Turbos and Carbs, a Good Match?

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hi guys
first off, im sorry but im not wrenching on an inline ford. my car of choice at this time is a 1973 dodge dart swinger. its powered by a 225 ci slant six. so far my mods have just been a 2 barrel carter bbd and larger exhaust. now ive been looking into going the turbo route. my most important questions are: how well behaved are yalls turboed and carbed cars? and how do yall deal with the lean/rich situation that occurs under boost and when not under boost? most of the info im getting elsewhere is to just forget it and get efi then do the turbo. i just dont have the money for this and hope you guys can shed some light on these subjects for me. thanks for any help that you guys might be able to give me.

shawn
 
Welcome brother. Slant sixes rock. It's just not right that a four bearing engine with a lean on it worse than the leaning tower of pizzia should be so darn tough!

:splat: :fume:

:smash: :smash: :smash: :smash: :smash: :smash:

The turbo size is limited by peak rpm being no more than 5000 rpm. In Aussie and New Zealand, slant 225's were raced extensively, and over 5000 rpm , even with the good early forged crank, they could loose bits if really pushed. Good thing is a well organized 200 + hp turbo will put less stress on the block than 200+ natural Hp.

The best turbos would be the later GM 231 Buick and the bigger Turbo Coupe.Merkur or SVO turbos. Some K-car Mopars ran a variety of turbos, but it's best to look for one that does 175 hp or more in a stock application. T5 Volvos ran Mitsubishi turbos, so did a lot of 2.2 and 2.5 Chrysler K's.

Good thing is that a too big turbo won't surge on a six like it will on a four cylinder.


The rest is up to just tidying up the great Mopar exhast, and getting the flanges sorted. I'd strongly suggest a better intake. The slant is much better than our poor little old logs, :x but if your gonna whip our collective butts, then might as well start with a 2-bbl intake, wack on a 350 or 500 Holley, and boost it with 9 pounds from a bigger Volvo, Mitsi or Ford 2.3 turbo. :oops:

Hope that helps. Do a search through the pages in this turbo section, and do some, errr, light reading :shock: :shock: :shock: :wink:
 
Read this thread (and some others over there also)
http://www.turbomustangs.com/forums/sho ... adid=17458
http://www.turbomustangs.com/forums/index.php?s=
Lots of info about junkyard turbo conversion and they even have a Mopar section
Also have a look here regarding Holley carb mods to run blow through
http://www.hangar18fabrication.com/blowthru.html

IMHO the slant 6 is an ideal engine to turbo,
1 low compression
2 sturdy construction
3 good low end torque for when off boost
4 heaps of room on the exhaust side of the engine due to the slant
Go for it and post some progress reports and photos/timeslips when its done.
 
so far this is just an idea that im trying to learn about. i dont have any parts yet, but after reading the turbo article at slanstsix.org i was thinking about going with a turbo off a 2.2L. its seems that they are easy to find and pretty cheap. the guy in the article cut the heat riser off his exhaust manifold and had a turbo flange welded on. this was my plan i guess, but after reading some more, why couldnt you just run pipe from the bottom of the stock manifold in a "u" up to the turbo, situated under the intake to the side of the block? would this create any problems like possibly with more lag?

my main concern with the whole deal is the fuel delivery. do you just have to jet the carb up enough that it has a good mixture under boost and deal with the rich problem when out of boost? if anyone has experience with carbs and turbos id love to hear from them and the problems they might have run into. this car IS my daily driver though i have other cars to drive, so how will a turbo set up and the carb negatively affect its abilities as a daily driver?
 
can anyone tell me how they deal with the fuel delivery being rich out of boost and keeping it from going lean when under boost? id appreciate any help.
 
if u have a progressive carb u can make the primary jet smaller and the secondary jet larger...that way u actally run a little leaner when cruising or whatever and then richer to supply enough fuel when under boost because of the secondary jet
 
It's real simple! Don't boost over 10 psi, if you do your on your own! Short of that just jet your carb to run rich as needed at full boost (10 or under) beyond that you need a computer and lots of other stuff. Their is no easy fix to your problems that will be presented when you go for max bost over 10 psi. How do you expect a non computer engine, no FMU, to meter the fuel from no boost to over 10 psi boost and still run correctly, if you expect it to run without problem's then you don't understand engines! Can you do it without FMU and computer's maybe depending on the engine, boost, carb, how many beers you have had? Really a simple boosted engine can run great, I just don't think you can at higher boost levels (There's always exceptions) without lots of help!

P.S> How do you know it's not too lean, very simple pay to have your engine dynoed and have them check the fuel air ratio, be pepared to change jet while on the dyno, it's cheaper to buy jets and not need them than to need them and not have them!
 
i planned on running boost around 5-8 psi. so it shouldnt be hard to keep it from going lean with boost levels this low?
 
