Why Didn't The TJ Get a Stock "Cold Air" Induction?
- Thread starter TJRick
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OP
The CJ-5/7/8's of the late 70's early 80's had cold air plumbed from the grille, there's a fitting for the air tube on the back of the grille. When I installed the CJ Grille Kit on my LJ a few years ago, since the air connection on the CJ grille was right in front of the TJ air box, I adapted the TJ air box to accept tubing to connect it to the port on the CJ grille...
I can't tell if there's any performance difference, although my Scangauge does show that in general the input air temp is a bit lower than it was before the conversion. Mostly I plumbed the air intake this way "because it was there" and not because I expected any performance enhancement
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I can't tell if there's any performance difference, although my Scangauge does show that in general the input air temp is a bit lower than it was before the conversion. Mostly I plumbed the air intake this way "because it was there" and not because I expected any performance enhancement
.Blaine did something similar recently, I don't remember the details.
https://wranglertjforum.com/threads/almost-a-cold-air-intake.35050/
https://wranglertjforum.com/threads/almost-a-cold-air-intake.35050/
Yeah, that was a side project I did when I was doing the cowl mold for the CJ Grille Kit. I made the Cool Cowl mold and made a few prototype parts for testing but never did anything further with it.
If you want to believe your TJ's 4.0L engine will benefit from a CAI, go right ahead and run one. This subject has been raised countless (!!!!) times over the past 20+ years and few think it does any good whatsoever.
Not to mention Jeeps are not high-rpms racing machines and very few are interested in such minor gains some think a CAI will get them. My current TJ bought used came with a CAI and it wasn't more than a few weeks before I got rid of it and installed a used factory intake system I obtained from mrblaine. Zero before/after difference discernable... not that I race my TJ at the quarter-mile dragstrip.
Not to mention Jeeps are not high-rpms racing machines and very few are interested in such minor gains some think a CAI will get them. My current TJ bought used came with a CAI and it wasn't more than a few weeks before I got rid of it and installed a used factory intake system I obtained from mrblaine. Zero before/after difference discernable... not that I race my TJ at the quarter-mile dragstrip.
OP
I am absolutely NOT talking about any of those so-called aftermarket "cold air intake kits" that replace your stock intake assembly and are nothing of the sort.
I am NOT talking about *any* system that uses any kind of oil-filled air filter.
I am asking about why the bottom of the stock air cleaner box has a horn attached to it that points UP and draws in hot, underhood air rather than a different attachment to the same STOCK air cleaner box that connects to the front of the grille that brings in cooler outside air.
If you want to worry about that horn sucking in the air from under the hood, that is your decision. You won't find many here who would worry about anything so insignificant. We're driving JEEPS, not performance race cars whose owners are often obsessed with such things.
From Jeep engineering its narrowed neck after the trumpet opening helps to both speed the flow of air into the intake for more complete combustion and to help make the intake quieter.
It probably comes down to a cost-benefit analysis. Ultimately, the point of the Jeep design isn't to maximize performance, it's to maximize the profit of the manufacturer that made it.
Would a cold air intake improve power? Possibly, maybe a few horsepower. Would that extra few horsepower increase sales? Probably not. People aren't significantly more likely to buy a 193 horsepower car over a 190 horsepower car. So it wasn't worth the cost to install.
Would a 4 link suspension perform better off-road than a 4-link with trackbar? Probably. But it would add complexity to an already new and largely untested system, and be significantly more expensive. Would it increase sales enough to justify the cost? Probably not. So 4 link with trackbar it is.
Would a Dana 44 axle be stronger than a Dana 35? Sure, but it's more expensive. But would it significantly increase sales? Certainly would. Customers wanting an off-road vehicle will likely recognize the importance of a modestly stronger axle. Since the Dana 44 offered a significant sales advantage, it was offered in many Jeeps.
Would a cold air intake improve power? Possibly, maybe a few horsepower. Would that extra few horsepower increase sales? Probably not. People aren't significantly more likely to buy a 193 horsepower car over a 190 horsepower car. So it wasn't worth the cost to install.
Would a 4 link suspension perform better off-road than a 4-link with trackbar? Probably. But it would add complexity to an already new and largely untested system, and be significantly more expensive. Would it increase sales enough to justify the cost? Probably not. So 4 link with trackbar it is.
Would a Dana 44 axle be stronger than a Dana 35? Sure, but it's more expensive. But would it significantly increase sales? Certainly would. Customers wanting an off-road vehicle will likely recognize the importance of a modestly stronger axle. Since the Dana 44 offered a significant sales advantage, it was offered in many Jeeps.
OP
Yes, and up until the TJ models, the older CJ and YJ Jeeps used cooler outside air to feed the engine.
All of the older trucks made from the Big Three from this same era used cooler outside air to feed the engine.
Hell, my wife's 2013 Jeep Patriot (2.4L) has a stock true cold air intake system. That is, cooler outside air is fed into the engine, not hot underhood air.
None of these are examples of "performance race cars."
But hey, sorry for asking a stupid question.
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The reason is probably a mix of cost and practicality. The difference would be minimal if the older "CAI Intake" existed at all on a TJ. In addition, the TJ design gets the intake horn further back and also higher, which is good for water crossings. Moving the intake back only adds functionality since a large number of water crossings have steep entrances. I would rather have the TJ style intake than the CJ style. I think it is an improvement.
Actually, they take hot air off the manifold full time in arctic conditions to keep the carb from icing up.
That sounds right to me - I figured it was some kind of mini velocity stack - but I didn't know about quieter. Thanx!
Like I said, after making a few prototypes for testing, I never did anything further with it. But recently I lent the molds to someone who is having a fiberglass shop make a few, if that goes well maybe more will be made.