New prototype Porsche cooling shroud on 2276cc turbo EFI

[blue thunder]

Finally getting close to completion. This build has taken waaaaaay too long, but hopefully I can take it to the track this year.
Still waiting for a whole bunch of parts for the 6 speed sequential gearbox before I can bolt this baby on.... Waiting sucks!

[gearheadgreg]

Wow - how did you come up witht he design? Are the tubes fiberglass or metal?

[doc]

Sure looks freakin cool! Please post some kind of results.

doc

[blue thunder]

Well, as equal distribution of the cooling air is the biggest problem with Porsche cooling shrouds (or actually all cooling shrouds), I tried to find a better solution. As the air does not leave the fan in an axial direction, but more in a rotational/axial vector, I decided to utilise the guide vanes of the original Porsche fanhousing to direct the air to the heads/cylinders individually. Dividing the air at this point ensures an equal flow area for all the cylinders/heads. The only factor which could slightly influence the flow to the cylinders/heads is the different length and radius of bends of the individual runners, but as the shorter runners have sharper bends, I think the difference in flow will be minimal. I still need to do some more testing, but so far it's looking quite promising.

The runners, cooling 'tins' and dividers are all glassfibre. Fabrication of the molds has taken alot of time and I've made about 5 different designs before I was happy with it.

@ doc: Thanks! As soon as I have some results (I will log the temperatures of each cylinder with thermocouples and a datalogger) I'll post it.

Cheers,

Robin

[gearheadgreg]

Sure looks freakin cool! Please post some kind of results.

doc

Ba-dump-ba! Cool. Heh.

[Alamento]

Its a cool design! Two things I got from my first impression:

You've created the hole the middle of the fan housing where the alternator goes, and blocked off the outer part of the housing where the fan blades will be pushing air! The fan blades will be pushing the air into a wall, and then it will be taking two 90 degree turns to find its way behind the alternator and into your main fiberglass inlet. This is a huge bottleneck.

Also, you've spent a lot of time bending 2 individual tubes that start in the same place, and end in the same place. Why not one tube per side?

[blue thunder]

Its a cool design! Two things I got from my first impression:

You've created the hole the middle of the fan housing where the alternator goes, and blocked off the outer part of the housing where the fan blades will be pushing air! The fan blades will be pushing the air into a wall, and then it will be taking two 90 degree turns to find its way behind the alternator and into your main fiberglass inlet. This is a huge bottleneck.

Also, you've spent a lot of time bending 2 individual tubes that start in the same place, and end in the same place. Why not one tube per side?

I don't think you have looked well enough at the design. I haven't blocked off anything: look at the 2nd and 3rd picture. The air is directed into the runners very smoothly (nothing blocked off at all). I've used the guide vanes of the original Porsche outer ring and molded a collector between each guide vane which directs the air directly into each individual runner. Why use 4 runners instead of 2?: I wanted to be sure each cylinder gets the exact same amount of cooling air, and the Porsche cooling has 4 equal 'pockets' between the guide vanes. I just made use of this to divide the air equally over the 4 cylinders/heads.

Cheers,

Robin

[Alamento]

Ahhhh! I see it now. I misinterpreted the pictures. Thanks!

[Steve Arndt]

Now you should make your intake manifold runners individual and snake them the same way to a plenum!

[gearheadgreg]

THinking of selling some when you get the bugs ironed out?

[Stripped66]

This is the coolest (no pun intended) adaptation I've seen yet! Do you have plans to run thermocouples to all 4 cylinders? I'd love to see how this design turns out...makes the rest of us look like we're splashing in the shallow end of the pool

[Piledriver]

Neat!

I'd love to see how that compares to the horizontal fan setups (Reichert/LAPerformance)

They have the advantage of using the natural airflow off the fan, and disadvantage of needing to "bend" the fan belt 90 degrees.

[Steve Arndt]

How did you mold/shape and glass this thing together?

[blue thunder]

@ Steve: That's a cool idea, never thought of that For now this inlet will have to do, as the build has taken way too long already
I first started off with a piece of foam, and made one collector between the guide vanes of the Porsche outer ring (alot of sanding, bondo-ing and cursing involved ). After finally finding the right shape, I made a 2 piece mold around the collector, so I could make a serie of collectors. As all 4 collectors are equal, a good 2 piece mold was essential. After that, I made an inner ring, which corresponded with the boltpattern of the Porsche alternator, so I could mount it to the Porsche outer ring. I glued this on the inside of the collectors with epoxy. Finally I used fiberglass weave on the outside all around the Porsche outer ring to get an airtight seal and to keep the collectors together. After that, I made the engine 'tins', using original tins as a mock-up. Again I used foam, aluminium sheet, wood and bondo to get the shape. After that, I laminated another 2 piece mold for the engine tins. I then used aluminium hose to connect the tins to the collectors, and epoxied fibreglass around these hoses (used alot of wax). When the epoxy was dry, I could remove the aluminium hose by unraveling them from the inside.

@Pile: Thanks! The horizontal cooling system is indeed a very nice design. The 90 degree bend in the fanbelt is actually the biggest drawback of this system, but it is very effective.

@Stripped66: Thanks! I was planning to measure the heads at 4 points with thermocouples and maybe 4 more for the cylinders. I still need to do alot of testing and tinkering to optimise the air distribution in the 'tins', and this type of data is essential. As soon as I have some measurements, I'll post it on the STF.

@Greg: Not for the moment. Maybe when I have tested and optimised everything and I have found a way to simplify the process of making the shroud. At the moment it just takes way too much time to fabricate.

Cheers,

Robin

[gearheadgreg]

Another benefit of this Porsche setup, is that there are a number of different fans avail for different CFM ratings, plus the obvious ability to change pulley size as well. Very cool.