Stealth cab heat issues! Help!!

Hello RIU

I've just recently switched my cfls out for a 150 HPS due to my girl entering flowering. My stealth cab which measures 36x21x19, is equipped with a 100 CFM inline fan attached to 4x8 phresh filter, and a 45 CFM case fan for intake. Also have a 5" O2 fan for circulation. Lately the temps have been hitting 92F and I was wondering if there's anything I can do about lowering the temps.

I've looked into creating an extra passive intake, and was thinking about putting another 4" hole next to my case fan for the passive intake. This brings up a couple concerns. First off, let me say that when my case fan is off, my inline fan isn't strong enough to pull the fan which makes me wonder if I have negative pressure going on in my cab. Which brings me to my second point... if I put another 4" hole next to my case fan intake, will it create any problems for negative pressure? Should I drill a decent amount of 1/4" holes?

Another question is, if I have fans bringing air in and taking air out, do I need another fan for circulation? B/c I think my fan is just blowing the hot air from the HPS everywhere and causing problems. So I couldn't really find anything on CO2 being enough from just the fans exchanging air. Or does anyone know if adding another 5" fan in there would make things cooler.

And just as a side note... I am on an extremely tight budget atm, so unfortunately, switching out gear like my fans or light just isn't an option right now.

Thanks in advance!

As of now, the only options that seem reasonable/in my budget are to either drill another hole for passive intake, or get a slightly stronger case fan. (I'm guessing my inline is running somewhere around 50-60 CFM while attached to the CF). Another thing that has me worried is my temp range from lights on to lights off. Lights off I believe gets somewhere around 67-72F, which is generally what my basement temp is at usually. (70F~) Any ideas from anyone?

Nothing too helpful here but a 16 dollar box fan from Wally world puts out a lil over 2000cfm

2000 CFM? Think that's a bit much for my needs. And its 16 dollars? I've just read up on a couple things, and I saw that your passive intake hole size needs to be 2x your exhaust. But the thing is, my intake is powered by a case fan atm. Would I need to take out the case fan and just put two 4" holes there? Or if I want to use my case fan, how do I know how big my extra passive intake hole has to be o.o

Lol I don't know bro I use box fans...but I think it would be perfect for you besides not as noisy when not on high.
But my grow space is 2x2 the 20" box fan built in the side keeps my temps exactly the same as the rest of the house and that's with a 600watt hps

wow, got a link by any chance? couldn't find any wally world fans...

I have practically the exact same set up - similar sized cab, 117cfm exhaust, 69cfm intake. I added a hole for passive intake just below the intake fan to allow all the power cords to go through, and also to prevent the negative pull of air from the exhaust. That, and make sure your intake is relatively close to an A/C vent. With this set up and ~70-75f temps indoors, my temps are almost always in the 82-84 range with lights on.

Cough cough box fan cough

get a nice fan facing your box pushing cool air to it not warm air,
i was ahving the same isuue now im good.