Weber 40s on 16v

4th April 2013, 18:39

Just got some weber 40s with a vtr manifold and I'm wondering how I would go about fitting and setting them up? Never looked into doing this but these came up for 100 and I couldn't resist. Where could I get a manifold ? What management would I need to use and what other bits would I need to get this setup working? Any advice is appreciated as I'm a total noob with fitting these to a 16v. The engine is a jp4 in a 106 Gti. Cheers.

6th April 2013, 10:59

you will need a different inlet manifold to start with --then a dif fuel pump ,find some way of mounting the tps sensor on the carbs
recalibrating the carbs with jets + choikes could cost £150 in parts--then you can use the std ecu --but it will never pass an emmissions test for the mot using carbs
If this hasn,t put you off --it should have done --

6th April 2013, 11:02

Quote:

Originally Posted by axsaxoman

you will need a different inlet manifold to start with --then a dif fuel pump ,find some way of mounting the tps sensor on the carbs
recalibrating the carbs with jets + choikes could cost £150 in parts--then you can use the std ecu --but it will never pass an emmissions test for the mot using carbs
If this hasn,t put you off --it should have done --

Why won't it pass the emissions? My mate has twin 40's on his gti and it's better on emissions than a standard gti. All depends on who sets the carbs up and if they know what they are doing.

6th April 2013, 11:06

I love DCOEs your fuel consumption will be awful generally, whatever the setup, but if setup well they can be great. i would be tempted to put some on the VTR, all i would need is a throttle cable and your manifold.
The fuel pump business puts me off though. What pressure to Saxo pumps run at?

6th April 2013, 11:10

if your mate has made such a wonderful job --why are you coming on here asking how to do it --ask him
and i don,t believe for one minute that his car passes a REAL mot test
why would car makers change to injection if they could get emmisions correct with carbs -
thats why all cars since 1991 ,and most had it before that, have injection and not carbs ,and if car makers cannot get a single carb to work -- what chance do you think you have with s/h units that were not specced for that engine -

6th April 2013, 11:17

In 1990 when we started racing an AX sport --we used carbs (not road use) ,but soon discovered that changing to t/bopdies and ecu we made much better power .wider power band ,less fuel consumption and better engine life,had no weather related problems (carbs have no air or water or ambient pressure correction ).
It was great all our competitors used carbs ,so we prayed for hot weather as they lost 10%+ of power and ours just ran the same every day
If you have a vtr black top head i can supply you a manifold to suit downdraft (no space for sidedraft carbs in a saxo and have decent length trumpets)carbs /tbodies --£100(reduced price)

and induction length is even more important to carbs ,so you get a good vac signal ,as that is what sucks the fuel from the jets--bad vac signal means poor fuelling at low rpm --another problem of carbs,especially for emissions

6th April 2013, 11:20

easiest carb set-up to get to fit a blacktop saxo is those from an MG maestro 1985-86
dcnf type carbs --late 86-87 they changed to injection --i wonder why could it be trouble complying with emmison laws --YEP
this is why no one makes an inlet manifld for silver top saxo engines --no market for it

6th April 2013, 11:20

Aren`t carbs more likely to go out of balance & need frequent adjustment as well?

6th April 2013, 11:23

yep-- you have never seen a car with carbs that has lambda control --cos it don,t work and there is no way it could adjust carbs

6th April 2013, 11:31

So fucking narrow minded, so just because you can't do it means it can't be done? Yeah ok mate.

6th April 2013, 11:41

Quote:

Originally Posted by Bedford126

So fucking narrow minded, so just because you can't do it means it can't be done? Yeah ok mate.

Go Bedford, as far as I'm aware in this thread, Bedford hasn't asked how to use carbs it was the OP. and as far as I'm aware you need to setup the carbs for what you need to use them for, eg if you set them up for power you will not pass an emmisions test, so you need to set them up for the best of both worlds. Please correct me if I'm wrong.
John might be knowledgable but he is an ass.

