Borla Exhaust/Mileage decline!

[LoyToy]

Installed Borla header and cat back dual exhaust last week. First tank of gas got 17!!!! mile per gallon. With stock exhaust I was getting 27. I'm on my second tank now but just filled up yesterday. Does it take several tanks full to get the computer to react to the different configuration? The tail pipe is clean. No black soot.

Cruiser Boy, did you experience similar results? What about anyone else that has done this mod.

By the way I got rid of the check engine light by leaving the battery disconnected more than just a minute.

Wayne

[Cruizer Boy]

Mine has gone down, but I tink it is from the fun factor of it. Before I done my mods I was getting around 23 in the city. I haven't figured it since the mods, but I would guess around 20. I just can keep my foot out of the power band ya know.
later, Greg
PS I take it your light went out???

[LoyToy]

Greg, I believe the computer has caught up with the mods. My mileage appears to be back where it previously was.

I forgot to tell you that I put the exhaust manifold shields back over the header. That is - I attached the top metal shield to the bottom quilted shield and then reinstalled the bracket to the bottom of the combined pair and bolted to the block. I couldn't get the bottom metal shield in place with out another pair or two of hands. As it was my wife lent her capable small arms and hands to the project for over an hour.

However, I believe I have replaced most of the shield effectiveness. So it is possible with a little patience.

No rattles yet either. However I made sure when I was tightening the bracket that I had plenty of room between the shield and the header - maybe 3/4 inch. Shield seems to be plenty sturdy.

Wayne

Had my Borla duals for 3 months got a sweet sound and 30 mpg goint to the Niagara cruise

[Powertrip]

Instead of the shields you can use a cool itel called thermo-wrap from Thermotec. It looks almost like woven seatbelt material and is intended to be used for wrapping headers and exaust systems to keep in the heat. I have done my complete exaust from the manifold right to the rear axle... Keeps the heat in the exaust, thus increasing flow rate......

[turboholic]

Powertrip (29 Jun, 2001 10:07 p.m.):
Instead of the shields you can use a cool itel called thermo-wrap from Thermotec. It looks almost like woven seatbelt material and is intended to be used for wrapping headers and exaust systems to keep in the heat. I have done my complete exaust from the manifold right to the rear axle... Keeps the heat in the exaust, thus increasing flow rate......

Good stuff for RACE cars, not so good for street cars.

Header wrap does hold in the heat and improve exhaust gas flow in most cases, it also lowers under-hood temps. Unfortunately, it also holds in moisture and SEVERELY shortens the life of the exhaust system.

Just my $0.03. YMMV