Air Ducting to CAI DIY Mod #Motorama

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What benefit is there to routing air from the lower bumper to the cold air intake?

Spectre Performance 8746 Blue Air Duct Hose

I have a Spectre Cold Air intake on my 2008 Cadillac STS-V.  Today’s question is, what if we ducted cold air from the bumper to the CAI instead of to brake cooling as designed?

I shopped for this air duct by Spectre on Amazon.  It was available in a few colors, and the price differed by color, so I got the lower price blue one.

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This is a shot of the hose in the package as received.

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The end pieces are rubber; the hose itself is plastic.  It stretches out like an accordion, and holds it shape once adjusted.

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The coupler for the ducting is tucked into the brake cooling duct.  It is a press-tight fit, but I will keep an eye on it and see if it stays in place at speed.  I tested up to 45 mph or so and it was still there.  I would prefer to put a inner locking ring or similar to ensure it stays in place at speed.

The inner diameter of the brake duct on the Cadillac is larger than the outer diameter of the coupler on the ducting.  A 3.5″ diameter duct might be a better fit here.

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This shot is looking down past the filter into the top of the ducting.  This is where the incoming air will blow out of the hose and onto the air filter.

Only had time and temperature for a short test run to make sure the ducting stayed in place.  I will be testing next available good weather day.  Stay tuned.

Do you have other hints or suggestions for this setup?

Update:

Ran a new baseline / test run this morning.  Weather was okay but ambient read 81F, and test area 76F.

2013-05-18 reset 1-2 added ducting

Virtual Dyno with 1st gear and 2nd gear together detected no improvement due to the new air ducting to the CAI.  The previous run Virtual Dyno vs HPTuners Delivered Torque Curve was at 379/345 hp/torque at the wheels.

comparison of virtual dyno runs

This shows a comparison of the two virtual dyno runs in 2nd gear side by side.  Technically 4 hp less for the ducted version.

hptuners more1-2 run 2013-05-18

HPTuners data shows perhaps a lower run-up in IAT2 max of 125F instead of 130F, but incoming air temp at speed would seem to have less impact on this — already cooler at that point.

comparison of maf readings

In an attempt to discern how to measure a difference, this chart shows the raw mass air flow coming into the intake.  This would show if we are presenting the engine with more air, regardless of what the engine is doing with it.  Although we might conclude given different days etc these are equivalent, it is notable that the ducted air is ahead of the unducted intake.

The ducting did stay in place through my test drive.  I plan to continue to test and evolve this setup.  I have a new replacement cone filter on the way also; mine is quite dirty.  I will put the new one on then clean this one and have it in standby.

 

CaddyInfo Cadillac Chat 2013-05-17 #Motorama

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Thursday was a unique chat — an unplanned monologue as our normal panel guests were not available.

Forum Link: http://caddyinfo.ipbhost.com/index.php?showtopic=42712&hl=

Planned Topics:

  • Cadillac XTS 410 HP AWD potential
  • Owning and enjoying a used Cadillac
  • Head gasket diagnosis and repair
  • RamAir / air ducting

Even before the chat started a moment of learning, as with the new Google+ layout it was not immediately obvious how to even start a Hangout on air any more.  The way I ended up doing it was going to “hangouts on air” off the main menu then there is a button in the stream that says “start a hangout on air”.

I am used to the luxury of having other people talk while I get some things done behind the scenes; sorry about the silences/gaps.

What would you like to hear in future chats?  To participate in our Thursday evening CaddyInfo Cadillac Chats contact me on Google+.

What can we expect of a Cadillac XTS AWD Twin-Turbo?

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Motor Trend measured performance for the Cadillac XTS AWD 3.6L normally aspirated model at 6.9 sec for 0-60 mph, and the quarter mile in 15.2 seconds.  What can we expect from the upcoming 410 hp / 359 lb-ft of torque twin-turbo 3.6L V6?

The new Cadillac Twin-Turbo 3.6L V-6 is available in the XTS, delivering SAE-certified 410 horsepower (306 kW) and 369 lb.-ft. of torque (500 Nm), making it one of the most power-dense six-cylinder engines in the segment. A pair of smaller turbochargers and an efficient charge air cooler help provide more immediate power delivery, while peak torque is sustained over a broad range – 1,900 to 5,600 rpm – for a confident feeling of power in almost all driving conditions, such as accelerating or overtaking traffic on the highway.

One thumb rule is for every 10 hp added, 0-60 mph goes down by 0.2 sec.  Another rule is for every 100 lbs added, 0-60 goes up by 0.1 sec.

The XTS TTV6 is likely to add around 200 lbs, so we’ll keep up with that +0.2 sec change.

Horsepower
(hp / kW @ rpm):		 304 / 224 @ 6800 (SAE certified) 410 / 306 @ 6000 (SAE certified)
Torque
(lb.-ft. / Nm @ rpm):		 264 / 355 @ 5200 (SAE certified) 369 / 500 @ 1900-5600 (SAE certified)

The 3.6L in the normally aspirated XTS is rated at 304 hp, so the new model adds 106 hp.  At 0.2 sec reduction for 10 hp that would be a 2 second reduction in 0-60 time — which might drive the 0-60 time down under 5 seconds.

Now, usually reduction don’t perfectly translate for large changes in horsepower.  Energy is lost to spinning tires etc.  But in this case we are looking at an AWD model only, so traction should be assured.

Let’s think of this another way:  the CTS VSport will have 420 hp and 430 ft-lb of torque (the XTS variant loses a lot of torque to protect the AWD drivetrain).  Cadillac said the CTS VSport will do 0-60 in around 4.6 seconds.  With 10 hp less, and perhaps 500 lbs more weight, we might expect the XTS AWD TTV6 to be 0.7 sec slower, at 5.3 seconds?

A full size Cadillac XTS AWD TTV6 then might be expected to come in at 4.9-5.5 sec for a 0-60 mph metric.

That will certainly be surprising performance on the street for the big Cadillac.