My appologies for thinking along the lines of turbochargers only, to be honest I'm helping another friend of mine with his carbureted 5.3L twin turbo setup and another forum member with his 4.8L single turbo setup in his truck, so the word "turbo" is on my mind a lot lately and I forget who's who. Too much math lately, not enough beer...that's my excuse.

Here's the scoop on a supercharger/turbo. I've never looked into what you're calling a D1 of F1 supercharger, so I haven't a clue what they produce or are capable of. Any forced induction system I've ever worked with has all been nitrous injection or turbocharged because all my friends are either really cheap or do the job right the first time and throw cost to the wind. If your "kits" can produce the amount of boost necessary to hit the horsepower goal you're after then research into those kits to find the efficiency of the compressor, I assume D1 and F1 are from Vortech? If so, they'll have all the specs on their compressors on their website. So should any self respecting company who values their product. If neither superchargers can produce the amount of boost and flow the amount of CFM you're looking to capture, then perhaps a turbo setup is your only option. I'm interested to see what you come up with, because I've never researched into anything but the stock supercharger that came on my car, but that's an Eaton twin screw and I assume you're looking into a centrifugal compressor; right?

By the way, neither a supercharger nor a turbocharger will be "plug-and-play". Both will at least require all the piping, intercooler, BOV(s), wastegate(s), tuned PCM and larger injectors. The turbo will require a custom exhaust manifold, the supercharger will need a new serpentine pulley system and some kind of bracket to mount to the accessories. Pick your poison I guess then, IF, the supercharger can produce numbers like a turbo; which I doubt. A supercharger is only as efficient after two of it's drawbacks are factored in; 1)it's a load on the serpentine belt and at the power levels you're looking at, will probably require more ribs on all the pullies, and 2)it's efficiency at charging the air without putting too much heat into the charge, which will always be more heat than a turbo simply due to the design of the systems. Typically a turbocharger puts less heat into the intake manifold than a centrifugal supercharger, all other things equal. But, like I said I've never looked into your D1 and F1 kits so maybe I'll learn something new soon, because only Chuck Norris knows it all. I sure as hell don't.

Good idea on playing it safe. Granted, your PCM will automatically shift to a lesser spark table if it detects so many knocks in a given time period, and will automatically assume fresh gasoline every time you add more than 8 gallons, but playing it safe never hurts and will sometimes allow you to fill up on cheap gas if need be. So, assume 92 octane.

Compressor and intercooler efficiency have everything to do with compression ratio once you know at least 2 things, 1) boost limit and 2) octane level and/or what the computer is able to already tune itself for and recalibrate based on O2 sensor feedback of the air:fuel mix. So, now that we know the target boost (figure 13.5psi at the compressor outlet so that you can assume 12psi at the intake manifold figuring a 1.5psi loss through the intercooler and tubing/ducting, ect) and we know the octane (92) all we need now for the calculations is compressor and intercooler efficiency.

A custom ground camshaft for boost is a good idea. It will look a lot like the stock camshaft specs except for an emphasis on dragging out the RPM band to red line more and increase cylinder filling with high lift. I'd hesitate to have a cam go any higher than 6500 rpm's, to save on the stock bottom crankshaft. I would also hesitate to swap heads if you absolutely do not have to, especially to a high winding head like the 243 casting. Boost likes small-ish head designs to really pack the air into the small ports and valves. The reason why I like 317 heads is because you have the ability to use flat top pistons like stock, and just mill down the huge chambers to get your target compression ratio. If anything, save your money and just have the stock LS1 heads reworked with a simple port match, bowl job in the combustion chambers and final polish; then once we know the target compression ratio either mill the LS1 heads to get it or leave them be and mess with the piston dish instead. Considering the stock LS1 sits at 10:1 compression you will most likely have to leave the heads alone and find slightly dished pistons. From the way this build is looking, only speculating at this point, I see the build coming in around 9.3-9.5:1 compression but like I said I don't know the efficiency of a few things first so don't hang on that target CR just yet. I would however dive deep into an exhaust system to support your future mods, a tranny that wont explode after a hard day's abuse, and a rear end that can handle a good clutch dump from red line. But that's just me.

 

Good stuff, good good stuff.

