Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) +4 GDI Air Temps

OBD2 readings are the tell all Chris for efficacy of your mods. It doesn't matter the specific ambient temperature its the (minimal) difference between IAT and ambient that proves the mods worth. Both parameters should be available to view via the OBD Torque app and your dongle.

FWIW you should be able to get 5% bhp improvement mid winter compared to mid summer on a normally aspirated engine assuming a cold air inlet. A very rough guide is one percent improvement for every 4°C (or 7°F) reduction in intake temp. It's not my imagination that Morton pulls harder on cold crisp mornings.

On piston engine aircraft it's doubly noticeable, you get the extra power but the wings bite on denser air with the plane seemingly wanting to leap into the air, allowing much shorter take off runs.

It is Aluflex FI 70 from Prostko

Update

Just filling the gap at the front of the Heater matrix intake made no difference so went the whole hog and replaced all the foam which eliminates the gap above the factory foam and the bonnet. I copied Gordon D's work se below thread. I also fitted extra heat shielding.

https://www.talkmorgan.com/ubbthreads.php/galleries/589560/heater-box-upgrade

I did fit little space fillers to the bonnet like Gordon but had to remove them, you can see in the picture that my bonnet stays are kept in that space when not in use, I realised when closing the bonnet.
So the seal is not perfect but I also discovered drain holes on the left and right of the Heater box that will also let in engine bay air so it will never be perfect.



Anyway retested with the following results/Conclusions

The foam does make a difference to the entry temp, but it's still 8.5 degrees over ambient (down from 14) the question remaining is how much of this is from heat rising from the hot water in the matrix?.

With the matrix on the Cold setting the Vent Temps are unchanged, still adds 5 degrees over the entry temps, so that must be down to the Hot water going through the matrix.

With the matrix on the Hot setting the vent temp is over 8 degrees cooler than before, presumably because the foam has reduced the entry temp. This is not what you'd want in winter so I've made the foam at the front so it can be removed in winter, just not glued it in.

One thing I noticed this time was the entry temp rose rapidly once the fan was switched off and continued rising with the engine off, this must be the result of the hot water in the heater matrix causing air to rise from the cabin.

So… (When the car is just Idling)

There's no real benefit from just replacing the foam.
You can't get fresh air in the cabin it's at least 8.5 degrees above ambient and when it's cold you reduce the temp of the air you can get.

Would preventing hot water passing through the matrix bring down the entry temps any further??

Only one way to find out, so I've added this back on to my to do list.
Can anyone advise best way to remove some water from the system, not drain it fully, Just enough to take it below the Heater Matrix to fit a bypass?

There should be a rad drain Mark on lower n/s allowing a little coolant to be removed.

^ knowing how flaky some of the OE rads are, I wouldn't risk disturbing the drain plug, I'd just drop a hose that's accessible

Drain or siphon the coolant from the expansion tank. That is what I did to replace the plastic t piece. I filled a siphon tube with deionized water and the led the fluid down to a clean container to reuse it. Dont suck up the fluid it isn't good for you.

Hi Mark+4

Your foam is not quite deep enough, it has to seal to the bonnet under surface so that's where your hot air is still bleeding in to the heater box. check the closed bonnet side by looking through the open bonnet for fit.

Don't remove your bonnet sealing blocks, rather cut a slot into it where the bonnet stay wants to sit and fit the foam around it as you fix it in the stowed position.

Oh! and that's a plus +1 for not messing with an original radiator, buy a cheap syringe and some tubing and suck it out of the expansion/ header tank.

Good tip. When I tried to remove the plastic radiator drain plug a couple of years back to renew the coolant, even though it didn’t feel over tight, the plug sheared in half, with one half stuck inside the rad. Thats when I decided to replace the whole thing with aluminium.

Thanks all for the tips!


HI Sewin, the foam does touch the bonnet, took me ages to get it right but checked it by applying a bit of grease to the top of the foam and then checking the grease mark left on the bonnet. I applied some Ali Tape to the base and up the side of the foam which may make it look a bit thin.

I have been thinking along the same line about the foam around the bonnet stays, I have decided to try and push the stays through the foam so that when stowed it sits in the gap.

Thanks again