Hello All,

I am currently in the market for a slant 6 A-body (67-72) and was ultimately hoping of adding a turbo too. This is going to be a multi-step process with the hopes of driving it and modifying it at the same time. Ultimately I would like to have the Slant 6 Turbo, with power steering, power brakes, A/C, manual transmission, 73-up front discs, with an 8 1/4 3.23 posi in the rear. This car would be set up as a daily driver with some pulls at traffic lights. I doubt this would see much track time but there is a possibility. I would like this to be a very reliable vehicle that would I be comfortable with taking on long road trips. If anything it would be something I would use to bend some corners for fun. 300 hp would be amazing, but is highly optimistic (I think?) for this build, but I would be okay with over 200 hp. I am not sure if anyone has done a combination like this before, so I guess some of my initial questions would be:

All I can find is people using the 904 auto in these. Would there be a problem going to the manual transmission (A-833OD)? I have heard of people using that transmission behind 440's at the strip. So it should be able to handle the power I am looking for

If I am planing on keeping the engine as close to stock as possible (stock internals, stock exhaust manifold, cam, crank), and running close to 10 psi boost, would I have enough vacuum to run the brake booster?

The A/C system would probably be an aftermarket kit that was made for the particular vehicle. Besides space constraints, would there be a problem of running a turbo set up with A/C?

I cant see of any problems of running the factory power steering set up besides the space that it takes up. Would there be any other disadvantages with this? I understand I will have to move the battery to the trunk

A lot of individuals say to use the 2.76 gearing for a set up like this. Would there be a disadvantage of using a 3.23? The turbo would probably be the last thing that I would add. I have a 68 Dart with the slant six in it that has 3.23 gearing in the rear (I Believe) and it adds a little bit of sponk to it.

On turbo Selection I heard anything from the Buick GN turbo, to the T3/T4 turbo to even the turbos from the TII motors of the shelby chargers and such. I was planning on adding an intercooler. Am I on the right track with these turbo assumptions? Would this give me what I want?

I am sure I will come up with more questions along the way. I figured I should start looking into this before I add in all the systems I want only to find out the turbo wont be compatible with them. I have no problem doing all this stuff with a V8, but it appears to be a lot cheaper when done with a slant 6. So any help is appreciated, if you could suggest other places for research, that would also be appreciated. Thank you


Joe

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Joe
68 Dart GT - Slant 6

I may not know as much as a lot of others, but I'll toss in my 2 cents

HP goal, @ 10lbs, I'd say around 250ish

Turbo selection: GN turbos (this also includes all turbo regals) are t3/t4 variants I believe. If you are looking for an OE turbo, I would say this would be the go to turbo. On the turbo from the 80's turbo Dodges, I'm pretty sure they are way too small, unless you want to make less than 200 horse and not take it past 3k. I personally wouldn't recommend them. A dude named Matt Cramer could tell you more about that. If you are looking at aftermarket turbos, the first one of the top of my head would be a GT35 or maybe slightly smaller. The GT35 should get you close to 300 I think. I was using a turbo calculator on squirrelpf.com, but they just up and disappeared recently.

I think the main reason no one uses a manual is finding a clutch. I can only think of one car off the top of my head, and he may have had trouble with his clutch recently, he'll chime in hopefully.

Another thing, can/are you willing to tune a blow thru carb? From all the ones I've seen, some have troubles with it, and others if they do have problems, don't talk of them . Draw through may want to be an option you consider, as it's more similar to tuning a carb on a N/A motor. The problem then comes that you can't run an intercooler, only a chem spray intercooler.

Best of luck, always interesting to follow these!

I have the A833OD in my pickup. It's ok, but for daily driving I find the gear spread to be awfully wide. While I appreciate the overdrive, I don't like it much for driving around town. I plan to use some kind of 5 speed as my project progresses.
2.76 gears would make the overdrive way too tall to be much use. I think you will find that anybody running 2.76 gears has an automatic or possibly a non-OD 4-speed. If you would be satisfied with 200 HP that can be achieved without adding the complexity of adding a turbo.

_________________
--> Check out my FI Turbo build <--
--> And the race truck build project <--
--> The Diesel Corvette <--

Sounds like a fun project, and welcome to the site!

Agreed. 200 HP is not hard with a NA 225. You are going to pack a lot of hardware (and heat) into that engine compartment, which is challenging. Sam Powell has done what you are asking, but had turbo trouble and went back to NA. I have a 64 Valiant with PS, AC and NA 225 at ~ 200 HP that is pretty fun.

If you are not going to do EFI, then I would avoid the turbo. I have a 68 Dart with T4 turbo that has made ~330 HP on 9 psi in street trim. Megasquirt port EFi. I decided the carb would not be tunable enough for me with boost. No PS or AC.

For a stick, I would go with an 833 std trans (non-OD) with 2.94 gears or 833 OD with 3.23s or 3.55s. OR, find someone with the T5 adapted bellhousing and do a T5 manual and use 3.55-3.91 rear gears. My 64 Dart TBI has 275 HP (quite bumpy cam) and T5 trans w/3.91s.

