Did 0-60 tests before & after seafoam w/ 200k I6 4.0

89 XJ with 4.0 Renix I6, about 200k miles. Unknown when last rebuilt, if ever. No unusual engine problems besides being gutless. Passed smog. Sometimes has lifter noise.

New 29" a/t tires, dry pavement, 5 gal gas in the tank, 150 lbs aftermarket equipment.

Bought 16 oz seafoam at autobone for $11.99

Drove jeep about 5 miles, got nice and warm to operating temp.

Did first two 0-60 runs back to back on flat street. (runs #1 and #2 in spreadsheet)

Then pulled over into a parking area.

Popped air intake hose off throttle body.

Poured about 6 oz seafoam into throttle body slowly, engine stalled on first pour. After that I went slower.

Turned engine off, or tried to. It dieseled for several seconds and wouldn't shut off. Then finally did. (this never happens, obviously its burning seafoam as fuel, not surprising)

Split remainder of seafoam into crankcase and fuel tank. So each got about 5 ounces I think.

Waited about 10 minutes.

Started it up. Exhaust started pumping out white stuff. Not tons and tons, but definitely a cloud.

Drove away. White cloud started disappearing almost immediately. 10 seconds later I dont think any more smoke was coming out.

Did some hard driving for about 5 minutes.

Then went back to same spot as run #1 and did two back to back 0-60 tests (runs #3 and #4). Then went to another nearby flat area and did the final 0-60 test (run #5).

Overall the jeep feels slightly peppier..but not sure if thats just placebo effect. The test results show a slight improvement but only barely. Might just be I got better at launching the Jeep.

At this time I would say the seafoam was probably a waste of time on this particular engine. Maybe I'll see more improvement as the seafoam in the oil and fuel gets through things.

But its nice to know that the 0-60 time is definitely 3 to 4 seconds slower than it should be. That gives me all the reason I need to rebuild the engine.

http://i.imgur.com/8bzwAxd.jpg

Really cool!

You'll need to run the engine for a longer time to allow the seafoam to clean out the fuel system and crankcase. You may even need to give it a second treatment.
I treat my fuel system with STP Fuel System Cleaner once/year to keep the lines, injectors, and intake valves clean. It's good preventive maintenance and helps with the gas mileage.