Hi I am relatively new to the world of slants. I picked up a 69 Dart about 2 months ago. I am currently making it road ready. I have replaced the gas tank and now im putting brakes on it. After that it will pass inspection. I have been looking around for performance upgrades. I thought about swapping a 318 or a 340 in it but i think the slant in it is pretty cool. So i got to looking around and ive seen numerous posts about a turbo slant 6. ive done some research on it and i found that you could make a fun daily driver with a small turbo.
So that got me thinking about putting a turbo on my stock 69 225 engine.
From what ive read about 7 or 8 psi is a safe amount of boost to run on a stock setup for a daily driver.
but i have a few questions.
What do you think the best turbo is to put on it for mid range power
What should i do for the manifold
What cfm carb should i run
And should i go blowthrough or drawthrough

Thanks for the help
-Casey

In the words of Ak Miller: "You can blow more air through an orifice than you can draw." Blowthrough seems to be the best for several reasons, one being the length of inlet between carburetor to valve is shorter, which means better throttle response.

Having said that, my turbo experiences have only been on 4 cylinders for which there was a factory turbo option, so I didn't need to fabricate much. Do a search on this site because I seem to remember this being discussed before. The good thing about a slant six is the bottom end is stout enough for forced induction already.

Yeah ive heard blow through is better. i just wasnt sure about the benefits at only 7 or so psi

you can run a little more boost than that on a stock setup and keep it safe. the buick grand national turbo is a pretty good low boost turbo. for the manifold i would run a j-pipe. a quick search should net you a thread about them. its the easiest and works well. wrap it with header wrap and it retains the heat. for the carb, cfm requirements dont change because of boost. the closer you can get to 325 cfm the better it will respond. blowthrough. its pretty easy.

sounds good. anything else i should be concerned with?

Casey,

You should be concerned with the TUNE, which means that building a satisfactory turbocharged slant six requires that you get very good at making sure that the mixture, under boost, is within the parameters that will let your engine LIVE.... and that means an air/fuel ratio of, as close to 11.5:1, as you can get it.

If you can maintain that ratio of air to fuel, and keep your total spark-advance to 18 degrees, you will have the most important part of tuning under control.

What this means, in the real world, is that the first and most important purchase you should make, is a wideband, data-logging air/fuel ratio meter. They are not cheap (I think I paid a little over $300.00 for mine about 6 years ago,) and, that's a lot of money, but you simply cannot do this build without one. If this is outside your budget, then I would suggest that you take a different route and build a naturally-aspirated motor using conventional hop-up methods. That method would not require a $300 meter.

So, ask yourself if it's going to be do-able, and which engine to build.

The turbo route will give you, using stock pistons and rods, and a 350cfm Holley 2bbl on a Super Six intake manifold, with a J-pipe exhaust, an 8-10 pound boost car that will use a stock cam and will have excellent road manners and a stock idle, with a quarter-mile performance, probably in the mid 14's (3200-pound car) which would put you in a position to match a 340 V-8 (stock) pretty closely.
To get that kind of performance, naturally-aspirated, would take a LOT of mods to a stock motor and you'd probably end up with an engine that would have a big appetite for high-octane fuel, a ragged idle, and poor driveability. Of course, you woudn't HAVE to build such a radical engine, but to get anywhere near the turbo motor's power, you would, even if the turbo motor were just utilizing 10 pounds of boost.

Neither route is cheap, but there's a lot of fun to be had with these leaning towers of power.... a LOT!

Good luck!

Bill, in Conway, Arkansas

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1964 Valiant 4-door sedan, 225 turbo/904

Honestly i am not sure if id rather have a turbo or a supercharger at this point. I like the idea of no lag with a supercharger plus i feel as theyre a little more simple. The exhaust could be left untouched and there would be less custom fabrication. And because superchargers are run off a pulley the boost is more stable and predictable psi. Please correct me if im wrong. im still new to all of this, but this is just what ive heard online.
Does anyone know a good supercharger to use. it could be roots or centrifugal, im open to either
what size carb should i run
what other parts would i need besides an intake, carb, and supercharger?

Casey,

I own one of each; a supercharged V8, 360 Magnum, and a turbocharged slant six (225 motor.)

I like 'em both... pretty much, equally... partially, becauce at the moment, I think a drag race between the two would be very, very, close and might even be a dead-heat, if that is possible. I never intended that; it just turned out that way...

The difference is, the supercharged car (a 1972 Valiant 4-door) is about 600-pounds heavier then the '64 Valiant, turbo-slant. But, its V-8 engine is 60-percent bigger...

The V-8 has a Vortech, V-1, S-trim, centrifugal blower, running a maximum of ten pounds of boost, while the slant 6 is running a 66mm Turbonetics turbocharger currently, with a waste-gate limited 15 pounds of boost.

They both have 904 transmissions and moderately; higher-than-stock stall speeds.

