DmcL

had a thought but i dont know if its been done before or what the results would be but what about a carb setup that keeps the standard ECU. specifically im talking about a zetec but that doesnt really matter.

i was thinking what if the carbs were put on and an intake chamber (for lack of a better word) went on the carbs which had a fitting for the air temp sensor and mass airflow sensor? would it work? in theory it should because everythings still there its just basically replacing a single tb with 4 individual ones...

the reason for asking is it would be far cheaper than alot of other ways of getting a half decent power gain as it would really only require carbs, adaptor and rectangular plastic box and a random section of intake pipe, very very cheap

AlexF

it wont work well...

you want to tailor the ign timing to the engine with carbs EVEN more than you do with EFi

Carbs are awful and you go along way to covering up their short commings with a mappable ign system.

what about mega jolt lite jr?

alex

Markb_s1

Sorry to hijack, but could you explain why carbs are awful please Alex?

DmcL

bumpity bump

AlexF

Carbs can not provide the correct air/fuel ratio for all drive conditions:

start up
cold running
idle
hot start
acceleration
cruse
over run

They are a compromise and limit fuel economy, power output and emsissons.

Fuel injection on the other hand is much more controlable, it relies on electronics not ventui and holes!

Alex

Fudgey

iTrader: (4)

i.e throttle bodies


with management that is

Anonymous

Gotta agree with Alex, for a cheap way to get more power over a limited section of the range carbs are ok, but generally they suck arse.

DmcL

yea but the idea isnt just carbs.

the fuel would still be supplied via the standard injectors, the intake manifold would be replaced with an adaptor and carbs with a box over the carbs to make an intake chamber like the standard manifold has and to allow fitting of the MAF and temp sensor.

basically im thinking of an EFI carb setup...

Anonymous

Ah right, ive done that (although i used throttle bodies not carbs) with retaining the standard injection setup (by using a plenum to mean they all still worked through one air flow meter etc).

Its shite, cause the TPS signal now represents a different amount of flow, so it doesnt fuel right, and as alex says the timing is all to pot.

would be ok if used in conjunction with something like a unichip i guess.

Fudgey

iTrader: (4)

bit like this then...

Fudgey

iTrader: (4)

doh, pic didnt come out...

Anonymous

dan, thats exactly the way mine was.

i lost a whole load of bottom end, with very little gain up top.

Fudgey

iTrader: (4)

thats what i was gonna do with my bike tb's ive modded, but thought better of it...

SECS S8 will be here soon

AlexF

arr ok

you want to use carbs as throttle bodys...

yes you can, but carbs don't flow as much air as tb's as carbs have a venturi (a narrowing).

Go for TBs its very little extra cost!

alex

Anonymous

If you do that and use SECS, you should be able to get good results, assuming the head and cam want to flow more than the std TB can handle.

DmcL

well ive got zetec-s cams in..

im aiming for as much BHP as possible on the cheap. dunno if its worth anything but the transmissions constantly variable so once im on top of the hp curve thats where she stays till i let off.

its just an idea tho.. you lot reckon it would flow better than a bigger intake manifold and bigger tb? i have acess to a 1600cc intake mani and tb off a zetec-s.

Anonymous

just use the larger single one

DmcL

that answers that question

also about the single tb.. its not just gonna be slapped on with the intake mani. im gonna take it apart and polish it, maybe even bore it out a tad and fit a slightly larger butterfly.

Fudgey

iTrader: (4)

chip, ive only got a kent fast road inlet cam at the mo, std zorst cam, and std head....

DmcL

why the standard exhaust cam?

and who said you could steal my name

Fudgey

iTrader: (4)

no zorst cam cos it was in my mates engine, and it snapped

so i nicked the inlet off him

DmcL

ahh.. ok.

5 finger discount

Fudgey

iTrader: (4)

no, i only got 3 in

DmcL

lol

AlexF

errr why are you tuning a CVT?

by a faster car... there is no such thing as CHEAP when it comes to more power!! lol

alex

Anonymous

Cheap
Reliable
Powerful


Pick any TWO

AlexF

lol

yes Adrian!


alex

Anonymous

PMSL

The "Dodd Triangle"

Anonymous

TBH though, all the engines ive ever built at his place he has given me the choice of:

reliable
powerful

pick any TWO

Cheap hasnt even been an option, lol

DmcL

thats not what my £150 catback, £35 cams, £40 intake and free intake manifold wrap say

why a CVT? why not.. around a track it would be quicker. im also proving a point about how "useless" they are

something ive noticed about the CVT is that when i do something to the engine its alot easier to feel on the road so i know if somethings working or not.. for example, before wrapping the intake manifold it had a more or less constant pull from 5k onward, with the wrap on it pulls like before but at 5.5 theres a little extra kick in the ass, far easier to tune imo.

Anonymous

If you call that powerful mate, then fair play to you, you are obviously a bit more easily pleased than me and alex, lol

Karl

Intake manifold wrap? What?

DmcL

nah it aint powerful its fun

im never going to set any land speed records with a 1.25 but i can make it a beast in the corners and around a track.. which is the idea. i want enough power to do till the next corner basically.

intake mani wrap.. funny idea but it worked. probably nothing but 1 or 2 hp from it but something is better than nothing. btw it started life as heat reflective backing for behind a radiator lol

Anonymous

Fit a bigger engine mate, cheapest way to get more power reliabley.

No point trying to get a quart out of a pint pot.

DmcL

i might end up doing that.. i want to take the 1.25 further than any other 1.25 has ever gone first tho, just to be different.

the 1.25 is good for 180bhp with a computer controlled nitrous system and only a stronger head gasket and bolts. also the turbo and supercharger kits for the zetec-s are straight bolt ons to the 1.24/1.4

id probably be able to count the days till it goes pop on one hand but still.. it would be fun

Anonymous

Im going to leave this thread now before i end up wanting to give you a virtual slap in the mouth.

One minute you want to be doing it cheaply, then the next minute you have a budget of 10s of thousands of pounds to push it further than its ever gone, talk about wasting all of our time trying to give you genuine advice.

Make your mind up first what your maximum budget is then come back to us and we'll give you the options, fair enough?


Chip

Fudgey

iTrader: (4)

IS IT??

how come ill only have about that with a 2.0l on throttle bodies....

Anonymous

Because you arent using Nitrous.
If you were then you could have 300bhp instead.
150bhp per litre is realistic on most standard modern multivalve engines using nitrous, ive done it several times.


If you want big power use nitrous or a turbo, if you want nice throttle response and not having to fill a bottle then use displacement combined with TBs etc.

DmcL

sorry.. i wasnt too clear there.

alot of the parts needed can be had off the 1.4, 1.6 and 1.7 vct from scrappies. once ive got everything done and get bored with it then i will look into an engine swap or turbo/supercharger.

basically i want to do the little cheap shit first then ill see where it stands and consider bigger and more expensive options.

to take it past any other 1.25 (naturally aspirated) id probably only need to spend about £500 on it and time sourcing various bits off larger zetecs.

Anonymous

IF you are considering nitrous then do that first.

It will give far better results than anything else can (other than more displacement) and it is transferable to a new engine.

Dont bother pissing about looking for 2bhp from a different TB etc if you can get 75bhp by bolting on a nitrous kit.