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Turbo tuning - chat - story



I realise this thread has now died, but this might be of use/interest for
some of you, but its not Toy related.
I had used turbo diesels in the 70's & 80's and was never impressed
especially with industrial engines that ran at varying speeds where the
full potential of the turbo was not used. I always preferred the grunt of a
6 cylinder rather than a turbo four to get more than 100 bhp.
In 1989 my old Vauxhall Senator needed to go at 100k + miles and I decided
a big diesel would be better. The best deal was on a then 'new shape'
Carlton. But the 2.3 engine did seem somewhat agricultural to me. My dealer
told me that he had sold one with a TB turbo conversion on it, and it
seemed to go well but sometimes ran a bit rough. In those days TB used
Garrett turbos exclusively and they were very much bare bones turbines with
nothing fancy about them, unlike those Garretts on the Bentley's of today.
Anyway, whilst I thought about this aspect for a week, my dealer called and
said that he had been at a Vauxhall dealer event and sat next to a young
man running a dealership, but who also prepared all the Vauxhall
competition and rally car engines on contract. He also specialised in
putting a state-of-the-art (then) Japanese IHI turbo on the Vauxhall range.
It was a small turbo that had an integral wastegate and in practice and on
a rolling road gave better throttle response and output than the TB Garrett.
So I went ahead and ordered the new car, which when delivered was trailered
down to Chris Courtney in North Walsham in Norfolk for the conversion. It
was delivered to me about a week later.
It all seemed neat and well engineered and off I went for a long business
trip for a couple of days. I did notice that there was no apparent
pneumatic compensation system boosting the fuel supply at the pump.
However, it appeared that 25 or so of the horses under the bonnet were
dead, even though the boost gauge was showing plenty of wind going up the
spout. But I forgave it as it was new. But after it was run-in there was
little change. I was disappointed and it seemed my bad experience,
especially with the Ford 7000 tractor was being repeated.
My dealer arranged for me to call-in to see Chris Courtney one day when I
was down his way, to get it fixed. Chris had told him that he would soon
put it right.
I duly called-in as arranged and was shown into Chris's office, it was a
huge dealership for such a sleepy little town. Chris was busy and he was
obviously more mechanic than managing director and chairman - his desk
showing all the signs of the vesuvious style of business management.
After a phone call or two and a coffee, he said OK Jon let's go and tune
your turbo. We walked though a large workshop and I expected him to direct
me to the rolling road and all the diagnostic gear. But although dressed in
a business suit he picked up a spanner and screwdriver from a bench and
asked me for the keys.
He explained that a turbo had to be tested under load, and at best on the
road. He said the thing was spinning OK but that the fuel pump needed
tweaking. He said, we''ll go to our test track. It was in fact the North
Walsham by-pass !!
If any of you have passed that way you will have noticed that this road is
about 2 or 3 miles long and for its entire length goes up a reasonable
incline (well for Norfolk it is !). We went to the bottom of the by-pass
and Chris said ' well this old bus will be right when its doing 110 with
6psi pressure on the gauge and the exhaust smoke just disappearing - hold
on Jon'.
I don't remember how many runs we made up that by-pass that afternoon,
though I do remember that we seemed to go down the slope just as fast as we
went up it. My job was to observe the exhaust smoke at maximum -110mph -
speed. Every time we got to the bottom Chris tweaked the sealed fuel
adjuster screw a tad more till it was right. (He told me that they had an
'arrangement' with the local police for their antics on a 70 mph public
road, whatever that meant).
The end result was marvellous, it appeared that his man had not run it at
110 when he installed the turbo, hence not enough fuel getting into the
engine. Chris told me that he tuned all turbo's that way and that was why
his prepared cars went well. I had no reason to disbelieve him.
The point made - and well taken - is that no matter if there is a separate
pneumatic compensation system. The whole works must be calibrated under
realistic conditions.
As a footnote, about 3 years later I needed a new bend to be welded into
the downpipe. I called-in to North Walsham only to find that Chris had
moved-on. Apparently he had gone bust in a big way thanks to over-extending
himself leasing hire fleets to industry. Not an easy logistical exercise
from a sleepy Norfolk town. But I managed to find Chris out on an
industrial estate having gone back to his roots and specialising in
preparation of competition engines and doing turbo conversions still.
I don't think I will ever be tempted to have a turbo put on my HZ engine
'92 HZJ 80 ex UN surplus in Bosnia