If I were going to recommend one forced-induction method vs. another, I think a centrifugally-blown slant six with a belt-driven supercharger would be the ideal setup for the street. Ten pounds of boost could be easily attained with either. a Vortech, Paxton, or ProCharger head unit, and it could run on pump gas and no intercooler would be needed. Stock engine internals would work fine, I think.

Steve Nitti has a slant-powered Duster with a belt-driven, ProCharger blowing thru an elactronic fuel injector, and it is pretty fast.... very low 11's, the last I heard. Might be in the tens, by now...

There are reports of turbo-slants that are faster, but not much...

That would be my druthers..... for a near-stock motor.

You pays your money and, you take your choice!

Bill, in Conway, Arkansas

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1964 Valiant 4-door sedan, 225 turbo/904

thanks bill. I appreciate the advice. At this point i am leaning towards the supercharger. im not sure what setup though. i would like to keep it around 8 or 9 psi just because id rather be safe than sorry.
i was looking around and centrifugal superchargers are a little pricey. (well so is all forced induction) And i would need an $800 blow through carb. im not sure about a roots supercharger needing a blow through. i was looking at some with the carb mounted on top so im guessing thats draw through. i like the old school look of a roots supercharger sitting under the hood with a carb on top (plus the noise is awesome). so i was wondering if a roots supercharger/blower would work as well and if i would need a special carb for that setup? What sized supercharger/blower would work? 144?

Casey,

My own personal preference, is for a flat hood (no scoops,) but that's just me... I like the element of surprise in this case... think it outweighs the badsass-look of a Roots blower poking through the sheetmetal, but, like I said, that's just ME... lol! Your mileage may vary...

Additionally, research tells us that a centrifugal blower is considerably more efficient than a positive-displacement supercharger... it heats the air less and dellivers more boost for the amount of input energy, so, I have gone that route, but, again, that's just me..

As a result, I am woefully ignorant of Roots-type blowers, but Detroit seems to like them a lot, and uses them all the time. The 3800 V-6, G.M. motor is almost identical in size, to the slant six, so that blower should work well on your motor. Two caveats here; one, the blower G.M. puts on those 3800 motors changed in size at one point, but, I don't know when. I think they got bigger, in swept-volume. You'd probably want the bigger (later) one. and two, I read somewhere that the rotors are Teflon-coated (on the rotor-tips) and that coating will disappear with time if you run anything but air (no fuel) through them, so, you'd need to port-inject the gasoline. There are other aftermarket manufacturers whose blowers don't have thet problem, though, I am sure. You need to research that, if you decide to go the positive-displacement blower route.

I think that locating the carb on top of a Roots supercharger makes it unnecessary to perform "blow-thru" modifications to the fuel delivery system, but, some mods are still necessary; just a whole lot fewer and simpler. You MIGHT get away with a heavy-duty mechanical pump and not have to worry about boost-referencing the carb nor running a high-pressure system, nor a return line to the tank.

Think about it... It's YOUR car!

Bill

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1964 Valiant 4-door sedan, 225 turbo/904

The first question is what do you have currently on this car? If it is a 1 barrel carb and stock sub 2 inch exhaust I would suggest getting a 2bbl or 4bbl intake and putting a good free flowing exhaust on it. this will make a huge change and would all be parts you would continue using later for any build except a MPFI turbo setup. Also the first upgrade i commend if you don't already have it is the electronic ignition. It became standard in 73 but I think was optional even before that.
lastly for carb size you would be happiest with a holey 325 cfm 4bbl if you can get a 4bbl manifold.
For a 2bbl manifold the webber 38 DEGS is the carb you want.
Both of these will perform well naturally aspirated and boosted.

I'd vote turbo but that's just me. I like the idea of wasted energy spinning my forced induction and not a parasitic belt. They both have huge differences in the pros and cons area though. Supercharger huge pro is ease of installation and mush less custom fabrication specially due to the lack of turbo kits for these engines/cars. I like the aw factor more on turbo setups since they tend to be more intricate and involve fabrication. I'm no pro on superchargers since and have not fiddled with one yet but I hear the mpg is better turbo vs supercharger? Both options sound great but I lean toward the turbo in that area also. The lag department goes for the supercharger but a well sized turbo seems to be just fine my car has no real lag that I notice, she makes 19psi in 1st gear!

Hope it helps
Kev

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I was thinking of going with a Pontiac 301 draw through turbo on a 4 bbl intake, improve the exhaust. Anyone tried this setup ?

Charrlie Did a draw through back in the day.. It was some sort of GM or Corvair setup I believe.

The Blow thru is better and EFI is even better.

Best of Luck!

When you get into the boooost and nitrous you cant be scared of essentially re engineering the entire intake and exhaust paths alond with oiling / cooling (to the turbo) and ignition / timing system.

Greg

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http://www.youtube.com/hyperpack

I have a 65 Valiant (not running at the present time) with a 170 and a Corvair (Rajay) turbo, with a 500 cfm Holley 2bbl in draw thru configuration. Someone on this site did a early GM V-8 draw thru (might have been Doug Dutra). I have a complete 301 Pontiac using a Q-jet, system on the shelf, but I doubt I'll ever use it.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225