355 Challenge Grill from Exotic Auto Recycling?

Yes, but the car isn't stationary, is it? It's going down the road at often high speed with air entering the engine compartment through the radiator openings and then trying to continue on out the back. With a closed back panel, it has to then change direction and go up. With the open panel it can keep going out the back. My point was that a small amount of opening can make a huge difference, and the percentage here is not the point, the actual area is, which is quite large and equivalent to a large hole in the back of the car.

 

Agreed yes every little bit helps!!!!

Want to really help get that big muffler heat sink out of the back and change the heat shields.

Played extensively with thermal feedback, runaway loops in vehicles (diesel) that balance areo vs cooling, cooling always wins.

The 355 can get huge improvements on what we learned last 5 years, was thinking of doing a bit of it but the car runs cool enough and I dont track it

 

There are actually 2 different #15's.....yes, 2 different CH grilles

Guys do your homework on fundamental aerodynamics....The side inlets do not flow thru the engine bay..part #11 on the right and left wheelhouse vent to the wheel well opening.

 

I think there are two thermal challenges to consider though:

1. Intra-engine temps - which based on a couple of threads I've seen (the "what temp do you run at?" poll), and my experience so far - are not a problem. Seems Ferrari engineered the cooling system to keep the block and heads suffeciently cool, which is good.

2. Intra-engine BAY temps: These, on the other hand, stike me as a problem. I have a point-and-shoot thermo and check several spots around the bay after each drive. I'm seeing 540 degrees F on the top of the (stock) header headshields - and about 212 F on the top of the oil filter right after shut down. I always drive slowly before shut-down.

There are countless threads about baked motor mounts, CV joints, ign wires etc.

So - I'd love to know what the collective wisdom is around lowering the bay temps as much as possible.

I searched for some wind-tunnel test pics - in the hopes of seeing how things flow off the back of the car. If there's a mild vacuum there - the CG might struggle to overcome that.

Or - with the substantial longitudinal flow I suspect exists through the bay (hampered by the solid rear panel) - the CG will help a good bit.

I'm keen to learn more.

RK

 

#11 and #14

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I understand that and if you look at Dave's car with the grill removed, the amount of open space under that grill is not even the full surface area of the grill. The small windows further limit the space and with the perforated covering, as I said, I bet the effect is marginal at best.

As far as radiator openings and air flow, again that is all impeded by structures in the engine bay. There is hardly a line of air flow from the back of the radiators to the grill area.

If yu were to remove the lateral diffusers under the car you would probably actually get some airflow through the engine bay.

 

Exactly. There is no air flow across the engine bay that this minimal grill is receiving as an exit point. It is just radiant heat from the engine and the exhaust system and with all the obstruction I just doubt it is a factor.

 

Bruce, when my car was first raced in 1995, the Challenge grill was not yet available...

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It looks neat and is another source for vertical dissapation.

As Bruce said, the radiator airflow does not flow into the engine bay. There isn't a direct source of incoming air into the engine bay that the minimal opening in the challenge grill is vacating. There may be some coming from under the car and up and as I said , removing those diffusers would actually increase it I think.

 

I am sure that they realized they had a heat issue and made changes accordingly.

Common sense just tells me that the minimal openings in the body under the grill, covered by a less than 25% perforated sheet of metal on the back of the car, behind the muffler and heat shield with no direct input of cooling air just isn't doing much.

Again, if you like the way it looks then that's all that matters.

 

Think a little about aerodynamics. At speed (not necessarily high speed) there will be a low pressure area behind the car. That will suck out air from the engine compartment through the grill. The internal path doesn't have to be clean. Air can go around corners.

 

Well that is the only factoid so far that makes any sense to me if it is more than theoretical as far as "sucking" out of the engine bay is concerned.

Oh, but the 355 has a deck lid spoiler that reduces drag
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Dave, once again listen to what the man said. You can test your theory at Watkins Glen 8/29-31.




[ame=http://www.youtube.com/watch?v=OF2wmiE3yzo]Listen to What the Man Said - PAUL McCARTNEY & WINGS - YouTube[/ame]

 

A) Rear deck spoilers do not generally reduce drag. More likely they increase it. Their function is primarily to increase down force.

B) Here is a picture I just took. At the left the camera is sitting on the muffler heat shield looking at the engine. At the right it is at the same position looking out the back. need I say more?
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That's not what that image I posted says John about the drag. I don't know enough about that to debate it or whether it adds to heat extraction.

If there is significant air movement (volume) through the perforations then the heat will get carried with it. If its just passive radiance, I don't see it.

 

Johnk just took a selfie of his crotch.

You guys have too much free time. Challenge grills look good, and likely help remove heat from the engine bay. Not sure where the debate lies.

My next 355 will have one for sure.

 

Yes, free time today Luke. I am the only one on the other side of the debate so that's where it lies

An hey...you don't own a 355 anymore. Others have been crucified in here for participating in discussions. Now you know I'm joking. Smiley face coming

 

Don't confuse the fastback Mustang with a classic "notchback" "butressed" Ferrari mid engine body design. The vertical rear window causes a pickup truck style curl above the engine compartment. This low pressure area pulls the pressurized air from the compartment up out and back over the rear tail lights and bumper. The fans and side scoops allow air into the compartment slightly pressurizing it. That's why the 348 and 355 grills are angled backwards or open in that direction. I thought the lid scoop on the 355 may actually draw air in but I suspect now that it does not unless there is some other route along the front of the engine. In fact, the slight bump may create another curl to draw air up from that area.