I'm Thinking of Running a Supercharger

[vdubn]

So I have an opportunity to get a good deal on a Vortech setup for my 1985, and I wondered if I could get some advice?

I currently have basically a 1993 Cobra EFI setup for my car, 65mm BBK TB, 75mm Pro-M Maf with 24# injectors, and an adjustable fuel pressure regulator. Obviously doing the conversion from speed density to MAF.

The kicker, is that I am running 10.5:1 compression, but I would only run between 6 and 8 psi of boost, and the engine has just been gone through, and I'm running ARP head bolts, Keith Black hypereutectic pistons, Trick Flow Stage 1 cam, etc.

My heads are Edelbrock Aluminum heads with 2.02/1.64 valves, dual springs, Edelbrock Performer Intake and am running Walbro 255 fuel pump.

So, the fuel pump should be plenty, but can I get away with 24# injectors if I increase fuel pressure, or should I jump up in Injector/TB/MAF size?

Is there an off the shelf tune that I can safely run, or am I going to need to get a dyno tune to get things to run right?

As always, I appreciate the advice

[homer302]

Did you purchase the car setup this way? I can't imagine putting hyper pistons in an engine with all those speed parts on it and planning on running boost on top of that. But if that's how you got it then I see, your desure to work with what you have. That is obviously your weak link here and what I would be more worried about. Every engine is different but I doubt seriously that 24# injectors will suffice with 8lb of boost but that's an easy change and you can turn the 24# injectors over easily and make some $$$ back to boot. I just did a quick search on your MAF on ProM's website and it looks like it will support boost with a custom ECU tune and mapping. How much power is enough I guess is what I would say about the TB size. It won't hamper it from running well or safely (once the tune is installed) but it would run better with a larger setup sure.

[vdubn]

I actually chose the Keith Black Hyper pistons, mostly because I had no thoughts of going SC, plus a number of testimonies stated that they were a great all around piston (nothing like stock hyper pistons), and lighter than forged counterparts. Obviously for a Turbo or SC application where you are running more than 10psi of boost, they wouldn't be a good choice, but I figured that for low boost scenarios they should be fine. I guess I should call and see what KB has to say, that would be a good start.

And... I didn't think to check ProMs page.. that is a good idea as well.

Homer, what is your experience with hyper pistons, and do you have any with the KB series?

[vdubn]

Ok, after doing some more research, the hyper pistons are perfectly fine for what I was looking to do, but they recommend a top ring gap of around .030 versus the .025 that my builder used. I told him initially no Nitrous, no boost, which is why he went with the tighter ring gap. Its not worth having him tear the bottom end apart to change the ring gap, so I will be happy with my NA setup, and the extra money I would have spent on the SC.

[homer302]

Sorry, never got back to this one. Glad you got it sorted out. I don't have experience with failure, It's just a fact that hyper pistons are not as strong as forged. That part can't be argued. You can safely take a stock long block Terminator to 700+ HP......because it comes with forged pistons. The question in your case is are they strong enough? A lot has changed though. I am not going to research it because I don't care that much. I am just curious with nearly everything being turbocharged these days, how many have hyper pistons? F150s, Fusions, Chevy Cruze...they are ALL turbo now. Technology is real. But that would not apply to a pushrod windsor anyway because they are nowhere near as efficient at combustion as any new car at all. It's not even a comparison. You just can't burn fuel efficiently like a modern engine can. I am just wondering.
I think your combo is badarse. I mean that. I would love to build what you have. I have an old stock-head 5.0 (that came from Ford with Forged pistons and has less than 200 HP).

[erratic50]

If I were Keith Black I would have put my name on forged pistons and left the rest to chance.

In all seriousness, it really depends upon actual sizes down to the CC as that heavily influences pressures. You can go from 10.5 down to 9.5 or up to 11 pretty easily based upon factors like weather or not gasket thickness was factored in and if the block was zero decked, etc.

Also it really depends upon how many miles or passes or laps you are looking to get out of it.

That being said, if you are going to boost it, boost it. An engine with 8:1 or 8.5:1 on boost will allow you to make a lot more power under boost due to additional combustion chamber size eking in more air/fuel.

And then there's factors like fuel. An 8:1 motor at 8 psi should still run on pump gas if you want it to. It's E85 or race gas neck of the woods with 10.5:1 and 6 psi.

