fabbed up cooling shroud

[Sandeep]

Originally Posted by Massive Type IV

Sandeep, While there is a documented 6HP loss from the Porsche set up, there is also a documented 23HP loss on the same dyno, with the same heads and cylinders and same drive ratio as the 6HP loss. Six HP is the absolute least i have ever seen with any 911 system- ever. Most are 15-18 or more..

Is this with the same shroud as well ? Interesting ... any idea why ? I would think that HP loss has to do with the fan trying to compress the air in the shroud as the shroud can't get rid of it quickly enough (too much restriction from cylinder and heads + tin).

Originally Posted by Massive Type IV

Look for that one to come from right here in late 2006 or early 2007.....

Cool ... If you can get one to cool evenly, even if it does not beat the DTM, you will have alot of buyers .. me included. :agree:

I blew out a CV joint this week, have the parts to fix it, datalogger is installed ... looking forward to seeing some graphs. I'd be happy to share them.

Originally Posted by BOBTAIL

I really have a problem with accepting that a T1 fan is the best solution. If it were that good then Porsche would be using it too..

I believe the reason the T1 fan works on a T4 is because there are only 4 cylinders to cool, and the output of the T1 fan can be routed between the 4 cylinders like on a stock T1.

I'm thinking in the early days of the T4 upright conversion, someone found out that the 911 fan was easy to adapt to a T4 for upright cooling, and designed a shroud just to get the engine in the bug and that was the main reason, not even cooling.

With all of the tuners offering the 911 shroud, each seems to be a variation of that original theme, but trying to take cooling into account.

Sandeep

[Bad bug]

This is what i am talking about, finally a 911 shroud that will work. Can someone post pictures of a diverter i want to check if i have the correct item.

[Massive Type IV]

If it were that good then Porsche would be using it too.

Nope, the 911 engine was designed for an Axial fan- Thats why it works well on a 911 but not a TIV..

BTW- It IS that good, ask Zen or email nosubt2@aol.com and ask him what his race engine (F prod 1800 TIV) did after removing the 911 shroud and opting for a DTM..

The DTM works well enough to keep my 3 liter cooler than a stock 2 liter and thats with 10:1 CR....

The dyno says it works and the satisfied users back it up.

[BOBTAIL]

I'm thinking evolution here, the 356 had a bug style fan and the cammer had a different style ...why?

The Gol had an axial fan, at the end of play its about air flow and pressure.


Ah I don't know why I'm posting this who am I trying to convince?

BTW I think you'll find the cooling was designed for the engine, not vice versa.

[Wally]

Originally Posted by BOBTAIL

I'm thinking evolution here, ...

True, the later a new engine type is designed, the more one would presume its a better design than its predecessor.

However, the engineers had a lot of constraints they had to stay within. One obvious one that comes to mind (especially regarding fans and besides build-cost) could be the available 'space' on top, in front or whatever side of the engine.

So, the best technical solution, is not always what has been produced...

Greets,
Walter

Edit: The mail just brought a 993 head by today Nice design. I believe it has a 49mm intake valve and a 41mm intake port stock for a 100 mm bore

[Massive Type IV]

The fan was designed for the engine and the engine designed to work with the fan as a unit...

Sit down and look closely at a 547/587, 616 engine and the 911... Then look at the TI and TIV and compare them all to each other. Compare the thickness of the fins on the cylinders and heads, their placement and even their length...

I think Russ's 911 shroud works fine for what he does because the engine is more closely related to the 911 than a TIV or any other radial fan equipped engine. I would like to get some data from all 4 cylinders of russ' engine to see how they compare to what I have seen with the TIV head based engines and even what I have seen with my billet heads and the DTM. It might help shed some light on why some things occur.

VW didn't spend the huge money on equipping the engines with Aluminum cylinders and etc so they had to create a coling fan that had a ton of potential. This was way cheaper than putting more into the money into the engine internals that would generate less heat.... Thats my hypothesis on why that fan works so well on the TIV, the added surface area gets the heat into the cooling ai stream faster and the high pressure air is forced in ever nook and cranny to get that cooling air stream more powerful and effective.

In EVERY dyno test I ran my dyno cell ran hotter with DTM cooled engines than with any of the 911 systems, while the engines ran cooler... Proof that the air was being shed into the room at a much higher volume. These temps were as much as 30 degrees on the same day without variable weather between a DTM and two different 911 style shrouds...

Just an ironic thing that we noticed while plotting every damn temp we could!

[Bad bug]

Hi Guy's
Can someone tell me if this is the original 911 turbo fan. The markings on it are 901 106 101 5r. Wally what ever happen to the photo of the diverter.

[BOBTAIL]

Originally Posted by Massive Type IV

The fan was designed for the engine and the engine designed to work with the fan as a unit...


I think Russ's 911 shroud works fine for what he does because the engine is more closely related to the 911 than a TIV or any other radial fan equipped engine. I would like to get some data from all 4 cylinders of russ' engine to see how they compare to what I have seen with the TIV head based engines and even what I have seen with my billet heads and the DTM. It might help shed some light on why some things occur.

Worth noting that Russ has used the same cooling setup from 100 hp all the way to 400+ and always using the stock undercyl shrouds
In 10 years of racing i think he still is using the same crank and rods (we keep telling him to push the boat out and treat himself to some new stuff!!)
Its true he's had less sealing issues now he's got 911 heads on but it could be for more than 1 reason i.e better sealing technique, better air managment of 911 heads etc