Come to our banquet in Pigeon Forge, TN on the Feb 21 weekend, or hook up with Greg Ondayko or Brian Droschak in Pittsburgh and talk Slants. They have lots of knowledge, esp Greg, on these topics. Lots of knowledgeable people at our drag races next spring/summer too.

Happy researching!

Lou

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Home of Slant6-powered fun machines since 1988

So it whats brought up that a blow through carb is hard to tune. I really dont know what this is or how this differs from a "normal" carb. So does anyone have information on this?

There is an individual from California on forabodiesonly.com that is currently added a turbo to his slant six dart and is using what i believe is a blow through carb, with an intercooler. It doesnt sound like that bad of a set up.

How would I get in contact with Greg Ondayko or Brian Droschak?

Thank you for this information all

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Joe
68 Dart GT - Slant 6

diy blowthrough. http://www.hangar18fabrication.com/blowthru.html

Am I the guy from California?

Man, i just strapped a turbo to my Dart and pushed 8psi and I got about (less than)200 at the crank. I did Dyno it so that's not even a guess either. lol. It was having ignition issues, so that was 164hp at the wheels @3700RPM, and 234'lbs of torque. I also had a pretty wavy power curve and it wasn't really "hitting its mark" so to speak. This was at 18* adv with no additional advance hooked up, and the 8psi mentioned earlier. Blow through on a 2bbl 350 Holley. It stayed at 11.8 throughout on the Air Fuel gauge.

The whole setup has cost me around $1500 and I've built pretty much everything myself except for the exhaust connection to the downpipe which I had a shop do.

I'd imagine if I got it to spin faster on the Dyno and stay stable at 8psi and fixed all the various vacuum leaks that keep popping up, and get a better spark going. You can see on the sheet where the RPM literally dropped off at some point where the ignition cut. - I may make 200 at the wheels if i fix all of this - maybe more. I will Dyno it to be sure. I've documented every single thing I've done up to this point and will even keep Dyno-ing it just so the information is out there for others to learn from my mistakes or learn what they want to do in the "cheap realm" of turbocharging. Also - I only know what I've read - never built a turbo before - and I don't have a garage. I did it all in the driveway at my apartment.

Happy modding.





And a video of my turbo beast strapped down - trying to escape.

https://www.youtube.com/watch?v=HElZ4DB49k0

Serjj22, yes you are the guy I was talking about lol. It was actually you who inspired my whole idea of getting a project car and drive it while fixing it up. I figured if you could take your daily driver and add a turbo like you did, then I should definitely be able to do something similar lol, so we will see where I end up.

But Yes you also said to come here to find out information on doing something like this so here I am, trying to find out what I can on adding a turbo. Basically hoping to find the do's and don'ts of the process.

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Joe
68 Dart GT - Slant 6

This is truly the place to learn. I asked questions about what I didn't understand, and then borrowed from others' builds. I took everything I could find, compiled it all together, and worked from that. If someone put a part on, and then it failed, i just skipped that and went straight to the part they used to fix it.

Some of the failures in my design were:

The oil sandwitch failed. It was a cool idea, and very clean setup - easily removed, but the bolt adapter that goes over the stove pipe was too thin, and the oil pressure blew it apart and popped the oil filter up. Luckily i caught it. To Fix - I built a threaded insert, AND listed every single part you need to make it - there are only three parts -AND I gave the sizes so you can make the exact same part.

The second failure was using a second-hand wastegate. It leaked and caused a lot of issues. I switched to a internal wastegate to simplify everything instead.

O rings do not work for the carb to carb hat gasket - I tried it - use the felpro gasket. It works just fine.

The gasket between the two manifolds did not seal well. I added a copper spacer to crush and fix it. leaking between the manifolds caused no heat whatsoever to reach the turbo.

My original J pipe sucked and put the turbine too far away from the engine - and didn't allow for a filter - and leaked, so I trashed it and built a better one.

I suck at welding.

And putting the distributor back in wrong after fixing it.

And other things, but it's ALL documented on my close to 20 page build thread. If I change anything - I list it and what the effect was.

One of the things missing from a few other builds is the specs and sizes. How can you go to the store and prebuy all these parts if you don't know what sizes you need? It's very difficult. I had to figure it all out with my daily driver.

The main thing with a daily driver is to do one system a day. I did the fuel pump one day, electronics another day - etc... anything that you can change and the car will still run (but run weird) is worth doing. Then I did one final push on a weekend to install everything else. I've also taken the manifolds off and on several times so I'm a veteran to putting those triangle washers back on and lining them up. I also prefer to remove them seperately rather than in one piece.

If you see something that works - weather on mine or someone else's build - by all means you should copy it.

One thing that I think will be critically important for you as you try to tune this engine once all the pieces are in place and operating is, it is virtually impossible to get the mixture right under boost without employing a wideband data-logging, air-fuel meter. I can't imagine trying to get this done without one, but no one has mentioned it, or I missed it.

