and thanks Mike, I read the article, I just wasn't sure how much boost that could actually handle. I plan to only run 8 p.s.i. until I get the rest of the engine sorted out. Lets hope to god I can make 300 without turning up the boost alot
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| Any articles on turbo carb'd engines? https://www.slantsix.org/forum/viewtopic.php?t=50666 |
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| Author: | RyGuyTooDry [ Sun Dec 30, 2012 1:39 pm ] |
| Post subject: | Any articles on turbo carb'd engines? |
I am thinking about boosting my slant, but I know nothing about turboing carb'd engines. If someone could give me some insight on it I would be very thankful. I have helped build boosted hondas, but the carb is whats confusing me. |
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| Author: | billdedman [ Sun Dec 30, 2012 11:48 pm ] |
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There are some turbocharged, blow thru, carbureted engines around that run pretty well. Ryan Peterson and Tom Wolfe both have Holley 4-bbl, double pumper 4150-series carb'd engines that make around 500 HP (give or take a little) and push A Body cars pretty fast, in the quarter mile (Ryan's '66 Valiant, about 2,800 pounds, 127 mph, and Tom's heavier '71 Dart, about 3,300 pounds, 120mph, into a 15 mph headwind.) Those engines have no "heroic measures" empolyed, and use stock blocks (filled, in Tom's case; dunno about Ryan's) O-ringed, and flat-tappet cams (no rollers,) distributor ignitions, and both use alcohol/water injections and are intercooled. I am pretty sure they are both bored .065"-over and use the 198 (long) K-1 rods and forged pistons by Wiseco. Stock-stroke cranks... They both have ported heads and bigger valves (nominally, 1.75" int. and 1.5" ex.) and stock rocker arms and shafts. Someone please correct me if I'm wrong. Ryan uses a power-absorbing 727 transmission, while Tom has a 904. The 727 in Ryan's Valiant is probably costing him over a tenth in e.t. and 2mph on the big end, maybe more. I have a partner and am trying to somewhat duplicate the efforts of these two cars, and so far haven't been able to get it done. Our car is a '64 Valiant that weighs 2,680 pounds without driver and has basically, the same configuration as Tom's and Ryan's, but is still in the test-n-tune stages, so we'll have to wait a while longer to see what the fruits of our labors have wrought. So far, I have this to say: Tom and Ryan make it look easy to get 500 horsepower out of these engines. It's not. They have proved that it can be done, yes, but the secret is in the tuning, I think, and getting the right mixture at the right rpm isn't just a matter of reading an A/F 02 sensor and jetting accordingly... at least, that's been my experience. Of course, you may not want or need 500 horsepower from your leaning tower of power. You can have a LOT of fun with, say, 300 horsepower in an A-Body, and that is somewhat easier to come by with a hairdryer. A Holley 500cfm two-barrel carb may be a lot easier to tune than the 4-bbl, but most of the rest of the recipe for engine goodies is pretty much the same (as the 500hp motor.) I think it's pretty much a matter of boost level and the quaity of the exhaust system. T think they both run about 25-pounds. To make 500HP (and, this is just my opinion,) I am pretty sure you're going to need a hand-crafted header to mount the turbo.. I think it might be pushing it, but I believe that 300HP is attainable with a stock exhaust manifold hooked to the turbo through a J-bend pipe, like the one Pishta designed. As I said, this is just my opinion; there are lots of ways to skin a cat. The nice thing about turbocharging a slant six is, you can start out with a Pishta-style manifold attachment to the stock exhaust manifold, with a two barrell on a basically stock engine and make improvements as you go along, adding such things as first, a two-barrell carb, then a ported head, then a higher-lift cam, and then, a tubing header, an item at a time as you can afford it, and all along the way, you never lose your driveability; it will always idle smoothly and have good low-rpm power, because turbo engines don't like long-duration cams... so, that's not a factor that's going to make it hard to drive, down the road. I'm sold on this type of modification for slant sixes in particular, because they have such a strong infrastructure; they just seem to be built to be boosted. The fact that the original design was to me manufactured in aluminum, dictated that the engineers design the stress-carrying parts of the engine such as the main bearing webs, the cylinder-head deck, and the pan rails, strong enough to "live" in aluminum, was actually, "overkill" in cast iron, but they left them that way when the production shifted to all-cast iron, in 1962. I didn't hurt that the crank was a short, stiff, forging, making for a final product that was all but unberakable... almost like a Diesel. So, from my standpoint as a layman, (not an engineer,) it looks to me, like the slant six and turbocharging is a marrriage made in Heaven! Add to the above that the small-bores make fitting large-enough valves in those tiny bores all but impossible, it begins to look like forsed-induction is the ONLY way to get really impressive power-per-cubic inch out of the 225 motor. The 170 can be a real killer normally-aspirated, because there is room for appropriately-sized valves for that displacement, but there's just not enough room for valves appropriate for 39 cubic inches per cylinder, once the displacement climbs 35 percent (after thee 1-inch stroker is installed!.) Nitrous oxide is available, and could be used to make a "breaather" out of a 225... There's no denying that, but I think the constant filling of bottles might get old pretty quickly on the street... Just my 2-cents'... Bill, in Conway, Arkansas... |
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| Author: | RyGuyTooDry [ Mon Dec 31, 2012 12:42 am ] |
| Post subject: | |
Thanks, I would like to make around 300 horse, without putting too much into the motor. 2 bbl carb, (500cfm), custom turbo mani, ported and polished head, and a cam (thinking about the clifford mechanical). Intercooled as well. |
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| Author: | Charrlie_S [ Mon Dec 31, 2012 2:03 am ] |
| Post subject: | |
Quote: Thanks, I would like to make around 300 horse, without putting too much into the motor. 2 bbl carb, (500cfm), custom turbo mani, ported and polished head, and a cam (thinking about the clifford mechanical). Intercooled as well.
