Is it possible to take a carburated application, and not one that is EFI converted, and supercharge it? If so, what are the steps, and what does the carburator consist of?.. Lots of help needed on this particular idea..

 

Yes its possible, yes lots of help is needed as by nature a carburetor doesn't know a thing about boost, only velocity. Yes it works once you get it right.

First I suggest a professionally built carb by either Carb Shop, C & S Specialties or CSU. I also suggest you troll though the posts here:http://www.turbomustangs.com/smf/index.php?board=13.0

 

theres no point. EFI> carb for a boost app. well really, any app.

the only reason to use a blow through carb is because you're not efi yet and dont wanna spend that much money on converting to efi.

 

Not true at all. People are making almost 2000 hp now with a single 4 barrel blow through.

A carburetor offers a performance benifit that port efi cannot. The vaporization of fuel in the plenum is more effective than any air/air intercooler or non-ice water air/water without the added complexity and service of methanol injection. You may also add intercooling to the blow through setup for higher gains. I see over 90 degrees of temp drop through the carburetor at 13 psi.

 

ive seen a gt4788 on a old big block with a blow through and it works fine.. it also runs low 9's with no intercooler.. and with be in the 8's next year...go for it!

 

you cant argue with the power, but i have to dissagree on the vaporization of the fuel! all your doing is using eat fuel to cool the air! thats not the best intercooler in the world now is it????

you will see more power with an intercooler on any setup simply cos you not weasting the volume with evaporatged fuel.

am i right in my thinking??

thanks chris

 

Use methanol then.

A carb may be able to make power. But no way will it be as versatile as efi, even more so in a big power build.

With efi, it can be a DD and still pass all emissions, be pretty fuel efficient, and make silly amounts of power.

I dont beleive that is possible, with any carburetor.

 

Where are you measuring the intake temps ??

And have you done a comparable test, at the intake valve of an efi motor...as thats where the fuel gets injected, so I would imagine some cooling takes place there too.

 

One problem we had on a non blown 502 that we had installed an overdrive transmission behind, was that when in overdrive and the carb used up the pump shot, the car bogged terribly. We ended up adding fuel injection to it, which solved the problem. Bob

 

I built a blow-through carb setup earlier this year. IT WORKED GREAT! I bought a 750 from CSU Carbs. The combo was a 377 with a T76GTS. I was amazed that the carb worked flawlessly right out the box. We made everything from 480 hp at 3.5 psi on up to 930 hp at 18 psi with NO CHANGES TO THE CARBURETOR WHATSOEVER. We spent $1700 TOTAL on the entire fuel system, carb, and ignition and were making 900 hp with no tweaks, programming, cables, wiring, configuring, or other headaches. Try THAT with fuel injection. HIGHLY RECOMMENDED!

 

im pretty sure andereck works for procharger in some fashion so i imagine hes pretty informed of what a blower can do/wont do...

as for methonal... whens the last time you had ice hanging off your intercooler when it was 90* outside? never right.... well with methonal your blower hat is like a big ice block at the end of the 660'.... just something else to think about.

 

which is great i you want to drive the car at WOT for a 1/4 mile, then idle around the track, but driving a blow through car with over 12psi on the street sucks.

 

About 5 years ago, I dumped my blow through twin turbo Rover V8, in favour of efi.

The carburettor drove fine, made power, and generally worked very well.

When I changed to efi, my mpg pretty much doubled. I wouldnt say power increased, but in general, efi was miles better, and a damn sight easier/cleaner to tune.

 

I am measuring inside the air filter, inside the hat and directly under the carburetor inside the plenum between two throttle plates.

There is no doubt some cooling in a port injected engine but with the injector spraying fuel at the backside of the intake valve its a bit too late to have a positive effect on air density. And no, I haven't machined a cylinder head to measure temperature there.


How so? A great deal of fuel comes from the power valve restriction and secondary side. If you're just driving around you're not really getting into much boost or the secondarys and the bypass valve is still mostly closed and free to crack open.

