Wayne Presley explains his XTerminator

[Purple Venom]

Kerry, you have something to aim for now. Check out Wayne's twin turbo supercharged car :D :eek:
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[rednour1]

I've seen his kits, and he is supposed to have one for the SOHC. Looks like alot of plumbing!

[Purple Venom]

Yeah, and money, $6k for the turbo kit alone. Will someone explain to me why the turbo quiets the exhaust so much to a point that the shorty exhaust doesn't sound like open headers?

[MPTech]

Twin-turbo'd/Supercharged 4.6??!!??!! GEEZ! Did he say 50+lbs of boost!? What holds that thing together?

[Kerry & Kathy]

Wayne is a very talented guy....but twin turbos with supercharger on a street car... limited by street tires.... is overkill to the nth degree. A single supercharger or single turbo could easily achieve the same 18 psi boost he is running without the added weight and complexity. However there is some merit to mixing a supercharger with a turbo. The supercharger can provide low rpm boost and driveability that the turbo can't produce, while a turbo can give high rpm variable boost that could not be achieved with a fixed boost supercharger alone. It's an interesting combination.

Wayne apparently wanted a showcase to display his skills and capabilities and to that end...it serves his purpose very well. It is an impressive calling card for his business.

Tim, the reason that he does not need mufflers is that the exhaust impeller in each turbo housing serves as a VERY effective muffler. The multiple impeller blades provide both dampening and resistance which effectively breaks up the strong exhaust pulse coming from each exhaust valve into many very small pulses. At an idle when the impeller is not spooled up you hear only a burble since the exhaust gas flow is being restricted by the impeller blades. However at boost the impeller will spin to VERY high RPM....often 60,000 plus....giving the high pitch scream / whistle that is common to a turbo at speed.

Kerry

[Kerry & Kathy]

Twin-turbo'd/Supercharged 4.6??!!??!! GEEZ! Did he say 50+lbs of boost!? What holds that thing together?

The 50 PSI boost comment was referring to how much the combination was capably of producing. Certainly enough to grenade the motor. He indicated that 18 psi is what he actually runs.

However modular motors with modified forged crankshafts and factory Teksid aluminum blocks with ARP studs and hardware have survived 1500 HP on alcohol. The weak link are factory hyper-eutectic pistons and factory powdered rods. With aftermarket forged pistons and forged rods they are as durable as any factory engine ever produced.

The block and crankshaft are amazingly capable of handling high HP.

K&K

[Purple Venom]

Ok, let me get this straight in my head. The supercharger provides low rpm hp/torque because it is forced induction bolted right to the top of the intake manifold. The Turbo's provide higher rpm hp/torque because they work off of exhaust gases. So, what would a air plumbing diagram look like? Where's the output from the turbo's going?

[Kerry & Kathy]

Ok, let me get this straight in my head. The supercharger provides low rpm hp/torque because it is forced induction bolted right to the top of the intake manifold. The Turbo's provide higher rpm hp/torque because they work off of exhaust gases. So, what would a air plumbing diagram look like? Where's the output from the turbo's going?

OK...

What Wayne has is a two stage blow through system.

Ambient air goes through an air filter on each turbocharger's intake side and feeds that air through two ducts into the intake side of the supercharger.

Below 2,000 rpm or so...the turbos' don't create any boost as they don't have enough exhaust volume to provide sufficient impeller rpm to create boost. So the engine runs on a fixed amount of boost being generated only by the supercharger. That amount of boost is determined by the relationship in circumference between the pulleys mounted on the engine crank and the supercharger rotors.

However, at higher rpm the engine is now producing increasing exhaust volume which spins the exhaust side of the turbo impellers faster and faster. As the impellers speed up they begin creating boost pressure on the intake side which builds very rapidly. As a result, the air that is being fed to the supercharger is now being compressed by the turbos... creating variable boost...and then...compressed again by the supercharger which is creating fixed boost.

The net effect is you start out with fixed boost of perhaps 8-10 psi from idle to 2000 rpm...and when the turbos begin working... that 8-10 psi boost starts increasing VERY rapidly to a maximum of 50 psi. It becomes a vicious circle. The more turbo intake boost...the more engine exhaust volume is created...which then increases turbo intake boost...only to produce even more exhaust volume. If left unchecked...the engine will self destruct.

However at some point, to protect the engine, a waste-gate will be used. I have not seen Wayne's actual installation but depending on how he has the exhaust routed... he will have either one very large waste-gate on a common exhaust pipe for both engine banks feeding both turbos...or more likely... a pair of waste gates will be placed...one on each turbo exhaust side...with a preset relief valve set to discharge excess exhaust volume once a predetermined level of boost has been reached. In Wayne's case he has that set to 18 psi maximum boost. When the relief valve in each waste-gates opens...the additional exhaust volume is released to the the atmosphere through a waste-gate exhaust tube preventing the turbo impellers from spinning any faster...thus keeping the boost pressure limited @ 18 psi to avoid damaging the engine.

Make sense now...?

Kerry

[Purple Venom]

Yep, thanks. Just couldn't figure out the turbo to supercharger hookup or how it was done. Double compressed air, seems like that would generate a ton of heat. So, I'm assuming some type of intercooler is installed as well.

[Kerry & Kathy]

Yep, thanks. Just couldn't figure out the turbo to supercharger hookup or how it was done. Double compressed air, seems like that would generate a ton of heat. So, I'm assuming some type of intercooler is installed as well.

It would.

There is a factory liquid to air intercooler under the Terminator supercharger....

Kerry