So last week I purchased a VCM OTR intake, for the VF, from a company here in the states. I like how it can almost pass for a factory option and it definitely feels like the car picked up some power from 4500 to 6500 rpm range. What do yall think?
OTR Intake Installed
DangChung
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It sounds great, especially under wot. It does drone around 1800 to 2200 rpm range but nothing that radio volume won't solve.
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Any chance on getting a sound vid? Perhaps idle, revs, and a little accel run?
Maybe. I've been real busy at work.
I bought it from improved racing.
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The link is in the first post of this thread.
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Optimum placement of MAF sensor
The OP and I had a short discussion about this when I visited with him in Savannah (GA) last month, as he was showing me his OTR intake setup.
I don't know where it's written, but here's something that makes the implication that GM has some numbers they consider of significance when designing an intake:
(from Chevy Performance Parts Catalog)
Air Inlet Kit for LS-Based Crate
Engine Installation
19301246 NEW
Designed for universal LS and LSX EFI crate engine installations, this
kit contains intake tubes with provisions for the mass airflow meter and
vacuum line, along with a reusable, high-performance air filter and mounting hardware. When joined, the kit’s straight and elbow tubes provide the optimal distance between the throttle opening and mass airflow meter, including the minimum length of straight tubing required for accurate mass airflow meter operation – saving the time and guesswork involved with fabricating a similar system. The intake tubes are polished and the kit also includes couplers, worm-style clamps and a vacuum hose. The mass airflow meter provision accepts all GM production meters, which must be purchased separately.
The OP and I had a short discussion about this when I visited with him in Savannah (GA) last month, as he was showing me his OTR intake setup.
I don't know where it's written, but here's something that makes the implication that GM has some numbers they consider of significance when designing an intake:
(from Chevy Performance Parts Catalog)
Air Inlet Kit for LS-Based Crate
Engine Installation
19301246 NEW
Designed for universal LS and LSX EFI crate engine installations, this
kit contains intake tubes with provisions for the mass airflow meter and
vacuum line, along with a reusable, high-performance air filter and mounting hardware. When joined, the kit’s straight and elbow tubes provide the optimal distance between the throttle opening and mass airflow meter, including the minimum length of straight tubing required for accurate mass airflow meter operation – saving the time and guesswork involved with fabricating a similar system. The intake tubes are polished and the kit also includes couplers, worm-style clamps and a vacuum hose. The mass airflow meter provision accepts all GM production meters, which must be purchased separately.
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466 Posts
One could pair this with the AirAid CAI setup since it doesnt include the tubing, only the heat shield and filter. the two could make a CAI setup is someone didnt want to wait for the rotofab or doesnt like the VCM.
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862 Posts
guys, this is NOT how you fix this. This problem that the intake causes is real, and can cause damage. Doing this is just like throwing electrical tape over the check engine light, it doesn't actually fix anything.
These intakes have a major design flaw in them that we have been trying to educate people on since they came around for the G8. This design flaw allows unmetered air to enter the engine, causing it to actually run lean. The problem is on a GM is that as it learns it needs the extra fuel at lower throttle, and lower RPM it carries over those changes when you go WOT, which then is not needed. so basically, you have a lean condition at low speeds, and an overly rich condition at higher engine speeds.
To answer at least one question that I know will follow, they dont have this issue in aussie as they usually go "Mafless" or Speed Density for their tuning so its not an issue. It is a problem on a stock car, or how these cars will get tuned here. For this reason we do not use this intake without at least fixing this major oversight in it's design.
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Good information.
Does anyone know if this intake, with the flaw outlined above, is limited to the G8 or does it impact the SS as well?
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So how do you fix it?
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The fix is simple. There is a fresh air hose that runs to the front of the intake between the air filter and maf. This hose must be rerouted to in between the maf and throttle body. The issue here is there is almost zero room to do so with the way the intake is set up so you usually have to drill into the maf, which we do not recommend, but its the only way to fix it. Ideally, it would be to run a different style intake, as otr styles have never proven to have an advantage in any test we have ever conducted anyways. Dyno, street, or track the stock location style intakes like a rotofab have always proven the best on a g8. Of course we will be testing the ss but I see no reason to think it will be any different this time.
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Looking at the third picture in the first post, the design flaw exists for the ss as well.
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I never had a problem with my VCM on my G8 ... Dyno tuned with it installed @ Next Level Performance in Orlando// This is a very popular and by far the best intake in Australia, they are on nearly every Commodore I noticed when I was there.
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The problem is that they likely tuned around the vacuum leak. This might make it not set a light, but it's not the right way to fix it. Look at where the stock airbox gets it's fresh air for the PCV at, it's in between the MAF and throttle body. There is a reason for this.
Also, by what measure are you using to say it's the "best" best at what?
Again as I mentioned before, in Australia most cars are tuned via speed density, eliminating the MAF entirely, so this will not cause a problem, but going speed density requires continual changes in the calibration to keep it optimized.
To date no G8 with that has switched from an fenderwell style cai, to an OTR style cai and that was their only change ever went any quicker, or made more hp at the track all things being equal. Sure, there are guys who went slow in july who then switched intakes and ran in november and went quicker, but that's not a fair comparison. I am talking same day, same track changes.
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103 Posts
Most of the Commodore's I saw in Australia at the track running NO MAF had the Double filter Growler or the Orssom intake System installed the biggest percentage of street cars had a VCM ..check out any of the dyno pulls on face book from AUSTRALIA and you will see VCM is the intake of choice.
Any problems with a VCM should be directed to there web site for clarification...
Any problems with a VCM should be directed to there web site for clarification...
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