Corvair DiagramCorvair Photo
Corvair Center
home forum corvairs calendar links Corvair Podcast
California Corvairs
Clarks Corvair
Clarks Corvair
“CORSA"



Chevy Corvair License Plate
Chevy Corvair Chrome Wheel
Corvair Center Forum :  Corvair Center Phorum The fastest message board... ever.
Corvair Center 
Tatra Air Cooled Double Diffuser
Posted by: JimBrandberg ()
Date: October 17, 2020 07:47AM

I didn't want to sidetrack the Porsche 911 fan thread so started a new topic.

I did a search but couldn't find much about the Tatra double diffuser and how it works but it is certainly compelling. I never paid much attention to Tatras but I remember Larry Claypool was interested in them.

Apparently besides the double diffuser there was another system with an outlet fan on each side, belt driven and parallel with the crankshaft. Two oil coolers and rather sizable air intakes on the side of the car body alongside a sloping roof that we don't have.

The engine I saw is a 2.5 liter air cooled hemi V-8. It sat there idling for a long time before getting underway so airflow while in motion is apparently not the only factor.

Another interesting vehicle was an air cooled naturally aspirated diesel.

Anyone ever look into doing something like this?
Any books on the subject?
I suppose it uses the exhaust flow to help induce cooling air flow.
Diffuser talk come up in Formula 1 but I always just assumed it had to do with ground effects.

[www.carthrottle.com]

Jim Brandberg
Isanti, MN
CorvairRepair.com



Options: ReplyQuote
Re: Tatra Air Cooled Double Diffuser
Posted by: MattNall ()
Date: October 17, 2020 07:59AM

It works on the same principle as Kevin Willson's exhaust driven PCV.

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

Options: ReplyQuote
Re: Tatra Air Cooled Double Diffuser
Posted by: Allan Lacki ()
Date: October 17, 2020 08:07AM

Listen to it here....

[www.youtube.com]

Options: ReplyQuote
Re: Tatra Air Cooled Double Diffuser
Posted by: Allan Lacki ()
Date: October 17, 2020 08:31AM

According to one of the Czech websites, the noise is rated at 145 decibels - which is way beyond what most tracks allow. Cool concept though!

Options: ReplyQuote
Re: Tatra Air Cooled Double Diffuser
Posted by: JimBrandberg ()
Date: October 17, 2020 08:42AM

I'd like to know more about the PCV system although I understand not sharing if it's proprietary.

I've thought about a heat riser to run along center mount intake tubes like VW but never looked into how it works. The heat must go in one side and out the other somehow.
Yes I know about the oil chamber under the center plenum idea.

My brother had dual megaphone long tube headers on an ice racing Corvair in the early 70s. It sounded fantastic but was REALLY LOUD.

Jim Brandberg
Isanti, MN
CorvairRepair.com



Options: ReplyQuote
Re: Tatra Air Cooled Double Diffuser
Posted by: MattNall ()
Date: October 17, 2020 08:53AM

Jim it's available from Summit, etc. Drag Racers use it.

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

Options: ReplyQuote
Re: Tatra Air Cooled Double Diffuser
Posted by: Phil Dally ()
Date: October 17, 2020 11:23AM

Tatra Engine Pictures.

Attachments:


Options: ReplyQuote
Re: Tatra Air Cooled Double Diffuser
Posted by: JerryM ()
Date: October 17, 2020 01:44PM

JimBrandberg Wrote:
-------------------------------------------------------
> I didn't want to sidetrack the Porsche 911 fan thread so started a new topic.
>
> I did a search but couldn't find much about the Tatra double diffuser and how it works but it is certainly compelling. I never paid much attention to Tatras but I remember Larry Claypool was interested in them.
>
> Apparently besides the double diffuser there was another system with an outlet fan on each side, belt driven and parallel with the crankshaft. Two oil coolers and rather sizable air intakes on the side of the car body alongside a sloping roof that we don't have.
>
> The engine I saw is a 2.5 liter air cooled hemi V-8. It sat there idling for a long time before getting underway so airflow while in motion is apparently not the only factor.
>
> Another interesting vehicle was an air cooled naturally aspirated diesel.
>
> Anyone ever look into doing something like this?
> Any books on the subject?
> I suppose it uses the exhaust flow to help induce cooling air flow.
> Diffuser talk come up in Formula 1 but I always just assumed it had to do with ground effects.
>
> [www.carthrottle.com]

Julius Mackerle's book "Air-cooled Automotive Engines" has a section on the subject. Another interesting concept he mentions is an exhaust driven blower...

Options: ReplyQuote
Re: Tatra Air Cooled Double Diffuser
Posted by: Allan Lacki ()
Date: October 17, 2020 01:52PM

The science behind Tatra engines that were cooled by the "diffusers" rather than blowers is described on pages 171 - 177 of this book. Lots of detail there!

[www.eurospares.com]

The name of the book is AIR-COOLED MOTOR ENGINES By Julius Mackerle, M. E. He was the head of the design department of the Tatra Works.

And here are links to two pages that show the fancy exhaust plumbing used on these particular engines:

[www.ecorra.com]

[www.ecorra.com]

But from what I read in that online Mackerle book, a much simpler set of headers could be used.

Options: ReplyQuote
Re: Tatra Air Cooled Double Diffuser
Posted by: JimBrandberg ()
Date: October 18, 2020 07:12AM

I might have to read the PDFs. Looks like going rate for the book is $350 with one example for $112.

Jim Brandberg
Isanti, MN
CorvairRepair.com



Options: ReplyQuote
Re: Tatra Air Cooled Double Diffuser
Posted by: JimBrandberg ()
Date: October 18, 2020 05:34PM

I looked at the link pages 171-177 of the book. Not exactly casual reading but interesting.

I couldn't get the 2 ecorra links to work.

Thanks for taking the time to post them.

Jim Brandberg
Isanti, MN
CorvairRepair.com



Options: ReplyQuote
Re: Tatra Air Cooled Double Diffuser
Posted by: JimBrandberg ()
Date: October 18, 2020 05:42PM

I got a look at the exhaust by going to ecorra.com directly. Pretty cool stuff, I like the c or star shaped ends on the exhaust tubes.
I believe it was an exhaust diffuser system that allowed Brawn to win the F1 championship.
I probably don't have the time or resources to attempt something like this but it sure is interesting.

Jim Brandberg
Isanti, MN
CorvairRepair.com



Options: ReplyQuote


Sorry, only registered users may post in this forum.
This forum powered by Phorum.