6th April 2013, 11:54

Haha weber 40s and vtr mani for sale

6th April 2013, 15:44

Its an 8v 1.6 engine with pretty low compression. Classic cars all over the world run webber DCOEs successfully. Technology has moved on and there are better setups, but few will sound as raw and i bet none will cost less.

6th April 2013, 16:12

Quote:

Originally Posted by m4tt274

Its an 8v 1.6 engine with pretty low compression. Classic cars all over the world run webber DCOEs successfully. Technology has moved on and there are better setups, but few will sound as raw and i bet none will cost less.

And some one decent who knows how to set up carb's you will be singing all the way to the bank.

Rs tuning in Leeds set my mates up and his passes the mot every year with no back handers. Just because its old technology doesn't mean its rubbish they can and do work well on many applications.

6th April 2013, 16:57

Our pug 205 git had carbs on it and passed its last emissions test with flying colours. You also probably don't need to change the fuel pump (not 100% sure on a saxo) but you can often just run a regulator with a return on it.

6th April 2013, 17:11

You can but should you? Even setup well, i doubt theyd significatnly outperform the standard plenum and injection - if at all - so it makes me wonder whats the point? Money and hassle spent for a bit of noise tbh.

6th April 2013, 18:11

Quote:

Originally Posted by Kebabman

Our pug 205 git had carbs on it and passed its last emissions test with flying colours. You also probably don't need to change the fuel pump (not 100% sure on a saxo) but you can often just run a regulator with a return on it.

205 gti would not have a cat --so emmision spec is totally different requirments

6th April 2013, 18:14

Quote:

Originally Posted by m4tt274

Its an 8v 1.6 engine with pretty low compression. Classic cars all over the world run webber DCOEs successfully. Technology has moved on and there are better setups, but few will sound as raw and i bet none will cost less.

and I can say for certain that if they changed to injection + electronic spark they would run better
and classic cars do not have cats nor are they fuel efficent or even good bhp by comparison to modern cars of same capacity

example mini cooper S 1275cc made 68bhp THATS SAME bhp as a CI 998cc ,3 cylinders + a cat and at least 50% better fuel consumption --add that the c1 weighs 25% more than a mini as well and you can see what I mean

6th April 2013, 18:26

Quote:

Originally Posted by wadoryu

Go Bedford, as far as I'm aware in this thread, Bedford hasn't asked how to use carbs it was the OP. and as far as I'm aware you need to setup the carbs for what you need to use them for, eg if you set them up for power you will not pass an emmisions test, so you need to set them up for the best of both worlds. Please correct me if I'm wrong.
John might be knowledgable but he is an ass.

my replys in the first instance were to the OP
then mr bad manners joins in and asks why?

so i told him why

as for yourself If you find it hard to comprehend + digest facts .not opinions mind ,but facts then don,t bother replying , I have given all the reasons why you shouldn,t ,nowhere have I been rude or aggresive as you are being
as for setting up for the best of both worlds ,that is just not possible with carbs for the reasons i have previously stated.
I leave it up to the OP to decide what he wishs to do and who to believe

myself with 40years of tuning both carbs + injection or people who do this for a hobby and have probably not even been on the planet 40 years ,never mind making a living from it and have seen the changes over that time .
If i were narrow minded i would still be using carbs by choice

6th April 2013, 21:34

Quote:

Originally Posted by axsaxoman

my replys in the first instance were to the OP
then mr bad manners joins in and asks why?

Mr bad manners I use a Capital letter at the start of a title as I have manners, have you actually read your posts, If you have maybe you should look at your own manners before commenting on others.

Quote:

Originally Posted by axsaxoman

myself with 40years of tuning both carbs + injection or people who do this for a hobby and have probably not even been on the planet 40 years ,never mind making a living from it and have seen the changes over that time .
If i were narrow minded i would still be using carbs by choice

So just because you have 40 years in The industry makes you the be all and end all in performance, I think not. People like Bogg Brothers have been tuning carb's and making kits for any car recent or classic with decent results and keeping them within the emission control for the M.o.t. But I guess they have no idea too.

