bahdeets sorry i cant answer your question but i have seen your thread on ls1tech. you have an awesome monte hope you get your temp issues fixed. what coolers are you running now? i have a mobile home sized (7x20") one ready for install on my ls4.

 

Just a question... I know u said a guy at GM said the cowl is good for heat extractors but.... The cowl where he hood and windshield meet is a "high" pressure area not a low pressure vac area. That is why they use to make. Cowl induction hoods. The high pressure infront of the windshield would force air into the hood and into the intake a speed.

Either way your trying to fight temps at low speed or stopped so changing the cowl won't effect the temps... But I still think if u were to add heat extractors just behind the rad on the hood it would allow the hot air to escape faster

 

Xxtheshockerxx: Thanks for the compliment. I have had a real issue with space and what was used was two small coolers. The coolers are the plate style with individual fans and not the tube and fin that most use. If my memory serves me right they are about 7" x 12" in size and they are both located on the passenger side near and offset from the foglight, now with the change of bumpers they are open to air flow. If you do put your cooler in, my only suggestion would be to try and put it in a location where you get direct airflow across it and if you can mount a small fan on it also.

Z34 phoenix - you have me wondering now if I have received accurate information or I misinterrupted what I got. GM on their duramax trucks in high elevations were having compartment temperature difficulties. Their solution was the extractor but at the cowl (if I understood them correctly). I definitely will re-do this research. Upon their recommendation holes were cut into my supporting crossmember at the cowl. As it appears to me now your idea of extractors just behind the radiator on the hood seems logical to me. You got me going now, could I have made an error and got my instruction backwards and like you said, could I be forcing air back into the compartment through the cowl instead of extracting it? I really appreciate your help, I will respond back shortly after I contact my source again.

 

Z34Phonenix: After a long discussion with my guys at GM I understand now what they had in mind for me with the problem I have and their explanation makes alot of sense. My problem is low speed/high temperatures. Their partial if not complete solution was a cowl induction/extraction application through the back brace of my hood. Now you have said that is a high pressure area and you are completely correct, however they explained the complete dynamics of the application down to graphing it for me the best they could over the phone with me drawing pictures as they spoke to me. There is a point on the pressure-side/speed equation/curve in which the pressure is reduced to 0 PSI but not at a speed of 0 MPH. 0 PSI is achieved well above that and in my case somewhere around or under 40MPH this is where my temperature consistently goes up. Now at this point (let's say 40MPH) as charted pressure becomes negative at the lower speed(s) a vacuum is created at the cowl or reverse pressure drawing heat out of the engine compartment instead of pushing it in which would occur at higher speeds. So in fact what they have recommended should work to remove hot ambient air from my engine compartment at lower speeds. What I did not ask is what result there would be if the extractor is behind and above the radiator on the hood as you have suggested. In our discussion there was a brief mention of the heat extractors that are used on some of the newer Corvettes but we never got into that. If I am not mistaken I have seen pictures of extractors on the hoods of some of the newer Corvette's probably using the exact principle of extraction you have recommended to me, but now that I think of it, I thought this was assisting in the pull of air through the radiator and out more so than extracting hot air from the engine compartment itself. My only objection to hood extractors is cutting holes in my hood deviating from the stock look of the factory supplied hood. With that in mind I think the cowl induction/extraction should suit my purpose. I just hope along with the tranny pan spacer, deeper pan and the opened grille I now have on my tranny coolers I can get my temperature down those 10 degress F I need. With my grille open more I should have greater flow also at the lower speeds taking in a higher volume of cool air and once passed that vacuum/high pressure threshold it only makes sense to me that temperatures should come down.

 

would an MPD hood help with heat extractors?