LS3 is installed in the TR8. Just about finished adapting a Corvette LS7 K&N fresh air filter setup down in front of the radiator. Had to cut out the front cross tube behind the bumper and relocate it slightly and also need to make a new lower radiator support to drop the rad another 1/2". The stock LS3 92mm intake points straight ahead. The end of the plastic fresh air snorkel points upward about 20* or so. Need to install some kind of coupler between them, so I've been looking at those turbo silicone hoses. They pretty much come in 4" and thats about as close as I can get. What happens if one of these hoses fits loosely. Is there enough play in them that the hose clamp will take up the slack? If its loose, can I wrap a piece of rubber around the throttle body and then clamp the hose on? I know thats acceptable in the plumbing world on drainage pipes. I set the fresh air up this way because the Fitech ultimate LS intake points downward at an angle and when and if I swap intakes, they should point straight at each other. The Fitech has a 102mm throttle body, so I may have to revisit this again. Need to button up all the fab work and make mounts for the snorkel so that this thing can go off to paint. So, how much play is there in these fancy hoses??? Will they stretch a tiny bit as well?
They give some. I used one in the Esprit (RIP) for the turbo to the intake manifold, and there was a slight misalignment it managed without issue. I think I bought it and the clamps from siliconehose.com, if they advertised in The Mag.
I use the 4” ones on ls throttle bodies and they clamp on just fine.
They generally can squoosh down a bit (you could probably put a 4" coupler on a 3.5" pipe if the coupler had a little length to it, if you really had to) but they don't stretch well. Sometimes they can be a bear to just get over a rolled/raised lip on a tube even with generous amounts of silicone spray.
Where's the MAF in all of this? They can be rather sensitive to the plumbing geometry before and after the sensor. If it is fairly stock-like, then it shouldn't be too bad, but I've seen some awkward installs that ended up with bizarre looking MAF transfer tables.
Just a quick thread jack to ask how long of a run can you make before you're worried about a silicone intake collapsing under engine vacuum?
In reply to mazdeuce - Seth :
That depends heavily on the coupler. Some of the cheaper ones are about as substantial as inner tubes. The beefier ones are a bit tougher than coolant hoses but not by much. (Coolant hoses are usually burst rated to 125-250psi)
Given that coolant hoses suck shut at about 15" of mercury I'd say they probably won't like it.
Be sure to use the correct hose clamps because the regular gear clamps will slice right through the silicon. And silicon does not like to be squeezed to much. They are actually kind of fragile. But you can buy rubber inserts to take up the extra room. One of the radiator hose manufacturers makes them.
There is about a 4" gap between the throttle body and where the plastic for the fresh air duct starts. The MAF sensor goes into a slit in the plastic a few inches later. After the MAF the plastic starts to flatten out and curves downward. Original application was for a 7.0L Corvette. Certainly a lot less complicated than the fresh air intake that came on the donor Camaro. I used a sheet of aluminum road sign to make a partition. Any air coming in under the bumper gets directed to the radiator. Anything else ends up where the huge K&N filter sits.
Is the throttle plate 92mm or the lip OD? I'm running a 92mm LS style throttle body. The inlet OD is just the right size for 4" silicone hose. 92mm + 2x(wall thickness) =~102mm or 4". The filter side is upstream of the throttle so no worries on collapsing.
I'll second bearmtnmartin on using the right hose clamps.
"Liner hose clamp" are the type that has an extra solid strip to shield the worm drive perforations. I also like the "european" clamps with rolled edges and indents for the worm drive.
mazdeuce - Seth said:
Just a quick thread jack to ask how long of a run can you make before you're worried about a silicone intake collapsing under engine vacuum?
The intake on the MS3 is about 2 feet long, has multiple bends, and necks down into the turbo (3" ID to 2.65" ID.) It's supposedly a 5 layer wire reinforced silicone construction. It has a bit of give in it for positioning but I've never had a problem with it collapsing.
tr8todd: You want T-Bolt clamps to secure the ends (like so). The reinforced hoses don't like to stretch length wise. They'll open up a tiny bit but they're pretty rigid. They do have more lateral play than metal or plastic will give you however.
RXBeetle said:
Is the throttle plate 92mm or the lip OD? I'm running a 92mm LS style throttle body. The inlet OD is just the right size for 4" silicone hose. 92mm + 2x(wall thickness) =~102mm or 4". The filter side is upstream of the throttle so no worries on collapsing.
^This. I'm 90% sure pretty much all LS throttle bodies, factory or aftermarket take a 4" coupler. My stock LS1 throttle body took had a 4" to 4" 90* elbow and it fit just fine.
