That's nice! Yeah, this little QFT 450 on my slant 6 has impressed me so far. It has a ton of adjustability. But I agree. I think on dead stock or VERY mild daily drivers, EFI might be the better choice. None of mu projects will ever be "THAT".
Turbo six on a Budget
- Thread starter Slant Six Bumblebee
- Start date
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That's nice! Yeah, this little QFT 450 on my slant 6 has impressed me so far. It has a ton of adjustability. But I agree. I think on dead stock or VERY mild daily drivers, EFI might be the better choice. None of mu projects will ever be "THAT".
TT5.9mag
Two atmospheres are better than one
I agree with you on a lot of things but this,
I have to disagree on. My daily is a turbocharged 700whp big block Chevy in a 3500 dually on the stock ecu. The turbocharged Honda v6 in my falcon is 620hp on pump gas and much more on e85 (haven’t dynod it yet on corn fuel) on an AEM infinity ecu, my dart has the twin turbo magnum on the jtec with megasquirt and I don’t think any one of them would be as good without EFI. But for my boat, I felt the simplicity of a blow through turbocharged carbureted big block was the best solution.
Yeah well, you're fortunate enough to have gotten some right. lol I feel certain the problem is with all I have actually SEEN is the "builder". The guy thinks he knows WAY more about EFI than he does. I'm quite sure if I ever decide to do one, I'll have much better luck with than he has. He's just not a mechanic. He's a good paint and body man, though.
I ain't a Honda guy but I'd like to see that Falcon. That's different.
TT5.9mag
Two atmospheres are better than one
You’ve seen it. I’ve posted pics of it here a few times.
The car is currently apart and going back together with a whole new front end. Coilovers, electric rack and pinion, wilwoood 13” brakes and I’m moving the engine back 11”.
TT5.9mag
Two atmospheres are better than one
Now THIS I could not agree more with. 100% correct.
I thought so. Nothin sticks with me anymore. I'll probably be eatin outta a straw before too long.
pishta
I know I'm right....
Ok...I read enough. You wanna build a cheap turbo wth a blow through carb On the cheap? Cap it at 9psi ....Get a 350/500 cfm holley/Motorcraft 2300 2bbl. Yeah, 2 bbl! Do all the hanger 18 mods on it (sealing the base, pvr restriction drilled out, power valve crutch...) and run a straight distributor With a turbo Volvo distributor vacuum advance with retard. Yes it goes both ways.....vacuum advance and boost retard in one unit. Run a turbo pressure line to the weep hole of a stock fuel pump, it will boost reference to 9psi. Get yourself a WIDEBAND o2 meter and monitor A/F and file the rings a bit. No forged pistons, no $900 K1 rods or $600 msd needed. Check out mega-jolt for your timing needs, or even a craigslist MS1 or 2 only for the timing control although there are other cheap standalone ignition ans out there. I know where your coming from on the cheap: sole bread earner in a 5 person household with 1 kid in $$ college and another in football. Neither are cheap! My initial budget was all parts hustle profit so I couldn't just drop $600 on an ignition box that I didn't even need. The 5 pin retards timing by ~5 when you take it high or low (forgot) originally for start assist but tie it to a hobbs switch and it can be used to trigger it for boost retard if you need it. when all this stuff comes together and you decide its a waste of time your not out 2 grand. If you need more boost, then your 2k ahead to get the K1and the forged pistons as well as the boost controller. The 2JZ-GTE Toyota 6 banger turbo didn't even have 280hp so 300 (3x stock) is kinda lofty.
pishta
I know I'm right....
Once you build this, you'll realize EFI is about the only way to go when doing a turbo. So much of these mechanical controls are now tunable with a laptop or even a phone: timing , boost control, fuel maps...its just so automated when you got the control efi offers. Drill 6 holes in a intake, epoxy in some DIY injector bungs drilled out from heavy wall SCH 80 3/4 aluminum tube and get a junkyard TB off a jeep with a round intake so you can clamp a 3" elbow to it off the turbo. Then run the whole thing of a cheap MS2, or a newer arduino based efi controller. Could be cheaper than the old fashioned blow through once you add stuff up. Run the high pressure to the injectors from a surge tank (just a small 1G tank with a high pressure pump inside) by your radiator and use the stock pump to supply the surge tank with a low pressure return line. Keeps the high pressure up front. Have fun, have a plan and measure twice, cut once.
Slant Six Bumblebee
Well-Known Member
I like this idea but my current 225 was not taken care of. (No oil change sum gunk in the oil) what is a decent compression I tested it and got 75-90 psi but I don’t think I tested right. I just cranked it once then checked.
Slant Six Bumblebee
Well-Known Member
Everyone is talking about the 5 pin hei and I don’t know that much about it. Is it a control module that you plug into the distributor. Or is it a box like the msd. I know that mpf is the way to go but I don’t know too much about it other than that mega squirt is the way I want to go. With the indjectors in the head like 68 barracuda did.
pishta
I know I'm right....
5 pin ignition module is a GM part that can be grafted to the slant electronic distributor to provide a Mopar ECU like ignition system in a small package. The 5th pin was used to retard the ignition for starter assist.
Slant Six Bumblebee
Well-Known Member
Can this be used with my points setup?
my68barracuda
Well-Known Member
Google ‘slant six HEI ignition’ there are probably six billion threads on the internet that address that common conversion.
Please don’t take this the wrong way, as we all have to start somewhere, but Pishta and others have provided sound advice and then you trip up on some of the most minor details.
Just an idea, consider instead of building a low budget turbo slant, just do a low budget stock internals rebuild on the existing engine. You can put in a turbo friendly cam, maintain turbo friendly compression, put a Holley 350 cfm carb or a super six carb or a MSII with MPFI and get yourself some engine building and engine tuning experience. After you have your arms around that, then think about adding the turbo.
