My 85 4WD DL wagon with a 5 spd and Hitachi carb has seemed slugish for the last year or so. Not really a big worry since it's mostly a snow car, so I don't need it to run all that great. But tonight I was passing a couple of cars on a two lane coming home from work, and had it wide open in second for a pretty good way. The speedometer is off from the big tires, and it doesn't have a tach, so I can't really say how red-lined it was - but it was screaming pretty good before I heard if over the new stereo and shifted. The next 1/2 mile or so it was acting like it was starved for gas as the cars I just passed started to catch back up. Then presto, its starts running better than it has for the last year. It even made it up a hill in 5th gear

 

So whats the deal? I remember this urban myth about blowing the carbon off valves by running wide open, but never believed it. Did I force something out of the fuel line, or unbind something in the tranny, or what?

 

- James B

Actually you probably just cleaned the crap out your exhaust system.

 

It builds up a lot of crap as a city car, so when you hit a really high rpm, boom (well, its silent) you shoot a black charcoal, sooty blob out your tailpipe onto the car behind you.

 

I did that on the front of a brand new white Lexus SUV which was on my tale when I got stuck behind some heap on the expressway and wanted to pass him quickly.

Quite a satisfying expierence, but I would not do it often.

 

The reason it feels like it is running better is that you had been building up backpressure due to the crap in the exhaust, and now that the crap is no longer there, our engine can run easier.

 

And no, you did not remove any carbon from your valves. MMO and Techron can do that. (Techron for intake, MMO for exhaust)

all cars need to be ran hard once in a while

it just goes to show that suby motors love to be thrashed. I follow that philosophy pretty strictly if you know what I mean

have had a few cars like that, you just gota beat the crap outta them every once in a while so it can clear its throat. my old 82 soob was like that if i babyed it it started to run like crap , but when i redlined doing a race or soemthing it would start running great

Ok, this is a bit of literary personification here; but I think my car was indeed thanking me for driving it hard. I'll have to remember that it likes that. I even left my comparitavely new truck sitting in the driveway this morning to drive the Subaru to work . . . on dry pavement.

 

- James B