car mechanic advice needed?
 

I do banger/hot rod racing at layhams farm as many of you no from another thread (:blush:) and im starting another season in march and i wanted to no about a carburettor change, now in the car at the moment is a 1300cc push rod engine with the standard carb, now i was wondering if it would run any better if i were to put a carburettor from a bigger engine on it, i had in mind a carb from a 2litre pinto engine. Ive had a look and it should be a straight swap but i didnt want to take my carb off and find that the other one doesnt work properl and having to get a new carb gaskett.
Any help will be greatly appriciated.:thumbsup:

may do to an extent, but there is a point where a larger carb even jetted properly starts to give less power rather than more... twin weber DCOE 40's are quite popular, for 1300-1600ish cc.

edit: you'd also need to jet them for your engine, and get them set up properly for the best gains.

What car is it?

I would have thought swapping the engine out for something else (even an OHC 1300cc) would be much cheaper/better.

I had a Webber 32/34 on my 1300 Nova which defo gave it a bit of a kick, best mod I ever did as it ran better in general too.

will prob be worse unless you rolling road it and get it jetted correctly

Remember a petrol engine is an air controlled / limited engine rather than a fuel controlled engine (like a diesel).

Basically there will be a maximum amount of air / fuel charge an engine can injest and that is controled by things like cam duration / overlap, valve sizes / shrouding, pumping efficiency (such as intack and exhaust mainfolds) etc, etc.

Once you have a carb / intake on that can flow that much air fitting a bigger one will give no more power. Usually the only thing that a bigger carb does is ruin the part throttle and idle stability / sensitivity and make the car a pig to drive.

Any change to the carb will require a proper set up, ie. on a rolling road or engine dynometer, to give any sort of benefit .... which will not be cheap.


My advice is to look at the regulations, talk to other people who run the same engine and find out what you are allowed to do and what works in your formula .... then do that!

What engine is it? Guessing it's either a ford X-flow, BMC A-series, Renault or the old Fiat OHV 1300. Sould be plenty of info on all these out there, if it's the A-series then just ask ..... more than happy to help.

Making it a pig to drive doesn't mean it's a bad thing, I hear F1 cars idle like school porridge and overheat loads sat in traffic, bit quick tho :woot:

It'd see a power increase if the engine has other mods too, on a standard engine probably not so noticable, but with high lift cams, exhaust system, headwork etc it'd be worth it for sure... but you have to start with one of those things or none of it gets done :p

:thumbsup: Nova SR's were the best looking model they did imo, have seriously considered doing a Mk1 facelift on mine with the sr vinyl etc :D

How long do you expect an Engine to last after you start thrashing it around a field aiming to crash into other cars (out of interest)??

Surely there's absolutely no justification in modifying an engine with head work, cams, carbs etc when you're going to drive it around a field crashing into people??

I forgot about that, very true though, be better off chucking something better in that fits on the same mounts etc :p

Im doing it in a production hot rod class, supposed to be non-contact, (didnt stop me fireing a stupid fiat uno into the bank when it was in my way :blush:)
The car is a mk3 Ford fiesta with a 1300cc ohc, and its pretty quick at the moment, wipes the floor with nova's and civic's but next year im going in a diffrent formula with novaa's but theyve all had uprated carbs and air filters and all thee other mumbo-jumbo aand im probaably gonnaa need to be a bit qquicker than usual.

just been looking at a few things you can do,one of them is also the exhaust, now ive got a mate with a load of old style ford engines, like the 3.0l v6,2.8l,and the 1.6-2.3 pinto engines, hes also got an exhaust spare from a v6, now i was thinking that as its got two down pipes and one exit pipe running to the back of the car, what do you reckon my car would run ike if i were to turn the v6 exhaust round so that the two down pipes are straightened (sp?) and instead of connecting to the engine, are then pointed towards the back like a twin exhaust, if you no what i mean? With one silencer in the middle somewhere to keep noise level down and create some back pressure.

no point, if your going to do it fit a better carb, strip the engine and fully decoke it, re seat valves, re ring it if you can(if compressions are down) and fit a good exhaust not some chaved up system, good service on it and a rolling road

sounds like my wallet is going to have a nervous breakdown :bored:
Ive also decided to replace the oil,change most of the gaskets.

why?

