Cold Air Intake on TBI 350.

There is an episode of Enginemasters on Motortrend where they play with various air filters and configurations on a dyno. Granted, they were only testing single filter top mounted options on a carb, but the best possible config for HP on the dyno was an air filter that was breathing through the top, sides were closed, and sitting on top of a funnel. Makes sense that there is less turbulence straight down than from the sides and then 90 degrees down. In the end though, the aluminum tube cone filters are a gimmick. The good K&N does flow better than a stock paper element but it's breathing hot under hood air so the flow is negated. A good paper element in the factory housing with restrictions removed is the ideal situation.

Erin said:

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Erin said:

Can anyone tell me what goes where the can is taped? It was this way when I got the truck.

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First Guess: Totally wrong part--someone slapped in a silencer from some other vehicle.

Reminds me of the unit on my Trailblazer, with a spout to the side for a resonator.

https://www.summitracing.com/parts/...jtqSeUoiSziJjMp6pD-wBj6aonWGheKhoCwucQAvD_BwE

FYI - if anyone has an older style throttle body (mine was an '89 C2500 5.7L) with the old style TPS sensor, the Volant won't fit. I ended up using a TPS off an S-10 that sticks out at a 90, but then that hits the bracket for the EGR solenoid so then you'll need to sort that out.

I called Volant customer service, this was maybe two years ago, was told basically that I didn't know what I was talking about.

Gave them some pics and part numbers, then was told I was correct, and .... good luck, hopefully I could figure out a way to make it work. They said they were going to re-design it but that it takes a year at best before the re-design would be available.

On top of that, the tube is about a 1/4" too short so the air filter never clamped on properly and would keep falling off in the box.

I really want to like the Volant but I'm not there yet. It's been a PITA.

The air box on the Volant is nicer but I believe the Summit Racing brand CAI is the same as the K&N which sits up a little higher and you wouldn't have this issue.

The one nice thing that came of all that is that the S-10 TPS has the mounting holes elongated so you can set/adjust the TPS voltage.

Anyways, Just wanted to post that in case someone else runs into the same issue.

The 89' 5.7L TPS - Part# TH41


The S-10 TPS - Part# TH32

Schurkey said:

First Guess: Totally wrong part--someone slapped in a silencer from some other vehicle.

Reminds me of the unit on my Trailblazer, with a spout to the side for a resonator.

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Thanks for responding. I was thinking the same thing.

I have a Volant CAI on my 1998 K1500. It didn't change either the sound or the performance as I could tell. It does allow more air from the fender as evidenced by two hand rags that it sucked into the air box that had been in the fender for God knows how long (I inherited the truck from my mom two years ago and she from her husband, the original owner, in 2012). But the only "seat of the paints" difference that I felt was due to a thinner wallet. I have a throttle body spacer as well from Transdapt. No change at all. But in that last case I only purchased because I have a marine intake that I'll be putting in come warmer weather and I'll need the spacer for it. I never really expected it to do anything else GM would have done it themselves. But if you're looking for a new sound (which I wasn't) or some performance gain (which I was) then I would look beyond CAI kits or TB spacers. I would think a made to fit cat back system would change your sound and if you stay away from the Volant CAI you're half way there on cost. I'm skeptical it would improve performance any as a stand-alone upgrade though.

JeremyNH said:

I have a Volant CAI on my 1998 K1500. It didn't change either the sound or the performance as I could tell. It does allow more air from the fender as evidenced by two hand rags that it sucked into the air box that had been in the fender for God knows how long (I inherited the truck from my mom two years ago and she from her husband, the original owner, in 2012). But the only "seat of the paints" difference that I felt was due to a thinner wallet. I have a throttle body spacer as well from Transdapt. No change at all. But in that last case I only purchased because I have a marine intake that I'll be putting in come warmer weather and I'll need the spacer for it. I never really expected it to do anything else GM would have done it themselves. But if you're looking for a new sound (which I wasn't) or some performance gain (which I was) then I would look beyond CAI kits or TB spacers. I would think a made to fit cat back system would change your sound and if you stay away from the Volant CAI you're half way there on cost. I'm skeptical it would improve performance any as a stand-alone upgrade though.

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I have a Volant system that was on my brothers 99 Suburban and my 99 Tahoe. It improved power noticeably in back to back testing at the track. 2 tenths of a second ET reduction in the 1/8 mile. Yes I could feel the difference. 2 tenths is 2 car lengths in a typical 0-70 mph merge. Then again neither of those had the stock cam, exhaust or exhaust manifolds at that point either. Both had a slightly hotter cam, headers and a real exhaust system. Both also had ported lower intake manifolds.

