Turbo Slant Setup
So I have been reading all over the web about building a turbo slant. I do not plan on ever racing this engine and I am mostly wanting to help increase my fuel mileage/ moderate acceleration increase/ and a small power increase. I don't have any misconceptions about this being some 10 second vehicle or anything along those lines so that's not a big deal. I have read about the boost referencing of the manual fuel pump and what not but it seems like for my setup I don't really need that. I plan to keep my stock 2bbl carter and super six manifold.
1:I need to know how to set up my 2bbl Carb for a blow through setup or if I should just spend the money and buy a 350CFM 2bbl Holley but either way how would I set that up for a blow through set up
2:I am still trying to figure out exactly how I need to "adjust" the wastgate so I can control my boost pressure from inside the truck. Ideally if I could make some kind of mechanical turn knob to increase/decrease my boost pressure that would be ideal. I plan to run a boost gauge in the cab to monitor everything.
3: I plan to run an intercooler that has the inlet and outlet on the same side and run them both out the drivers side with the intercooler mounted in front of my radiator behind my grille. (I will post some picture of my idea tomorrow when I have the time)
4: I am an extreme neat freak so everything and I mean everything will need to be mounted routed and wired in as clean and organized a manner as possible.
5: I plan to use a Garrett turbo out of a Turbo 2.2L engine just for the record. Also if there is someone out there that can "weld" cast iron and can attach a turbo flange to a stock manifold please PM me because I am having one hell of a time finding someone in my area.
All this will be going into my 83 Stepside pickup with a 225 Slant and a Super Six setup. Also I recently just got done installing an A833OD trans that I pulled from the junkyard. When I calculated my mileage I am actually getting worse now with the OD vs the Granny low 4 speed and I think that is just because I have to warm my truck up completly before I go anywhere otherwise the damn thing spits and sputters like hell. Once it's warm though it's ok. Choke is a pos.... Before you go and tell me to go post this on .org because it's not an A body I realize that but there is a lot of good knowledge on this site and a lot of people turboing slants. Also I own my fair share of A bodies.
Jeff
I think you might be better off building (fabricating) a 90-degree, short-radius, exhaust pipe to attach to your existing, stock, cast iron exhaust manifold, and mounting your turbo to that "elbow." That would alleviate the necessity of welding on the cast iron manifold, a piece that is notorious for cracking in normal usage... I can't imagine that welding on it would make that any better. I'd HOPE that a pickup truck would have a fairly roomy engine compartment, and would accommodate this 90-degree pipe.
Having said that, I need to quantify my comments with THIS disclaimer: I have never owned a turbochaarged vehicle OR a slant 6, before. About 2 years ago, I, and a racing partner, decided we'd build a turbo slant 6 (he had no experience with them, either) so we started trying to educate ourselves as to the vagaries of turbocharging in general, and, as it applies to slant 6's, specifically. We've literally made a religion out of trying to understand the whys and wherefores of this operation (slant 6/turbos) and have learned some things along the way, but there's still a mountain of information we don't know.
So, take my comments/information, with that in mind. I am ANYTHING, but an expert when it comes to this stuff.
I do feel that I have some things to offer though, but if someone who actually has hands-on, practical experience with this subject reads something I wrote that is inaccurate, or misses the mark, PLEASE do us
all a favor, and correct me. I'll appreciate it, and so will Jeff.
Now, to get to what I THINK I know about this:
First off, as you've heard many times, I am sure, an engine is just an air pump. Well, so is a turbocharger. Because they are going to be both deasling with the SAME air, there needs to me some correlation in the amount of air that they are expected to deal with.
You want to put a turbocharger off a 2.2-liters (134 cubic inches) motor, on an engine that is
70-percent larger 3.7-liters, (or 225 cubic inches.)
As a novice in the turbo business, I am not speaking from experience, but, that seems like a lot to ask of a turbo that relatively small compared to the engine it's going to be installed on. In short, it seems to ME that you're going to need a turbo off a bigger OEM application. (Like a 3.8-liter Buick Grand National.)
Somebody correct me if I'm wrong. I'd think this 2.2 turbo would be in danger of over-speeding, trying to handle the exhaust from an engine 70-percent larger than the one it came off of, and also would run out of breath REALLY early (like 2800-3,000 rpm).. but then, maybe not...
Turbo's create heat when they compress the air, but it is generally accepted, I think, that under 10 pounds of boost, an intercooler is not necessary, or even desirable.
A better anti-detonation "crutch" would be a water/methanol injector, such as a Snowperformance "BoostCooler." They have a boost referenced sensor that turns the spray on at some pre-adjusted (by you) boost level (usually about 3 pounds of boost) and the spray into the intake charge is atomized with a jet, and takes a lot of heat out of the compressed air, on its way to the carburetor.
I am not familiar with a driver's seat adjustable waste gate, but at the low boost-levels you are talking about running, I am not sure you'd need something like that. Set it on 10 pounds and forget it...
The original, mechanical fuel pump can be boost-referenced to provide added fuel pressure by running a small (1/8") line from the carb hat to the pump, so that the back side of the pump has real-time information as to how much pressure it REALLY needs to overcome boost pressure in the carb. About 6 pounds over the level in the intake, is adequate.
As far as which carb to use, and what modifications they would need to be used in a blow-thru application, I am not going to be much, if any help. I don't have experience with modifying the pertinent circuits inside to deliver the appropriate increases in fuel necessary when an engine goes on boost, but I can tell you one thing: I don't believe you can get away with running an un-modified carb of ANY kind, with that much more air going through it (due to the forced induction.)
You're going to see a significant increase in available torque, even with only 5 pounds of boost, and it takes a lot more fuel to produce that power.
Having said that, I will say that, IF you can keep your foot out of the firewall, I wouldn't be at all surprised to see better gas mileage from the boosted motor. That is not at all uncommon, in my limited experience.
One thing that is VERY important, is to be extremely careful not to allow much total spark advance under boosted conditions. Nothing will kill a turbo motor as fast as too much spark advance. I am talking sbout spark advance UNDER BOOST. Eighteen degrees (total) is a lot....
Yeah; normally-aspirated 340s like 34 degrees, total... That much will kill a turbo'd slant six in a heartbeat. Be VERY careful on that score.
Keep us posted on your build; it's an interesting one!:D
As a reference point, although this is definitely apples/oranges, I stuck a Vortech centrifugal supercharger (not THAT different from a turbo) on my almost stock 360 Magnum V8 and went from 102mph in the quarter to 118, and from 13.35-seconds (e.t.) to mid 11's, with only 10 pounds of boost.
Five pounds of boost in your truck will feel like a V8... a strong one.
Worth doing...
Hope this helps!!!