Draw through slant six turbo setup

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CordobaDart

CordobaDart

318 SLANTMAN
Joined
Nov 26, 2011
Messages
226
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Location
Wabasso, Minnesota
Hi all, I am addicted to the forced induction forums and and am just getting my feet wet in the realm of turbocharging. Thanks to all who have posted all the great info in the forced induction forums already!

Probably should have started a thread on my build months ago, I started my build in March 2014.

Anyhow, the 1983 Dodge W-150 that I turbocharged is obviously not an A body, but I want to share my experience on my evolving build.

A little background on me, a 26 y/o Minnesotan, changed jobs and cities recently, made the move back home in rural sw mn last week, it is good to be back. My wife and I are buying a house, so I will finally have my very own working on my projects area. :)

In the following posts I will post pictures and info on my unconventional slant six build. I am open to ideas to improve it, it is not perfect, but so far it works well. This has been a budget build, $165 ebay turbo, tubing bends from summit, all fabbing done by me. I believe I have around $600-$700 in the build so far, I really need to add up all my receipts though.

Lets begin.
 
Does your turbo have the proper seals for draw thru? Where did you get the plenum to mount the carb on? The early (as in, before GN) turbo Buicks were draw thru, and had an electric heating element to keep the carb from icing. I think they were all Qjets tho, so you may not get one to work with your AFB.

May I ask why you decided f/i instead of a mild n/a buildup?

Best of luck!
 
Hey Brandon! I like your Dart Sport, I have a 73 Dart Sport, I finally got that out and driving well this past summer and put 1500+ miles on it, it was a blast.

To answer your question, this turbo does not have the proper carbon seal for draw through use, I will be buying the matching Buick turbo that does from the guy I got the 4 barrel Buick pre-turbo carb manifold from. For now though, it works very well!

It does suck about a quart of oil through the turbo into the engine every 300 miles, I am fine with that until I find a proper turbo for draw through, or revert to fuel injection as I plan to in the future. I have 5 other vehicles to drive, and access to my dad's Dodge Ram if mine has a sudden problem, so this build does not have to be perfect yet. But dang, am I learning lots doing it!

When the truck sits after being driven for awhile, some excess oil sits in the compressor housing and emits a "mosquito fog" for the first 5 seconds or so. It does not smoke while running though, and the seal I believe is actually functioning under boost, as pressure is against the seal. It does not have a dreaded throttle lag like I was told it would have.

To answer your other questions, the manifold for the carburetor I got from a swap meet(the guy had the turbo for my manifold, but I did not but that since I already had a turbo, I should have bought it, but since I know the guy, I plan to buy it and a complete one with the carb, manifold and turbo as well), it was made for a q-jet. I got an aluminum Mr. Gasket spacer to adapt it to the square bore, it needed height for the wide AFB throttle shafts to clear the plenum exit anyways. The manifold was from a 1980 Buick T-type I believe. It has coolant running through it to heat the carb base. Time will tell if it will be enough for the brisk winters here in MN.

I am running an in-line electric fuel pump, bypassed the mechanical fuel pump, and will be removing the old pump completely.
 
I am going to take higher quality pictures of it today and upload them. My three and a half year old blackberry phone has seen better days, and the picture lens is scratched to hell. Sorry for the fuzzy pics.

The last picture shows me putzing around at 5lbs of boost part throttle, I have seen it build nearly 9 pounds of boost, but let off before getting to wild as I want to do more work with timing. The vacuum/boost gauge is plumbed into the intake manifold on the rearmost intake runner.

Currently running 10° initial with about 16° mechanical, which i want to get down to 8° for 18° total. I will be hooking up the vacuum advance straight to the manifold to get more advance under vacuum that will be gone in boost.
 
Brandon Weaver said:
May I ask why you decided f/i instead of a mild n/a buildup?
Click to expand...

I was bored with the 4 barrel n/a setup, it was a power improvement, but hauling stuff uphill with my heavy truck, I found it would be nice to have more power, especially under load.

I pulled a car trailer with some stuff from my apartment on it and a bed full of stuff last week. going uphill, I just gave a little more throttle, and it almost instantly goes from vacuum to boost and shortly builds up pressure. I lugs uphill with ease under load now, and accelerates better than ever! I do not even have the setup dialed in yet.

It is a 4 speed manual trans by the way. Running 91 octane currently.
 
Awesome. Pishta's right, all our J-pipes wind up looking the same. I was trying to find that gnx carburetor mount you have but could never figure out what it was called - to initially do a draw through setup, but instead i opted for blow-thru and so far I'm ok with it.

Definitly digging the carb hat as well. No extra material, just as big as it has to be.
 
Serj22 said:
I was trying to find that gnx carburetor mount you have but could never figure out what it was called - to initially do a draw through setup, but instead i opted for blow-thru and so far I'm ok with it.
Click to expand...

If you were looking for a GNX one, that may have been part of the problem. GNX was the last year ('87) of the 'black' cars, and the g-body in general. The ones that got the draw thru carb plenum were 1978-82 turbo regals
 
CordobaDart said:
Hey Brandon! I like your Dart Sport, I have a 73 Dart Sport, I finally got that out and driving well this past summer and put 1500+ miles on it, it was a blast.
Click to expand...

