Single or Twin turbo setup for 360?

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gagembassett

gagembassett

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So I need everyone's opinions on a single or compound turbo setup for a 360 that I'll be putting in my W150 that'll be used for mostly towing and some fun of course. The original plan was to just budget build a 360 nothing too special and put it in there and roll BUT the other day I was discussing it with my dad and we brought up the idea of a turbo 360 for easier power, something different for us to do and because turbo, why not? Now I have only, and I mean only done a very brief search on google for turbo kits and you know it! I found a kit on ebay (I know I know its an ebay turbo kit, forgive me) but luckily the cam I already got for the original build was a Mopar purple shaft .410/.425 RV cam which would be good for a turbo build. Now I've heard the compound turboing is not the route to go for a semi-daily driver or tow rig. I haven't as to why that is bad it's just what I've heard so which route do I go? Now to clarify this engine is not going to be some 800-1,000 horsepower build. I'd only like to go in the area of 475-500 and that's decent for me. The rotating assembly will change from the original plan of stock rods and crank to forged if necessary and the pistons will be too. Everything will be accounted for accordingly in the transmission and transfer case as well as all else I can think of. I haven't seen or heard enough info ever on turbo small block mopar builds other than like ritter block W-headed engines so this is why I'm here. Help out a lost guy because I've always been an N/A engine type of guy and the land of boost is foreign to me.
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There is an eBay seller that has twin turbo headers for small block. They look to be a tight fit in cars but would probably work decent in a truck.
How about a supercharger like torquestorm or procharger?
 
My impression has always been that a compound turbo set-up (a small turbo, blowing into a big turbo, to spool it up) is for a diesel, or for a monster horsepower gasoline engine, over 50 lbs of boost.
A single turbo will easily get you what you want, a twin turbo set-up might be easier to find a kit for, but you will need twice as many turbos,waste gates, Bov's, etc.
Got a buddy making 1200hp with a single turbo on a stroker LS, 500 on a 360 is nothing.
 
I would probably choose a single unit over a twin setup myself for simplicity’s sake and cost. @TT5.9mag would probably have some good input here. With towing and boost, you’re looking at extended periods of high load usage and heat build up, so the tune becomes much more critical. I’ve known of Chrysler big block motorhomes that were outfitted with turbos, so it is possible.
 
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If you are just towing, and you don't need monster hp,
Have you considered Gears/torque multiplication?
An Overdrive trans, deep rear gears, and the right convertor, might be all you need.
If the engine build is still open, then for NA mode, I would suggest; high cylinder pressure and/or alloy heads and a bit more cam. You may not get to 400plus hp, but I fail to see the need for it; per your stated useage. Mostly, you just need some mid-rpm torque, and to gear it right. Whatever power you need for towing, the hi-pressure and naturally-aspirated 360 should be well able to make, just not at 2200rpm,lol.
Here is an engine that I am particularly fond of; The 360 sorta falls together like this, with small, closed chamber heads. This is a 230/237/110 cammed engine, which you don't need. You could easily move the torque peak down, with less cam, and increase it with ram-tuning. But your Purple is not the one I would run in NA mode. I mean you could, but in NA-mode, the top-end charge would be missing.
Of course if the engine is being rebuilt anyways, the stroker is a natural.

But, I mean, if you just want to turbo it, have at it.
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How heavy will you be towing? A single cheap Gt45 would meet your goals, and be very easy to plumb in that truck. I would just worry about making boost at too low of an RPM while towing.

Personally, a Cummins swap would be my choice in that thing. It will be easy to swap in, do everything you want with better fuel mileage, and cost will be close to turbocharging your 360.
 
Things to consider with boost is forged rotating assembly, closed chamber heads, and charged air cooling. I have seen people use a STS (remote) style setup w/ out an intercooler.
 
I think the only part of an eBay "kit" I'd bother with is the plumbing but that's just me. I'd also definitely go with a different cam, MP cams are pretty obsolete and "RV" cams don't give much better performance than stock. Not that it wouldn't work it's just there are plenty of better options out there. Although if it was my build I'd be looking at getting a junkyard 5.9L Magnum or roller-cam LA 360 for the factory roller lifter setup as I don't trust flat-tappet stuff much these days. If it had EFI the cylinders are likely in good shape too and won't require machining. According to Magnum Swap -your source for Mopar engine swap information. a 5.2/5.9L can safely handle 15 psi on a stock bottom end.