The one I use is made by F.A.S.T. and has a digital readout on a hand-held meter that is hard-wired to the under-hood components with a long pigtail, plenty long to drape over the cowl and into a side window to be read while driven. You can read the numbers while the motor is going through its paces, and jet accordingly.

Sounds easy, but carburetors are devilish in their vagaries, and will give you different results for seemingly no reason at all.

And, get it wrong (on the lean side, under boost,) and you just bought a motor...

Do yourself a big favor and get one of these meters FIRST,,, It's the most important piece of equipment you'll own!

Bill

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1964 Valiant 4-door sedan, 225 turbo/904

Two other things come to mind, both just personal opinions:

First, I think you are well within the ballpark with your 250 hp figure arrived at by using a stock reciprocating assembly and only10 pounds of boost. That willl give you a pump-gas capability and performance similar to a 340 V8. I have read a lot about such a combination and the general consensus was that 10 pounds of boost would generate so little heat, that an intercooler would be unnecessary. You could add a chemical intercooler and up the boost to 12 pounds, if the extra power appealed to you.

The other subject (and this is strictly MY opinion,) was the choice of a transmission for this project.
It has been pointed out to me several times that the nature of turbocharging (at least, as regards slant sixes) is, that they like to be kept in a constant pull, and held back, much like a fuel motor. For that reason, the successful drag sedans I am familiar with have shown in testing, to run quicker and faster with final drive ratios in the high 2's, than the usual 4's... weird, but true. That makes it seem to me that automatic transmissions work in conjunction with turbo motors, generally better than manual boxes. Add to that the difficulty in getting a suitable clutch for a high-torque slant six, and it looks to me like a manual is not a very good choice, but that's just me.

It's your car; build it so you'll like it!!

Good luck!

Bill

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1964 Valiant 4-door sedan, 225 turbo/904

+1
I've set up jetting for many motorcycles both carbureted and fuel injected.
The value of a data logging AFR meter can't be understated.

I use an Innovate LM-2 which will also log any other output that can be converted to a 0-5v signal.

Like Bill says, I can't imagine doing turbo carb tuning without piles of data for making those tuning decisions.

_________________
--> Check out my FI Turbo build <--
--> And the race truck build project <--
--> The Diesel Corvette <--

I'm running the innovative as well. SOmehow I managed to get the jetting right on my first guess. It runs 20 at idle, 13-14 on cruise and 11.8 on boost.

Serj22,

What are your current carb settings? Those running a holley 350 (me included) would have a good base line to start with. And what carb mods besides hangar18?

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225, Offenhauser, Holley 350, A833OD, 3:55, GM HEI,99 Durango starter
BOOSTED! WH1C, BIG FMIC, 10#
Operation Noble Eagle 03-05
Operation Iraqi Freedom 05-07
Operation Enduring Freedom 12- 13

Well, I'm happy to see that I am not the only one who realizes the tremendous importance of having access to these A/F ratio meters and the necessity of gaining the vital information from them, when attempting to tune a forced induction motor. They will pay for themselves in short order!
What I didn't know, going in, and what I totally failed to be aware of, is that leaded gasoline will destroy the oxygen sensor/probe in these meters, pretty quickly. I don't know how I missed that, in learning about using this device, but I did. So, I was running low-lead 100, aviation gas early-on, and destroying my meter in the process, totally unknowingly.

Fortunately, it causes the meter to malfunction in a way that makes it obvious to the user that something is wrong. I ordered a new oxygen sensor ($91.00) and plugged it in, still not knowing the "why" of the malfunction, and continued to run the leaded gas, so. that one got "poisoned", too... and it doesn't take long.

My frustration prompted me to try to find out what was going on.

Phone calls to F.A.S.T. educated me as to what the problem was, so I ordered another sensor, drained the avation gas, and pretty much evacuated the fuel system of the bad stuff, and finally, have a working meter, again. Unleaded racing fuel is, among other things, expensive...

This just gets better and better $$$$$$$$$$!

At ten pounds of boost, I am going to try and mix 93 octane, pump gas with this unleaded racing fuel in a 50/50-ratio, and see how that works.

I am not sure of the octane rating of the racing gas, but, I think it's around 112.

Wish me luck; I won't stay at 10 pounds of boost long, if it works okay, opting to modify the wastegate to allow for a moveable/adjustable seat for the spring, to adjust the boost-pressure upwards. It's a Turbonetics external unit, but the strongest spring I can find for it is rated at 9 pounds...

I may be the only person in the world who installed an A/F fuel ratio meter without knowing that lead will ruin the oxygen sensor, but if my story help prevent what happened to me from damaging someone else's meter, then, writing this and embarrassing myself was worth it; those things aren't cheap. I just didn't know...

I have some jetting to do, and she's ready to roll!!!

Bill, in Conway, Arkansas

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1964 Valiant 4-door sedan, 225 turbo/904