Just rolling down the highway my setup takes plenum temp well below the SC inlet temp and most often below ambient this time of year. The SC is doing some work so hat temp may climb up around 100 or so with plenum temps being in the 40's.

I will be installing an instrumented intercooler here shortly and I'll see what difference it makes to the overall system and just how low IAT can go.

Just don't discount those blow thru carbs! I'm not suggesting anybody convert their LSx to carb, efi has its obvious advantages.

 

I dont think that measuring intake temps, directly where the fuel will be hitting it, will give an accurate representation of actual IAT's

If the cooling benefits were so huge, then why dont more people run their fuel injectors on a 4 barrel style setup. That extra distance could help cooling then ??

Im not argueing with your IAT findings, I just dont feel they give a fair comparison with direct port efi.

 

I didn't either, that's why the sensor is out of the airstream from the throttle plates, between them directly under the base of the carburetor, actually behind the throttle bores. I'm confident its a fairly accurate indication of IAT.

Yes a tbi would provide a benifit on a 4 barrel intake manifold. The trouble is there isn't a wide choice of injector and you only have 4.

Have you seen the F1 videos on internet where you get to look down inside the throttle bores on the dyno? Notice where the injectors are? They're right above the airhorns. Same effect.

Whether you agree or not with my findings isn't important, I'm just trying to share some information on the poster's query based on real world data.

 

[QUOTE=andereck]Have you seen the F1 videos on internet where you get to look down inside the throttle bores on the dyno? Notice where the injectors are? They're right above the airhorns. Same effect.[QUOTE]

WHAT??????????

F1 guys stick the injectors all the way up there cos they need to to get the best mixture of fuel they can! and the longer the fuel is in the track the better the mixture is. as has been proven at MUCH MUCH MUCH lower levels of motorsport over here.

F1 also wouldn't like to use fuel to cool the intake as the fuel would tkae the sapce of the air, thus reducing the pwoer they could be making. plus it would reduce their fuel econnemy and make them slower over the race.

thanks Chris.

 

You're kidding, right?

 

ermmmm no!

its been tried and tested over here for a long long time! guys racing on sundays on very tight budgets have still gone 8 injector setups (on four pots) cos they are making more power than with four spraying at the ports. it takes a bit of working getting the injector timming right, and finding the best point to move over to the ourter set of injectors, but there are gains to be had!

F1 guys dont run two injectors cos they are not allowed under current regs!

i admit the intakes look very strange in some cases. i have seen a BMW with an intake thats about 18inches long, and sticking out the bonnet, but it made really good power for a budget 2.3ltr four pot!

that being said, it doesn't work on all applications (for some reason???). but the more raddical your engine is and the faster you spin it the better it seams to work!

also with 2 samller injectors spraying instead of 1 big one its easier to get a nice idle and its smoother throught the rev range. this is cos you dont have a MASSIVE injector trying to do the job of a little one! also it means you can spin the engine faster and not reach the point where your having to keep the injector open as the open and closing times get longer with big injectors. i have heard of some trying to run motorbike stlye injection (they spray twice as often. so once when the valve is closed and once when it opens. so as the vavle open the air is already full of fuel so the injetor doesn't have to spray as much. this means they can spin the engiens much higher and still use nice small injectors) but i haven;t really heard much about it.

as for boosted applications there are gains, similar to the above, to! Norris Design with their 900ish BHP evo are running twin injectors per cylinder.

dont get me wrong, this is not something i have tested myself, but it has been tried and tested, and seem to work!

thanks Chris.

 

Call me crazy, but I thought an engine will consume the same amount of air no matter what the amount of fuel is being introduced. What's motorbike style injection? I guessing direct fuel injection on a 2 stroke. I'll leave that alone.

But anyway, to the original poster, yes it is possible and very doable. And power is comparable to your budget. Andereck and Engineermike have posted their experience and if you go over to turbomustangs there are numerous people running blow through carb setups. When the season starts up again for outlaw racing, go to a 10.5 race and see what the blow through guys doing.