TURBOCHARGE or SUPERCHARGED - The $64 Question

[AL427SBF]

For you HP freaks, I might want to join your club lol. So, what are the pros & cons for each? The motor in question is an all aluminum DART 427w small block currently carbureted with a single Willey's 4-barrel.
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[blykins]

Have you driven the car with the engine in it yet?

I really don't like adding boost unless the rest of the engine is built for it: a cam with forced induction in mind, very low compression ratio, higher quality head gaskets, etc. Also, it's going to be harder with a carb setup and if you keep the carb, then it will need to be converted to a blow-through style.

[danc30]

Just wondering why you want forced induction. There is plenty of HP available without it. A 427 SB can get up to 500 and even 600 HP. *** Note the comment about the 427 stroker***

Here is a quote from "Badasscars.com":

With Ford small block's, using the 351W block, we can easily make 408 cubic inches and they'll handle upwards of 500 HP, and upwards of 600 HP reliably when a billet main support is installed.
Some people will even get them out to 427 cubic inches, but we don't recommend doing that because that additional .100" of stroke is just too much for the stock blocks to reliably handle for long periods of time. It usually causes cracked main webs.
For the little 289 / 302 blocks, 400 HP or so is about as far as you want to go unless you install a billet main support, which will raise the "reliable" handling capability up to about 550 HP. The only way you're going to get that kind of power out of a streetable 289/302 based Ford small block though is with a power adder such as nitrous or a supercharger, period... unless it's a race trim engine running race fuel.

[blykins]

I know you were just quoting another website Dan....

However, his block is an aftermarket block. I've never had any issues with running the 4.100-4.170" stroke crankshafts in a production block and there certainly wouldn't be any in an aftermarket block. The 4" crankshaft that you use in a Dart/World/Ford Racing block has the same stroke as a crank that's used in a 408.

As far as the 289/302 engines, 500hp is very possible with pump gas and nothing more than a stroker kit and a really nice set of heads. My 347's make over 500hp, peak at 6500 and run on 93 octane.

My advice for the OP would be to get the engine in the car, then see what *he* is able to handle. 550-600 hp in a Cobra is a hand full.

[mhacars]

I have first hand experience with this issue. Back when I was having my alloy CSX built, I had never even driven a Cobra. When it came to getting a motor for it, I ordered a supercharged dry sump aluminum FE from Shelby. I did not want to have any second would have could have thoughts. With 6 pounds of boost, it makes 760hp and 710 foot pounds of torque at 6200 rpm based on the dyno runs at Kroyer.

When the motor was complete, I made the trip out to Shelby in Las Vegas to hear it run. That day, Gary Patterson took me for fast ride in a supercharged Series 1 and told me that the car had 500hp and what I had purchased is exponentially crazy and that I should be very careful when I drive the car and slowly learn how to drive the car. After the ride, I was taken to the oops department at Shelby where customers with regular motors crashed their cars and were awaiting repair. The cars had the same damage....right front fender and drivers rear quarter panel. I took a picture of them to remind me of what can happen with a normally aspirated motor.

Driving the car educated me on how much power is too much power. At low speeds it is very docile but it spools up so quick that it is dangerous as you accelerate. It can get away from you very quickly and as a result I don't even take it out more than once a year. If I had to do it over again, I would go with the FE but without the power adders as too much power is not manageable and very dangerous.

[D-CEL]

That is almost too general a question, like asking “what is the better color red or blue?”
I think you need to give a little more detail as to what you want to do.
For Show or For Race? + 100 hp or + 500hp
Turbo: Single or dual? Side pipes?
Supercharge : Roots or Centrifugal? Hole in the hood or not? (Please not!!)
Induction: Blow thru or Draw thru? Carb or Fuel Injection?

Both make power, both have unique complexities.
Typically turbos make more power at a given boost level. Supercharges tend to be simpler to design and install and are a little less expensive.

