The 355 'spider' idle stumbling problem is solved!!!!

So the last pic shows a happy Ferrari owner now or is that the mechanic you had been talking to about the problem!!!!!!!!!!

 

Pretty cooooooool.

 

Very nice design---Simple yet very practical!!! Kudos to Goth!!!!!!!!!!!!!!!!!!!

 

Good on ya, Goth!

 

Very nice fix. Nice clean approach.

Another approach that takes a little less effort is to pop rivit an extension to the fin between the air inlet for the fan and that for the engine Behind the door opening and only on the left. About a 3" extension does just fine at seperating the air flow and eliminating the issues you speak about.

"as far as I was told it was an unfixable problem" Nope, fixing them since 97.

Dave

 

I'll drink to this.

What did he do again? And where are the pics of women sprawled out on his car?

 

Nice work goth!!

 

Is this problem only Spider related or can any 355 benefit from this?

 

First off great work Goth! But how did you figure out this is the cause, and not just a voltage drop from the fan kicking on? That was my first guess when I saw your issue posted elsewhere...

As for our intake vents, I think they too are fed from down low (at least on the '99, maybe all 5.2 cars) I won't be able to verify this week, maybe 285Ferrari can take a look - aren't ours fed the same way? I think I just read somewhere here that the 2.7's are fed up top through a separate inlet, while the 5.2's are fed through the bottom an could feel what Goth described.

Edit: also any concern with blocking some radiator area for cooling while driving? I know while driving I'm normally well under 190, but maybe spirited driving in 100F ambient could tax the system, or track days

 

I can think of two cars locally where your mods would benifit them regarding enhanced cooling. Your approach to this and your fab skills are first rate.
I do believe by making the fan more efficient you might find over time the idle problem gets worse.
The root problem relates to the cooling fan drawing air flow away from the engine air pick up. Due to the sensitive nature of the MAF, the temporary slow down of air flow to the engine when the fan starts caused, in many cases, the engine to actually stall at idle.
I found on the effected cars that the one fin between the rad. air duct and the engine air duct was radiused and cut back away from the cold air side. Extending the fin a couple of inches seperated the air flow between the two areas and eliminated the problem. We had new cars on the showroom floor that would die when the fans first kicked on.
If your ducting works as I suspect and increases the efficiency of the fan on the radiator I can see where it may well agrivate the idle problem in the long run.
What I do see here is a possible perfect fix for the long run time of the cooling fans on the 355. I would be very interested in weather you see a change in the run time of the fan after a hard drive. This is something I have been chasing for years and have not found the answer to.

Dave

 

Oz, I am impressed. Great work my friend.

 

348 Spiders have similar (or identical) cold air intake plumbing above the side radiators, and on mine I do notice the expected dimming of the dash lights when the left side radiator fan kicks on.

I'll stick my hand in there this afternoon when the fan kicks on ("Hey y'all, hold my beer and watch this") to see if that area is hot on 348's, too.

...but I haven't personally noticed the engine itself stumble when the fans kick on (just the dash lights dim briefly). Maybe it's happening and I'm just obtuse, though.

348's don't have an intake air temp sensor other than the MAFs. Perhaps that is where the 355 sees an issue (since 355's do have additional temp sensors).

However, if your shroud is reducing cooling time and fixing a hot air intake problem, then 348's might benefit from added performance and gas mileage with your shroud even if 348's aren't seeing the same engine stumble that you see when the fans kick on for 355's.

So your shroud might help 348's with power even if we don't have the 355 stumble issue.

Frankly, I think that you are on to something.

My old Porsche 928 used such a fan shroud, and it ran like crap when that shroud was removed. But with the shroud it ran fine.

Now here you are improving a 355 with that shroud, and 348's have a similar fan and intake plumbing setup.

 

So lets re-cap here - Oz has a fabulous car, he drives it a lot (unlike a certain 348 owner near him), he gets the hot babes, and he makes a mod that impresses one of the three repair gods on fchat.

Oz, WTF do you eat for breakfast eh? You must be walking on air now.

Maybe you will be new celeb at the Fchat awards ceremony and not poor Pap - he is like the third act now.

 

Goth,

Watch for the cooling fan to be running while you are driving. The ducting will be slowing down / possibly limiting the ram air flow through the rad. while driving

Dave

 

Ha! Good point. He needs vents/flaps that open only one way (i.e. when driving) but that close when the fan kicks on.

That would be a slick mod.

 

ABSOLUTELY correct Dave......what Oz has brought to the forefront though, is the cold air intake on the 355 IMO sucks big time.

I am amazed at the underhood temps at critical areas. YOU CANNOT restrict the air flow in any way at the radiators and coolers.....if you do,long term, it may lead to premature failures of the catastophc kind. I will be looking to redesign all of this further down the road as intake air temps are already ridiculous, and adding extra heat from radiator/cooler dissipation into the engine bay is unacceptable.

If I owned a resturant I would buy a 355 and use it to cook all the meals on....the whole back of the car is hot enough....lol

 

OK, I took the 348 out for some lunch (had to go make a deposit at the bank, too). As she got hot, I opened the driver door at a stop light and felt nothing but cold air in there. Once she got slightly hotter, the left fan kicked on.

Non-cold air was then blowing forward, out of my door vents (at the corners and left/outter side)!



...so, we need fan shrouds.

No problem with the idle, though. Rock steady 1000 RPMs prior, during, and after the left fan kicked on.