911 Cooling Shrouds - Improving Internal Air Distribution

[plynch]

what kind of performance does the 911 5 blade have? will this keep a 2056cc cool with a 96plate mesa with fan?

[Tony Z]

come on guys dont let this thread die.

Any updates lately??

[Sandeep]

The shroud with the mods to the back of the 911 fan is working great. The hottest temp I have to date is 361F on #4 at 17 psi, 5400 rpm in 4th.

The car runs awesome with the turbo with temps averaging around 320F while driving around town. On the highway they average about 340F with all cylinders within about 10F of each other.

The Megasquirt EFI really helps as well, as does the LC-1 because I can dial in exactly the A/F ratio I want. The EDIS helps as well because of the programmable ignition.

I really did not know what A/F ratio I was running with the 44IDF's and not exactly sure of the timing with the 050 Dizzy, because the temps I am getting with the EFI/EDIS/Turbo are close to what I had with the 44 IDF's/050 Dizzy/No turbo.

So overall, I am extremely happy because I KNOW I have a 911 shroud that cools well enough for me to run a turbo at 17 PSI

Engine is currently apart to fix a loose valve seat and is getting an overall refresh. Will be terrorizing the streets again in spring 2007

Sandeep

sandeep

[Wally]

I think I have a clua why the FAT shroud works well. Like the type 1 shroud, it guides the air left and right untill it dumps it onto the heads.

Here's a comparison of a different approach to mimic the original porsche air deflector.
Both are Remmele shrouds.
The blue shroud is actually an adaption of a Remmele shroud for an Ahnendorp machined case. However, the only 'remmele'touch is that it has a more flat (hollow actually) back side, intended to divert the air better to 2 and 4th cylinders.
The second one is an all original Remmele shroud (the carbon one). There the flat back is even more pronounced and it also has very distinct 'paths' to direct more air to 2 and 4th.
I have no conclusive data in the forms of temps on either tho. That will take time





Best regards,
Walter

[Massive Type IV]

Off the shelf, the FAT shroud was the worst shroud I tested for temperature delta, despite the drive ratio or amount of blades on the fan it always kept the same delta. I have seen #4 more than 150F hotter than #1 with that system and no mods made to it.

[Bad bug]

jake will you be any at all interested in developing the 911 shroud you have from joe ( god rest his soul ).

[Massive Type IV]

Yes, with some drastic changes to any other shroud ever completed before. I have two ideas right now that I just need time to work on.

I had planned on 2007 being the year i work on this, but its looking like our roller lifters and the Turbo development will take us clear through 2007..

I am still not ready for another cooling challenge really- it really is sucky work!

[063bug]

Sandeep,

Is there any chance of getting pictures of the mods to the 911 fan.....?

Regards
063bug

Originally Posted by Sandeep

The shroud with the mods to the back of the 911 fan is working great. The hottest temp I have to date is 361F on #4 at 17 psi, 5400 rpm in 4th.


sandeep

[Wally]

Well, since I need to make my own shroud for the 2,7 anyways (its VERY wide and the Oettinger cylinders are quite some wider as well) and the case has been cut for the Ahnendorp system may many moons ago, I have started sculpting class:

Here's a picture of a RMB shroud with an even more pronounced 4th cylinder air path:



More pics in the next post:

[Wally]

Obviously this idea has worked better than the older BAS 'low' shroud, so I will 'use' this idea in my own 'mold':









I need to make a mold from this form later, then make a shroud and then cut that one up to make a wider one from it...Pfft lots of work ahead. Luckily its X-mas holiday and I can foul around a little.

Walter

[Wally]

This is version 2.0



Yeah, I know what it looks like

The idea is to help the air make the 90 degree turn towards the heads and than again 90 degrees so that the air flows alongside the heads and air comes from the front (again, like original) and from above.
With this form I hope the air stays laminar and the heads that need more air get it in this way.
Also hope that overall cooling is better now the heads are more favoured for cooling

Walter

[bigwigracecars]

Originally Posted by Sandeep

The shroud with the mods to the back of the 911 fan is working great. The hottest temp I have to date is 361F on #4 at 17 psi, 5400 rpm in 4th.

The car runs awesome with the turbo with temps averaging around 320F while driving around town. On the highway they average about 340F with all cylinders within about 10F of each other.

The Megasquirt EFI really helps as well, as does the LC-1 because I can dial in exactly the A/F ratio I want. The EDIS helps as well because of the programmable ignition.

I really did not know what A/F ratio I was running with the 44IDF's and not exactly sure of the timing with the 050 Dizzy, because the temps I am getting with the EFI/EDIS/Turbo are close to what I had with the 44 IDF's/050 Dizzy/No turbo.

So overall, I am extremely happy because I KNOW I have a 911 shroud that cools well enough for me to run a turbo at 17 PSI

Engine is currently apart to fix a loose valve seat and is getting an overall refresh. Will be terrorizing the streets again in spring 2007

Sandeep

sandeep

I know this thread is old, but Sandeep, can you repost the pictures of your shroud mods? They're not showing up any more, and I'm interested to see what your final set-up looked like.