| Author | Message | ||
     Martin Taylor Frequent User Username: martin_taylor Post Number: 77 Registered: 7-2013 |
What is the purpose of this device? I have just replaced the intake tubing, new eBay kit fits beautifully and isn't full of holes, I haven't reinstalled the restrictor and so far it is only slightly noisier. | ||
| richard george yeaman Grand Master Username: richyrich Post Number: 767 Registered: 4-2012 |
Hi Martin its purpose is to act as a silencer !! Richard. | ||
| Martin Taylor Frequent User Username: martin_taylor Post Number: 78 Registered: 7-2013 |
Thanks Richard, it certainly does that, but does it rob horsepower while performing this task? | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 1732 Registered: 5-2012 |
Hi Martin Are you referring to the device situated under the front wing? If so, in addition to the benefit Richard mentions, it is used to regulate the air temperature entering the induction system. Here is what Bob Reynolds wrote about it a while ago: The hot/cold intake duct was one of the emissions kludges introduced on most UK cars in the early 70s. My 75 Shadow used to have one.  It is underneath the wing, where the air filter is. You will find a diagram of the system on page U70 of the workshop manual 'Temperature-controled Air Intake'. Basically there is a moveable flap underneath the wing, that directs a mixture of cool air and warm air into the air filter, to try and regulate the temperature of the incoming air. The warm air is picked up by the hot air scoop above the exhaust manifold. That's the thing that you have to keep removing to get at the spark plugs! If your car is fited with this scoop, you will see that the hose disappears into the wing. The moveable flap is powered by a vacuum, through a heat sensor on the inlet elbow. The idea was to enable a finer control of the fuel/air ratio by trying to keep the air temperature constant. Where is Bob? - he hasn't been on for quite a while now. This forum is missing his expertise. Geoff | ||
| richard george yeaman Grand Master Username: richyrich Post Number: 768 Registered: 4-2012 |
I think the term they used when asked about Horsepower was adequate!!! Richard. | ||
| Mark Aldridge Grand Master Username: mark_aldridge Post Number: 440 Registered: 10-2008 |
I have blanked off the vacuum supply to the hot/cold flap on both my Shadow and my 1983 Mulsanne. I get better hot idle and lower emissions with the flap set permanently cold. I only reconnect the flap in very cold weather.. Martin do you have a link for the ebay kit ? Mark | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 1733 Registered: 5-2012 |
Mark I concur. My 74 SY1 was not fitted with the temperature controlled air intake. I believe this was introduced in 1975. On the earlier models the intake scoop above the exhaust manifold is permanently in place, so always delivers warmer air. I too find cooler air much better and so have removed the scoop. I would only replace it in very cold weather. Geoff | ||
| richard george yeaman Grand Master Username: richyrich Post Number: 769 Registered: 4-2012 |
Hi Geoff I think Martin is referring to the silencer halfway in the trunking from air cleaner to carbs, all the rest o the stuff is good reading. Richard. | ||
| Robert Noel Reddington Grand Master Username: bob_uk Post Number: 1474 Registered: 5-2015 |
My 1974 17768 is so fitted with temperature controlled air intake. most cars of the period were fitted with these. It stops carb icing and helps with emisions a bit. As you know any restriction in an inlet will effect mixture. So the system should be fitted and working. I seen lots of these systems disconnected because the heat proof bit of silver hose has collapsed and it seems to make no difference to the running. The flap should move under a spot of vacuum by mouth. No vacuum could mean pipe leaking which will upset the mixture so blank off for now. If the system works then all well and good. If not don't worry and just fix when you get round to it | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 1734 Registered: 5-2012 |
Hi Richard Thanks for the correction. I replaced my trunking a long time ago as the original had holes in it. My car is without the intake silencer so I will be interested to check out the ebay kit if Martin puts up the link. As per my policy, I kept the original damaged trunking so may be able use the silencer part from it. In regard to Bob_uk's comments, this is another reason why the dial test indicator method of balancing the carbs is better. The air flow meter method requires the air intake trunking to be disconnected. Geoff | ||
| Martin Taylor Frequent User Username: martin_taylor Post Number: 79 Registered: 7-2013 |
Copy the following into an eBay search, 9751 air duct hose It fits perfectly but internal diameter is slightly smaller so I may have to machine some of the outer restrictor off to reinstall it, My car has the hot air intake but no vacuum device to shut it off. | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 611 Registered: 4-2015 |
Hmmm... As in "exactly the same...only slightly different"? LOL | ||
| ross kowalski Grand Master Username: cdfpw Post Number: 486 Registered: 11-2015 |
Martin, Does the tube from ebay look like the same material as OEM? I looked it up and it appears to be plastic of some sort. The one on 8824 appears to be OEM and appears to be fabric covered rubber. | ||
| Martin Taylor Frequent User Username: martin_taylor Post Number: 80 Registered: 7-2013 |
It is plastic, it looks newer and shiner and is one piece not two  | ||
| ross kowalski Grand Master Username: cdfpw Post Number: 488 Registered: 11-2015 |
Martin, That looks good. And a clean looking engine compartment too. |
