Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Cold air hose for open K&N

Quite good and effective result. MAF sensor shows the same value as the outside temperature, today it was 18 degrees C. After a red light temp is down again after 30 seconds. No more an issue concerning the negative pressure situation with this placement of the open air filter. At the entrance of the hose I will attach a kind of fly screen against stones next weekend. The product/hose is a HJS (the catalyst manufacturer) "preheating hose" for exhaust systems, it measures 70mm diameter and it is one meter long, I cut some 15 cm away and perhaps I will do so a bit more in case the end is to close to the filter which I will check. I think there are no problems regarding the low positioned input of the hose. So cold air is coming in for sure. The filter can be cleaned easily.

I left the original air box in place as you can see because I use it with the original metal tube when we do long tours e.g. to Italy because it's quieter. The change only takes 10 minutes. For weekend trips the open air filter is very good and the 4/4 is driving as fast as it‘s stolen.

Nice idea and material selection, besides the different temp measured, any change in how engine improved? Dud you have a specific complaint, other than high temp read out?
Bert

Bert, the spontaneity of the throttle response and the performance is noticeably better with the new air hose. Without the hose the open K&N is already good. But now the third gear pulls up to 145 km/h like a rubber band.
Actually this position of the filter is a low-pressure area. In principle this is not optimal. Therefore the additional hose.

What I would like to try out is the correct distance from the end of the hose to the air filter. But this is only a fine tuning for very high speeds which I normally do not drive with the 4/4 anyway. I'd say it's very good up to 150 km/h now. If the car drives faster, my 4/4 manages GPS measured 190 km/h on the straight motorway, it can be that the air from the hose becomes too fast and thus undesirable turbulences develop at the air filter, which can have an opposite effect. K&N writes that the cold air hose should not be closer than 10 cm to the filter.

Heinz... When in a VERY hot Italy, I did the opposite... in that my +8 has a fresh air intake tube facing the front of the car just behind the radiator... I disconnected the tube from the air filter to let the carbs suck HOT air from the engine bay, the thinking being that more air would be sucked through the louvers to encourage cooling within the engine bay when at a standstill in traffic and perhaps less so when driving.... My thinking was not to improve engine performance, but to try to increase cooling.... Whether it worked or not and to what extent...I have no idea...?

Luddite, to cool the engine compartment in general, there were two different hints here in the forum. On the one hand there is a very detailed thread which I have to find again. This thread dealt with the test results of an American Morgan driver. He had his car in the wind tunnel of a truck factory in the northwest of the USA. I mean it was Freightliner. The whole thing was in the 90s if I remember correctly. It was about the topic that the the engine went much too hot. At first the driver thought that a bigger radiator would solve the problem. But the guys from Frightliner had realized that the original Plus 8 radiator was big enough. The solution was elsewhere. The Morgan has typically no base plate in the front area between the radiator and the oil pan. They installed a base plate. In this way much more air flowed through the radiator and the engine got good cool water.

The other point is that with Trad Morgan not enough hot air can escape from the engine compartment in hot weather. This is especially true of the Plus 8 with its large engine in a confined space. For this reason there are these hood spacer which you can buy and which are used at the bottom of the rear end of the bonnets, i.e. in the area of the doors. I didn't try this on the 4/4 because it's not necessary. But with a plus 8 this can have noticeable effects.

If you look at the new Plus six, there they have created a very large opening in the form of a long vertical Louvre in the same way at the end of the hoods shortly before the doors so that the hot air can escape.
Your idea to "suck off" hot air using the carburettors is very inventive. I don't know but maybe it worked well.

Heinz, thank you very much for taking the time to type that explanation. I remember tufts of wool being involved.. (-:

I am very reluctant to type this...but.. keeping my fingers crossed.. My +8 has never overheated

We were far from home and I just wanted to give the engine as much air flow around it as possible and removing the tube from the air filter intake seemed to have potential to achieve just that..?? Whether it helped or not..??

einz are you not concerned that in wet weather water may flood up the tube & into the engine?

If the water is as high on the road as the inlet of the hose it would not be advisable to drive it. In normal heavy rain and wet road I really have to test and check it. But your point is not to be ignored at all, John.

Heinz, I have fitted extended rear bonnet fixings on my Plus8. It does seem to help the hot air escape as the fan does not cut in as often.
A while back I did a run with my OBD meter connected to see what the incoming air temperature was.
Ambient air was 15decC and incoming air 35degC and still rising slowly. I have not repeated it since putting the extenders on though.
The air intake points roughly towards the side louvres but is ineffective as the exhaust manifold is unshielded and below it.
I’d like to try your idea but limited room with the big engine so some thought needed. A winter project.....
“Modern Engine Tuning” by Graham Bell is a good book and he looks at air flow with actual examples of results from various modifications, filter types, designs etc..

Heinz,
Your post is interesting and reminded me that I tried something similar, albeit from over the radiator on my 1989 Plus Four.