Just got Darwin back from the shop last Friday. As great as it is to have my wagon back on the road, I'm now faced with a little mystery. While I was having the short in the turn signals fixed, I also had several changes made that I thought would improve efficiency. The Comp Cams 252H (206/206 [email protected]; .425/.425 lift; 110 sep) stick was replaced with a new Crower Level 1 (182/190 [email protected]; .386/.387 lift; 114 sep). The stock rocker arms were replaced with Comp Magnums with 1.52/1.60 ratios. A 195 deg thermostat was added and a distributor recurve kit was added. The problem is that my mileage seems to have dropped a bit. During some recent road tripping/testing I recorded 18.5mpg on a tank on a 170mi trip that was 98% highway. Last Summer's road trip ended up netting tankfuls in the 20-24mpg range. In other words, I did all this work to improve fuel economy only to see it drip. ](*,)
I'm now trying to figure out what's wrong. I've already noted that the tire pressure was a bit low (in the 28-32psi range), I have since brought the pressures back to 35psi. I have also removed the spoilerette that is under the radiator. The one on Dar takes a lot of abuse and is in danger of falling off. Those things may help, but I don't think they explain the difference.
I am wondering if it is possible that sitting in the shop has caused the gas in Dar's tank to decompose and possibly clog the fuel filter a bit or leave deposites on the carburetor. I am going to run the tank down to 1/4 or below to get rid of any bad gas and then change the fuel filter.
Other possibilities are that the recurve kit was installed in a way that reduced distributor advance and that the cam/rocker arm combination is making things worse.
Any thoughts or suggestions?
I'm now trying to figure out what's wrong. I've already noted that the tire pressure was a bit low (in the 28-32psi range), I have since brought the pressures back to 35psi. I have also removed the spoilerette that is under the radiator. The one on Dar takes a lot of abuse and is in danger of falling off. Those things may help, but I don't think they explain the difference.
I am wondering if it is possible that sitting in the shop has caused the gas in Dar's tank to decompose and possibly clog the fuel filter a bit or leave deposites on the carburetor. I am going to run the tank down to 1/4 or below to get rid of any bad gas and then change the fuel filter.
Other possibilities are that the recurve kit was installed in a way that reduced distributor advance and that the cam/rocker arm combination is making things worse.
Any thoughts or suggestions?