Ls1 lid conversion with fitment issue: Wich rubber coupling do i use ?
For anyone else thinking of doing this, avoid Lowe's American Valve brand plastic coupler - it will warp after a day, put a damper on the air flow and its a little pricier than the Fernco:
American Valve Brand:
American Valve Brand:
Fernco:
Fernco:
Fernco:
American Valve Brand:
American Valve Brand:
Fernco:
Fernco:
Fernco:
Last edited by marc1130; Jul 10, 2011 at 01:44 PM.
This is the one I used. Figured I would get something that is actually made to fit instead of some ugly sewer connector.
http://intakehoses.com/Merchant2/mer...gory_Code=RHH8
http://intakehoses.com/Merchant2/mer...gory_Code=RHH8
I've noticed on other peoples setups that used the complete lower airbox that the lid sat much higher. Mine lines up very well, but I just used the upper rad support piece. I used a 1/2 fernco from maf to tb, then flexible part of my old rubber intake from lid to maf. I think it looks very clean and factory. Link below.
i used the smooth air bellow that came with the LS1 lid. It worked ok, not entirely happy with how it connects but it works. If it was 1in longer and had a little more of an angle it would be perfect.
I had the same issues with it being at a different height then the throttle body.
I had the same issues with it being at a different height then the throttle body.
On The Tree
Joined: Mar 2010
Posts: 107
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Good thread. I’ve been wondering how I’m going to address this problem when I do my lid swap. My engine already sits lower than normal thanks to my BMR k-member, so I know its going to be a challenge to link up the MAF between the lid and TB… and I won’t be carving up the lid base/rad support b/c it can clear my ram air hood.
A 45 degree silicon pipe or this other one someone posted http://intakehoses.com/Merchant2/mer...gory_Code=RHH8 looks pretty smart. As for coupler widths, aren’t we all running 3.5” MAF regardless of year? Until now I understood we needed (and as far as I know I’m currently using) a 3.5” to 4” coupler to connect the MAF to TB. Guy’s are using a 3” to 3” to do this??
A 45 degree silicon pipe or this other one someone posted http://intakehoses.com/Merchant2/mer...gory_Code=RHH8 looks pretty smart. As for coupler widths, aren’t we all running 3.5” MAF regardless of year? Until now I understood we needed (and as far as I know I’m currently using) a 3.5” to 4” coupler to connect the MAF to TB. Guy’s are using a 3” to 3” to do this??
Part of the misunderstanding here is due to the fact that the Fernco 3" coupler that sooooooooo .......... many people are using is NOT really 3 inches in inside diameter!
Please reference my post in this thread: http://www.camaroz28.com/forums/showthread.php?t=645462
to see the actual dimensions of the "3 inch" Fernco.
I like this piece you are using
http://www.fquick.com/garages/viewga...wimg&id=311346
is that a 3.5" to 4" fernco reducer?
http://www.fquick.com/garages/viewga...wimg&id=311346
is that a 3.5" to 4" fernco reducer?
On The Tree
Joined: Mar 2010
Posts: 107
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INteresting... so what would the inside diameter of a 4" to 3" fernco coupler be on the 4" side? This is the closest/quickest thing I've found and something I can buy locally:
http://www.homedepot.ca/product/4-in...oupling/977091
As long as the 3" side will fit over the MAF that's great. And if the 4" side is actually larger then it will fit over the TB no problem but hopefully it won't be too wide (although the clamps would tighten it either way).
I still like that reducer with the bulge in the middle ( http://intakehoses.com/Merchant2/mer...gory_Code=RHH8 ). This one looks ideal for those of us who need to bend the coupler to correct the downward angle from the lid.
http://www.homedepot.ca/product/4-in...oupling/977091
As long as the 3" side will fit over the MAF that's great. And if the 4" side is actually larger then it will fit over the TB no problem but hopefully it won't be too wide (although the clamps would tighten it either way).
I still like that reducer with the bulge in the middle ( http://intakehoses.com/Merchant2/mer...gory_Code=RHH8 ). This one looks ideal for those of us who need to bend the coupler to correct the downward angle from the lid.
As for that being TOO wide, remember the 3.5" inside diameter 3" Fernco coupler and be "forced" over the OVAL throttle body quite nicely, a 4.5" inside diameter round rubber coupler end would be significanly larger than the LT1 throttle body "oval".
They designed ls1 lids to accept an lt1 maf? That's surprising....I tried to connect my slp lid to my lt1 maf and they wouldn't fit. I had to really force it in there, and it didn't want to stay there. I was afraid I would break the lid. I also trimmed the opening to correct the angle a bit. Before and after the trimming it didn't fit too well though. I thought the flexible bellow made a much better and cleaner connection.
On The Tree
Joined: Mar 2010
Posts: 107
Likes: 0
On The Tree
Joined: Mar 2010
Posts: 107
Likes: 0
They designed ls1 lids to accept an lt1 maf? That's surprising....I tried to connect my slp lid to my lt1 maf and they wouldn't fit. I had to really force it in there, and it didn't want to stay there. I was afraid I would break the lid. I also trimmed the opening to correct the angle a bit. Before and after the trimming it didn't fit too well though. I thought the flexible bellow made a much better and cleaner connection.
^^^Mine didn't? 
I bought it new for a 99 ls1 from slp about 2 years ago. maybe they changed something cause mine would not fit easily at all. Then it was much worse fit after I cut the opening to correct the angle. That's when I decided to use my rubber bellow connector.
I bought it new for a 99 ls1 from slp about 2 years ago. maybe they changed something cause mine would not fit easily at all. Then it was much worse fit after I cut the opening to correct the angle. That's when I decided to use my rubber bellow connector. 
They designed ls1 lids to accept an lt1 maf? That's surprising....I tried to connect my slp lid to my lt1 maf and they wouldn't fit. I had to really force it in there, and it didn't want to stay there. I was afraid I would break the lid. I also trimmed the opening to correct the angle a bit. Before and after the trimming it didn't fit too well though. I thought the flexible bellow made a much better and cleaner connection.
Those of us LT1 guys who do the proper LS1 lid conversion (not cutting out the base) end up having the open end of the lid sitting much higher than the level of the TB. So some guys need to use flexible coupler from the lid to the MAF and a second one to the TB in order to form a bent pathway. The trick is forming a pathway that's seamless and without any major kinks or folds in the coupler.
Last edited by speed_demon24; Jul 11, 2011 at 06:00 PM.
TECH Apprentice
Joined: Sep 2014
Posts: 321
Likes: 88
From: Fort Wayne, IN
http://www.intakehoses.com/mm5/merch...duct_Code=4H35
[QUOTE=CamOnlyJabroni;18991848]95 percent positive it is this one. I used the link on LS1tech while it still worked a year ago and am pretty sure it is the 4 to 3.5".
http://www.intakehoses.com/mm5/merch...duct_Code=4H35[/QUOTE
You sir are the man! Thanks!
http://www.intakehoses.com/mm5/merch...duct_Code=4H35[/QUOTE
You sir are the man! Thanks!
