Gunson Gastester - any good?

[Last S4]

I want to check the mixture of my engine and have seen the Gunson Gastester on the bay for around £75.
Has anyone used one and are they any good? Dont want to waste money if its useless. I had a Colortune years ago and that was a real waste of space.
Cheers, Steve.

[sparkypete]

I have one, I find it very useful and easy to use.

Pete

[Loubaruch]

Last S4 said:

I want to check the mixture of my engine and have seen the Gunson Gastester on the bay for around £75.
Has anyone used one and are they any good? Dont want to waste money if its useless. I had a Colortune years ago and that was a real waste of space.
Cheers, Steve.

If your S4 is fitted with a Catalytic convertor and has to meet low emission limits the Gunson will not be much use.

The Gunson does not measure CO content directly and is useless for modern cars as the CO limit is far below the Gunsons accuracy. I have found it OK for older cars such as my 1600M without cats that have fairly high emissions but for the S3 and Griffith a waste of time. MOT stations have to update their gas measuring equipment regularily to meet ever stricter requirements so there are usually many for sale on Ebay. Be warned though and try before you buy as if they are faulty the repairs are both specialist ad expensive.

Edited by Loubaruch on Wednesday 20th May 19:38

[Last S4]

Loubaruch said:

Last S4 said:

If your S4 is fitted with a Catalytic convertor and has to meet low emission limits the Gunson will not be much use.

The Gunson does not measure CO content directly and is useless for modern cars as the CO limit is far below the Gunsons accuracy. I have found it OK for older cars such as my 1600M without cats that have fairly high emissions but for the S3 and Griffith a waste of time. MOT stations have to update their gas measuring equipment regularily to meet ever stricter requirements so there are usually many for sale on Ebay. Be warned though and try before you buy as if they are faulty the repairs are both specialist ad expensive.

Thanks for the info, I have removed the cats from my S4c - the mot is not due until next year. The specs on the tester say its accurate to 0.5% and I wondered whether it is any good for setting up the mixture for the smooth running of the engine? What do you think? I will worry about the mot when its due.
I have seen the full gas analysers you mentioned on the bay but thought the same, what if they are broken?

[sparkypete]

I use mine on the V8s with no problems at all, when MOT time comes, the emission results from the garage are pretty much what the Gunson displays.

Cant speak for CAT cars as mine is pre cat.

Pete

[Loubaruch]

for the info, I have removed the cats from my S4c - the mot is not due until next year. The specs on the tester say its accurate to 0.5% and I wondered whether it is any good for setting up the mixture for the smooth running of the engine? What do you think? I will worry about the mot when its due.
I have seen the full gas analysers you mentioned on the bay but thought the same, what if they are broken?
[/quote]

Yes if you dont need to adhere to the Cat level of emissions it should be fine for tuning the mixture. As Sparkypete is happy on his V8 I am sure it would be OK for a non-cat V6.

Edited by Loubaruch on Thursday 21st May 23:14

[Barkychoc]

The problem may be with 'Last S4' that as his car is a 1995 I think it will have to be cat compliant - you could try and find a sympathetic garage and get away with it