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-   -   5 bike carbs? (http://www.classic-audi.co.uk/forum/showthread.php?t=1790)

Gaz 07-08-08 04:54 AM

5 bike carbs?
 
anyone know details about fitting 5 bike carbs to a kv? :D

like this guy has done?

Cause i want!, i want! i want! i want!.. :D i wonder if power will be much improved at all once set up properly? any one know? :confused:



on the move
http://www.youtube.com/watch?v=oW1HHDrH48I

under bonnet
http://www.youtube.com/watch?v=DBOttDwCru0

http://www.youtube.com/watch?v=Dz7lkHEqddk

http://www.youtube.com/watch?v=7_6R84Xqv8g

http://www.youtube.com/watch?v=jlfmw7zHAAo

http://www.youtube.com/watch?v=tBfGC9EYOd4

oops! :eek:
http://www.youtube.com/watch?v=lNn21xj1Fks

pimpdriver 07-08-08 06:55 AM

nice!

20vcqdriver 07-08-08 07:32 AM

Nightmare
 
If its anything like the DCOE carbs on my Mk1 escort many years ago it must be a nightmare keeping them all balanced and where is the air filter?!
A properly set up K-jet with ported head will be far more reliable, produce just as much torque which is what you need and be more economic with the fuel. Looks impressive if that's what your main aim is?!

Gib 07-08-08 09:57 AM

This seems to come up a lot on the usual forums.
Do people understand the differance between a Carb and a Throttle body or just mis-use the terminology?( genuine Q)
TB's on a I5 will give an improvement but are a pain in the arse to source (ask Lee folley about his set on his ex works rally cross running a 2 stage K-pump). Where as carbs are a retro step and you lose the gains from injection.

Gaz 07-08-08 05:25 PM

Quote:

Originally Posted by 20vcqdriver (Post 15085)
If its anything like the DCOE carbs on my Mk1 escort many years ago it must be a nightmare keeping them all balanced and where is the air filter?!
A properly set up K-jet with ported head will be far more reliable, produce just as much torque which is what you need and be more economic with the fuel. Looks impressive if that's what your main aim is?!

ok.. TB's gain i understand.

but surly these carbs would have some advantages? Allowing less restriction doing with out the air sensor plate in a K-jet, & if set properly with right fuelling give more power? Maybe not as good as modern TB's but maybe better than using a single inlet manifold perhaps?

i know people who have seen gains using twin carbs on a 2.0L ford ZETEC compared to the original inlet EFi set up. :confused:

But either way,.. the noise will be nice? and as said will look cool when u pop the bonnet. :)


Also, the cost of TB's would be a LOT more expensive? right? :confused:

Octanejunkie 11-08-08 04:29 PM

Big hassle, big money. Maybe more power.., but at the expense of your sanity. You'll be forever tuning it and fiddling under the bonnet. I'm sure it would get right on your tits.
Bit of head work, as mentioned above would be far more economical.

Gib 11-08-08 04:45 PM

You realy need to spend some time in a book and read up on this subject.
How often do single venturi side mount carbs come up for sale??? and then you need 5
What manifold are you going to use?
If you find 5 carbs that will do the job where are you going to get jets and needles?
I would be amazed at any gains by just swaping efi for carbs, those situations that are reported are always with the cavat that some engine work was also done at the same time .

ANY THINGING IN 5'S WILL BE EXPENSIVE OR REQUIRE WORK SHOP TIME.
Tb's are a lot simpler to make as you make how ever many you need, and you can set out the manifold direct. But you need a stand alone ECU.

Get a 100 turbo and strip it for the engine.

This is for another project along side the 2.5 ??? as that is tuned for K jet.

4v6 11-08-08 05:05 PM

Quote:

Originally Posted by Gaz (Post 15117)
ok.. TB's gain i understand.

but surly these carbs would have some advantages?

Maybe easier to actually install (if possible as per Gib's doubts) but thatd be about it.

Quote:

Originally Posted by Gaz (Post 15117)
Allowing less restriction doing with out the air sensor plate in a K-jet, & if set properly with right fuelling give more power?

