to carb or not to carb

[5.0_sleeper]

Hey, guys its been awhile since I have been on here. The question I have got for you today is a big question. It has ran across my mind many times in the past, whether or not to carb my 5.0 or not. The only thing that I find diffcult about fi is don't quite understand why you can modify a maf engine and get by with and not a speed density engine? All I really want to do is different heads, and cam, headers, and exhaust. Thats it, so how could I go around about doing this? If I keep it fi then I have to get a maf conversion kit for it, to do the things I wanna do. Or would it be better off to switch to carb and not monkey around with the electronics. I know this is a faq, but if I can do all of this stuff (including a 500+ lift cam) and still run fuel injection that would be great. So the main question is to do all of the stuff listed above would I have to buy a conversion kit? My car is a 88 mustang gt, automatic.

thanks 5.0_sleeper

 

[z2o_what]

correct me if im wrong, but...
the reason speed density is a problem when running most aftermarket cams is: SD uses vacum (MAP) to tell how much air is going into the engine and MOST cams (mainly if the duration is different than stock) change the amount of vac. an engine has.
MAF meters the air as it enters the engine.

unless you like having to shift to neutral (sp? lol) when you stop to keep your car running, you will also need a stall converter.

yes.. you would probally need a MAF conversion kit to do the mods you have planned.

 

[bullitstang1313]

There are many high performance engines out there based on Speed Density. The F.A.S.T. system is based on a speed density setup rather than MAF. You can throw the argument out there that switching to carb will be cheaper than modifying electronics, but then you add cost by losing driveability and fuel efficiency with a carbed motor. I suggest you decide on the power levels you are looking for and base your combo on research rather than throwing a big cam in with new heads and an intake. If the parts don't work well together it won't matter if you are running fuel injection or carbed.

 

[ronburgundy]

some people say that you get more hp out of a carb, just remember for every top end hp you might gain, you've more than lost in the bottem end and mid-ramge. stay with efi, your seat of the pants dyno will thank you.

 

[Modular2v]

correct me if im wrong, but...
the reason speed density is a problem when running most aftermarket cams is: SD uses vacum (MAP) to tell how much air is going into the engine and MOST cams (mainly if the duration is different than stock) change the amount of vac. an engine has.
MAF meters the air as it enters the engine.

unless you like having to shift to neutral (sp? lol) when you stop to keep your car running, you will also need a stall converter.

yes.. you would probally need a MAF conversion kit to do the mods you have planned.

that is correct.....i was faced with the same problem when i did my stroker/head/cammed motor......it was cheaper to just go to carb than to convert to MAF and buy a better upper/lower intake and tune it....

 

[SQUEEZE&STROKE]

I converted my 94 to carb...331 to be exact. I gained a lot of power but for any type of mileage...forget about it. It is easy to tune, but it is also harder to start in cold weather. There are many pro's and cons for efi or carb...it just depends on your situation. Is this a Daily driver, do you have access to another car? Do you have the funds to buy the new pickup, fuel pump, filter, lines, regulator, Manifold, carb, etc? Do you have the technical know how to keep everything else working while wiring up a separate fuel system...is the trans AOD/AODE...one of which is computer controlled. What about emissions?

I am not trying to insult you in any way...I am just saying that unless this car is pretty much dedicated to the track...and by track I mean ONLY a 1/4 mile track...you might want to reconsider...in the long run it really isnt much cheaper...a decent carb is just as much as a set of injectors...just price them both out and I think you'll see they are pretty close in price

 

[jrichker]

Ford's implimentation of Speed Density wasn't as good as it should have been. As mentioned, on Ford Speed Density, a nice steady vacuum is a must have for good performance. Mass Air isn't affected by vacuum, so wild cams, high flow heads and manifolds are not a big problem. A lot of the street driveable Mustangs can run hot setups without a custom tune and still get good performance and driveablity. It depends a lot on how well the combination is matched.

 

[Lxstang306]

thing with a carb kinda easy to tune if now how holleys are good carb.with carb u dont have no limit no fuel cut off almost no wiring. but to have to fine tune them. EFI u can only go so far with what cam is in. becuse of the computer dose some thing make them rev up and down.

 

[jrichker]

thing with a carb kinda easy to tune if now how holleys are good carb.with carb u dont have no limit no fuel cut off almost no wiring. but to have to fine tune them. EFI u can only go so far with what cam is in. becuse of the computer dose some thing make them rev up and down.

I hope that your mechanical tuning skills are better than
your grammar. Your post is very hard to understand.

 

[fastranger347]

the problem with early SD fuel systems was lack of computing capacity by the factory computer, which is no longer an issue,ive said it before and will say it again that i like the holley projection tbi, gives you the best of both worlds, and imposes no "vacume" limitations on its speed density setup im running a comp cam XE274hr in my 10.5-1 347 and it idles at 800 rpm and runs 12.2@114

 

[wicked84gt350]

Before you knock a carb rember that most people dont konw how to tune it properly therefore low end power suffers it bogs and the throttle responce is not all that great thats why they get a bad rap. BUT when you have a properly tuned carb I would choose it over efi any day The throttle responce is ten times better but you must rember that you get what you pay for hence 300 dollar ebelbrock is not going to be impressive out of the box or that impressive at all. But a 650 dollar quick fuel with some jetting and tuning will do the trick. If you really want fuel milage then why are you worried which will give you more power just go with the obvious efi. A carb can be fitted for fuel milage but you need to get the proper cfm jetts and most likely vaccum secondaries etc... Most people go over board on cfm on there 302 thinking more is better which cause added fuel consumption and a lack of power and responce untill high rpm. You know the old 10 pounds of sh-t in a 5 pound bag.

 

[86bluecobra]

I love that i went to a carb. I have learned lots about tunning them. So much info to read specially at holleys web site. My carb seems to be very touchey. But i always get rid of the bog issue. Now time to jet it to get the AFR closer to 12.5 to 1.

 

[gt1986]

I recently built a killer 5.0 for my 86 i went back and forth on the carb vs maf conversion myself in the end i decided to convert to mass air. there's no doubt carb would have been cheaper, considering i had to get bigger injectors, computer, mass air meter and harness, throttle body and an expensive intake manifold, ect. however all that aside iam completely statisfied with the results. dont be scared wires they make you go fast

 

[fastranger347]

i did 15 years of carbs and got tired of power valves, accellerator pumps, bowl gaskets jet changes etc, air bleeds,etc. but considering the simplicity of carbs they do a wonderful job, i dont know about the whole carbs are better than efi thing, its been almost 20 years since detriot manufactured a vehicle with a carb, and since the addition of fuel injection detriot is introducing 500+hp "supercars" that get 20 mpg and still idle at 800 with the a/c on, so fuel injection cant be that horrible