I've read conflicting info on the pros and cons of going to carb from EFI, so I'm trying to clear this up. So, what are they?

your engine might breath a little better with a carb setup and that might give you a couple hp over a stock rx7, but there is no comparison, in programmable fuel injection and a carb



fi= better in every way shape and form



carb= less complicated

Carb:

cheaper

simplier

more hp vs stock efi: no afm, less restrictive intake manifolds

tuning can be a hassle, every 10 deg jets need to be retuned

hard cold starting/running

harsh, abrupt powerband





Aftermarket efi

more expensive

more complicated

WAY more control

WAY more tuneablilty

Makes more power than carb



Moral of the story if you have money; you have aftermarket efi

Oh, I mean stock FI. I sure nothing beats programmable FI, that goes without saying.

If its a street car don't waste your money with a carb, save up for Programable EFI. And a carb isn't a lot cheaper than EFI unless you can do ALL the work your self (this includes tuning).

carbs were great about 20 years ago https://www.nopistons.com/forums/pub...IR#>/bigok.gif



I would never want one today.

https://www.nopistons.com/forums/pub...1047683785.gif So true!

I'll take a nice set of Webers for an SA

carb:

easy to tune

cheap

not verry good for turbo setup

hard start on cold weather, speacially 30 and below

great power

sucks on fuel mileage



FI(stock):

non tunable

not cheap sensors

on N/A you cant put a turbo or in turbo II is verry limited

great HP but limited

great fuel mileage

and with the right stuff is easy to start on the winter



FI(tunable):

from what i heard is hard to start in the winter

depends of the tuning it can suck or be good on gas

depend of the engine configuartion can get alot of HP

can be tune for turbo

not cheap at all



pic your choice. https://www.nopistons.com/forums/pub...#>/biggrin.png

there are NO advantages runing a carb then EFI

the power u are gettign is nto coming from a carb but the manifolds that u

have to change out to put teh carb on which flow a lot better then the stock

ones, if u get the racign beat lower manifold and then some twm fuel

injection throttle bodies u will be able to make same if nto more power

because of the better tunning tha tu can achieve with the EFI.

carbs are not cheap and goign with the twm is either it pretty much

comes out to be the same price but EFI is much better.

thanks for info, much clearer now

Don't forget a carb requires a venturi to function, so optimal carb vs optimal efi, efi will always win. venturi == restriction. Theres also the issue of altitude, carburetors will not correct for this so if you drive through mountains and valleys your car will run like **** with the carb. Guys with carbureted bikes that go on road trips through largely varying altitudes have to bring spare jets along and tune the bike to run well in the mountains, right after they adjust their chains heheh, nutty people.



if yer short on cash though slapping a rb carb/manifold setup on a fc with otherwise stock intake will net some significant gains if it's tuned well enough, but a bunch of negatives come with that.

the TWM TB requires an aftermarket ECU, right?

it does , unless u want to put afm in front of it, or make some sort of a hack to have a map sensor but keep teh stock ecu with some loig circuit

afm is a big restriction when goign with the twm, that woudl kinda kill teh point of the ITBs

duh, I just didn't think of that. https://www.nopistons.com/forums/pub...1047683664.gif thanks!

Carburetors aren't terribly difficult to tune. The real challenge you people face when trying (and I use that word loosely) is ignorance. It isn't necessary to adjust a carb when the temperature fluctuates 10 degrees. I've been using one regularly for quite some time, and I've barely touched it. A choke that functions properly handles the cold start problems you think seem to exist. Knowing how to turn an electric choke on and off will help greatly.