Thanks, I absolutely love my Dart! It's a 225, but it feels more similar to a 273. Not blazing, but a good foundation for sure.

Do you have an AFR gauge of any sort? I'd be cautious of running that thing lean, especially under load. Fuel Injection would do absolute wonders, that would be about the only way you could get me to go turbo, plus with blow through, you can intercool it.

I like the draw thru setup, I can only imagine it would be much easier to tune!

What kind of fuel economy are you getting? Or do you even worry about it lol
 
Brandon Weaver said:
Thanks, I absolutely love my Dart! It's a 225, but it feels more similar to a 273. Not blazing, but a good foundation for sure.

Do you have an AFR gauge of any sort? I'd be cautious of running that thing lean, especially under load. Fuel Injection would do absolute wonders, that would be about the only way you could get me to go turbo, plus with blow through, you can intercool it.

I like the draw thru setup, I can only imagine it would be much easier to tune!

What kind of fuel economy are you getting? Or do you even worry about it lol
Click to expand...

Are you thinking of turbocharging your dart? It would be a good foundation for a turbo since it sounds like it is healthy. My Dart has a 318 warmed over, which is fun, but it needs better heads to make more power, that or boost. The original slant was removed by one of the previous owners.

I do NOT have an AFR gauge. Yet. I will be getting one to see what is happening though. One of the benefits of draw through is that the carburetor's fuel metering is not modified, so it works like normal. The other benefit is my vacuum assisted brakes hooked up to the carb manifold like a conventional manifold, that and the HVAC vacuum line. Being that the carb was jetted for a 273, it likely is richer than a slant needs, only way to know is to get the AFR gauge though.

My fuel economy when hauling stuff stopping and loading was 11.5 mpg, that was also with side and headwinds that are common this time of year in MN during season change. I have gotten as much as 15 mpg with the 4 barrel setup before turbocharging it when I was accelerating gently and kept it around 55 mph on the highway. I feel I will be able to pull off that mileage again when I get the vacuum advance hooked back up and drive nicely without a load. Do I care about mpg? Yes, but I also care about power and capability.:burnout:
 
Brandon Weaver said:
If you were looking for a GNX one, that may have been part of the problem. GNX was the last year ('87) of the 'black' cars, and the g-body in general. The ones that got the draw thru carb plenum were 1978-82.
Click to expand...

I was looking for any kind of "GN" intake, but there was no way to search what that piece where the carb bolts to is called - therfor couldn't locate one. But alas, it's all good - and I figured it out blow-thru instead.
 
Sounds almost like a cummins! Very cool setup, I actually considered doing a draw through on my wagon. If the hot-rod VW guys can get away with it, so can we right?!
 
Rockerdude said:
Sounds almost like a cummins! Very cool setup, I actually considered doing a draw through on my wagon. If the hot-rod VW guys can get away with it, so can we right?!
Click to expand...


I said the same thing to my friends when I first drove it. It does sound like a mini Cummins! Haha!

For my low boost, the draw through will work fine, and as far as intercoolers go, the world is my inter-cooler from November-March here in Minnesota.

There is no muffler on it, just the down pipe dropping out by the trans bellhousing. Surprisingly, it is not that loud and I love the sound! My grandfather would be proud if he could see his truck now:salut::)
 
I have been driving my truck to haul stuff in the cold, it does start a bit harder with the long draw through tubing, but with the choke hooked up finally and the electric fuel pump, it still starts up in the cold. Today I started it with minimal effort in 26 degree F.

Next project for this setup is to fine tune the timing, install a finished exhaust system, and remove the unused mechanical fuel pump.

I have heard rumors that the bb chevy and bb mopar fuel pump block off will work on a slant, anyone with experience on this?
 
Here is a quick update of this experiment/build. I have been using this setup to haul wood, various car parts, an in bed camper, navigate bad winter roads last winter, and I took it to a couple shows for fun.

Cold winter starts are difficult below around 10 degrees Fahrenheit, though it is better when the block heater is plugged in. Temperatures above freezing it works really well.

Winter driving with warmups, 10-13mpg depending on roads and speed traveled.

Lately with the weather now warmer, I have been averaging around 13.5 mpg, which is not bad for an old 4x4 without overdrive. With a set of worn out 31" tires I picked up off of craigslist on a set of rims I wanted, this turbo slant knocked down 15.98 mpg on my way back from Mopars in the Park in Farmington MN. That got me pretty stoked.

The exhaust with a straight 2.5 going into 3" pipe out the drivers side is pleasant and not to loud, no muffler, just a cummins like sound then smooth turbo spooling noises. I am already planning other turbo projects in my head, though there are a couple improvements this setup will see before going to something different eventually.
 
Currently have about 4k miles on my budget draw through setup. Drove it to work the last 4 days. Checked the ebay turbo shaft play and it feels pretty tight yet, but I will definitely enjoy a blow through setup and a better turbo in the future for less oil consumption and more power. My current plans are to go fuel injection on the slant and blow through, although I will keep this draw through setup on at least until fall of 2016.

Also I have thought up an improved draw through setup with parts of this setup on my dad's 74 Valiant 4 door with a 318, using a factory 2 barrel single plane intake I have laying around. If I start that build I will make a thread on it.
 
Just read through the thread and it's a pretty cool and different build. Keep on boosting!
 
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