Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Bonnet extensions plus8 experience?

Try to increase bonnet airflow, are the bonnet extensions any good?

You might want to read this on GoMog if you haven't already. I have never had a +8 but lots of folk use the extensions.

GoMog +8

I use them on mine in summer. I haven’t done any proper tests to measure temperatures under the bonnet but I do get an impression that they do help in that the fan seems to cut in less frequently. That may be due to better airflow out of the engine bay reducing some back pressure reduction allowing easier airflow through the rad(?). I took them off for the winter. When they go back on I will do some test runs to see if the incoming air to the filter is lower plus a thermometer to get some readings.
I do get comments about the bonnet not being closed!

I’ve had the rad conversion and raised the number plate so it’s halfway up the bumper on my +8 and no overheating issues anymore

I do recommend the bonnet extensions, they will help in the summer.

The only downside is that you will get lots of "helpful" bystanders and other drivers kindly informing you that your bonnet is open!

I have the Librands crossover manifolds installed so there is probably a lot more heat generated from them than standard, and I find the standard fan (with an override switch), a deeper alloy radiator, and the bonnet extensions cope pretty well. Again the only downside is that the fan seems noisier than the engine at times.

And marshals at hill climbs and sprints...
As a course controller, no need to ask how I know!

From a personal point of view, I could never detect any measurable difference. For me, the biggest difference was fitting an aluminium rad.

Thanks will do