suited to your application,
Whether or not it's deemed to be "dark ages" technology - My Pinto on points run great and I also intend to use the cav
dizzy on my XE , with webber 45's,
Many have used this path before!
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ned
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| posted on 16/8/06 at 12:39 PM |
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I think what nsdev etc are saying is that it should work fine, but don't expect great figures from the engine on a standard cav dizzy, with a
modified one it will be better but injection still offers better power/torque curves, fuel effeciency and more responsiveness from the engine.
Ned.
ps doing it on a budget i'd personally go for bike throttle bodies (which are no more expensive than bike carbs) and get either a megasquirt if
you want cheapness and diy or for a bit extra (not a lot by the time you've bought/built a ms system) an emerald ecu that you could probably get
a reasonable map for. You can argue that to get the best out of any system, carbs or tb's you should get the car rolling roaded.
[Edited on 16/8/06 by ned]
beware, I've got yellow skin
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nige
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| posted on 16/8/06 at 01:00 PM |
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carbs
as i said early doors i dont want to and cant justify the expence of an ecu and throttle bodies , i know that is the best way forward in regards to
power and
finite tunning , but i dont understand it enough .
i would be much happier with carb s for now
i have a cav dissy it was just a thought
about bike carbs as this seems to be popular at the mo
ive looked at the h&h site , very interesting, welcome all the comments and dont diss any ,because we all cant have the same opinions, this site
would be very boring if we all fitted the same gear
when you start this journey
you think it will be done in " no " time but then " no " turns into a " bloody " long time
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Mr G
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| posted on 16/8/06 at 01:37 PM |
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 OPTION IS AS FOLLOWS:
Cut down the standard alloy injection manifold to leave oval stumps. Depending on what bike carbs you go for you'll then have to get the correct
diameter rubber tubing and jubilee clip them to the manifold. Due to the oval nature of the cut down manifold you'll have to get it undersized
so it will be a tight fit. Carb Float bowls need to sit horizontal to the ground btw.
Pic Courtesy of Cidersurfer
Grab a vauxhall dizzy & coil module from a mk2 shape non ecu ign cavalier - They come in a few different shapes, my coil & module looks more
like a coil pack than a coil -billys unit is more of a traditional coil style.
You'll have to cut the end down on the main dizzy shaft as it's too long as standard to fit into the end of the cam on the xe. There are 2
different types of protruding drive shapes on the dizzy's - you want the one the same as in the picture :
Wiring is your simple Ignition feed, earth and rev counter. Spark plug leads can be a hassle as you need ones that fit the old style dizzy cap and
also have enough reach for the recessed spark plugs in the xe head.
I read that adjusting the bob weight spring rates to alter the ignition curve made little or no difference so I'm not sure if it's worthy
the hassle to have it modded.
Get a professional to set up and sort the bike carbs.
Job's a good un.
I replaced this setup on billy's with a MBE 906 (Caterham XE map) ECU + Wasted Spark Coilpack setup (Throttle position/Water Temp etc) - It ran
ok but he's since swapped it back to the traditional dizzy and reports that it run's the same if not slightly improved.
So in all honesty it's each to their own 
Next weeks instalment :
THE  OPTION
[Edited on 16/8/06 by Mr G]
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MikeRJ
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| posted on 16/8/06 at 03:47 PM |
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quote:
Originally posted by Mr G
I read that adjusting the bob weight spring rates to alter the ignition curve made little or no difference so I'm not sure if it's worthy
the hassle to have it modded.
If that was really the case then we could fit a universal advance curve to every engine!
Engines can run apparently "ok" with the wrong advance curve provided it's not miles out, but the difference between a fully
optimised advance map compared to a distributor designed for a different engine should be significant. For starters, a distributor can only ever
advance with increasing RPM. Often the engine requires a bit less advance toward peak torque as volumetric efficiency increases. This means the
distributor based system will over-advance, so any detonation has to be fixed by retarding the static timing, hurting the entire power curve.
That said, I know some people prefer the simplicity of a distributor, so if you are prepared to accept the downsides then fair game.
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nige
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| posted on 16/8/06 at 07:00 PM |
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carbs
three cheers for that man
big up mr " g "
just the down to earth simple laymans terms i was looking for
ive got a dissy and a coil
also the stock manifold , so just need the carbs
when you start this journey
you think it will be done in " no " time but then " no " turns into a " bloody " long time
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NS Dev
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| posted on 17/8/06 at 11:49 AM |
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see where you are coming from, no problem.
I used to think that carbs were simple and injection complex, until I started to use an aftermarket injection system.
Yes its not cheap, but done secondhand its not too bad.
The big plus is that it is so much more simple than carbs!!!!!!
What you don't want to do, if you are new to injection, is get into the megasquirt stuff on tinternet!!! It put me off straight away, yet I am
fine mapping my MBE stuff!!
With all the aftermarket race type systems you basicaly stick in number sofr injector opening times and ignition advance. much simpler than peeing
around with holes in bits of metal in carbs!!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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roadrunner
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| posted on 18/8/06 at 06:11 PM |
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bike carbs
I have a set of bike carbs if you want them, zx10 racing carbs, in good nick, and i only live 20 mins from you.
I bought of some one who was going to put them on an xe for racing , but decided to pack it up.
[img]zx10[/img]
[Edited on 18/8/06 by roadrunner]
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Mr G
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| posted on 20/8/06 at 02:00 PM |
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quote:
Originally posted by MikeRJ
If that was really the case then we could fit a universal advance curve to every engine!
Are you actually reading this thread or refering to the principle in general?
He said he wants the car for a bit of fun & this is the 'locost' forum after all. Of course i'm not saying that on the quote I
made you could run every engine on the same curve. However i've think i've differentiated between joe public and someone wanting maximum
performance for motorsport etc. What i've heard about the difference faffing about with spring rates/vac on this 8v dizzy makes to actually
running 'ok' is negligible compared to a vanilla one just popped in unaltered.
Time and effort spent trying to mechanically convert this to the correct curve would be best spent on a cheap mapped ignition as already mentioned.
Once again it's horses for courses, your going to want the performance going by your avatar
Cheers
G
Normal is getting dressed in clothes that you buy for work and driving through traffic in a
car that you are still paying for - in order to get to the job you need to pay for the clothes
and the car, and the house you leave vacant all day so you can afford to live in it.
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the_fbi
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| posted on 22/8/06 at 08:55 PM |
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In case this is of interest.
BRAND NEW dissy for 20XE on carbs that has been recurved to suit an XE by H&H Ignition Solutions. £80 ono.
Linky
[Edited on 22/8/06 by the_fbi]
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