But the limiting factor we haven't talked about is the block. While some hero stockers have somehow lived through a morning of thrashing at the dyno with a 375 shot via 3 kits on a 225 HP motor, many more have cracked right down the middle at around 500 HP unless they are debuted, etc. Granted tune is a factor.

[vdubn]

Great points erratic, just curious, your speculation as to approximate hp numbers with the following setup I'll be running (granted there are tons of variables, so I am assuming that each setup runs adequate:

302 with calculated 10.6:1 (zero decked block, .040 head gaskets, 60cc heads)
Edelbrock Aluminum heads with 2.02 intake valves
Edelbrock Performer Intake
Trick Flow Stage 1 Cam
No boost

My guess was around 300 hp

Now, the real question, estimating about 20hp per psi of boost, if I run about 8psi, do you think that I could be approaching the 500hp mark? I guess I figured 450 tops with low boost so I figured the block wasn't in danger of any issues.

Just curious

[Ourobos]

You're probably approaching 300 now, yes.

I'd say about 400 to the tires at 8 psi.

I'd jump up to 42# injectors and meter and let the tuner do their thing, don't run an FMU.

[erratic50]

Timing and fuel have a HUGE influence on motor output. I can make a motor capable of 500 run just fine but only make 200 just by messing with those two variables.

It is impossible to know for sure what it makes without measuring it. That being said, you can put that particular head on a stock cam 302 with 1.7:1 rockers and decent intake and get at or north of 400 HP at the crank with a good tune.

You didn't mention fuel type either. You can pick up 12-15% running E85 instead of premium through the added pressures from 35% more liquid in the chamber and from still being able to add more timing.

But we've all seen the high dollar combos of parts get their ass handed to them by something mysterious that's mostly straight out of a junk pile and appears stock. Assembly and tune make as much difference as parts in many cases.

How many people know how to taper the top of the cylinder above the compression ring to ease air transition from a big valve in a small bore? Engine masters has a writeup on it - the motor picked up HP with all other changes avoided. Then they gave the motor what it now wants and picked up more.

Your parts with a touch of boost would be able to go well past 500 HP if everything is on point. Have one thing out of spec from cam to cam timing to ignition to fuel, etc, and you won't see that.

[deathbypsi]

Check out the build thread here for my 83 Tbird...

I have a 97 Explorer 5.0 in my car I rebuilt 98% stock. I added a TFS#1 cam and good valve springs. I run a Vortech S trim pullied for 10psi right now. I do all my own tuning with Microsquirt and so far with 38lb injectors maxed out at 96% duty cycle I have made just over 400hp to the wheels and in my 3588lb car it has ran 12.09@115mph.
I run a very soft timing map and will be putting in some 60lb injectors today actually. Motor still has the factory pistons and nothing has been ported.

[homer302]

You're probably approaching 300 now, yes.

I'd say about 400 to the tires at 8 psi.

I'd jump up to 42# injectors and meter and let the tuner do their thing, don't run an FMU.

This^^^

The block is the least of your worries at 8PSI. That is 400 HP. The block can handle well more than that. Can you get to 500HP with more boost and your combo? Sure you can. But not with that exact combo and 8PSI.

[homer302]

I guess I should call and see what KB has to say, that would be a good start.

What did they say? This is obviously the correct answer. They made the pistons.

[vdubn]

What did they say? This is obviously the correct answer. They made the pistons.

They said no more than 10psi with my compression, and I need to set ring gaps to around .030", versus .025" for NA. So, since my builder already buttoned it (I never told him I was considering running boost), I'll be happy with where I am. Even at the .025 ring gap, I would probably be fine with small boost, but I probably won't push my luck. KB said that the pistons were more than strong enough, and that they actually have a couple customers running over 500hp, boosted, with hyper pistons (not sure if they are Ford's, but people are out there doing it).

[homer302]

Okay. That's about what I expected. Those people running them with 500HP are probably modern engines like the LS or Coyote. They are just so much more efficient. The darn Coyote 5.0 is freakin 11.0:1 and you can dump boost on top of that with pump gas! It's amazing what they have done with modern engines.

[vdubn]

Agreed... direct injection, and other bits of technology open up lots of possibilities

[Ourobos]

I ran 10 psi on my Marauder, with stock cast pistons, through an automatic it made 398/406.. So I'd HOPE the KB are just as good as the factory pieces.. Go for it