This old thing?? It really does run cooler ........... the LH fan hardly turns on with this grill ....... Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Have you thermally scanned the engine compartment before/after (the muffler changes)to see what the temperatures variances are? If so, what was the difference? I have run my 355 both with many different exhaust confirgurations (stock exhaust with bypass valve, stock exhaust with challenge bypass pipe, race tubi with bypass valve, race tubi with bypass pipe, race tubi with cat delete pipes and bypass valve, race tubi with cat delete and challenge pipe). I also have the challenge grill and through out all the above configurations I noted NO difference in engine bay temperatures.
Have to wonder how it is possible to replace a significant part of the engine bay wall with mesh and see no reduction in engine bay temps? Seems odd to me. Surely it would allow heat to dissipate due to having another 'open' surface. Also, the diagram Oz posted above explains the theory on the exhaust outlet scavenging effect.
I am not familiar with the build on those systems. However I can say the thermostat (rightfully so) controls the engine temperature and unless you are measuring the engine bay temps when the car is running down the road, you will see little to no difference. The exhaust muffler I build, has a built in 'multi layer' heat shield so as to 'slow' radiant heat and keep it in the exhaust pipes, but if there is no air circulation, everything can eventually saturate (sitting in traffic) and be at the mercy of the radiator fans. Also on my exhaust the flow path does not change in cross-sectional area, so there are no stagnant chambers or extra metal baffles that can trap heat inside the muffler (heat sink effect). With my rear grill (and driving) the temps on the gauges go down far quicker than with the standard grill. I timed it and it was about a 50% improvement to get to the same place on the gauge. This effect gives more cooling 'capacity' .......... so you can drive a bit harder and the temps will take 'longer' to rise. The challenge grill is better for cooling than stock. My grill has a tad more vented area than the challenge grill. It is all about air circulation and the net gain is more cooling 'capacity'. Think about boiling water in two identical pots and identical BTUs under them, one is covered with a lid (standard grill) and the other is open (challenge grill). Which will boil the water first? +1 .......... it is all about moving heat saturated air out, which allows unheated air to take its place ........... the cycle repeats itself .... .
Were Bernoulli and Heimholz acquainted? Perhaps married to sisters? Was their study of "effects" carried on simultaneously? I can see Heimholz standing at the intakes and Bernoulli at the exhausts. Maybe they shared tools.
My car has the challenge grill but I was not referring to the effect of the challenge grill or Goth's grill in this post , rather I was referring to the many different exhaust combos I have had with no evident heat reduction in the engine bay.....and so was wondering if anyone had any thermal heat readings of the Goth muffler/engine bay temperatures.
The challenge grill is a 100 % mesh grill but the Goth grill is not but has what appear to be larger vents/slots in the middle but with sheet metal around the taillights......I would say cooling capacity is somewhat similar though. I don't see much of a difference here (cooling wise) when I look at your pictures and my challenge grill. Both vent with little obstruction. I re-read your post and see you are comparing the cooling capacity to "THE STANDARD GRILL", NOT THE CHALLENGE GRILL. Then there would be a major increase in cooling capacity because "The Standard Panel (Grill)" is just a closed piece of sheet metal bodywork (thats only purpose is to hold the tailights) with NO cooling capacity at all.
The challenge grill has about a 25% 'open area' ratio. My grill has about a 70% 'open area' ratio. The area around the tailights is blocked off by the car structure (behind the grill). .
I just shot a flashlight through the inside of the Challenge Grill and it is 100% slotted on ALL SIDES, even around the tailights. And the taillight area is NOT blocked off or obstructed by the cars structure (there is an 1.5 inch x 7 inch opening on the centre inside portion of the grill).....so heat can vent out through inside of the tailight area as well. Anyone with a challenge grill on their car and a flashlight can see light streaming through almost 100% of the grill. Regardless if the car has the Challenge Grill or the Goth Grill, the car is well ventilated with the hood venting and rear grill venting be it at rest or at speed.
I'm going to remove all rear body panels and the rear bumper on my 355. It will be very well ventilated. Nice work Goth. I really like the exhaust cut outs.
[sigh]..... Scroll down to the section that explains 'open area calculations' http://www.marcospecialtysteel.com/perforatedmetal.htm Simply because there are holes 'all over' does not mean it is 100% 'open area' ........ More 'open area'= more cooling 'potential' ......... that said larger 'open area' can only do so much, so any engine compartment is better ventilated when the car is moving. So if the car is moving in 'addition' to more 'open area' there will be better cooling capacity.
I will be getting video and sound in a week or so and dyno will be first week of August. These projects are big and take time. Goth worked on this exhaust for over 6 months so please be patient.
Exactly! Too many people don't realize that the shape of the metal around the holes and how big the holes are, has a big effect on how the air flows through the holes also. Anybody ever see those honeycomb or mesh filters that go on top of injector stacks? They aren't worth a crap at filtering air, but excellent and blocking airflow. But then again, we're talking about air moving at a lot higher speed. That grill and exhaust are very nice. Very interested in hearing soem dyno numbers. Too bad we don't live closer together, Oz. We could colaborate on all kinds of things, I'm sure!
