Pfadt Cadillac ATS 2L Turbo Performance

[Bruce Nunnally]

I like the look of this -- turbo's heat up the air as a byproduct of compressing it. The intercooler lowers the air temp before it hits the engine & is key to making power

The Pfadt intercooler design has vaned flow to ensure the air to air intercooler takes advantage of the entire face to the wind.

Some quick photos of what separates Pfadt from the rest of the field. I/C internal vanes distributing the flow across the whole core. Had to snap some shots of this before our welders go to work and hide the hard work behind the scenes. You may not see the difference, but you will FEEL IT.

Here it is all buttoned up:

Not on sale yet -- but should be a nice speed part for the 2L Turbo Cadillacs.

[Texas Jim]

[Bruce Nunnally]

Pfadt releases its highly anticipated ATS turbo kit!

• Multiple Turbo options for street/race
• Ram horn style 304 Stainless Tig welded exhaust manifold
• Custom, flow optimized, air-to-air intercooler
• Pfadt custom software mapping (Trifecta Optimized!)
• Carbon fiber high flow cold air intake
• Engineered low restriction turbo downpipe
• Available with factory-fit high efficiency intercooler
• Estimated to produce 450 HP+
• Prices Starting at $4999 (depending on turbo selection)

Pfadt ATS, Find your Inspiration

[Bruce Nunnally]

[Bruce Nunnally]

[Bruce Nunnally]

[Bruce Nunnally]

[Bruce Nunnally]

[Bruce Nunnally]

More Info: I asked:

Dyno charts for different stage levels? Example, for $4999 expect to do this (a), or if you move up for $xxx to Turbo B expect ( ? Does this replace the stock intercooler in the ATS, which is on top of the engine, completely with the front-mounted intercooler? Does that introduce any turbo lag from the air going now to the chin then to the engine instead of straight thru the stock intercooler blocks?

To which Pfadt responded:

I think that is a fantastic idea Bruce! I'll start working on some images comparing the individual stage levels and post them soon. The second question is easy....at Pfadt we only design systems that will make driving a high end car the experience you deserve. The intercooler was carefully designed to avoid the types of issues you mentioned....and the end result was an intercooler that gives the maximum cooling effect and incredible throttle response.

So clearly they feel there is no issue with turbo lag. Turbo lag is largely perhaps cancelled out by the tightly coupled turbo and turbo selection, regardless of the cool air path.

I suspect the relatively high turbo pressure the ATS uses also helps -- as well as the relatively small engine size.

Looking forward to seeing stage by stage results and pricing.

[Cadillac Jim]

When boost increases, the air between the intercooler and the intake is compressed, heating it. You can compute how long it takes for that air to be replaced by fresh air through the intercooler at the higher boost pressure the usual way,

<Time to consume air in minutes> = <volume of air to be consumed> / (<displacement/4> X <rpm> X <volumetric efficiency>)

where the volume of the air to be consumed and the displacement are in the same units (liters, cubic inches, whatever).

If the volume of the air is about the same as the displacement of the engine and we use 80% for the volumetric efficiency, this is 3.6 seconds at 5,000 rpm. So, Pfadt has some 'splainin' to do.

But I think in practice the air is being used as the pressure is increasing so you won't see anything like a three-and-a-half second delay. In any case I do think that we are looking at a trade between higher torque and horsepower for a slight increase in turbo lag. How slight is up to Pfadt's design.

[Bruce Nunnally]

Here is a note from the previous 2L Turbo, the LHU -- the new LTG was a clean sheet improved design, but share this sort of characteristic.

Twin-Scroll Turbocharger

An advanced, electronically controlled turbocharger with a unique twin-scroll design is used to increase power in the Ecotec 2.0L turbo. Each of two scrolls on the turbine is fed by a separate exhaust passage one from cylinders one and four, the other from cylinders two and three to virtually eliminates turbo lag at low engine speeds, giving the engine immediate throttle response associated with a naturally aspirated high-performance engine.

The turbocharger generates maximum boost of about 20 psi. Because direct injection cools the intake process compared to port injection, it allows the Ecotec 2.0L turbo to safely operate at higher boost and a relatively higher compression (9.2:1) than a conventional turbo engine, increasing both output and efficiency.

[see further discussion below; this is wrong]

[The factory approach has the turbo tightly coupled to the engine; turbo output goes a foot or two into an intercooler on top of the four, and then down into the cylinders. This takes nothing like 3.6 seconds if throttle response is 'immediate'.

Pfadt Difference: The Pfadt approach routes the air from the turbo forward to the air to air intercooler and then back to the cylinders -- so say 2 feet forward, 2 feet across, 2 feet back. Air scooting along at 21+ psi pressure, not sure what cubic feet per minute.]

The actual turbo compression and flow are common to the two approaches. Pfadt's testing suggests their additional flow path doesn't add any lag.

[Bruce Nunnally]

Hmm -- the stock ATS intercooler is also air-to-air, so I may be confusing the ATS intercooler with the upcoming CTS TTV6 intercooler. Here was the ATS 2L write-up but now I am unsure of the stock air flow path / intercooler setup.

Among the 2.0T engine’s highlights: a direct-injection twin-cam, four-valve-per-cylinder engine with continuously variable valve timing; twin-scroll turbocharger with air-to-air intercooler; forged-steel crankshaft with modular balance shaft system; and a two-stage variable-displacement oil pump with jet-spray piston cooling.

[Bruce Nunnally]

This photo may be the stock air to air intercooler behind, and the replacement? supplemental? Pfadt air to air intercooler in front. The previous LHU engine had a similar setup so I think I was just confusing the issue. What Pfadt is offering is a higher capacity item as a direct replacement for OEM item

[Cadillac Jim]

It does look like the Pfadt intercooler has a lower volume than the stock intercooler and the conduit back to the intake does look like the total displacement there is a whole lot less than two liters. If it transfers heat better too - and that seems to be the first design priority - it will improve torque *and* response time.