Years ago I also did a 4" air intake modification on my 97 Express van using a 2001-2002 van air box. K&N drop-in intp the factory box and replaced the stock tubing, plastic 90° elbow and TB hat. Used a 4" dryer connection to the 454 TB with a silicone spacer to fill the gap between the throttle body lip and the 4" dryer connection then hooked 4" silicone piping to it. Since I tune with HP Tuners I also added a cartridge style 4" MAF. Woke it up noticeably.

I did not use a spacer for my marine intake as I did not have space for one. Just bent the cruise throttle linkage tab slightly to clear the fuel rail. Cruise still worked perfectly.

Some stock vs modified pics of the van intake setup I created. I have run that setup for 2 years now minus the 6 months I ran the thing with a dual plane MPI marine intake and 1,200 cfm throttle body. Had to go back to a stock intake manifold with EGR for emissions reasons.

L31MaxExpress said:

I did not use a spacer for my marine intake as I did not have space for one. Just bent the cruise throttle linkage tab slightly to clear the fuel rail. Cruise still worked perfectly.

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I had that problem with the spacer too. The Volant air neck is too tall so the TB with a spacer wouldn't clear the hood. But the air neck is made of PE so I got the idea to shape it the same way that PE pipe can be shaped. I filled it with sand then put 50# of lead weight from my rifle rest in a frying pan on the top for continuous pressure and used a pair of heat guns to soften the neck. The weight of the pan coupled with sand inside to keep it from deforming slowly, as in about an hour slowly, pancaked it the 1" the spacer added so now mine is now marginally wider and shorter so fits. So I'm glad I tested it before the intake swap so it will be one less thing. I asked Volant if I could buy a neck from them so I wasn't experimenting on the only one I had but they said they only sell whole kits so no. But what I ended up with looks like it was made that way.

But with regards to the rest and returning to the op topic. A CAI may, emphasis may, add performance in combination with other upgrades which seems to be your case. But it is doubtful as a stand-alone upgrade to do anything significant which was my case. I still like it because the intake tubing is much shorter than stock which means resident time of cold air in the hot engine compartment should also be shorter. The filter is likely superior to stock as well. So my feeling is that it is an improvement but not one that will noticeably affect performance. But the op was interested in sound and it didn't change anything on my stock set-up. Nor did the spacer.

PlayingWithTBI said:

Maybe, it still runs lower ETs in the cooler temps. I'm thinking about installing a IAT sensor so it'll adjust timing automatically. My EBL is capable of doing it. But when it's 110* ambient, a CAI is pretty superfluous.

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I put an IAT on mine. With an open element air filter, it reads about 50C (122F) once the engine is warm, regardless of the outside temperature as long as I'm moving. If I'm stopped in traffic, it quickly goes up toward 80-90C (176-194F). That 110F air might not be as bad as you think.

Schurkey said:

I want to see REAL dyno testing of ANY of those aftermarket intake systems. This includes PART-THROTTLE driveability, not just full-throttle, mid-to-high RPM power. Removing the constriction in the OEM silencer (or using a non-restricted silencer) may work OK. Scrapping the whole works for an aftermarket, poorly-engineered mess is just crazy.

As a rule, the stupid "hats" on the throttle body/carb are an aerodynamic disaster. They tend to have directional flow, where the OEM air cleaner has wonderfully diffused flow. They "could" be designed for diffused flow, but generally they aren't because the folks making them are too dumb to understand what they're doing wrong.

And "cleanable" (i.e., oiled-gauze "K&N style") filters are typically cleaned too often. If they don't have a HEAVY accumulation of crud on the outside, leave them the hell alone. They filter better when they've got dirt build-up on them. The dirt becomes part of the filter media, when you remove it the filter is less effective.

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Not to argue "Shurkey" , I agree about the dyno testing of all the CAI systems. I was merely making a statement towards the cooler air from the fully-enclosed CAI vs. the open element into the engine bay. We all know, making horsepower requires the correct parts in the correct configuration. The hotter the IAC, the less dense, therefore, the less potential HP. The cooler (denser) the IAC, the more HP potential. That's all I was saying. The only real HP gains (in real life without other mods and a good tune) is the wallet HP gain where you spent the $$$$ so it has to be better, right?!? . All I was saying was coupled with the aluminum heat sink tubing and an open element air filter into the engine bay, it's going to heat that air far more than the fully-enclosed system pulling from the fender well.