hood vent water temperature difference

[aeronaut]

Those of you that have installed hood vents on an E36, what water temp difference did you see, if any?

[The sage]

Those of you that have installed hood vents on an E36, what water temp difference did you see, if any?

I was running temps ~220 degrees at the end of track sessions in the summer in new orleans. after my HG went (after 3 years of tracking) I installed a lower temp thermostat, mishimoto fan kit, smaller water pump pulley and track spec hood vents. I did an event last weekend. air temps were around 95degrees. My coolant temps were around 185 during the whole day. I think all of it helped but i can see heat radiating out of the hood vents. I know its helping to get air out.

[aeronaut]

Good info, thanks.

My water temps aren't out of hand (~220 ish or less at end of session). But my hood is f'd up anyway, so there's no mental barrier to cutting holes in it.

[bimmerboy318]

I want to do this too for a little extra insurance. I see the big center vent helping, but what would the side vents?

[Haifisch M3]

I did it too and AFAIK the engine bay is being pumped up while driving at speed so any openings in the hood will help evacuate hot air.
I did the coyo rad at the same time + oil cooler and had major cooling effect (mainly the coyo rad) .
Another benefit of hood vents may be less aero drag and more down-force.

[aeronaut]

I want to do this too for a little extra insurance. I see the big center vent helping, but what would the side vents?

I'm not sure it would make a ton of difference (side vs center vents). That said, I believe the side vents can be put in without removal of hood bracing. The center vent is right were there is significant bracing. If that matters.

[olemiss540]

I am a firm believer in huge hood vents. Placed in a low pressure zone, they can only help and my experience has been wonderful with temps. Running 400whp/wtq at 185 degrees under full bore.

[aeronaut]

I am a firm believer in huge hood vents. Placed in a low pressure zone, they can only help and my experience has been wonderful with temps. Running 400whp/wtq at 185 degrees under full bore.

Sweetness!!

Ok, magic sauce.....center? Sides? Any will work, or must be...where?

[olemiss540]

I did the largest I could find (vraptor I think its called?) Center and sides. Do us all a favor and make no other changes so we can all compare your temps!

[aeronaut]

If I do, I will!

[Haifisch M3]

Next chance I get I will run a few laps with vents taped shut and then open them. Same ambient temp , same track, same engine load...should give real results

[aeronaut]

Next chance I get I will run a few laps with vents taped shut and then open them. Same ambient temp , same track, same engine load...should give real results

Great idea, and awesome!

[olemiss540]

Next chance I get I will run a few laps with vents taped shut and then open them. Same ambient temp , same track, same engine load...should give real results

That's an awesome idea. Please please please follow up!

[jdehaan]

Next chance I get I will run a few laps with vents taped shut and then open them. Same ambient temp , same track, same engine load...should give real results

Did you ever do this test??

[Z-Thrizzle]

Would removing the fan shroud help in bring down my coolant temps on the track? I'm running an lower temp thermostat and oil cooler. Aux fan and AC condenser were removed.

[olemiss540]

Would removing the fan shroud help in bring down my coolant temps on the track? I'm running an lower temp thermostat and oil cooler. Aux fan and AC condenser were removed.

Almost certainly. Poorer performance in traffic at slow or stopped speeds but removed mine as at speed it is nothing but a restriction. My car with no shroud (spal fan mounted direct to radiator) and hood vents almost runs too cool!

[Haifisch M3]

turbo m3
taped the vents shut, did back to back laps and after 5 laps
the highest coolant temp was:
192 with vents
198 with vents taped shut

IMGE2808sc.jpgIMG2820s.jpgIMG2802s.jpg


only 6 degrees but ambient temp was in low 70s...in warmer weather it might be more

[aeronaut]

I just ran a high-rpm track (some 2nd gear stuff, low average speed, etc) with 96 deg air temps (who knows what the track temps were).
Similar conditions last year, I was seeing 225 mid -session.
This year, the highest temps I saw were 215.

Also, on skid pad: (high rpm, lowwww speed).
Last year, I was limited to 2-3 min sessions because water temps would have reached 225 quickly.
This year, water temps stayed below 210.

I'm convinced, 10 deg improvement minimum. I'd bet 15deg on average.