If you can change camshaft, get a good head, fit a set of twin 40 webbers, and fit a 4 into one exhaust system. You could also beef up the bottom end as well. It is possible to get 130+ BHP out of a ford 1300 pushrod engine.

the caburettor gaskett needs changing this is because the engine was originally injection but ive learnt to change to carburettor and have minimal wiring.(got an esc)The gaskett fell apart when i took the injection unit off and has now got sealent on it but it still has a small leak, and the exhaust manifold gasket and exhaust down pipe gaskett have perished.

my mates got a set of twin 40's,wont be cheap but i could always get an early xmas pressy lol.

the single point injection that's supposed to be on that engine is basically an imporved form of carburettor. Put it back on, or spend a few hundred quid on twin 40's. Then spend a grand on an exhaust, air filter (with the single point the power gain is larger...), plug leads coil and plugs. Either that or leave it all as it is and stay in the production class.

the thing about changing the engine back to injection is a wiring problem, ive a got a spare injection loom but i dont have the no how to work out where all the wires go, you need to have 2 electical boxes on an injection, the main ecu and a smaller esc box under the bonnet, second of all is that ive got an injection fiesta and a carburettor version, both exactly the same spec and the carburettpr just creams the injection car, the main problemis that with autograss racing is that you have to remove the original fuel tank, and the fuel pump for an injection is built into the tank.
Its just like i said, i dont have the no how to work an injectio, anyway there banning injections next year because people are getting the ecu's chipped up to remove the limiter, obviously the carburetors dont have ecu's so its abit unfair.

the carbs don't have limiters either :p

thats what i said didnt i?:eh?:

the new v8's switch off half the engine to keep temperature down i think..
so they can que up early to go out in qually 3 :)

Not really.

If injections having ecu's chipped to remove the limiters which carbs don't have is unfair, a circle is square :p Sure it's not to bring down the costs of racing, i.e standalone/personally mapped management (i.e not a quick flash install of a pre made map, not sure what you call it now, they're not quite as expensive at all)

thing you sum this up, your on a looser, either run standard or paysome one who does know other wise your going to screw it up all together.

depending how old your donor is, part of the wiring your taking off is for the electronic ignition timming!! all controlled by the ecu

i see what your saying, but the ecu box also has a inertia switch (in a crash it will unlock all doors and turn everything else off) wired in as well, the ecu has a sensor in it that nos if the switch is wired in or not.
The switch has to be wired in along with all the wires under the dash, in wich case you must have 95% of the wiring to make the engine run.

if its an early ford fiesta the cut off is not in the ecu, the ecu does not open the central locking, if you know what your doing you do not need all the car wiring!

ive worked for ford for 20 years so kind of know what im on about!

its the 1989 mk ford fiesta. Like i said though, i dont no too much about injections and am only saying what ive been told.

Do you have to run any kind of carb restrictor plate in that class, or are the carbs free?

When I raced in autograss I used Anglian Engines in St Neots Cambridgeshire for any kind of advice with regards to engines and carbs. On my old class 2 escort my engine was bored out to 1360cc and I had a specially made restrictor plate for the carb manufactured for a twin choke webber. Try getting in contact with Dave Robbins from the St Neots autograss club and he could help you out with advice etc. He may even have the odd carbs lying about the place.

cheers, ill have to get in touch before my first meeting of next year in january.

actually the first meeting is in march savman not january.

no actually i think you will find cwilson its in january:thumbdown:
http://www.rollingthundershow.co.uk/
get your facts right:p:p

i was talking about layhams farm not arena essex. and i doubt you'll get there as who is taking you and who is going to pay for the fuel to get there? and your car will proberly break before then.

Your dads taking me, im nt paying for fuel most likely as im the one who got the beetle going again so i get to have my car taken on the big trailer with the beetle, adn about my car breaking, its got new engine, struts and shafts so i cant see anything breaking, yourt just jealous because youve been banned.
Two things to say to that
HA HA

well i can say is this. the armco dont move so when you hit it your screwed.