Spectre Performance makes the most attractive cold air intake systems available! I reached out to Spectre Performance and was lucky enough to speak with Guy Smith. Guy has designed over 230 intakes in 2014 alone. He knew exactly what I needed to make a custom cold air intake for Project: Hot Rod Regal and overcome the obstacles without ever seeing the project. Follow along as I work with Spectre Performance to create a very cool way to get cold air into the LS engine of the Hot Rod Regal. First, take the time to watch this awesome research video!
When performing an LS engine swap into an older vehicle, many systems need to be re-designed or re-engineered. One such system is the air intake for the fuel injected manifold. A couple of design considerations I encountered when creating my cold air intake system were:
- Clearance of the intake tube and its path
- Placement of the filter element
- Source of air – outside or inside the engine bay
- Placement of I.A.T. sensor
- Horsepower output -necessary to calculate intake and filter size
- What parts I will need.
These considerations would all need to work together to obtain an efficient and attractive air intake system. So where do I start? Well, I started with the filter element size and where I wanted to place the filter element, because that ultimately will determine the other variables. First, I thought about simply placing an air filter directly in front of the throttle body. This is a very economical solution, but I knew that I would be getting engine bay air (hot air), and I really wanted a different appearance. Next I considered running an intake tube path from the throttle body, turning 90 degrees straight down, and picking up ram air from between the Grand National air dams. This was a bad idea for a couple reasons:
- Intake air close to road (10 inches or less) is very hot
- Potential for sucking in a large quantity of water from the road is greater
- Dirty – keeping the filter element clean will be a real pain
- The intake tube that turns 90 degrees down will need to be an oval shape or a small diameter due to clearance restraints – not going to work for me
- Intake tube directly behind several heat exchangers and in front of engine may heat up the air charge or sensor.
When I called up Spectre Performance and spoke with Guy Smith, I explained the clearance issues and how I wanted the filter element to be outside the engine bay. Guy requested a couple measurements and then we went over the options. Ultimately, I chose to go through the inner fender. The following photo shows the parts Guy Smith at Spectre Performance suggested.
I used the following parts, which can be viewed on the Spectre Performance website if you click the links. The list is also the suggested order of installation, but I changed some stuff up (keep reading to see what I changed and why).
- 97711-4″ Coupler
- 9704-4″ Clamps
- 97991-90 Degree tube w/16″ leg
- 9707-4″ Stainless steel collar clamp
- 97990-90 Degree tube w/6″ leg
- 9775-4″ Flex coupler
- Custom made close out plate – 1/8″ aluminum
- 91489-4″ Aluminum Mounting plate
- 9799-90 Degree tube w/4″ leg
- HPR9617K-4″ Opening Air Filter-6.75″ Tall Black
- Russel 670760 3/8” NPT Bung-for M.A.T. sensor (not shown)
- I.A.T. sensor from O’reily’s BWD part#WT382
- 1/4″-20 x 1″ stainless steel screw – 4ea
- 1/4″-20 lock nut – 4ea
- 1/4″ stainless steel flat washers – 8ea
- 1/4″ nylon spacer washers – 4ea
The 4″ dia. tubes are sent with extra length and will need to be trimmed to fit your specific application. (extra is good!) Keep in mind, this installation is how I accomplished building a cold air intake system and there are many more combinations to make this work for you. It’s best to make the call to Spectre Performance (909-673-9800) to get the perfect parts for your project.
I started with modifying the G-body inner fender.
I had previously modified the Buick Regal inner fenders but left the battery tray area untouched. I knew back then I would be installing a close-out plate over this area because it is simply not pleasing to the eye.
Another cool feature about the Regal inner fenders are the built in, forward splash guards – these will keep the filter element clean from tire/road grime.
To fabricate a close-out plate, I created a mat board template of the area seen in the last photo and then transferred the design to a sheet of 1/8th inch aluminum and cut it out. It took several trimmings to get it to fit just right, but take your time here, you want it to fit perfectly. I used a ban saw for the large cuts, and strangely enough, used a sawzall for the subsequent trimming. Finishing up with a file. I think a jigsaw would work equally as well for this operation though.
Once the plate was constructed, I had to measure my clearances to know where to start trimming the Spectre Performance parts. I started measuring at the throttle body. Seen in the next photo, first installing the connector boot and then measuring the space I had to work within. As stated eariler, I changed the order of the parts installed. I chose to use the flex coupler 9775 with the included 5/8″ clamps here on the throttle body because I could. The outside diameter of the throttle body was 3.95″. The flex coupler 9775 is designed to use on 4″ diameter tubes. This is important to know the diameter of your throttle body because you do not want air leaking around the flex coupler. Again this is only my choice to use the 9775 flex coupler here vs. the 97711 coupler.
