Is there any danger that if I tape the air filter box shut, where the preheat hose connects to the air filter box, after I remove the preheat hose? In other words, if the stat should get stuck in the cold air position, then where is the engine going to get its air flow from?

(I did this on my 240 also, but I also removed the stat [it wasn't working]. So I have a 100% full cool air flow for the summer weather. At the end of summer I will get a new stat for it and put it back together}.

Sincerely,

I reoutinely remove that pre-heat tube and block off the inlet at the airbox, using a 1-1/2" rubber end cao with band clamp bought from a local hardware or home center. Fit nice and tight.

On the other hand, I also am considering trying the "ram air" mod Rafael outlined.

See: www.pumaracing.com for more on modifying the airbox on fuel injected engines to give more HP. (drilling holes in it!)

Rip that stupid hose out of there. All it does is let hot air in all the time, esp if the t-stat is broken.

Remove the air filter box and remove the little air horn in the inlet to the fender. Use a plastic wire tie and tie the flap off in the cold position, ie cover the hot air intake.

I did this to mine and I plan on further mods.

Hello Warren:

How about this. Take out horn like you did. Take out door inside airbox so both cold air and hot air intakes are permanently open. Hot air intake elbow at the bottom of the airbox cannot be turned around to face forward because of transmission fluid lines to radiator are on the way. So replace the hot air intake elbow at the bottom of the airbox with a short plastic plumbing elbow from a hardware store together with a 3 inch diameter by 24 inch length automotive air inlet hose (from Western Auto) routed through 3 inch tapped hole on chasis in front of airbox and below headlights? This hose will run from bottom of airbox through chasis opening to outside of engine compartment away from its heat. Tight but possible. Right next to fog light there is a possible cutout in spoiler for a fresh air intake. Ram air? Otherwise, the fresh air intake could be kept a bit higher behind spoiler for protection against rain or other water being sucked up into airbox. It occurs to me these modifications could do no harm in hot weather. Parts cost is aproximately $15 for elbow, air hose, two 3 inch clamps and one 4 inch to 3 inch diameter round black plastic reduction from harware store to attach through or behind spoiler. A rectangular opening could also be fabricated to attach behind spoiler to be symmetric with cooling air intakes for radiators and such at the center of the spoiler. What do you have in mind for modifications?

No harm, as long as this is done only in warm months, since in colder months the preheat helps fuel vaporisation just after startup. If the stat freezes and shuts air off, your engine will let you know. No damage can be done by doing this.

I removed the preheater hose 2 years ago - lived through 2 Co. winters with no problems. '91 740 N/A

My iunderstanding is the preheat is not needed above 0 F. So block it off and only reopen it if your winter s are that cold. make sure to keep the parts as your smog laws may require the hose to be there.

Bill D.