jacko
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 posted on 2/1/04 at 08:19 PM |
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su carbs
hi all
Has anyone fitted twin 1.75 su carbs
on a 2 ltr Ford Pinto. Any comments
welcome. Cheers Jacko the Bus Man
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sg_frost
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| posted on 2/1/04 at 09:32 PM |
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Why use SU cards, balancing them is a pig of a job. Where would you get a maifold? Why not use a DCOE Weber?
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jacko
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| posted on 2/1/04 at 09:49 PM |
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su carb
hello to sgfrost from Jacko the busman
thanks for your reply Im new at this website game. Ive already got a pair of Su Carbs and made a stainless steel inlet
manifold. I havent tried it yet and was
curious to know if anybody else had. Im not using a DCOE carb as it is a low cost car and im trying to keep it that way.Cheers Jacko the busman
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sg_frost
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| posted on 2/1/04 at 10:02 PM |
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Theory says that they should work because they are a variable choke carb. 1 3/4 carbs were used on 1275 a series engines, so two should be enough on
a pinto. make sure that there is no burrs in the inlet manifold to upset fuel charge flow.
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jacko
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| posted on 2/1/04 at 10:07 PM |
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su carb
thanks sdfrost ill give it a go
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theconrodkid
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| posted on 3/1/04 at 08:29 AM |
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been there,prob is the manifold will ice up unless you heat it with water
who cares who wins
pass the pork pies
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Peteff
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| posted on 3/1/04 at 09:59 AM |
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I've seen one 1.5" SU fitted to a mk1 1500 Cortina years ago. The only problem with that was finding the right needle to suit the engine
characteristics. If it's going to ice up it's too cold to go out anyway .
yours, Pete.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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theconrodkid
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| posted on 3/1/04 at 03:23 PM |
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pete,its cos the fuel picks up heat from the manifold as it travels,take away heat =lower temp then ice
who cares who wins
pass the pork pies
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JoelP
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| posted on 3/1/04 at 05:10 PM |
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quote:
Originally posted by theconrodkid
pete,its cos the fuel picks up heat from the manifold as it travels,take away heat =lower temp then ice
easy. stick a beer on it, then get pissed whilst you wait for it to defrost.
Beware! Bourettes is binfectious.
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david walker
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| posted on 3/1/04 at 07:25 PM |
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In my opinion, and based upon a fair degree of experience, the best carb setup to use today is to utilise bike carbs. Taking cost into account as well
as performance, the worst to use are Twin Side-draft carbs such as Webers or Dellortos. My reasoning is that firstly, they cost too much and secondly
I have seen few cars where the set-up is anything more than a compromise.
With the sidedraft you have so many vaiables to get right - choke tubes, emulsion tubes, air correctors, main jets, pump jets, pump bypass, idle
contol, etc... Few rolling roads get them all right and unless they are the things may look nice but they drink fuel - and obviously are not running
on the optimum mixture. If someone tells you that his carbs are thirsty, it's because they are not set up correctly.
SU carbs are excellent carbs and I'd encourage you to persevere - use the HIF6 type off a Metro or Maestro. If you can make a manifold then you
should be able to build into it some type of water heating - which is always necessary with steel manifolds. The carbs will be much easier to set up -
balancing carbs is dead easy. Talk to a rolling road that is used to setting up minis and get a pair of more suitable needles fitted. With this carbs
style of operation you will be closer to optimim fuel mixture when you start than most of us ever achieve on DCOEs!
Dave Walker, Race Engine Services - 07957 454659 or 01636 671277
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craig1410
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| posted on 3/1/04 at 07:56 PM |
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Hi,
I agree with David, one thing with SU's is the ease of setup and they will tend to run to some extent even when way off optimum setup. The trick
is to get them running well at all RPM and load ranges but this can be accomplished using different needles and damper springs, trying to keep on the
rich side to avoid lean running which can overheat the pistons. You can also use the technique of filing flats on the existing needle to richen the
mixture at a given RPM and load point but I'd recommend you get a good SU carb book before starting that game. David Vizard is the man who I
learned most of my SU and Mini tuning knowledge from in his many excellent tuning books. Make sure that you renew the jets before any rolling road
work is done because the jets that the needle goes into will be worn and will be oval. This would invalidate any rolling road work you did if you ever
had to replace the carbs because the jet wear would likely be different on the new carbs.
Also, as David says, balancing the carbs is easy although many people do question the need to balance the carbs in the first place. If it's
power you are after then as long as both throttle butterfly's are fully open at full throttle pedal then all will be well. I balanced the carbs
on my Dad's Rover SD1 V8 a good few years ago and it did idle slightly better but that's about it. Twin SU's on the Rover V8 engine
can achieve up to about 200BHP so your pinto should be fine on a pair of these but as mentioned, make sure you have a heated manifold or it will ice
up. I had a flowtech inlet manifold on my mini and it just had a straight copper pipe cast into the aluminium casting on the top. You could possibly
get away with welding a 16swg bit of steel tubing onto your manifold to get the same effect.
Cheers,
Craig.
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rusty nuts
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| posted on 3/1/04 at 09:26 PM |
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S.U carbs
May also be worth looking at a pre heat system where you have a pick up pipe attached near the exhaust manifold to the air filter housing , as used by
most manufacturers on models using carb{s} may not completly solve problem but would help . Rusty
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jacko
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| posted on 4/1/04 at 06:51 PM |
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su carbs
hi all
thanks for the input and info advice much
appreciated
ps David bike carbs was my next thing to try
jacko
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