Take a look into the mouth of any carb and youll see a venturi- a restriction now times that by 5.
The air sensor plate on a kjet wont be anywhere near as restrictive as 5 carbs and itll meter the fuel more efficiently because thats what Bosch engineers designed it to do.
If carbs were any major advantage at all, everyone would be using them, but theyre not.
Carbs need extreme amounts of know how to set up and even then, theyre a compromise setup compared to a bespoke injection system that can be altered at will to supply fuel in just the right quantity and atomisation levels to promote good idle, part and full throttle.
Then theres the absolutely compromised fuelling for economy and power- DCOE's are a good carb, but compared to a fully mappable injection system ( even compared to Kjet) theyre a very poor second choice.


Quote:

Originally Posted by Gaz (Post 15117)
Maybe not as good as modern TB's but maybe better than using a single inlet manifold perhaps?

Not at all. That inlet manifold serves a good purpose; its a tuned length to enhance torque.
If you replace it with a shorter setup say 5 carbs, you lose the resonance effects that the manifold provides and end up with a big hole in the torque curve, for a possible gain in power at the top end- but very likely itd be out of the engines normal rpm range.

Quote:

Originally Posted by Gaz (Post 15117)
i know people who have seen gains using twin carbs on a 2.0L ford ZETEC compared to the original inlet EFi set up. :confused:

But are you comparing like for like?
Did engine A have some fault before the swap?
Injection really IS far and away superior in most every way over carbs and its not even that hard to understand- try working out whats happening within a carb at any particular time......

Quote:

Originally Posted by Gaz (Post 15117)
But either way,.. the noise will be nice? and as said will look cool when u pop the bonnet. :)

Might look "cool" but itd be a backward step as regards power and torque- which is where youd like to go? :)


Quote:

Originally Posted by Gaz (Post 15117)
Also, the cost of TB's would be a LOT more expensive? right? :confused:

Bike TB's can be had off ebay for little cost in triple and double forms, the expense comes when you go to get it all mapped if you can do the rest yourself, but in any case why bother?
Optimise the original head, induction and exhaust system and then force induct the engine to take advantage.

For me, its a no brainer- would i like a "cool" looking setup or a powerful one?
;)
Whichever you decide id not knock the plan as its each to his own, just dont expect much in the way of exceptional outputs if you go the one direction. :D

Gaz 11-08-08 06:16 PM

Quote:

Originally Posted by Octanejunkie (Post 15473)
Bit of head work, as mentioned above would be far more economical.

already have all that side of it sorted. apart from getting a different cam... hopefully a fast road cam will be in there after i've fixed my car. :)


Quote:

Originally Posted by Gib (Post 15475)

This is for another project along side the 2.5 ??? as that is tuned for K jet.

i was thinking about it for the 2.5L . it was only an idea...

i had 'thought' a standalone ECU and TB setup would costly?? :confused:

rado-steve 12-08-08 01:41 PM

Bike Carbs are very reliable, much more so then DCOE Weber 40's or 45's that go out of balance every 3000 miles!!!! Especially if you get some of the more modern set up like from an R1 or GSXR750/1000 etc as these use electronic fuel pumps aswell! The only prob I can see is getting 5 of the things as they usually come in banks of 4!!!

Good power gains can be had from them aswell, once properly set-up etc! I know a guy who as a set of R1 carbs on his 16V 'rocco. Only other mod is a polished and ported head and that pushing the 170bhp mark!!! Pretty good i'd say, plus it sounds awesome on full chat!

Like This:http://uk.youtube.com/watch?v=-vvUc3...eature=related

You can pick a set of R1 carbs complete with pump etc for £100 or so on fleabay! Company you really need to talk to are Bogg Brothers! They are the daddies, they will build you a custom manifold and can even redrill and set up your carbs for your particular car! Looking at your you tube links in the 1st post Bogg Brothers actually sorted the manifold etc on that audi so would deffo be worth talking to them!

Here: http://www.boggbros.co.uk/index.html

You will need to keep the ignition side of fuel injection system etc but I reckon you could be up and running on bike carbs for £500 to £1000 including the carbs, manifolds and RR set up!

Plus who else has done this in the UK??? Bet they're ain't many, modding is about doing stuff that ain't been done before.......I think it would be cool!

The Noise will be worth it :)


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