Mustangaroo,
10 lbs? That's it? We've had Kelly's Falcon up to 15 without any problems at all (other than grenading a C4!)! So the myth of a high boost, blow-through carb is bunk. Just go to http://www.turbomustangs.com and go to the carburated forum to see how to go up to 20-25 lbs of boost.
Later,
Will
 
does10's

you are running an IC though aren't you? mustangaroo is not so i thought 10 psi is the max you would want to go without an IC

thanks
John
 
Well what about water/alky injection? Cheap, simple and it works from what i've seen. I plant to use this method to push 15+ psi without your traditional air-air or air-water IC.
 
can anyone tell me how their carbed/turboed cars run on the street? are they reliable for a daily driver? on the slant six boards they just put it simply, dont try even try it, go with fuel injection. i need someone with experience to tell me if this is going to work on a daily driver, running low boost 5-8 psi, and not run lean and blow up or run rich out of boost and be a pain. i was planning on running a carter bbd 2 bbl. will i be able to deliver the fel i need under boost and not run so rich the car will be undriveable? the general answer from the slant six guys is no.

it sounds like you guys have done this with success where as the slant guys have not so i wanna hear yalls stories.

has anyone ran a nos type system that delivers extra fuel, (instead of nos) when boost gets to a certain pressure? this is an idea but im not sure how id set it up or how well it would work.

thanks guys, im really looking for some open minded answers that arent, just dont do it. thanks for the hepl so far though guys.
 
Dart-Swinger,
We drive my wifes '63 Falcon with a turbocharged, straight six using a blow-thru Holley 350cfm 2bbl on the street with no problems. The fuel system is VERY important. The fuel pressure needs to increase as the boost pressure increases.
I wouldn't recommend the Carter/Edelbrock carbs for blow-through setups. Everybody that I know of is using a Holley (or similar type carb, ie Demon) for blow-thru applications.
The carb will accomodate more flow. You don't need to run a solenoid to add more fuel. The more air that goes thru a venturi the more fuel will be sucked out of the float bowl. Given the jet size is large enough!
With only 8lbs. you won't have any problems. Just take care of the basics, fuel delivery, reduce the spark timing, and get a big radiator, and you'll love the results.
Later,
Will
 
thanks, i guess ill start looking for a holley. the prob with that is im going to have to get anf adapter because it wont bolt to my 2bbl intake. i also think there are issues with the throttle linkage and i know there are going to be problems with the kickdown linkage on the 904 automatic. guess i need to check into a lokar kit to solve that.

ive heard that the bbd will get its bowls sucked dry, i guess ur experience with the holley has been good. so for boost referencing, should i run a line from the aircleaner or "hat" above the carb to my fuel pump? is this how yalls setups are?

the few guys at the slant six website with experience have just run a line with boost pressure to a vent on the stock fuel pump. does this sound safe to you guys?

thanks for all the help. ive only been studying up on turbos for a short time and have learned a lot from you guys and elsewhere. i read parts of corky bell's book on turbos as well. thanks again guys and keep the info rolling.
 
does10s,
whats the displacement of ur falcons engine? what turbo are u using? what type of hat are u using on the carb? what size fuel line do you use? what kind of fuel pump do u run?

so u dont experience any problems being too rich when not in boost. i live in tx (where its plenty warm in the summer) and im worried about vapor lock from being too rich, especially with the added heat from the turbo.

sorry for all the questions but thanks guys
 
Our motor is a relitively stock 250. Well it's been bored so now it's up to 256cid. The only change from stock is the cam. And it's a very mild grind. Doesn't lope at all.
We're using a Garrett TO4B with a .58 A/R turbine housing. This is the smallest one you can get for the TO4. This is so it'll spool up faster using the smaller displacement motors. For a reference my turbo'd '86 5.0 Mustang is using a .81 housing.
The fuel pump is a Mallery 250. This is to big for us but it works. Just select one that can pump fuel up to 20psi or so. If you run 10lbs. of boost you'll need 16lbs. of fuel pressure. Assuming a 6lbs. normal pressure at the carb.
Our carb hat is one made by ATI. The Procharger dudes. If you have hood clearence, use a taller one. If you Google a search using "carb hat" you should get a couple of vendors for them.
Don't sweat the tuning too much. Just limit the amount of total timing to about 25* or so. We have a stock Duraspark distributor with the vacuum adv. disconnected and plugged. I plugged the vacuum canister on the distributor because it slowed down the rate of timing adv. We're using a #75 jet in a Holley 350cfm carb. Mustangaroo is using #78 in a 500cfm carb. In our 250 the #75 seems to be about right. Our altitude is around 3000' here in AZ. We're racing in Phoenix this weekend so we'll see if we need to jet up some more.
Later,
Will
 
Oh yeah fuel line!
We're using 3/8" aluminum both ways from the tank. The regulator is a Mallery 4309 boost referenced with a fuel return/bypass back to the tank. This regulator will increase fuel pressure when boost is increasing. Aeromotive has regulators to that'll do this too. As far as making an engine driven pump work....it can be done. I've seen articles about this topic but choose to not go this route.
Will
 
does10s, how does the car behave out of boost? im worried about being too rich. do you have a air fuel ratio gauge on your falcon?

ok, this might be a dumb question but im making sure i understand this correctly. from what the slant six guys say, they make it sound like you will either go lean under full boost or be waaay to rich out of boost. but, the engine wont be getting the same amount of fuel out of boost as it will under boost right? the jet might be a little large, but the fuel pump wont be pushing the extra pressure (which would mean more fuel in general, correct, or am i wrong?) when the motor is not under boost, so the fuel mixture wont be as rich out of boost as it is under boost. i hope someone can understand that and explain it to me.

you guys seem to have done this and had success with it, where as the slant guys just say go efi and i dont think any of them even have a turbo car. i just want this to work out and well see whos laughing in the end. :twisted:

thanks guys
 
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