Our final buttoning-up surprise came in the form of an intake manifold and carburetor problem. We couldn't get the fuel system to lean down at high speed. With the rules calling for a Holley two-barrel carburetor, we tried both a 500-cfm and a 350-cfm. This 350-cfm is a large carb for the small 1,500cc engine, but now it works with what we have. The problem was with the stock Honda manifold design. See the sidebar for the problem, the experimentation, and finally the fix.
This shot of the right-rear...
This shot of the right-rear suspension also shows a muffler shop spacer, but of a different length than the left-front. This is the way crossweight is adjusted. Look closely and you can see where the upper suspension link was cut, shortened 11/48 inch, and re-welded. This adjusted the camber at the rear.
Holding the driver in place is a complement of M&R belts, head nets, and a window net to boot. If the head nets seem superfluous with a window net, consider this. In a left-side impact, the seat holds your torso in place. How far does your head stretch your neck before the window net stops it? It might be too far. How about a right-side impact? In a frontal impact, my G-Force helmet with the G-Force neck restraint system keeps me from sticking my neck out too far.
Honda fever has caught up with us. The car is finished and waiting on racetrack availability. In my yard, I can only go about 100 feet on the gas. I got a little wide going down hill around the tree, and I got closer to the lake than I intended, but the front-wheel drive pulled me through.
I would do a few things differently if I were to build this car again. Knowing now how light the car is, I would have made it much stronger. Larger cage tubing (it is built to East Bay's rules) as well as more bracing would have been used throughout the car.
This has been a fun project. All of us have learned a lot. Now we are going to the next phase, which is putting our thoughts, activities, and theories to the test on the track. We will be back with progress reports of our learning curve.
As always, your thoughts, suggestions, and questions about our projects are welcome. Contact me at: firstname.lastname@example.org.
This shows the springs used...
This shows the springs used at each corner, the weights on each wheel, and percentages of left, front, and crossweights. This is the way the car is set up for its first testing.
Rich/Lean: The Manifold Story
You would think a large carburetor installed on a small engine would hardly be able to generate enough vacuum to pull fuel through the jets. Such was not the case here. The rules call for a Holley two-barrel carb, so I first tried a 500-cfm and then a 350-cfm. The problem was that the vacuum signal from the engine was so strong that at about 3,500 rpm, fuel would begin pouring out of the accelerator pump squirter. The signal was pulling fuel all the way from the pump. Additionally, the 65 jets in the carb may as well have been garden hoses. All this was with the 350-cfm carb I ran on my 383-cid IMCA Stock Car.
I spoke with Mark Campbell at Crane Cams, who said there might be reversion problems and that I might want to try the 500-cfm carb. Matt Held of Holley thought an anti-pullover squirter might do the trick. After trying these suggestions-with little change-I sent a new Stock Holley 350 two-barrel carb to Bob Oliver at Competition Carburetion. We spent quite some time discussing the situation. Bob went through the carb, modifying it for better response. He also had some suggestions on jetting and pump squirter type and size.
Still, there were only small improvements to the situation. The engine would foul a set of plugs to where the engine wouldn't crank in about four minutes of running in the shop. At this point, I tracked down induction guru Jim McFarland for his take. He said he had seen this before. When he and Smokey Yunick were developing a long runner, cross-ram manifold for a Chevy V-8, they encountered "standoff."
Jim explained that the carb does not know which way the air is going, only that it goes. His thought was the long runners on the stock manifold coupled with a small plenum might be the problem. He suggested I build a box under the carb to enlarge the plenum area.