Cowl Intake Questions

Hello,

I have found a couple of great write-ups on the DIY Cowl Intake systems, have also seen the spectre stuff and think that is a great option. Wondering if anyone has any first hand experience on a couple of items:

1) There are a number of vacuum lines going to the stock box, OK to just RTV them shut and zip tie them off somewhere?

2) Line into exhaust manifold - There is a line that goes from the stock box to the exhaust manifold with some really cruddy looking flex tubing from the factory. Removing it leaves a completely open line into the exhaust it appears, what do people do with this?

I am following the write-up here: http://www.jeepforum.com/forum/f11/another-cowl-air-intake-write-up-741764/

Great write-up and part numbers and prices are still relevant on Summit, but doesn't address these items and hoping someone has some experience?

Thank you for your help!

What year?

Sorry, should have provided that background information.

1989
4.0 six
Auto trans, if that matters somewhere... ?
Green sticker - so no smog

Murphster05 said:

Hello,

I have found a couple of great write-ups on the DIY Cowl Intake systems, have also seen the spectre stuff and think that is a great option. Wondering if anyone has any first hand experience on a couple of items:
I am following the write-up here: http://www.jeepforum.com/forum/f11/another-cowl-air-intake-write-up-741764/!

Click to expand...

Expect a lot of noise from this. The filter is much smaller than stock

Another, easier way to get a cowl intake is to use this method.
https://www.flickr.com/photos/lwade/sets/72157622703531169/
It's quiet, except under full acceleration, doesn't let water in, provides much cooler intake air and has 5 years of daily use to confirm the design.

Thanks for the feedback Lazy, I am aware that it is going to be quite a bit louder, but this is a straight beater crawler without exhaust, etc. so it is already loud and obnoxious.

I have seen that mod, it is a nice looking alternate method, but I am also very excited to free up some room under the hood and get the engine bay cleaned up, on board air and a shower are in the near future so I am going to need all of the room I can get...

I've done it on my 99, just added a little tiny air filter to that breather hose and disconnected it from the air intake.

Honestly I may change mine back, kept my stock box in case. The noise is loud but it doesn't bother me that much. It's just that it is so much harder to change an air filter now. And I've never been anywhere that I needed to worry about water that high. I'll probably stick with it for now, because my wife and I have plans for a Motor swap and we'll change it then

Thanks! What did you do with the small vacuum lines? I go to Fordyce in Tahoe a fair amount so all 4 river crossings give me pause each time... This will be a very nice addition.

This is what I run. Small cone filter in wiper cowl.

I like this one: http://shop.trailheadoffroad.ihostnetworks.com/productinfo.aspx?productid=XJCI91-01

I'm going to go with it, here shortly after I smog the xj.

That is what I have. It's pretty straight forward and works well.
It was a bit noisy in the cabin. Even with loud exhaust and noisy tires it would drone up hills on the hiway. So much so that I was going to pull it. But I cut out the bottom corner of a 5gallon bucket and made a baffle for the back side of it. It sort of isolates it a bit for the cabin air intake port. That did the trick. Even at startup I can't even tell its in there.

Nice, I see that one takes into account the line coming off the top of the block, I was thinking about going with the THOR kit as it seems to be very well designed also. Appears that one is only for 91 forward, wonder why it won't apply to an 89? I have emailed them to ask.

Do you have pics of that Gordo? Does that end up collecting water directly under the filter? or is the "baffle" behind the filter?

interesting... i'd like to hear more about this, or see a pic?

GordoSmasho said:

That is what I have. It's pretty straight forward and works well.
It was a bit noisy in the cabin. Even with loud exhaust and noisy tires it would drone up hills on the hiway. So much so that I was going to pull it. But I cut out the bottom corner of a 5gallon bucket and made a baffle for the back side of it. It sort of isolates it a bit for the cabin air intake port. That did the trick. Even at startup I can't even tell its in there.

Click to expand...

Murphster05 said:

Nice, I see that one takes into account the line coming off the top of the block, I was thinking about going with the THOR kit as it seems to be very well designed also. Appears that one is only for 91 forward, wonder why it won't apply to an 89? I have emailed them to ask.

Click to expand...

I don't see any reason why it wouldn't work on pre 91' motors. I'll see if I can pull it apart tonight and snap some pics. It's hard to describe.

Thanks Gordo! I have emailed them and will get their thoughts on why they list it as 91+ only, maybe it has something to do with that exhaust line or the vacuum lines or something?

Did you do anything with the vacuum lines that were connected with the stock air intake box?

I did one of these pretty simply. I wasn't trying to free up any space in the engine compartment, so I modified the stock box.

First, I bought a second box, so I could run it as stock set up or cowl air depending on what I am doing - running around town or off roading.

I took the box to modify and cut a circular hole in the back side of the box, (the one facing the back of the engine bay) and fit an adapter on it. Then I drilled a hole in the cowl next to the master cylinder under the driver's side windshield. I fit a second adapter on the cowl wall.

Then I cut off the stock rectangular air intake on the front of the box and sealed it up with a piece of metal. Then I RTV'd around the metal plate, the adapter, and any holes in the box to make it water tight.

I connect the air box to the cowl with a run of flex tubing. This allows me to use the stock valve cover vent and stock flex tubing from the lid of the box to the throttle body.

All said, it cost me about $45 to do - $10 for a second box, $20 for the flex tube, $10 for two adapters, $5 for three hose clamps.

i'm betting that it's because it's designed to clamp around the tb like the stock HO intake tube does.
the renix years have a flat tb mounting surface-nothing to clamp to.
you can buy the adapter piece from spectre to correct that, that's what i plan to do(mine's an '88). it's the adapter they include with their renix intake kit.

Murphster05 said:

Thanks Gordo! I have emailed them and will get their thoughts on why they list it as 91+ only, maybe it has something to do with that exhaust line or the vacuum lines or something?

Did you do anything with the vacuum lines that were connected with the stock air intake box?

Click to expand...