I would stay away from the Clifford cam. There are better options out there.
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| Author: | mpgmike [ Mon Dec 31, 2012 3:02 pm ] |
| Post subject: | |
Although a bit on the budget side, http://www.allpar.com/fix/holler/index.html Mike |
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| Author: | billdedman [ Tue Jan 01, 2013 12:18 pm ] |
| Post subject: | |
Quote: I'm sold on this type of modification for slant sixes in particular, because they have such a strong infrastructure; they just seem to be built to be boosted. The fact that the original design was to me manufactured in aluminum, dictated that the engineers design the stress-carrying parts of the engine such as the main bearing webs, the cylinder-head deck, and the pan rails, strong enough to "live" in aluminum, was actually, "overkill" in cast iron, but they left them that way when the production shifted to all-cast iron, in 1962. I didn't hurt that the crank was a short, stiff, forging, making for a final product that was all but unberakable... almost like a Diesel. So, from my standpoint as a layman, (not an engineer,) it looks to me, like the slant six and turbocharging is a marrriage made in Heaven! Charrlie Schmid pointed out some interesting facts to me in a couple of private messages that I will share with you here. Seems like I have erred when I wrongfully assumed that the cast iron version of this engine was a redux of the aluminum version, with cast iron simply replacing aluminum in the block construction. As most of you probably know, Charrlie has many years of hands-on experience with BOTH the aluminum and cast iron versions and points out that the aluminum version has a LOT of significant differences in its construction, from the iron engine, and that the differences are telling For example, the top of the block where the cylinder head rests, is an "open" configuration and has no "deck surface," as such. You can look down into the block alongside the cylinder walls and see all the way to the bottom. The cast iron version has a thick, solid, top deck. Also, the main bearing webs of which I spoke, are actually BOLTED into the block (if I understood this, correctly,) while the cast iron version has conventional main webs cast into the block. These two modifications would seem to me, to make for a stronger infrastructure, but, what do I know??? At any rate, I assumed too much, and I want to thank Charrlie for correcting me on thse issues. He has forgotten more than most of us know about these engines!!! I apologize for disseminating erroneous information. But, I stand by my contention that these engines (at least, the cast iron versions) make excellent candidates for forced induction. They are stout... Bill |
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| Author: | RyGuyTooDry [ Tue Jan 01, 2013 6:13 pm ] |
| Post subject: | |
Can anyone suggest what cam to use then? And also what size turbo I should use? I don't want alot of lag. The engine is a 1965 225, port and polished head, ported intake manifold/exhaust manifold, 3 inch straight exhaust, 3.23 gears, and a 904. |
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| Author: | RyGuyTooDry [ Tue Jan 01, 2013 7:37 pm ] |
| Post subject: | |
Also, if anyone could tell me what fuel pump to run with 10 lbs of boost, it would be greatly appreciated. There is another thread, but noone seems to have actually named a fuel pump that would work. |
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| Author: | Charrlie_S [ Wed Jan 02, 2013 3:40 am ] |
| Post subject: | |
If you are going with a "blow thru" setup, the fuel pressre at the carb must be about 5 lbs above boost pressure. At zero boost, at stock mechanical pump does just fine, but at 5 lbs boost the stock pump will not have enough pressure, so you must boost referance the stock mechanical pump. I don't think I would try using a stock type mecanical pump, boost referenced, over 5 psi. My preference would be an electric pump, with a boost referanced pressure regulator, preferably a "return flow" type. I can't really sugest what turbo to run, although it seems like a Buick GN works for a inexpensive build. My turbo setup is VERY old school (1979), with a modified Corvair (Rajay) turbo, setup for draw thru. |
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| Author: | mpgmike [ Wed Jan 02, 2013 10:28 am ] |
| Post subject: | |
The Allpar articles show how to tap the mechanical fuel pump vent to get a 1:1 pressure rise. I used an new stock-style pump and it worked just fine up to 10 psi. Mike |
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| Author: | RyGuyTooDry [ Wed Jan 02, 2013 9:45 pm ] |
| Post subject: | |
Turbo wise, I'm using a t25 off of a friends old Nissan Silvia, and I only plan on running 8 p.s.i. But, would the stock pump be ok? I was looking at the holley blue pump, which should feed it fine, but if I don't need to spend the money, I won't. |
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| Author: | RyGuyTooDry [ Wed Jan 02, 2013 9:52 pm ] |
| Post subject: | |
and thanks Mike, I read the article, I just wasn't sure how much boost that could actually handle. I plan to only run 8 p.s.i. until I get the rest of the engine sorted out. Lets hope to god I can make 300 without turning up the boost alot
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| Author: | mpgmike [ Thu Jan 03, 2013 7:03 am ] |
| Post subject: | |
During tuning I had boost up to 12 psi, but then lowered back to 10. Even at 12 psi the fuel pump pressure was rock solid 5-6 psi above pressure. You should be good at 8. Mike |
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| Author: | Junior [ Thu Jan 24, 2013 11:46 am ] |
| Post subject: | |
so all you have to do is hook up the vent in the pump to the boost? |
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| Author: | Junior [ Thu Jan 24, 2013 11:52 am ] |
| Post subject: | |
it seems so simple, i dont understand how it works |
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