I like Forced induction on late model cars where the op wants more power, but still needs to pass emissions and doesn’t want to violate the motor. In a Cobra I would ask “why?”
Brent or any of the other talented builders here could easily meet nearly any hp request without the added complexity, cost and weight of a forced induction system.
I do understand the draw if your building a “sleeper” I know “sleeper” and Cobra don’t normally go together, but Twin Turbo’s deal is just plain bad A$$!!
9’s at near a mid 140’s

Jason

[danc30]

Blue is the better color BTW......

[fordracing65]

TURBO, TURBO, TURBO, I cant say it enough, its free horsepower while a supercharger is running of your motor which is using and robbing power. These days the technology with turbo charging is a no brainer for CRAZY very streetable horsepower, plus mpg is uneffected if you keep your right foot out of it, thats if money is no option, plus you can run a single turbo with less piping and get 1000 wrhp easily. If you really want power just spray it with nitrous, it easy, instant power and with more torque than supercharging and turbocharging.

[twobjshelbys]

Define the problem you're trying to solve before choosing. If you want fast times from 0-60 (ie, fast response time) you want a supercharger. If you need mid-RPM response go with turbo.

Most of the guys running Ford GTs at the Texas mile are running a combo unit - turbos feeding the supercharger.

I also believe the plumbing system of the turbos will require you to surrender your side pipes. The header exit probably won't fit. Most of the small block 427s also have fairly high compression. These are not compatible with high boost.

I would also assert that you should listen to Bill Cosby's 200 MPH before adding a supercharger or turbocharger to a Cobra. The car in question had twin Paxton superchargers with low to medium boost.

On mine, the 550HP I get from the Roush engine is all the car and I can handle. It's almost too twitchy as it is. I can't imagine it at 750 or 1000...

[DougD]

Roots blower. Period.

[fordracing65]

Originally Posted by twobjshelbys

Define the problem you're trying to solve before choosing. If you want fast times from 0-60 (ie, fast response time) you want a supercharger. If you need mid-RPM response go with turbo.

Most of the guys running Ford GTs at the Texas mile are running a combo unit - turbos feeding the supercharger.

I also believe the plumbing system of the turbos will require you to surrender your side pipes. The header exit probably won't fit. Most of the small block 427s also have fairly high compression. These are not compatible with high boost.

I would also assert that you should listen to Bill Cosby's 200 MPH before adding a supercharger or turbocharger to a Cobra. The car in question had twin Paxton superchargers with low to medium boost.

On mine, the 550HP I get from the Roush engine is all the car and I can handle. It's almost too twitchy as it is. I can't imagine it at 750 or 1000...

With smaller turbos and tuning there is no lag with turbo charging these days instant throttle is always available.

[marcocsx3121]

Try it before you buy it. My C5 'Vette (~3300 lbs.) runs a Procharged 427 that makes right around 800 HP at the wheels, and is close to lethal in the first three gears. In a replica Cobra that weighs 700 lbs. less, has a short, 90" wheelbase and no traction control nannies, you can kill yourself right quickly.

For me, 500 RWHP NA would be about right for the car.

[lovehamr]

Some of you HP nannies kill me. mhacars; your car has too much HP, so you only drive it once a year?! WTF? If it scares you that bad lower the boost. You other guys telling him how much he doesn't need; lay off. The OP addressed "HP freaks." Not "HP nannies." My FE has just shy of 550 at the FW and though it'll act ugly if I do something stupid I don't consider it some sort of death warrant. In fact, I drove it almost daily for a month this summer just because it's so damn fun. Right now I'm in the process of replacing all the rubber bushings in the rear of the car with solids because I want less movement in the rear under power. That being said, I've considered a Paxton or Vortec on more than one occasion and still think it'd be a blast! To the OP: you go for it man! Don't listen to the "too much HP" grannies, build that gnarly beeeotch and have a blast! Are you going to have to be careful? Yes! Can you drive it like your Dodge Neon? No! Can you drive it and have fun with it without killing yourself or someone else? Absotivley! Even with (insert number)HP?

[mhacars]

lovehamr, I don't use it much as I have several other cars that although they have plenty of power, I feel safer in them as they are more predictable. Mine has the Vortec and have no compaints about the performance. The kit that they made for Shelby is very compact and well designed.

