Do I need an underlay or eq' under my new carpet in the front of my kombi. The carpet that I bought is quite thin and I planned on glueing it down. Is there any heat /noise concerns?
Dont glue it, if you get any water up thru the floor or spill some water and it gets damp its going to rust like mad.
It depends how quiet you want your car. No real heat concerns as there is no front mound rad and engine is in the rear (talking bay/split?). See how noisy it is with just the carpet, if its too noisy then look for some underlay, perferably waterproof...
Any carpet you have "under-foot" would benefit from a cork type underlay. Makes the carpet sit nice and flat on the floor..rather than follow the undulations of the floor. Reduces roadnoise through the floor as well. If you're putting it behind the pedals/under the dash, glueing direct wouldn't hurt.
If you still have the front rubber mat, even if it is a bit torn, then you could glue the carpet to that. It will make it sit flat, be waterproof underneath, and give good sound insulation.