A&Q about 350Z
Q:
I know this topic is bought up quite often, but I was just curious to know what psi standard twin 40 webers can handle, and when more boost is run through them and the start leaking the air, does this cause any damage to the carbs, or is it just that the additional air is being wasted?
A:
bump this.
im interested in the idea of fitting an eaton m45 to my 6a on dellorto 45's
can anyone offer us some advice?
Jason.
A:
bump this.
im interested in the idea of fitting an eaton m45 to my 6a on dellorto 45's
can anyone offer us some advice?
Jason.
Would it be easier if you just switched to fuel injection on a stand alone and inexpensive system like Megasquirt? Carbs can work but are more limited in fuel tuning vs a good 3D mappable system. And MS can inteface directly with your dizzy and ignitor so you can also throw away the oem spark ECU which is mapped for N/A applications. If you are supercharging you will need to optimise the spark for more boost anyway.
A:
Carbs will work with a charger or 'pre boost' turbo (where the carb is fitted before the turbo) however this is a very inefficient way of doing it. I agree with Toyotec. Efi is really the only way to go nowadays as it is easier for a home mechanic to tune properly. And its more reliable. And less likely to blow your engine. And cheaper than a pair of carbs. And plugging a laptop into your car is cool.
A:
as it happens the lotus espirit turbos (the really old ones) used twin 45`s that were sealed in order to run boost. i`m sure the various things needed to convert normal 45`s to handle boost are still available from dellorto. plus the renault 5 uses a blow-through carb, as did a variety of 80`s turbo motors.
A:
i remember the espirit actually having dellortos. i actually read an article in performance ford (always liked cossies too) about a mk2 escort with a zetec on webers running a t2 if i remember and he had an engine fire cos the float chambers in the carb failed under boost pressure, solved it using the espirit dellortos which as correctly stated above are different to normal sidedrafts. you would definatley need some for of ignition retard ecu tho
good luck, sounds fun
A:
it's certainly possible to do, but why, to get the best out of your installation then you need precise control of the mixture, carbs will be right at 1 point in the rev range, and a compromise everywhere else.
EFI is the answer
A:
EFI is obviously the ideal way to do it, but with time and patience carbs can be jetted fairly accurately. plus it keeps things a lot simpler, depends on peoples money situation really.
A:
Christ, I forgot about this thread. I'm still considering dong this. I fully understand that EFI is the way to go, but I have a 1.8 GU engine so it would mean converting to fuel injection. Also, I have a set of twin weber 40s sat in the garage ready to go on which set me back less than £200, and I was given an Eaton M45 supercharger off a Mini Cooper S for free, which was why I was querying it.
I've been told by a few people that twin weber 40s can handle about 6 psi of boost before they start leaking air, which is about the same as what the M45 developes, so I'm happy that the carbs shouldn't be a problem. Also, would I be correct in believing that supercharging would work better than turbo charging as it will produce constant boost through the rev range?
I am interested in what would need to be done for the ignition though, could anyone shed more light on any improvements that can be done to help it?
A:
the 6psi in the manifold will be higher than the 3psi in your jets.....
A:
would I be correct in believing that supercharging would work better than turbo charging as it will produce constant boost through the rev range?
What you have to remember with superchargers though is that as they are belt driven they consume some of their useable power especially at higher revs
A:
id go for it to be honest, dont go down electronic injection route, keep it old school. i have a mk2 gti that i have converted to twin 40 dellortos and would love to super charge it. i just like the old skool way of doing it.
if the eaton charger is 'roots' type it will develope a lot more bottom end torque but it would also take some power from the engine to run it but it would still be a awesome way of doing things. each to his own though...
A:
Superchargers generally run about 50% efficient, turbo's around 70%, so obviously you will have more bhp with a turbo once it has spooled up. A s/charger with carbs may be 'old skool' but it will be a pain to make it run efficiently (and will never be as good as efi). You will need to retard the timing under boost, there are controllers available to do this with a dizzy.
A:
I asked webber this when i had my mini turbo, they said yes, DCOE's CAN be pressurised, but gave no more details.
A:
What about TB's Jenvey say there TB's can take up to 6bar.
A:
the 6psi in the manifold will be higher than the 3psi in your jets.....
there are lots of things to consider, webers have progression drillings and all sorts of stuff, floats can collapse etc.