i know what he was asking as i said before im not sure how much u can force down the 4.3 throat...i was hoping to get more but powerdyne.com doesnt offer much more then what i posted...i was assuming 7lbs of boost considering that is what powerdynes supercharger is rated at...but i have a mag that says it can produce up to 25lbs if ur engine is built....i will post more bout the supercharger if i can find it...and what does WAT stand for?

With the plastic upper plenum, I wouldn't go much over 10psi. Beyond that and you want to drop the compression ratio via new pistons.

yeah 10lbs is borderline for reliabilitys sake. Its all about fuel and timing. Might make it to 15psi with enough fuel and with the timing backed way down but is very possible.If everything is right then the intake could be the limiting factor.

Damn, I want one... make a Forced induction blazer mud machine?

Wow, is this still considered street legal when you add all the turbo and everything???
And would you still be able to 4x4?

There are cars making 3x and 4x more power on Twin Turbos, SCs, and/or N2O that are street legal. I don't think a 300HP Blazer would be illegal provided you still have all of the required safety equipment, which this kit does not remove.

And I don't see why not. This kit makes no mention of taking away 4 wheel drive. Thats has to do with the car's drivetrain, not your engine. Look at the 4x4 and AWD turbo trucks, SUVs and cars that are on today's market from the factory.

I'm sure its probably not legal in cali. i know they have pretty tough emissions regs.

Ah, didn't see he is in Cali. The better question though is what IS legal in California? haha

As for wheelin with a turbo truck, it's possible but it better not be a rear mount setup.

I know this is an old thread, but I had to get on here cuz I like the little 4.3 so much. I'm not an expert, so don't come on here saying your engine didn't put out but 'x' amount after boosting what I said. That being said, theres a lot of different versions of the engine since its inception and most well maintained reasonably mileaged engines will run 7-9lbs of boost off the stock injectors depending on where they max out. Mine was 8lbs on stock injectors. I won't get into carbed engines because most people don't have them and a carbed s/c 4.3 is not something I'd recommend although it can be done, just as easily as anything else. Most people run 6-8lbs because this is where the kits usually come in, depending on the kit. The injectors for the 4.3 are the most limiting part of the stock engine and the biggest pain to get around. There is no automotive 4.3 that has upgradeable injectors, even brand new, don't get me started on 2004+ fuel injected 4.3's :icon_emm:.

8lbs will get you a decent 250-280hp and more torque, depending on a number of things, the tune, the condition of the engine, what year engine out of what model vehicle, the gas used, add ons (intercooler/meth/bolt ons), etc.

Let's say you don't want a wimpy 4.3, lets take a look at what needs to be done. #1 fuel. To get more fuel you have a few options, there are some very exotic and laborious ways, the easiest 3 being (in order from best to worst, not an opinion). 1)SDS EIC or similar piggy back extra injector system 2) marine intake manifold swap with larger injectors 3) the fuel management unit.

The SDS EIC will allow the use of the stock tune to be used until boost comes on, with the extra injectors kicking in, in tandem with the tuned ECM... which is a whole nother story I wont go into detail. This will run between 500-1500$ depending on used/new parts and accessories/setup/modifications (not including tuning $ price or other fuel system components)

Marine manifold swap is nice because it's possible to change out the injectors to larger ones. Problem here is the engine will loose low end or everyday driving efficiency with larger injectors, the ECM will need to be altered much more for the different injectors and flow rates etc. There's a little fab work involved but not too much, and you need to take a lot of the top end apart. This should run between 300-1000$ depending on how far you take the project and if you can score deals. (not including tuning $ price other fuel system components) Note this swap is recommended only for return style injector systems, unless modification to the fuel rails are made it can't accept 2004+ injector systems. If serious boost is the goal this could be the best way to go, you can't blow off the upper plenum which could be blown off somewhere in the neighborhood of 13-20+psi, no one really knows for sure but it's happened before...

Fuel management unit - I'd strongly advise against this, look it up for yourself but the engine is in your hands if this archaic piece of wonder equipment you decide is for your 4.3. This will run between 50-400$ depending on how much the unit is, etc (not including tuning $ price or other fuel system components) The fmu can in no way work on a 2004+ returnless system, don't even try swapping gas tanks and fuel lines, the older fuel pumps won't be compatible with the newer ECM's

#2 cooling - intercooler first, if more is needed water/meth injection (also cooler plugs and less timing -> that'd be in the ECM tuning which I won't explain here)
#3 exhaust - if youd like to pass emissions stick with the stock exhaust, if you don't care, shorty headers and a cat-back system, if you have no regulations at all, full headers and exhaust

How much power can it make? The stock internals have been pushed to 450-500hp+, but that's pretty radical. Forged internals and lower compression pistons should handle another 50-100hp, but the limiting factor here is the evenfire crank. Time to upgrade to a built sy/ty block and ignition system if you're looking for more than 550hp. Seeing as 450-500hp is as much as anyone would want to put out of a stock 2bolt or possibly 4bolt 350, that's a nice punch of power in a small package. On a good tune, 350hp will last forever in these engines. Prep the budget for an intercooler above 8psi and/or meth injection (or both which is my personal preferred method). That should get to 14-15psi, with a few bolt ons and shorty headers/exhaust it should be just south of 400hp. Likely around 360-380bhp, and I'd say thats the sweet spot in terms of reliability, longevity, and performance for the 4.3. More can be had with a full exhaust, cam swap, etc

Be sure to take into account that anything over 1 bar (around 15-16psi) will be more expensive than anything under that number. A new operating system for the tuning program will be needed (sometimes free, sometimes not even available through certain software), also a new 2-bar MAP sensor. Anything over 14-16 psi is starting to get in the gray area for these engines anyway. Some people have made upwards to 25psi on stock engines, but very well tuned.


edit - as far as keeping it legal, especially in emissions strict cally, a 4.3 with centrifugal supercharger (vortec) on the stock injectors and boost controlled computer will run as it was stock (maybe a little less timing) until boost comes on, so you don't have any worries about emissions controls. Add an intercooler to keep those IAT's down. Above 8psi timing could need to be pulled out which could also affect emissions. Turbos could quite possibly ruin the emissions, as well as the marine intake swap (unless tuned well). The fmu shouldn't affect emissions, but thats your call. Again, SDS EIC and centr. s/c kit is the best setup in my opinion, the supercharger in the stock vortec kits can spin up to 19-20psi if you really wanted or needed them to. Look at 1-2psi lost through an intercooler and thats about as much as any 4.3 can take