Hi all,
...1978 FJ40 2F...84,000 miles
Just installed Downey ceramic tri-Y header, and 2 1/4" exhaust with Magnaflow muffler (the Downey FJ40 "package"). In doing the install, I removed the air pump, rail, and associated plumbing, and the EGR system, plugging the appropriate holes and vacuum lines. I retained all other smog components.
Install went fine and there is a definite "set of the pants" improvement in acceleration and overall throttle response. The truck runs great, very smooth.
Took the truck to the local exhaust/muffler shop to install the exhaust hangers and to fabricate a custom tailpipe section, due to an aftermarket aux fuel tank. About a 20 minute ride to the shop, and when the guys went under to finish up the install, they commented that the exhaust system was unusually hot, even the tailpipe was almost too hot to touch...the muffler was REALLY hot.
They suggested timing and/or mixture issues...??
Drove it back home and sure enough the tailpipe is VERY hot to the touch. Under the hood, the header and surrounding area do not seem any hotter than with the stock exhaust manifold. The intake manifold was only slightly warm. The tailpipe is just a little "sooty"...not black like its running too rich, or white as if too lean...
BTW, I dont currently have a timing light, I have always done it by ear. The only adjustment I have made to the mixture screw at the base of the carb is to smooth out the idle. Its probably about 3 1/2 turns out (just a guess).
Any ideas are much appreciated. I guess I expect the exhaust system to be a little hotter with the header and free-flow system....? But I do think its a liitle excessive...
Thanks, Rob
...1978 FJ40 2F...84,000 miles
Just installed Downey ceramic tri-Y header, and 2 1/4" exhaust with Magnaflow muffler (the Downey FJ40 "package"). In doing the install, I removed the air pump, rail, and associated plumbing, and the EGR system, plugging the appropriate holes and vacuum lines. I retained all other smog components.
Install went fine and there is a definite "set of the pants" improvement in acceleration and overall throttle response. The truck runs great, very smooth.
Took the truck to the local exhaust/muffler shop to install the exhaust hangers and to fabricate a custom tailpipe section, due to an aftermarket aux fuel tank. About a 20 minute ride to the shop, and when the guys went under to finish up the install, they commented that the exhaust system was unusually hot, even the tailpipe was almost too hot to touch...the muffler was REALLY hot.
They suggested timing and/or mixture issues...??
Drove it back home and sure enough the tailpipe is VERY hot to the touch. Under the hood, the header and surrounding area do not seem any hotter than with the stock exhaust manifold. The intake manifold was only slightly warm. The tailpipe is just a little "sooty"...not black like its running too rich, or white as if too lean...
BTW, I dont currently have a timing light, I have always done it by ear. The only adjustment I have made to the mixture screw at the base of the carb is to smooth out the idle. Its probably about 3 1/2 turns out (just a guess).
Any ideas are much appreciated. I guess I expect the exhaust system to be a little hotter with the header and free-flow system....? But I do think its a liitle excessive...
Thanks, Rob
Last edited: