Amazon: My Amazon on a rolling road

[Brian M]

Ever since I replaced the single Stromberg carb on my Amazon with a secondhand twin SU set up I have had mixture problems. It would start easily when I enriched the mixture but soot up the front two plugs in a month or so, or if I weakened it, it would run a lot better but become almost impossible to start.

I met a guy who had just started a rolling road tuning business and was keen to resurrect his long experience of tuning SU's on his new high tech set up.

As a birthday present my family gave me the cash to do it so last week I took the car to ATSPEED in Rayleigh Essex (01268 773377). I know lots of you may have already had your car on a rolling road but it was new to me and I found it a fascinating experience that I would like to share.

He started by welding a plug for a lambda sensor in my exhaust downpipe, and the car was then strapped down on his rolling road.

The first run showed it was running rich and recorded a maximum of 65hp at 4400 rpm, and would not rev much higher.

A check of the carbs followed and the ATF in the dashpots was replaced by 20/50 engine oil, and the mixture roughly set. The next run showed the mixture was nearer the optimum but still not quite right so the jets were adjusted while the car was running at about 60 mph (try doing that on the road!) until the optimum was reached.

A full power run now showed 78hp at 5000 rpm, but they thought there was a bit more to come so the needles were shaved a bit by hand and max power went up to 83hp at 5000rpm, but there was a slight flutter at cruising revs, so to make for the best driving experience a little more was shaved from the needles and this gave an extra 5bhp between 3000 and 4000 rpm.

To see (and hear) my car doing 100mph in an enclosed space is exciting and this video gives an idea of the experience.

http://rides.webshots.com/video/3045...58258802VJqrgw

Original specs say my car should have 115 bhp at the flywheel, and losses to the rear wheels should equal 15-20% plus 10bhp, so mine should have 82-87hp at the back wheels. To hit this figure on a 38 year old engine is a credit to the longevity of Volvo engineering.

The car is transformed, from a lumpy idle, occasional misfiring, and no real top end power, to a crisp engine that pulls like a train.

All in all one of the best birthday presents I could have hoped for.

[JIM C]

Interesting. I enjoyed the video clip.
Thanks
Jim

[loon]

cheers Brian
how much interest did he show when you turned up
'cos im looking to do mine i went to redline in basvagas (basildon) essex but the guy i spoke to seemed to be a bit offish so i never went back.

LN

[Brian M]

Loon

The boss was very enthusiastic to work on the Amazon and to show his two young mechanics that cars do not require electronics to be able to run!

Incidentally, on my return from the Ace Cafe today, I topped up and found I got 33mpg for quite a spirited 150 mile trip. at that rate I only need to do 3000 miles to get the costs of the session back.

[222s]

Good to see you yesterday

Originally Posted by Brian M

Incidentally, on my return from the Ace Cafe today, I topped up and found I got 33mpg for quite a spirited 150 mile trip. at that rate I only need to do 3000 miles to get the costs of the session back.

What's your engine spec? Wondering whether mine could do with being set up like that to improve the fuel economy.

[Moosejaw]

Great stuff! I'd like to get mine done like that, but I'd probably be best to get the carbs rebuilt first. Maybe next year.
Love the colour of your car BTW, is it a regular manufacturer's colour or is it a custom mix? Looks a wee bit like the shade of blue they use on some Vauxhalls. (Sorry for swearing )

[Steve and his 244]

Nice Amazon, Nice vid. I dont think id have the guts to redline mine :S

[Steve121]

Originally Posted by loon

cheers Brian
how much interest did he show when you turned up
'cos im looking to do mine i went to redline in basvagas (basildon) essex but the guy i spoke to seemed to be a bit offish so i never went back.

LN

went there to have a rolling road session done on mine, (when the twin webers were on).. seemed an ok guy although he did ask me what it was!! the only reason I went there was as it was close to work (Ford) and a Weber specialist

[Brian M]

Originally Posted by 222s

Good to see you yesterday

What's your engine spec? Wondering whether mine could do with being set up like that to improve the fuel economy.

Paul

Mine is a B20A with twin HS6's and a D type camshaft. The unleaded head was "cleaned-up" but not really gas flowed. I have a 4 into 2 into 1 exhaust with a Simmons sports exhaust.

Originally Posted by Moosejaw

Love the colour of your car BTW, is it a regular manufacturer's colour or is it a custom mix? Looks a wee bit like the shade of blue they use on some Vauxhalls. (Sorry for swearing )

It is actually a Fiat colour. The guy who sprayed it was planning to do it in the light metallic blue that was used for a small series of 123GT's in 1967 (Volvo code 102) more commonly seen on 140's and 1800's, but then decided it needed a deeper blue and so went for the Fiat colour.

[222s]

Originally Posted by Brian M

Paul

Mine is a B20A with twin HS6's and a D type camshaft. The unleaded head was "cleaned-up" but not really gas flowed. I have a 4 into 2 into 1 exhaust with a Simmons sports exhaust.

Thanks - very similar to mine then! Will look into having this done too