[fordracing65]

Negatives of supercharging, heat soak, belt breakage or slippage, uses crank power so it is actually using hp to make hp, turbo is free of all these distractions so power up top is unaffected, supercharging gets it done but turbocharging now days really gets it done especially at the strip, I like them both.

[mhacars]

This is what my set up looks like.

[fordracing65]

Originally Posted by mhacars

This is what my set up looks like.

That set-up and look is actually my favorite look for a big block cobra.

[scootter]

I have the 514 with over 600 at the crank. Wouldn't have it any other way. I would like to get the Kieth Craft 572 with 750 hp next. I've always thought about a supercharger on my existing motor, but I figure it might be easier to wear it out and replace it with a bigger one!!
Scott

[RICK LAKE]

Al427SBF Al have been involved with HP and torque since 73. You didn't say what company your car is coming from.
Problem #1 is the frame up to the power you are looking for???
Problem #2 is the drivetrain able to handle the boost power???
Problem #3 is the DRIVER smart enough to handle this KILLER???
Has the driver EVER drivin a car with manual and basic everything like brakes, steering, maybe 15" wheels and tires with 500HP and or torque???
Odds are your reflexes are too slow to react to problem happening, mine are.
I have tryed the same thing with my car. A 452 Shelby motor with a Novi blower. I built my car with an FI system from F.A.S.T. Car comes on boost and WOW. 6 pounds hits like a tank. Rear tires go up in smoke or car start dancing across the street. This is on concrete and tar. The car needs traction control and a steering slow down responce.
Build a motor with 600ft of torque. Drivability is alot better, motor lives alot longer, have more fun, parts are not being pushed to the limits.
Blowers and turbos are both hard on bottom ends, blowers a little less under boost conditions. Pistons tops need to be coated and skirts need protective anti scuff to protect cylinder walls. Need a motor with a large bore and SHORT stroke. Heat coming from this motor is big. Largest radiator you can find. You said nothing about after coolers?? Air to air? Water to air? Water injection?? For turbos extra oiling cooler, Mobil 1 oil at $8.00 per quart.
I have gone to a 482 stoker motor with 600 ft of torque and 560 HP. This is a safe limit to what the car can handle for an average driver. Car is still a handful but more forgiven. Boost cars are not as quick to reply along the same lines. Banging of turbos or blowers happens, even with boost control valves. Talk to Cobra #3170. Bruce has a 800HP motor in his car and about 1/4 million dollars of R&D. It's streetable. Excaliper tryed the same thing with 650HP and if you look at the old threads he went back to a street motor got double the mpgs, more streetable, less breakage, less maintainance and happier to drive all the time.
IMO as far as the Shebly twin blower car, I don't believe some of the info. Those ball bearing blowers max out at 7-9 psi of boost. Slippage happens. Same for the 1 belt that drives both blowers, belts slip. This car is also a automatic trans car, Torque convertor slipping to at high rpms. Super heat coming from motor under the hood. Little air screens to the blower to keep dirt out. The BIG thing, I have the same hood for my car, at 138mph the car starts to lift in the front end. I am guessing at 145-150 you can become an airplane and get takeoff clearance. My car is 2705 with out my weight. A shelby is lighter by 200-400 pounds maybe more. I have thought about the 200 mph club, I can build the power, major problem is keeping car on the ground WITHOUT any extra down force help, Just like Dick Smith did.
Build what you want, I hope your brain is smarter than your balls with this. Hope Lovehammer sends flowers. Think he has been watching his avatar to long. Try Flow bench here on CC. He has and builds turbo and blower cars for speed records. FE motors too. He has a motor(FE) in the 2,000 hp range. Put this in a street cobra and see what happens Rick L.

[AL427SBF]

After sorting through the resonses I got my answer. If I decide to do it I will go the turbo rout. Yes, the car/motor/chassis/drivetrain/driver etc can handle a little boost - that was never an issue. So, question #2 - what would be a nice mild turbo to go with? I doubt I will ever want more than say 8 psi boost.