Terraclean on my 993
Since watching Ed China on Wheeler Stealers magically nurse the engine of an XK8 back to below the emissions limits I have wondered if it would have any effect on my 123k mls aircooled pride and joy. A bit of internet research had yielded conflicting opinions with some calling it a snake oil whilst other think it is a genuine breakthrough, but no one seemed to have actually tried it. I was finally prompted to give it a go when the readings on the MOT last month were noted to be quite high. I have a few days off work visiting family down in Hampshire so after supplying them with a post code the Terraclean website advised me of the nearest available garage with a unit, Collisons Motoring Services in Cowplain, and the cost is fixed at £99 all in.
In order to quantify if there was any improvement I asked Collisons if they would be able to provide before and after readings from the gas analyser. These guys were as intrigued as I was to see how it would work as they have only had the unit for a few weeks and only used it on diesels so far. To see if there was any discernible feeling of change from the drivers seat both immediately before and after the process I drove a favourite set route of mine through the Hampshire countryside containing lots of winding bends and requiring acceleration through 2nd, 3rd and 4th gears, with a return stretch on the motorway. Short of a rolling road this seemed to be the best evaluation I could perform.
The machine is connected to the fuel line just behind the pump, the supplied fitments were not a match for the old K-tronic lines so the technician had to fabricate an adaptor. The fuse for the fuel pump is removed and the return line is clamped off. Two canisters are then loaded; the first to run is labelled as "Fuel Injector Cleaner" and smells slightly sweet like gas. After ~15mins the second canister is run, labelled as "Fuel & Post Combustion Cleaner". During this time the accelerator pedal is set to run the engine at 3K rpm, but it was noticeable that as the procedure progressed the engine revs kept slowly rising.
Once all was completed and another gas analysis performed I was able to compare the results before/after:
%vol CO Corrected: 0.83 / 0.57 (lowest is best)
%vol CO2 : 14.4 / 15.0 (ideal is 15)
%vol O2 : 0.76 / 0.68 (lowest is best)
ppm vol HC : 0052 / 0034 (lowest is best)
Lambda : 1.009 / 1.013 (ideal is 1)
I am certainly no expert on what the limits for these engines should be, or even what lambda actually is, but it is clear that there is a genuine reduction across the range. On the test route afterwards I paid a lot of attention to how the engine felt and was performing. Even allowing for the placebo effect creeping in there was a noticeable improvement in the lower rev range, with a cleaner drive out of bends and subsequent acceleration up through the gears. Pulling away from a standing start also required a little less clutch slippage than normal.
So in conclusion; it is certainly not going add a major boost to your engine's performance but, in my experience, it will help it to run more smoothly and cleanly. Is it worth £99? That depends on whether you want your engine to be as close to 100% as possible and to last as long as possible, with all the self acknowledged OCD'ers on here that could be quite a few people indeed. And after all it is but chump change compared to, say, a carbon handbrake lever...
I would be interested to hear from anyone else who has tried it.
James.
