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Im planning out my build. I have heard a bit about engine air being a big deal for both cooling and breathing. If i had my body builder to add in these side vents, do you think i would be able to glass in some vent tubes behind to take fresh air in to the engine bay? Do you think i have space behind to do it considering it is in the wheel well? At speed, the air would be forced in its self. Could i also add in an electric fan to bring in air when stationary? Is this a good idea or is it just cosmetic and would add no value? Thanks for your comments in advance.



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Confirm timing and carb settings to reduce heat.   Open a 1" gap at the base along the firewall, openings (2" screened holes) in the sides of the engine bay, 12v electric solenoid actuator to raise the deck lid and inch or so. You can also make up a piece of steel etc. to go between the deck lid latch and the striker.. NO electric fan needed if you have the correct engine tins in place.

Even in Speedsters, because of the slight differences in inner body shape/construction with the different manufacturers, different details in each individual engine install and how the engine compartment is finished, seem to all be unique as to air requirements, how hot or cool they run and how they react to different ideas/ways to get more air into the engine compartment. With a Coupe it's a whole new ball game. I think what you're doing is a great idea and you'll have enough room, but mocking it up with some flexible tubing and mounting a tire will confirm, along with some experimentation and air pressure/temperature measurements and comparisons.

What I think some people don't realize is these bigger engines in their modified state actually radiate a lot of heat into the engine compartment itself (something that didn't happen with stock 1100, 1200 and even 1300 cc engines in their stock fully enclosed engine compartments), and there's a benefit to there being enough positive air pressure that not only do the fan and carbs get the air they require (very important for engine running cooling and life/longevity) but at least some of this radiated heat is removed via air moving through the engine compartment so it's not re-ingested (again, and again, and...).

Most of us run more powerful engines than the original VW engineers at Wolfsburg ever dreamed of, and even putting a dual carbed 1600 in an earlier Beetle without increasing air intake will cause 'issues'. I've seen and heard of lots of guys have problems with exactly this combination, and in every instance it was (at least partly) solved by getting getting more air to the engine. I've even heard of (read about, actually, on this wonderful inter web thingy) an engine lid collapsing on a Beetle during a 'rolling road' dynamometer run. If there ever was a case of not enough air into the engine compartment...

Engine compartment air pressure tests (with aquarium air tubing and a glass half filled with water) and air temp testing with a remote unit (the ideal being the temp inside the compartment being within a few degrees of the temp outside) will tell you when you've got it right. Alan's list is a good place for ideas. I do disagree with his last statement, only because if that's the only way to force enough air into the engine compartment, so be it. There really is no 1 right answer here.

Hope this helps. Al

I get it.  I ran into a similar issue with heating on my mid engine Subie Coupe. In the normal engine compartment, I had placed the radiator with 2 fans that sucked air in from the vent and louvers and blew the air downward.  Since I had dual Magnaflow mufflers in that same area, I had aluminum close out panels made to keep muffler heat from keeping increasing the ambient temperature around the radiator. 

The sheet metal guy went a bit crazy and added close out panels on the bottom of the space and put in dual naca ducts.  He was a knuckle head because he was thinking that the naca ducts would pull air up from underneath and push up air through the vents and louvers.  He never bothered to turn on the car and see which way the dual fans under the radiator were pulling the air.   The fans pulled the air in from the top and blew it down.    Duh!!  He had the whole system working against its self and the engine would never cool down.   I trashed the lower closeouts so the air now flows the way it is supposed to and the engine temperature stays at what it should for a Subie. ( about 180-190 F)

Live and Learn.    Physics always wins!!

I like the idea of the pop out louvers.  seems a bit more sexy that the rising scoop that you see on Porsches.  then again, What ever works the best.......... is the best.


I have seen one Speedster trimmed out in the engine compartment really nice. The air was directed from those louvers, by a 3" hose to a custom-made fiberglass funnel glassed to the back side (front side of the firewall void). To tidy up and trim this he covered the holes in the fire wall with two of the front turn signal/vents. The air flows in thru the vents and the two turn signal lights are now useable/switchable trouble shooting lights in the engine compartment.They were mounted up high in the area between the carbs and the fan shroud so they were completely visible. This was a really spectacular, nice and clean installation !.................Bruce

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