Cold air box installed.

Texasroadrunner

Club Member
I was happy to get the air box parts in the mail a few months back. After some head scratching, I decided to replace the base with a 6mm thick aluminum plate. Lots of measurements and sketching later I was ready to do some metal cutting. I milled 3mm deep slots for the clips to catch. I found some D shaped 8mm wide sticky back foam insulation on a roll for the box to base plate sealing. I cut off about 10mm off the box lip for more clearance to the strut tower during installation. Searched for 3" tubes, connectors and clamps from Summit Racing. Cut the 45- and 90-degree tubes for correct fit. I found that a little WD40 was perfect for sliding the tubes into the silicon adaptors while making adjustments. Without it they stuck together and refused to move. Later it dries and parts don't slip when clamped. I cut my own Weber to base plate gaskets from cork/rubber sheet. I used a previous filter base plate for a template. Fitting a K&N filter in front was difficult, and I am still looking for the best 3" x 90-degree tight radius tube to allow a bigger filter someday. Just like when I put on AC in November last year when I wouldn't need it. It's December and cold but I'm ready for hot Texas summers now. Thanks to Jon Bils for the air box. It will make for good power on hot days.
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richiep

Club Member
looks great, I would lose those nyloc's though for something better that's not effected by heat , don't want one of those down your carb..
I used nylocs on mine - but what I did was put a blob of JB Weld on each one as security. They won't be coming undone anytime soon!
 

Texasroadrunner

Club Member
looks great, I would lose those nyloc's though for something better that's not effected by heat , don't want one of those down your carb..
I did cinch them up really tight, but I also don't want a bent valve or cracked head/piston. Maybe additional nuts with some Loctite applied would help. I used stainless steel screws and lock washers to mount the plate to the carbs. Thanks.
 

Texasroadrunner

Club Member
Two weeks ago, I finally found a20230118_124536.jpg20230118_124546 - Copy.jpg20230117_151439.jpg 3" silicone elbow with a tight enough bend to fit a larger K&N filter. It squeezes between the Hood torsion bars and the AC condenser, just right. I fabricated a mounting bracket that attaches to the core support. Luckily, red caliper paint matches my car's paint perfectly, so the bracket got a coat. Went out for a test lap and AFR's are reading lean. Ordered richer Weber main jets and air corrector jets so the mains come in earlier. Another test lap and power is now far better and plugs look light tan. Summer heat will probably change things but Webers are easy to rejet. Ready for the first major car show at our local Airport in late February.
 

Texasroadrunner

Club Member
Final Jetting notes for anyone running Weber 40 DCOE side drafts. With the new cold air intake and still fairly cool weather, I was continually having the dreaded Weber mid range bog. I had decreased the Air Corrector jets down to 160 from 205 and that did bring in the main jets earlier but not soon enough. After a close look at my plugs, I decided to richen up the Idle jets 2 steps. Presto, the bog was decreasing. So, I knew I was on to something. I got bold and put in 55F9 idles (3 steps richer) and lo and behold, success. The stinking bog is gone. The AFR's read around 13:1 during cruising and 11:1 at WOT on E10 93 octane. What a difference. I'm now able to step on the throttle quickly or slowly and the bog is not there. After many sprints to redline through the gears, I'm very happy with my new powerband and will be taking her out for more back road fun tomorrow. Monthly car club meeting Saturday and I'm secretary so I'll be there in the red Z.
 

Ian Patmore

Well-Known Forum User
The Weber "mid range bog" is usually caused by a velocity drop inside the carb throat, and changing to a different design of venturi sorts it. And then a leaning of the idle and main jets to run smoothly.
 

Texasroadrunner

Club Member
The Weber "mid range bog" is usually caused by a velocity drop inside the carb throat, and changing to a different design of venturi sorts it. And then a leaning of the idle and main jets to run smoothly.
Ian, I'm running 30mm chokes which are about right for the smallish L24. The change in the idle jets give me tan plugs and nice throttle response. I now can smoke the tires in first gear when I punch it, which was never possible before. Great fun and the improved throttle response in every gear makes it feel like a larger engine. When I had the bog, the AFR gauge would rise to 18:1 or leaner. That is gone now, and I'm glad.
 
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