Also there's a sub-forum here called "Forced Induction Mopar" you might pick up some info browsing through there if you haven't already.
 
This is the guy to listen too. He has probably done more dyno research for the good of the public that anyone else.

 
man i'd love to do a small turbo on a 360 but know nothing at all about them or where to even start..
 
go-fish said:
This is the guy to listen too. He has probably done more dyno research for the good of the public that anyone else.

Click to expand...

I haven't yet watched that specific video but one thing I do know... fabbing the hot-side plumbing to have the least restriction possible (headers, mandrel-bent tubing etc) so that the pressure ratio between the intake and exhaust sides is as close to 1:1 as possible is ideal, then you can run any cam you want for your preferred powerband. "Turbo" cams are only useful when the hot-side (exhaust) pressure is higher than the cold-side (intake) because too much overlap will allow hot exhaust back into the cylinders which pre-heats the intake charge and causes massive detonation and heat buildup. This is why old-school turbo engines (like from the 1980s) had compression ratios in the toilet and cams with basically no overlap, they intentionally used turbos with undersized turbines and restrictive manifolding to make the boost come on at a lower RPM. With modern turbo technology (ball bearings, etc) that isn't necessary anymore.
 
Towing with boost can be absolutely awesome or go horribly wrong very quickly. Lots of load makes lots of heat and extended periods of boost in high load situations at LOW rpm means your tune has to be perfect and component selection/sizing has to be carefully thought out. A focus must be made on a very efficient intercooling system and engine cooling system. Turbo sizing is critical, you want to size the turbo such that you are not always in boost at light load, but also not so large that you have to spin the engine up hard to make any boost. This takes lots of math and lots of studying compressor maps. I would recommend reading as many books as you can get your hands on, I always recommend “supercharged” by Corky Bell, it has an incredible amount of good boost theory in it and the info applies to all forced induction set ups. Honestly for a small block in a towing situation in a heavy truck your money might be better spent on cubic inches. I think a Stroker at 408 cubes might serve you better as a starting point.
 
Oh and another thing, compound turbo setups should not even be part of this conversation. Compounding is for increasing map width and generating ridiculous boost levels (40-200psi), save those for the diesel world.
 
Twins vs a single are really a matter of packaging and ease of installation. With twins you’ll have to build a merge on the cold side. With a single you’ll have to build a merge on the hot side. The amount of work is very similar. Pick what fits the best.
 
Another often overlooked aspect of turbocharging is efficiency of the wastegate setup. More importantly on a towing setup, you have to have good wastegate priority and the ability to control the boost down to lower (3-7psi) boost levels.
 
MopaR&D said:
I haven't yet watched that specific video but one thing I do know... fabbing the hot-side plumbing to have the least restriction possible (headers, mandrel-bent tubing etc) so that the pressure ratio between the intake and exhaust sides is as close to 1:1 as possible is ideal, then you can run any cam you want for your preferred powerband. "Turbo" cams are only useful when the hot-side (exhaust) pressure is higher than the cold-side (intake) because too much overlap will allow hot exhaust back into the cylinders which pre-heats the intake charge and causes massive detonation and heat buildup. This is why old-school turbo engines (like from the 1980s) had compression ratios in the toilet and cams with basically no overlap, they intentionally used turbos with undersized turbines and restrictive manifolding to make the boost come on at a lower RPM. With modern turbo technology (ball bearings, etc) that isn't necessary anymore.
Click to expand...
When I was spec'ing out my 408" Procharger build I got guidance from some old schoolers. Wide LSA (114), 8.5 compression, ..... It ran beautifully but was pretty tame "feeling" for making 650 hp and 600 ftlb.
In the next 6 months I plan on pulling it from the 'cuda and going through it (sitting for years). It is a hydraulic roller LA engine with bushed lifter bores. I am going to look into a little more duration (230 @.050"?) and around 110 LSA. Maybe even mill the heads for a little more compression.

I have a new Snow water/meth injection system to put on this time too. Intercooler would be the preferred cooling but package constraints force the decision. I was thinking about putting that engine in my 76 D100 and couldn't find an overly roomy area , even on the truck, for an intercooler big enough. You can always do surgery on the trucks radiator core support and possibly space your whole radiator back about 1/2" (run electric fans?).

On my 76 there is a brace that connects the top and bottom of the core support right in the middle. Move that and space the radiator back and it would be enough room for the IC. I am unfamiliar with what the next generation's core and grille area look like.
 
You will also need to look into a blow through Carburetor or fuel injection system that will work with your Turbo setup.
You have alot of research to do to get all the details correct.

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go-fish said:
When I was spec'ing out my 408" Procharger build I got guidance from some old schoolers. Wide LSA (114), 8.5 compression, ..... It ran beautifully but was pretty tame "feeling" for making 650 hp and 600 ftlb.
In the next 6 months I plan on pulling it from the 'cuda and going through it (sitting for years). It is a hydraulic roller LA engine with bushed lifter bores. I am going to look into a little more duration (230 @.050"?) and around 110 LSA. Maybe even mill the heads for a little more compression.

I have a new Snow water/meth injection system to put on this time too. Intercooler would be the preferred cooling but package constraints force the decision. I was thinking about putting that engine in my 76 D100 and couldn't find an overly roomy area , even on the truck, for an intercooler big enough. You can always do surgery on the trucks radiator core support and possibly space your whole radiator back about 1/2" (run electric fans?).

On my 76 there is a brace that connects the top and bottom of the core support right in the middle. Move that and space the radiator back and it would be enough room for the IC. I am unfamiliar with what the next generation's core and grille area look like.
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Might want to run your plans through some "new-schoolers" lol. The low compression and wide LSA thing isn't really needed nowadays with what the hot-rodding community has collectively learned over the past 20 years or so. I'm guessing those old-schoolers cut their teeth on Roots blowers; centrifugal superchargers (Procharger, Vortec, TorqStorm etc) are much more efficient at not heating the charge air and have completely different boost curves. They don't hammer the engine with full boost right off idle like a Roots blower and don't require fuel flow through the supercharger just to keep it from melting down.

Gale Banks did an interesting test of putting a Roots blower on a Duramax diesel; since there was no fuel flowing through it like is typically the case in a carb'd gas engine application the blower basically ate itself alive from all the heat buildup.
 
From what I can see of the picture, It looks like it’s an ‘86 to ‘90 W150. You could get a core support for a 1991 to 1993 intercooled truck to allow use of a the big Dodge Cummins diesel intercooler or an aftermarket upgrade. The intercooled core supports have additional bracing and structure built in to deal with the additional stress the intercooler adds. It does require a 1991 to 1993 grille for the later core support, though. The Cummins swap is a good idea for a 4BT in a half ton. About the same weight as a v8 and 30 mpg mileage potential. A 6Bt is only suitable for a 3/4 ton truck, and the factory engineers added additional cross braces in the frames of the Cummins trucks, so there s lot to actually doing a 6Bt swap correctly. The 4 BT could be set up with compound turbos and also responds to the same fuel pump modifications as a 6BT, so you could still have really good power for towing and such.
 
A single turbo is all that would be needed for towing purposes.
You would not need a big turbo to do this. It would be helpful not to use a large one or one someone would use in a racing car. The goal would be to create boost early.

As mentioned earlier, a 408 would be a great place to start but that is just the internet spending your money. A great idea. But throwing money at an issue, real or not, like the USA government does at its issues is t something we all have in the bank.

Stroker = $$$$$
Turbo = $$$$$
Fuel system upgrade = $$$$$
Ignition upgrade = $$$$$

The idea of a Torque Storm centrifugal charger is IMO, not the answer since that is a rising boost curve rather than a properly built turbo system of almost RIGHT NOW - BOOOOOOST!

A roots super charger is boost now (AKA - Torque and lots of it.) starting as soon as the go pedal is pushed.

Pistons need not be forged and can be Hyperutecic but ether way, ignition timing is critical.

Good luck on your endeavor.
 
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