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View Full Version : Carbs Vs Throttle Boddies


seanofnp
03-12-2007, 01:56
Ive been told i can get similar power from both, but carbs will just be far less economical... and is cheaper, is this correct?

Or am i really much better off putting the extra money towards throttle boddies?
northy
03-12-2007, 09:37
carbs are rarely used now adays mate - most specialists stopped working on them as fuel injection is so much more advanced !
Yanoo_
03-12-2007, 13:43
The fuel injection is better then carb because:
- enables higher cylinder loading (smaller wad, higher overlap, better inlet manifold design)
- enables higher compression ratio (all cylinders get equal fuel quantity, the cylinders are cooled by the fuel, the higher overlap makes possible to less permanent exhaust gas in the cylinder, layered mixture in the cylinder)
- the higher cylinder loading and higher compression ratio make less fuel consuption and higher power (approx 8 percent opposite carb)
- less specific fuel consuption (higher efficiency)
- there is no fuel layer on the walls, no need to heat the mixture
- optimal and fast mixture making on every engine loading and rpm as the engine needs
- more environmental friendly (the ingredients of exhaust gas may be easier and better regulated)
- higher feasible charger pressure (turbo-, super charging)
- makes possible (better) tube and resonance charging
- better acceleration quality
- lower centre of gravity (in most case the carb sits on the top of the engine)
matty w
03-12-2007, 23:15
your going back in time removing injection for carbs,then theres having it setup all the time,my mate used to have a mk3 astra gsi with carbs on it and it was awful on fuel
number1
06-12-2007, 13:21
The money you spend on carbs might as well be put towards throttle bodies, car will drive completley different, will start easier and drive slowly much better, plus if you put carbs on, youll soon put the difference in price in your tank and wish you bought throttle bodies,

I was thinking of using some kind of throttle setup, using the standard injector ports in the head with a set of throttle butterflies, similar to itb's but cheaper to make

Dave
2 live
06-12-2007, 14:33
speaking from experience.the bodies arent cheap to run either lol.

may be tempted to try a set of 45s see how much diff there is to the webcon 45 bodies
stan
06-12-2007, 14:54
yours wasnt fully mapped though jon.

efi is the way forward, and has been for the last 30 years lol. a more refined system will be more drivable, its not just about making peak figures.
number1
06-12-2007, 16:00
If you drive your car with anything other than a full throttle load, tb's will be more economical,
Stan what do you think to bike tb's? as these are cheaper to buy and i can get a manifold fabricated easy enough obviously they wont be as good as proper jenveys etc but there smaller and i know of a vw caddy which was running a standard passat 20v motor and gsxr600 bodies and produced 180 at the fly..

Dave
stan
06-12-2007, 16:39
why wont they be as good as jenvey? so long as length and diameter wise they are suitable (inclusive of taper in some cases), then theres no downside. this is proving the manifold is supportive of decent flow.
2 live
06-12-2007, 16:45
If you drive your car with anything other than a full throttle load, tb's will be more economical,
Stan what do you think to bike tb's? as these are cheaper to buy and i can get a manifold fabricated easy enough obviously they wont be as good as proper jenveys etc but there smaller and i know of a vw caddy which was running a standard passat 20v motor and gsxr600 bodies and produced 180 at the fly..

Dave

you mean theres something other than full throttle??


i dont understand. :?
stan
06-12-2007, 16:51
YOU wouldnt mate.... :P
number1
06-12-2007, 18:12
Apparently so, often found when trying to stop wheelspin 8)

Bike Bodies it is then :P
2 live
06-12-2007, 22:45
i thought the clutch did that ;)
number1
06-12-2007, 22:49
Good idea! :lol:
MAXIBOY
07-12-2007, 04:40
any that can cope with forced induction on a bike...
number1
07-12-2007, 12:25
Gsxr600 injection model ones are perfect, there 36-38mm diameter and can be spaced out perfectly to whatever you need, will probably use original injectors and rail as its easier and cant get much closer to the valve

Going to start hunting ebay when christmas is over 8)
2 live
07-12-2007, 12:38
btm end.

if u top end power as well tho they need to moved further away.
2 live
07-12-2007, 12:40
grrrrr edit.


close to the valve good for btm end.


if u want more top end as well, they need to be further away.

maybe run 2 sets of injectors, std ones in head then switch over to stand off injectors for the higher revs.
number1
07-12-2007, 14:27
Yes could do! use the injector bosses in the throttle bodies.... :P lol
2 live
07-12-2007, 14:38
hehe.im thinkin run another fuel rail with injectors outside the bodies at the end of the trumpets ;)
AndyFielder
07-12-2007, 15:02
thats where the nos goes!
number1
07-12-2007, 16:12
hmm management just got dearer... :lol:
u33db
08-12-2007, 10:26
any that can cope with forced induction on a bike...

Chap has done this on my website;
http://gpz900.org/forum/viewtopic.php?t=408

Uses Keihin CVK36'es...don't know if they're be large enough tho.
number1
08-12-2007, 14:06
was told by one of the tech dudes at jenvey, 36mm is enough to flow up to just over 200bhp provided 36mm is the smallest diameter
2 live
08-12-2007, 14:28
the webers are 45s on mine.
number1
08-12-2007, 18:30
Ive heard bike ones even though there smaller, are more efficient for power, but yeh, i'll look into a bigger set, maybe the 1000 ones are 40mm or something

Dave
Rob72
22-01-2008, 01:39
anyway...much does it cost for throttle bodies supplied and fitted......
anyone..?
Laine_16v
22-01-2008, 09:11
A lot, around £3k for an installed setup with all the management, new lower profile rad e.t.c everything.
Fusionrs
27-01-2008, 23:17
A lot, around £3k for an installed setup with all the management, new lower profile rad e.t.c everything.

2nd hand setup installed DIY and you could third that price.