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05 CTS V
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Discussion Starter #1
the picture says it all.

Step 1: check out other thread on removal of plastic on inner fender well and front rubber snout removal.

Step 2: cut. I used a jig saw.

Step 3: Install K&N panel filter. purchased online from K&N 44.00

Step 4: button it up.

this mod works!!! If you don't notice a difference, I am just seat of the pants happy.

I did my StageUp tune and with my 160 stat, car is running very strong. as soon as i get my new mounts from 2003rc51, I will be at the strip.


[/IMG]
 

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'05 CTS-V, '00 SLS, 98 SLS, 89 Eldo, '80 Eldo
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Add a free flow intake tube, and it'll be as good as any CAI. If not better.
 

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04 CTS-V
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935 Posts
Add a free flow intake tube, and it'll be as good as any CAI. If not better.
the tube is the real restriction in our air flow
 

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I did a cold air intake using my left front brake cooling duct, which I converted to a CAI. I used simple, cheap 3" metal duct work from Home Depot to route the air from brake duct opening to bottom of inner fender at the air box location. I did not measure before air temps. But with a scan gauge and the car's outside air temp I note a consistent 11 degree differential (rise) from ambient air to intake air at steady state cruise.
 

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'06 Z06, '05 CTS-V 453rwhp/434rwtq (sold)
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I will be cutting a hole below my K&N air filter down into the bumper as soon as I get the time.
 

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Cadillac
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I did the same thing in my pullied 99 Riviera. It seemed to help and no problems yet at 135,000 miles. Getting ready to sell it,,,,,,
 

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2011 CTS-V Coupe
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1,635 Posts
Didn't someone perform the same concept by drilling a bunch of holes in the bottom of the air box a while back?
 

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2006 CTS-V
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1,415 Posts

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Cadillac CTS-V
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389 Posts
Is there a higher-rez picture somewhere?
This looks to me like it's just opening the air filter box up to hot engine compartment air, mixing with the cold air coming in from where the snout used to be. Wouldn't it be better to keep it sealed and increase the size of the snout or add to the front of the snout so it funnels more air down into the airbox?

I've played with DIY ram-air on every car I've ever owned (except this one - so far), and saw big gains on my C5 - to the tune of aroudn 2mph in the quarter. But in every case I was trying to come at the problem from the perspective of sealing the air away from the engine compartment air and cramming (and keeping) as much cold outside air in the system as possible. The ram air on my old '85GT actually produced measurable positive pressure on the highway - a buddy of mine had a super-sensitive pressure gauge for duct work, and I could see what effectively amounted to a half pound of "boost" at the carberator with that setup. Of course I also sucked in bugs, dirt, and anything else on the road since my intakes were in the high pressure area right below the air dam.

On the V I thought of extending the front snout out right to the metal mesh of the grill, but it's not clear to me that's as much of a high pressure area as, say, under the front bumper where the brake ducts are... But still, generally speaking having your CAI opening in a high pressure area packs your airbox with enough cool air that you shouldn't need additional holes in the airbox. Sure if might be better to increase the open surface area of the airbox if you see a measurable vacuum in the airbox under WOT but has anyone tested that on the V?

If you were to plumb in pneumatic lines at the airbox, in the tube, and in the throttle body, and attach those to a very sensitive vacuum gauge, you could tell where the greatest restriction is - I just can't see the biggest restriction being the snout feeding the airbox... Seems to me you could leave the lid off the air box and take the filter out and the squashed tube would still be the biggest restriction... Or like someone else said, the throttle body. Basically if the upstream air is enough to feed the biggest restriction *downstream*, then you won't see a significant increase in airflow by increasing the flow upstream of the restriction.
 

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2006 CTS-V
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The primary air flow restriction on the LS2 is the intake manifold.
Awww that is disapointing news..... those LSXR intakes by FAST are expensive.
 

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05 Raven V
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the picture says it all.

Step 1: check out other thread on removal of plastic on inner fender well and front rubber snout removal.

Step 2: cut. I used a jig saw.

Step 3: Install K&N panel filter. purchased online from K&N 44.00

Step 4: button it up.

this mod works!!! If you don't notice a difference, I am just seat of the pants happy.

I did my StageUp tune and with my 160 stat, car is running very strong. as soon as i get my new mounts from 2003rc51, I will be at the strip.


[/IMG]

Awesome work sir, glad to see someone else sawzalled the airbox. Go get some hose clamps, a 90 degree 4 inch tube, a straight section of 4inch pvc and some spray paint. Instant FFV. ;)
 

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2005 CTS-V
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8,363 Posts
Awww that is disapointing news..... those LSXR intakes by FAST are expensive.
There is some good info posted by Rey in the following thread:
http://www.cadillacforums.com/forums/cadillac-cts-v-series-forum-2004/168816-quick-mod-question.html

Since then, I have found that TPIS will modify an LS6 manifold to accept a 90mm (like LS2) throttle body for $350. If you can pick up an LS6 intake from someone who went the F.A.S.T. route you would be in business for less money.
 

