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Which cold air system are you using for your LS3 swap?
Engine SwapEverything about swapping an engine into your Third Gen.....be it V6, V8, LTX/LSX, crate engine, etc. Pictures, questions, answers, and work logs.
Re: Which cold air system are you using for your LS3 swap?
Driver side or passenger side? How much power?
LS1 GTO kits actually fits pretty well on driver side. You pretty much have to make your own on passenger side. And you have to make your own either side if you want something sizable.
Filter will almost always end up in engine bay. The few people that do route tubes thru battery in an attempt to get "ram air" end up with more losses from tube snaking all over the place than if they just left it in the engine bay. Firebirdo88 ran somewhere around low 10's or high 9's and he made the best times with filter open to engine bay. Went slower boxing it off from engine bay. Went slower under battery tray.
Camaro (with more hood clearance than Firebird) offers an opportunity to maybe go over the top of the radiator but that gets tricky since you need really good transitions when drastically changing shapes like that (round, to wide and thin, back to round), and that kind of thing is a bit hard to figure out without air flow simulations. Stock molded tube just isn't going to feed an LS3.
Re: Which cold air system are you using for your LS3 swap?
Not a LS or a 3rd gen here (Gen1 383 with ~420-430 hp in a 2nd gen), but I have a 4" tube going to the passenger side where the battery used to be. Filter on the underside, in front of the passenger side tire. MAT sensor mounted in the snout of the conical filter.
At WOT, MAP sensor is reading 98-99 kPa. So that tells me I don't have a restriction there. But the beauty of getting the filter completely out of the engine compartment is my air temps are equal to ambient temp with any amount of vehicle speed. In stop and go traffic, it may get up to 10-15 over ambient. But as soon as I get moving again, air temps immediately drop back down to ambient.
Re: Which cold air system are you using for your LS3 swap?
Yes, my intake air temp gets pretty high at idle on a hot day with air filter above battery tray in engine bay. Drops immediately once rolling (outside air comes in from the fender). Ceramic coating the headers helps a lot (and I do mean a lot) with under hood temps (my headers are bare stainless and let go of a lot of heat).
Re: Which cold air system are you using for your LS3 swap?
As far as "ram air" goes for a 3rd gen, you're better off funneling air towards the filter than trying to put the filter in front of radiator with miles of tube behind it. Long intake tract = loss of throttle response. Once air enters the tube it becomes part of an enclosed system and the engine has to move all the air to use it.
Re: Which cold air system are you using for your LS3 swap?
Originally Posted by QwkTrip
Ceramic coating the headers helps a lot (and I do mean a lot) with under hood temps (my headers are bare stainless and let go of a lot of heat).
Passenger side battery tray. Aluminum box, open to the outside behind the fender. The headers are ceramic coated as well as the inside of the filter box and I am considering ceramic coating the 4” aluminum intake tube. As QwkTrip mentioned above, ceramic coating does an amazing job of mitigating heat in the engine bay from the headers and also can be used as a heat barrier. In this case keeping the heat inside the header tubes, but also keeping the inlet air cool in the inlet tract.
Re: Which cold air system are you using for your LS3 swap?
My intake is long, and goes through the driver side area where the stock EVAP used to be. The filter is right in front of the front tire area but does not hang below the bumper. I'm using a smaller filter and it is choking the motor at higher RPM's (pulled 93kpa). Im going to change the filter size and re dyno. You might be ok if your LS3 is stockish. I would at a minimum use 4" tubing.
Last edited by ShiftyCapone; 06-19-2022 at 08:50 PM.
Re: Which cold air system are you using for your LS3 swap?
Originally Posted by QwkTrip
Driver side or passenger side? How much power?
LS1 GTO kits actually fits pretty well on driver side. You pretty much have to make your own on passenger side. And you have to make your own either side if you want something sizable.
Filter will almost always end up in engine bay. The few people that do route tubes thru battery in an attempt to get "ram air" end up with more losses from tube snaking all over the place than if they just left it in the engine bay. Firebirdo88 ran somewhere around low 10's or high 9's and he made the best times with filter open to engine bay. Went slower boxing it off from engine bay. Went slower under battery tray.
Camaro (with more hood clearance than Firebird) offers an opportunity to maybe go over the top of the radiator but that gets tricky since you need really good transitions when drastically changing shapes like that (round, to wide and thin, back to round), and that kind of thing is a bit hard to figure out without air flow simulations. Stock molded tube just isn't going to feed an LS3.
I love hearing about the filter being better exposed in the engine bay. Back when I had my 01' Z28, I was the only guy with the K&N system that was a large filter exposed in the engine bay. The other guys were always trying to get me to switch over to the system that had a drop in filter in the stock box.
My LS3 is projected to dyno 560-570hp
103mm throttlebody
Re: Which cold air system are you using for your LS3 swap?
I had to place my filter out of the engine bay because I shaved the engine bay and little air gets in there, except through the headlights. Had it not been this way, I would have placed it in the engine bay.
Re: Which cold air system are you using for your LS3 swap?
Originally Posted by blackgloves
Back when I had my 01' Z28, I was the only guy with the K&N system that was a large filter exposed in the engine bay. The other guys were always trying to get me to switch over to the system that had a drop in filter in the stock box.
With a 4th gen I'd rather use stock routing with a good air lid because you get the cooler ram air. But 3rd gen doesn't have as good provisions for that so you just got to experiment with what really works with your combo. Don't be surprised if you end up reworking it after getting some data.
If you do an air box then make it as freaking big as you can, lot of people make it too small. Also, the practical flow of an air filter is kind of finicky about the geometry. Filters that have straight line of sight to the tube tend to work better. Like a 10 in long conical would work better than a 10 inch long cylindrical because the taper gives more line of sight into the tube. A flat panel works great but it's kind of hard to find enough real estate with our battery trays.
I've had this crazy idea for the last year of tilting the radiator and putting a C6 Z06 Halltech intake system over the top of radiator. But I don't have the skills and I don't want to lose my hood latch. But it would work awesome!
Re: Which cold air system are you using for your LS3 swap?
Well, I now have functional hood louvers, and plan on going with the Starbuck vented turn signals. I should be good with cool air flowing in. Thanks for the info and pics. I'm gonna build something
06-19-2022, 12:24 AM