6th April 2013, 23:07

I think what johns getting at is you can pick a carb setup which will pass emissions but will be a compromise in one way or another, or you can go balls out w.o.t. carb setup but youll be compromising on mid range. Either way, they wont be on a par for an injection setup.

Also remember that classic cars dont have as strict emissions regs. Iirc, my mate said his minis emissions check was along the lines of "its smoking a fair bit, but its not taking the piss".

18th April 2013, 22:57

Can you still use standard injectors with these Weber's:https:// or am I just butting in...

As far as I can remember the only reason to fit Twin 40's is to HEAR how much petrol you are using. Especially on the DCOE one's.

Italian engineering at it's finest.

18th April 2013, 23:05

Quote:

Originally Posted by Norm7446

Can you still use standard injectors with these Weber's:https:// or am I just butting in...

As far as I can remember the only reason to fit Twin 40's is to HEAR how much petrol you are using. Especially on the DCOE one's.

Italian engineering at it's finest.

I was going to out a trolling comment, but when I knew nothing about carbs I thought the same, no carbs work in a different way, I'm not sure entirely but I think they work on a vacuum chamber and suck the amount of fuel needed.

Please correct me if I'm wrong, but they definitely do not use injectors.

19th April 2013, 19:31

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This is how a carb works... Its the venturi effect speeding up the air as it passes through causing a vacuum dragging the fuel out... The float bowl has fuel stored in it and when the level rises so does the float shutting the needle off... No more fuel needed... (Hence after market low pressure high flow pump) su carbs have a needle and this controls the low rpm fuelling, its attached to a plunger on a diaphragm and the needle moves in or out of a seat allowing more or less fuel through... The butterfly you see is on the clean air in side before it mixes...

And just to mop it up... Are carbs as flexible and widely usable as injection... No... Are they as fuel efficient... No... Do they need more maintanance... Yes... Are they susceptible to weather and temperature... Yes very...

However they can make good power depends how they are set up... High power = bye bye emissions... They can be set up to pass emissions but youll have less power and probably less diveability...

Raw noise and to feel like a kid agen, goose pimples... They win hands down no quibles!!!

19th April 2013, 19:40

http://youtu.be/UO1_6Izv6F8

Dont think link will work but for noise...

19th April 2013, 19:49

I hate carbs too, god don't fit them to your car. Nothing but trouble. PITA to have set up professionally, expensive to maintain, crappy changeable MPG, sub-optimal low/mid/upper compromised power balance, and on and on and on it goes.

John is cool when you meet him in person by the way (I promise!!), he's old and doesn't write so good on these new-fangled computery things. He's a Yorkshireman who moved to Scotland, I mean how happy CAN he be??

19th April 2013, 21:20

Quote:

Originally Posted by wadoryu

I was going to out a trolling comment, but when I knew nothing about carbs I thought the same, no carbs work in a different way, I'm not sure entirely but I think they work on a vacuum chamber and suck the amount of fuel needed.

Please correct me if I'm wrong, but they definitely do not use injectors.

Sarcasm

Would this not need a massive ECU remap + is there enough space to fit proper the venturi on the back of the carb's without interfering with the bulkhead. What about a set of twin SU's.

20th April 2013, 08:03

and the latest thing with the mot is that ALL warning lights ,including ecu light ,must work correctly
which means ti should be onwhen ignition is on and go ut when engine is started --
so that would be another problem with fitting carbs and keeping std ecu --the light will be on all the time
and just to be clear
I,m from lancashire --a manchester man
they say you can always tell a yorkshire man -
-aye but not much
LOL

20th April 2013, 08:05

LoL @ john writing LOL

20th April 2013, 13:29

Quote:

Originally Posted by axsaxoman

I,m from lancashire --a manchester man
they say you can always tell a yorkshire man -
-aye but not much
LOL

Aye - Are yorkshire men, not tighter than an Aberdonian.