Tumble Generators
I have been reading info on your site for years
now and love your articles. I have however been looking for information on
Tumble Generator Valves delete on your site with no luck. Do you have any info
on it?
Roger Roomes
Jamaica
We haven’t covered modifying or removing inlet
manifold Tumble Generator Valves.
Paper Model Engine
Cool V12 Four-stroke Engine, an unbelievable
magnificent paper model. www.yeesjob.com
German
Canada
Injector Plugs
In reference to Replacing Injector Plugs, I think it would be useful to include a hint in the article
for readers to note the location of the wires in the old connector and which way
they would fit onto the injector to ensure that the original polarity is
maintained. Young players learning EFI may not know the difference. Some
aftermarket connectors available already come terminated with wires, and those
wires may be simply be a black and a red. The new-style connectors are certainly
much easier to unlock from the injector should it become necessary later,
although clearance in a tight V engine can be an issue. The original design
connectors can be a real pain to unlock, maintainers of Nissan SOHC VG30 engines
would no doubt sympathise. The term "keyhole surgery" springs to mind.
Mister_T
Australia
Assessing Road Surfaces
Just had an idea for a project: a system which
could be fitted to a normal car to allow members of the general public to
perform quantitative road surface evaluations.
Greg Sullivan
Australia
We intend to soon cover a data-logging vertical
accelerometer than can be used to assess car ride and road surfaces.
Cylinder-Specific Tuning
Re: article Cylinder-Specific Tuning raises some interesting tangents in the area of modern engine design
and controls. It seems the background knowledge has been around for some time,
it just takes pressing emissions and fuel consumption factors to bring the tech
into general practice.
Before anybody goes berating emissions rules, we
should consider the flow-on effects of makers needing to improve the efficiency
of their engines to cope with emissions rules. Is it even possible to buy a new
car in Australia without DOHC, 4- valves-per and sophisticated EFI? Technology
that was once the domain of exotic cars eventually has and does filter down to
the humblest shopping trolley.
The reign of the four-stroke piston engine had not
ended yet, despite numerous rotary-based ideas. Perhaps when we see computerised
individual valve operation, somewhat like big solenoids running the valves, we
will see some real jumps in engine efficiency. Wasn't Lucas involved in the
development of "Helenoids" (High Energy solenoids) back in the 70's just for
that purpose? The promise of tractor valve timing at low speed and race valve
timing at high speed is too good to let go. Hell, you wouldn't even need a
throttle plate, just reduce the valve timing and lift and/or cut out cylinders
entirely.
The now pervasive electronic fuel injection was
once considered too complex and expensive for the mass market.
Cylinder filling imbalance was addressed to some
extent last century with the advent of aftermarket "scatter grind" cams. Owners
of BMC A-series engines might nod in agreement.
Even the humble Nissan SOHC VG30 engine might have
had some thought put into it to compensate for wildly disparate exhaust
secondary lengths, judging by the way the cam pulleys are indexed to their cams.
The VG20 might be the same, not sure about that one.
Back to modern day, I suppose it would not be
entirely unfeasible for a high-end car to have wideband sensing in each exhaust
runner. The computing power would be trivially cheap when mass produced these
days.
The article touched on the concept of spark plug
indexing. Perhaps there are grounds for an article on its own there?
By the way, what engine were those cutaway views
from in the article pictures?
I have seen the trend away from the toothed rubber
timing belt back to the chains which the rubber item widely replaced for a
while. It would be interesting to see a story about the evolution of timing
chains and what made them find favour again.
Mister_T
Australia
Some BMW engines control power with variable
valve lift. Not sure what the cutaway engine pics were of - we just had them on
file.
Possible HPV Springs?
Please pass on to Mr. Edgar another option: Life
Fitness "Lifesprings". They are under their home and commercial treadmill decks
and are readily available and cheap.
Larry Morgan
United States
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