Redex - Experience of its use on older cars

Page may contain affiliate links. Please see terms for details.
A statement like MPG improves by up to 10% has to be a joke and for me immediately labels the stuff as snake oil.

The important part is up to. I've never seen or come across a 10% improvement but have seen an improvement in throttle response and more importantly an emissions pass where a vehicle has failed prior to treating the fuel system. Now, by definition if emissions are improved so has the MPG.
 
Last edited:
Are these fuel additives mostly kerosene?
For diesels maybe, but not petrol engines. - Kerosene is essentially a clean, narrow-cut fraction of diesel anyway.

For petrol engines is probably something like xylene mixed with acetone. - The acetone is dipolar and aprotic, so it's good at dissolving water-soluble muck without hydrolysing. It's as good at stripping the varnish off the fuel system as it is at taking it off fingernails.
 
"Up to" is used in a few things.

Technically, up to 100% is accurate.

Bit like broadband. "Up to 24Mbps" except no one would ever have got that.
 
The msds give most of the game away... http://www.partinfo.co.uk/files/RDX10 Redex Injector MSDS.pdf I know some people swear by it but seems fairly pointless to me

Here's one for cataclean http://weblink.carquest.com/msds/CCN/CCN 120007.pdf less intermediate/heavy distillates (naphtha, kerosene and other cuts from refining crude etc) and more 'other stuff' that are very good solvents, probably raise cat temps a chunk to help it burn off crud (if it's too far gone for an Italian tune up to fix things) and also commonly used as octane boosters... xylene was one of the common ingredients in the toluene based 'rocket fuel' from the origional F1 turbo days I believe
 
The msds give most of the game away... http://www.partinfo.co.uk/files/RDX10%20Redex%20Injector%20MSDS.pdf I know some people swear by it but seems fairly pointless to me

Here's one for cataclean http://weblink.carquest.com/msds/CCN/CCN%20120007.pdf less intermediate/heavy distillates (naphtha, kerosene and other cuts from refining crude etc) and more 'other stuff' that are very good solvents, probably raise cat temps a chunk to help it burn off crud (if it's too far gone for an Italian tune up to fix things) and also commonly used as octane boosters... xylene was one of the common ingredients in the toluene based 'rocket fuel' from the origional F1 turbo days I believe

The argument against Cataclean was that the active ingredients can not survive the burn cycle and therefore it won't have any cleaning effect on the catalytic converter. So any improvement is in fact achieved by cleaning of the intake system rather than the exhaust system - i.e. no different to other (cheaper) fuel additives.

Not sure why you say that the list of active ingredients in Redex 'seems fairly pointless'?
 
None of the ingredients in any of these things are gonna survive combustion. I'd have guessed that something like cataclean might raise exhaust gas temps which in turn would raise the cat temp and maybe help a gunged up cat 'light off' and come back to life. Never used it and probably never will, only mentioned it as it's quite different to something like redex

The redex seems fairly pointless to me as it's mostly naphtha with tiny amounts of active ingredients some of which are probably either already in petrol or do much the same thing.
Granted the ancient injectors in my 215k + mile car might be cleaner if something like redex was regularly used but personally i'd rather take them out and have them put through ANSU cleaning if and when i suspect there's a problem. Doesn't cost much, flow rate and pattern is checked and new filter baskets and seals are fitted. Each to their own
 
I'd be wary of using additives on an older car if they had never been used before.

Say your engine is a bit dirty, could it be possible that a sudden introduction of detergent could dislodge some particles which then go on to clog injectors etc?

Only time I have used Reddex in diesels I've had problems with injectors afterwards.

I stay away these days.
 
Only problem I had with redex was the silver thing inside the cap fall into my tank.

2 grand later .....
 
[YOUTUBE]03nL8Z0dRkI[/YOUTIBE]
 
The incremental improvements were surely within the variability you get from a dyno so there is scope to generate a good story, but as they did multiple runs I can buy it. At least they weren't talking about nonsense increases like 10 % just from the fuel treatment.
 
I used redex and noticed that the exhaust pops and bangs alot more on overrun. No change in fuel economy. However the engine "felt" different (better), whether its placebo or otherwise I have no idea.
 
The incremental improvements were surely within the variability you get from a dyno so there is scope to generate a good story, but as they did multiple runs I can buy it. At least they weren't talking about nonsense increases like 10 % just from the fuel treatment.

1) They tested the car 8 times on each occasion and took the highest figure of each set of tests, so normal fluctuations does not seem to be a reasonable explanation in this case.

2) They do say that BHP increase through use of fuel detergents is only possible with very old/dirty engines - and they do point out that if the engine is not badly affected by gunk and/or carbon deposits in the first instance then the fuel additive will have little effect.

3) they do not claim any BHP improvement over manufacturer's figures, just restoring some of the power lost to gunk and carbon deposits.


In summary, this is one case involving just one car and one type of product (Redex), so you could well argue that this is not significant enough to imply that other cars or engine types will necessarily benefit from fuel additives in the same way.

But (unless they are outright lying) as far as this specific clip goes, I can't fault it. I really do think that on this occasion Redex did the trick.
 
Last edited:
Would've been interesting to see what sort of spread of data they got over the 8 runs for each change/bit of servicing... i'd have thought averaging them rather than taking the highest would be fairer/more accurate but obviously without knowing all the numbers dunno how that would've effected the results. Having just taken my daily cynical pill i'm thinking that if averaging the results from the rolling road (all of them, not just the redex) narrowed the gap between before & after it would ruin the impact of the piece... as said, a 'good story' is usually the top priority whether it's a newspaper or "factual" TV programme

Not fuel system cleaners and some of them did bump power & torque numbers a little but didn't improve economy if/when that was part of the marketing claim http://www.which.co.uk/documents/pdf/23-25_fuel20additives20r3-186207.pdf
 
Last edited:

Users who are viewing this thread

Back
Top Bottom