Exhaust running "hot" after header install... (1 Viewer)

[roverpilot]

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

 

[roverpilot]

Make that "SEAT of the pants"..

 

[2badfjs]

for one thing the ceramic coated headers are keeping the heat in the pipes,its gonna be hotter down the line. .02

 

[camcruiser13]

my tailpipe is to hot to touch, i think all exhaust pipes get hot to the touch dont they? is hot a problem?

 

[RHINO]

like badfj said, ceramis coating will retain a fair amount of heat in the header and send it down the pipe, also since you de-smogged you dont have the EGR anymore, that brings exhaust temps up a bit, you could do the regular checks for timing and fuel mix, but if its running good,,,,,, my exhaust runs pretty warm too, in fact its warm enough to bend the leaf spring when i had the tip pointed at it for some stupid reason.

P.S. mixture screw at carb only adjusts idle and transition, just FYI.

 

[roverpilot]

Thanks guys,

Hot IS GOOD.

Pretty much what I was thinking..The exhaust shop guys got me a little concerned. It is runnig great, so I'm probably gonna see how it goes..

I figured the EGR missing would heat things up a bit, just wasnt sure what to expect.

Thanks again.

Rob

 

[hodag]

I know my Flowmasters are so hot that they'll sizzle my arm skin like bacon if I touch them after running for a while. Ive brushed my leg on my tailpipe and left a burn mark. I think your shop guys didnt want to work on a warm exhaust so they made some bitches up about it.

Hodag

 

[roverpilot]

hmmm.... could be. They did do a nice job though. When we drove it in the lot, one of the guys made a comment "thats all I need today, to work on a Toyota. I bet his manifold is leaking!" Well I did sympathize with him, and he was happy to learn that all he was gonna do was reroute the tailpipe!!

Rob

 

[brian]

probably not used to working on older stuff, just mufflers on newer cars. pretty sure that stuff runs alot cooler, what with ALL the smog and 'puter controlled crap.

 

[RHINO]

pretty sure that stuff runs alot cooler, what with ALL the smog and 'puter controlled crap.

puter controlled or not the cat needs to run pretty hot to work.

 

[roverpilot]

puter controlled or not the cat needs to run pretty hot to work.

"..but it aint got no cat, Lt Dan..." Never had it, never will!