The D1 and F1 setups I was speaking with are in fact ATI Prochargers, centrifugal superchargers. To be honest, they actually are almost "plug-and-play" for the most part. They do include all the piping, wiring, aftercoolers, etc. Some kits even include a fuel system (pump, injectors, etc.) The only thing left is a tune, and thankfully I'm close to a respectable shop that can do a great dyno tune. The D1 and F1 are just names for the actual blowers. D1 is capable of up to about 15 PSI with a small pulley. The F1 goes much higher, and is more of a "race" blower. If you're curious, check out www.procharger.com when you get a chance.


As usual, you mention some good points. Belt load/tension and air temperature. These procharger setups are generally pretty efficient. I would imagine going with an electric water pump in an attempt to off-set some of the load. In terms of air temperature, I have no idea to be honest. Sound like a very important element to research in this decision.... Lets add it to the list lol.

You're last statement really rocked my brain though.... So forced induction likes a "smaller" head design eh? I thought I would be limited with my current 59cc 243 head, but you make it seem like this would be better. If you could elaborate more on that, it would also be very helpful. Learnin something new everyday I guess.

But don't worry, the 9 inch is on order. I'm working on the chassis and suspension this year so I'll be ready to go once we hammer out all these details.... With everything there is to consider, I'm guessing I have some time yet before I start puttin the setup together lol.

Thanks again

 

IM running a F1C on a ls2 pushing about 658hp if i put it in 4 gear and mash it 2 grand i have 2 psi of boost 3-4grand 5-6 psi at 6500 10.5 psi . 1-2 gears it like driving on ice 3 gear still hard to get taction. but do able. so even in the lower rpms range it is still pushing more hp makes a great DD. this thing is a beast i love it pulls great all over. i love the F1C only thing is when i pick up a girl they are like whys the car sound like a jet is it suppose to sound like that. i just smile.

 

Wow I totally missed this post. Forum members answer threads so quickly on LS1tech that this thread wasn't on the main page any longer after I looked at it only an hour earlier.

Anyways onto the head design. Boosted motors like smallish ports and intake runners because of the velocity increase into the combustion chamber that occurs when the forced air hits the narrowing ports. Imagine if you will a garden hose. Put your thumb over the end and narrow down the nozzle's size and pressure increases, thereby allowing you to spray the water further than without your thumb on the end. The stock 243 heads already have some of the largest ports available to Gen III/IV motors, so I'd hesitate to go any larger.

 

There is a saying on Corvette forum, what is the difference between a 650HP street vette and 1100 HP street vette? 3 tenths in the quarter mile and $20K

 

Interesting. So it sounds like the heads im currently running (Patriot Stage II LS6 heads, base valve size, and 59cc) would be pretty suitable if I were to stay with a stock-ish cube motor with some FI. All I would really need is a built short block with some domed pistions to lower the CR and I should be pretty much ready to go (plus obvious fuel system, etc). Maybe switch to a blower-based cam (higher LSA, duration on intake/exhaust)

I thought my setup was pretty far off from what it needed to be, but looks like it may be flexible with some changes

 

Boost and a stock motor tend to go well together until you start getting above 15psi and really greedy. But, you wont know how greedy until you start breaking things, so test away.

If you keep the heads you have, the best money you can spend will be on truing up the block and head surface, and investing into head studs. There's a saying that "head bolts are an accountants decision, whereas head studs are an engineer's decision". A perfect clamping force across the entire head gasket is what you're after. If boost levels start to get really high, perhaps invest in block prep that deals with creating a groove around the head gasket and adding an O-ring under the gasket for strength. Don't get me wrong when I reference a head gasket being weak at high boost levels A new stock head gasket, mated to a flat surface and accompanied by properly torque head studs, is a good joint. Head gaskets in general do not tend to "blow." Rather, one could say that detonation will blow anything, and the head gasket is often the first thing standing on the front line of attack. Almost always, the most effective cure for blown head gaskets is control of detonation which you can do by selecting the right gasoline for the intended boost and compression ratio, along with tuning the PCM very thoroughly.

As far as the camshaft selection goes, usually the stock camshaft works very well for boosted applications. However if you're going to purchase a new cam anyways, look into one that has decent vacuum at idle to keep the accessories running while having the right amount of duration on the intake and exhaust side to bleed off some of the high compression. The 02+ LS6 camshaft is a great example. If memory serves, it's a 204/218, .551"/.547" on a 117.5 LSA. Perfect for an LS1 IMO.

 

Wow I just learned a ton; I got to print this and soak it up some more!

Great thread!