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05 CTS V
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Discussion Starter #15 (Edited)
thanks VooDoo. I might be doing that this weekend!!

I still think more air to the box, whether coming from the front (snoutless, you can see right into the airbox) or the inside fender well (less 20% of the box) is better than what was from the factory. Air is moving through that box and doesn't just keep getting hotter. IMO, not much different than the LPE or K&N CAI and way less.

Everyone will always have their opinion on this and in my case, I believe it works. Maybe not by itself, but with my tune, the 160 stat, cutting off the coolant to the throttle body and the K&N all seem to be working well together. My car is running strong, even with outside temps in the 105 range.

As soon as I get my motor mounts, I will be at the strip getting times.
 

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2006 CTS-V
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The primary air flow restriction on the LS2 is the intake manifold.
Darkman. The link you provided was a good read, and educational to see what LS6 owners can do to get the 90MM TB.... but that thread did not point out that the flow restriction for a LS2 is the intake manifold. It did prove that the LS6 intake was better designed than the LS2 with the same 90MM TB on a LS6... but it didn't say that the LS2 was the squeeze factor when it comes to airflow.


 

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2005 CTS-V
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8,363 Posts
Darkman. The link you provided was a good read, and educational to see what LS6 owners can do to get the 90MM TB.... but that thread did not point out that the flow restriction for a LS2 is the intake manifold. It did prove that the LS6 intake was better designed than the LS2 with the same 90MM TB on a LS6... but it didn't say that the LS2 was the squeeze factor when it comes to airflow.
Naming the LS2 intake as the bottleneck is my own conclusion.

This conclusion is based, in part, on the fact that; (a) motors are virtual air pumps; (b) these two air pumps produce about the same horsepower and therefore about the same air flow rate (total throughput/ per minute); (c) these two air pumps have functionally equivalent air intakes upstream of the throttle body; (d) these two air pumps have functionally equivalent exhaust systems.

Thus, the major difference in air flow seems to be in the area of intake+throttle body. The LS6 is known to be good intake and the LS2 intake is known to be inferior. Then you have the throttle bodies - 78 vs. 90 mm.

I think the engineers, faced with the task of making the LS2 equal to the LS6 either (1) gave it large throttle body - the result of which is an intake/throttle body combination that is roughly equivalent to the LS6 intake with its smaller throttle body; or (2) used the inferior LS2 intake to restrict the LS2 with its larger throttle body to LS6 power levels, depending how you look at it.

My real point in this thread has been than unless and until you improve the intake/throttle body throughput on either of these two motors your efforts on the upstream intake will not translate in to meaningful gain. This is because I am convinced that these air intakes provide all the air flow required to produce 400+ HP at the crank.

I became even more convinced of this at the dyno day in Dallas as I watched a number of cars with modified CAIs post numbers not statistically different than those of us that had pure stock air intake systems. In fact, my LS6 was the highest LS6 without headers, and the best stock LS2 also had a stock intake. Those with modified CAIs included many with tunes.

Having said all that, I do like the howl that an modified CAI can give you.
 

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2006 CTS-V
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Ahhh now I see where you are coming from.... you know what would seal the deal? a dyno w/ the LS2 w/o the squeeze tube... just a 90 degree bend. If your assumptions are correct... they will lay down the same amount of power (give or take a little for heat soak and such) that would leave only the TB and intake runners....!!

where is dynojet man when you need him? :) He could do this over his lunch break w/ someone who brought in a stock V.... In fact I should search.. I'm suprised someone hasn't done this already.
 

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2005 CTS-V
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Ahhh now I see where you are coming from.... you know what would seal the deal? a dyno w/ the LS2 w/o the squeeze tube... just a 90 degree bend. If your assumptions are correct... they will lay down the same amount of power (give or take a little for heat soak and such) that would leave only the TB and intake runners....!!

where is dynojet man when you need him? :) He could do this over his lunch break w/ someone who brought in a stock V.... In fact I should search.. I'm suprised someone hasn't done this already.
Such a dyno test would need to be controlled somewhat. Specifically, we know that if you dyno a car with stock air intake and then take off the intake, remove the filter, or otherwise open it up you can get an instant increase HP. This happens because the opened up intake leans out the air fuel ratio and gives more HP. The problem is that HP comes under a lean condition that is not sustainable because it would eventually damage the motor. The computer soon eliminates this lean condition and the new found HP evaporates. Thus, the controlled test would necessarily either restore the original AF ratio or allow the ECM some relearn time.

We could also prove my conclusion either right or wrong by measuring the air flow in units such as CFM for the the various components. If I am correct the CFM rating of the stock intake already exceeds the CFM required at the input of the throttle body at WOT/redline rpm.
 

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2016 ATS-V (Blk, 6spd, Recaros), 2007 Cadillac CTS-V (sold)
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