I made a cut that was 2.85″ from the edge of the 97991 90 degree elbow so it would fit into the connecting boot and have enough room to fit between the fan and engine accessories. Your measurements will most likely be different and I only offer mine as a general reference here. It is always a good practice to make small cuts and increase as necessary. The next photo shows how tight of an area we are working with.
Before any other cuts are made, it is best to loosely mock up the entire assembly at this point. This will give you a general idea of where they will need to be cut and ultimately, where they will be permanently installed. All parts need to be located so they will not interfere with structure.
The HPR9617K filter element/9799 elbow assembly on the bottom of the close-out plate must align with the 97990 90 degree elbow on the top of the close-out plate. In the next photo, I marked where the 91489 4″ mount plate would need to be placed for the filter element/elbow assembly to fit. Notice there is not much room under here. Again, you will want to make certain your parts align with no contact points before you cut anything!
The 2nd cut to the 97991 90 degree elbow will be made to the end of the 16″ long leg (2.4″ removed). This will properly locate the 97990 90 degree 6″ elbow on the close-out plate (inboard/outboard placement) so it aligns with the 91489 4″ mounting plate.
The 3rd cut is to the 97990 90 degree 6″ elbow. This cut (2.1″ from the bottom edge) is made to level out the complete upper assembly (seen in the next photo). Note: the 91489-4″ mount plate will be butted up to the 97990- 90 degree elbow at the close-out plate. I used the 97711-4″ rubber coupler for spacing before making the 3rd cut (also seen in the next photo). Next is the photo worth the 1000 words I just wrote…
The next piece to this puzzle is to mark and cut the hole in the aluminum close-out plate. Again, it is best to make certain your measurements and marks are correct. As seen in then next few photos, I am glad I double checked – one of my marks was off!
This is why you pay attention in class in high school!!! Geometry time!
Power tools and the right tool for the job. 4″ hole saw made quick work of the soft aluminum. (wish I had a drill press though)
The next few steps, I had to get help from my friend Fish at Fish’s Chassisworks. He is able to create some of the best looking welds I have seen on just about anything. (see Flowmaster Exhaust). The 91489-4″ mounting plate needed to be welded to the 9799 90 degree elbow. Welding these parts together ensures the elbow and filter to never depart the vehicle due to vibration. The 91489-4″mounting plate will be bolted to the close-out plate. The next photo shows the before weld placement.
After Fish welded the parts.
The next part to be welded by Fish was the I.A.T. sensor bung (Russel part# 670760). I chose to put the sensor in the horizontal position (much like OEM). The I.A.T. sensor is for the Holley Dominator computer sys. The sensor was picked up from the local parts store (part # BWD WT382). I found terminology differences when searching for the I.A.T. sensor part. It can be refered to as a M.A.T. sensor also (as in the case for the Holley Dominator).
The last step was to assemble and install for a final fit check.
I was able to install the close-out plate and 4″mount plate/elbow as a single piece (filter element removed). Once in place, the rest of the cold air intake was assembled. In the next photo, it is easy to see the natural cold air intake box under the inner fender and how smoothly it will flow. Guy Smith at Spectre Performance stated this area would be the best option for my project to pick up cold air. He was 100% correct! This area is the farthest removed from any heat source and makes use of unused space. Probably the coolest thing about this area and the intake design is the science behind it! (science is cool!) As explained in the first video, the air under the car is a high pressure air mass. This area is one of the best places to take advantage of that high pressure, cold air mass. Lastly, as was demonstrated in the video by owner Amir and the Bonneville Salt racer, these filters work!
Spectre Performance cold air intake parts allow you to create a custom cold air intake that is performance based and aesthetically superior!
I really enjoyed working with Spectre Performance to build this intake system! It was easy, and very rewarding. Those are words rarely in the same sentence when building something custom. It is also comforting to know the Spectre Performance parts are high performance parts that are proven. Their intakes and filters have been 400 mph and have kept out salt on their salt flat racer. This kind reliability and quality is something I look for in aftermarket parts. Hopefully you can use some of these ideas from this build on your hot rod project to build your cold air intake system!
Keep Checking back for the conclusion to the NitroPlate coated, Flowmaster exhaust systems on both the Hot Rod Regal and the LSX El Camino. We will add that last bit of bling to the exhaust systems, add a fun toy, and let you hear what a completely ceramic coated 3″ stainless steel exhaust will sound like!
Thanks for keep’n up with HotRodRegal.com
-Matt