Slant Six Bumblebee
Well-Known Member
Don’t work I have a thick skull and don’t get offended easily. I respect everyone’s advice on here because 99.9% of the people have more experience than me. I know you are right and I should start off with a stock rebuild, mpfi, coil on plug setup because that will be the hardest part of the turbo setup. Everyone was 15 and impatient at one point.
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TT5.9mag
Two atmospheres are better than one
Great post. I like it. BUT (there’s always a butt) I find it hard to believe the stock fuel pump with a boost line to the weep hole will make 9psi. Maybe an aftermarket Holley or carter BB pump but not a stock slant. But (there it is again) I’ve never done one.
TT5.9mag
Two atmospheres are better than one
@Slant Six Bumblebee the first few items on your “to buy” list should be books. That’s the best advice any of us can give you. I recommended one and I can recommend plenty more if you’d like.
TT5.9mag
Two atmospheres are better than one
pishta
I know I'm right....
The way I learned it was like this: The stocker puts out about 5 psi...your turbo is gonna put out ~9psi (high estimate) to the venturi so its going to want to push pressure back into the fuel bowl through the boosters, but that pressure is going be inside the (non vented to atmosphere) bowl too so its going to want to push the fuel out at the same pressure, so your back to a delta of 0, no imbalance within the carb. Now the poor fuel pump is still only pushing 5 psi and thats never gonna get fuel into a 9psi bowl so you need to increase the spring pressure in the fuel pump itself. And the way you do that is to pressurize the back side of the pulsator diaphragm with compressed air at the weep hole, creating a pneumatic spring on top of the mechanical spring. Mechanical fuel pumps push the pulsator diaphragm with a spring, not a rod. That way the pump can maintain a certain PSI over its operating range. When the fuel pressure demand is very light the spring barely moves the diaphragm as its still somewhat pressurized on the carb side, when its demand is greater (WOT) its allowed to push with a longer stroke as the pressure to the carb is not pushing back on the diaphragm as much. Much easier to see than to explain. The boosted pressure behind the normally vented backside of the diaphragm provides that much more force to the diaphragm to pump fuel into the pressurized bowl and that is magically 1:1. for every "pound" of boost there is an equal amount of pressure added to the fuel pressure. now your 5psi pump is pumping at 14psi until the boost settles down and the pump follows suit. Check Allpar Turbocharged slant six: cheap power and gas mileage... or any boost referenced fuel pump:
"Carbureted applications will require higher fuel pressures. The simplest method is to drill into your fuel pump's vent hole, epoxy a tube into the hole, and run your boost to that port. The vent is a reference and if you increase the pressure above the diaphragm, then the fuel pressure will increase by the same amount. Do not connect this port to the bottom of the carburetor. You don't want vacuum, just boost. Someplace between the turbo and carburetor is best..."
"Carbureted applications will require higher fuel pressures. The simplest method is to drill into your fuel pump's vent hole, epoxy a tube into the hole, and run your boost to that port. The vent is a reference and if you increase the pressure above the diaphragm, then the fuel pressure will increase by the same amount. Do not connect this port to the bottom of the carburetor. You don't want vacuum, just boost. Someplace between the turbo and carburetor is best..."
TT5.9mag
Two atmospheres are better than one
The fuel bowls are always vented to atmosphere or there would never be fuel flow in to them. When you add boost, blow through style you must raise fuel pressure 1:1 with boost above static. Your pump HAS to maintain pressure of static + boost pressure. The bowls and the boosters will see the same pressure, delta 0. 6psi of static fuel pressure plus 9 pounds of boost, you’re gonna need 15 psi of fuel pressure. It’s that simple.
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pishta
I know I'm right....
Yup. 1:1 6+9=15. Fuel bowls are pressurized on a blow through only under boost..fuel can get in at idle just like a regular carb. That's why they tell you to replace the brass floats with nitrophyl so they dont crush under (bowl) pressure: Check out a Paxton carb box on a 57 Ford or Studebaker Avanti, completely enclosed AFB including bowls....
"..Replace your old plastic or brass floats with the new Nitrophyl floats, making sure to assemble them so that when finished, they look like this. [pic] The Nitrophyl floats are solid and will not crush or crack under boost..."
Blowthrough Carb How-To
"..Replace your old plastic or brass floats with the new Nitrophyl floats, making sure to assemble them so that when finished, they look like this. [pic] The Nitrophyl floats are solid and will not crush or crack under boost..."
Blowthrough Carb How-To
TT5.9mag
Two atmospheres are better than one
Exactly
TT5.9mag
Two atmospheres are better than one
Now do you think the stock slant fuel pump will make 15 psi AND enough volume for 300ish hp? That’s an honest question. I have no idea. I currently own zero vehicles with slants or mechanical fuel pumps or I would have already tried it.
pishta
I know I'm right....
Draw though's are alot easier.......put a larger carb at the turbo inlet and let it fly.
24GPH required for 300HP (theoretically)..24 gallons x 5.92 lbs = 142 pounds per hour out of that pump. Can it be done? a turret style Carter pump can do 110GPH. I dont see why a slants (with the same diameter diaphragm) couldnt do 24 even fighting some back pressure. Maybe @slantsixdan would know the output of a slant pump.
24GPH required for 300HP (theoretically)..24 gallons x 5.92 lbs = 142 pounds per hour out of that pump. Can it be done? a turret style Carter pump can do 110GPH. I dont see why a slants (with the same diameter diaphragm) couldnt do 24 even fighting some back pressure. Maybe @slantsixdan would know the output of a slant pump.
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