Accufab exhaust, tune, & pully warped my vents.

[Gulf GT]

Thoses at the rally would have noticed that Stillen's car had mods on the front splitter, rear spoiler, rear tunnel and flaps above the radiator exits. I presume that all of these changes are balanced to increase downforce and handling on Stillen's race car. Do only part of the changes and all bets are off.

Also, I think Stillen's car was set up for the rally in New Zealand, which has a maximum speed limit of well under 100mph. So, high speed changes in handling might not have been their target when making those specific changes to their setup. Just speculation.

 

[Specracer]

I know the answer to this one, told to me by a team member..... If you look at the CP cars, there are not these screen vents. These were added when it was discovered that with a good cross wind the direct "ram air" effect was messing with the MAF, causing the car to go lean. The vents allow the high pressure of a cross wind to vent into the engine compartment.

"He also did a cool air mod by blocking the engine bay air inlets and removing inner clamshell baffles. 100% cool air intake. Installed "

What is the story on having the screen there, was there an air flow issue of some kind the air box or MAF did not like?

Are the balles behind the screen or in the air box?

What is the downside of blocking these?

 

[427Aggie]

Ahh someone was standing there when Mark was talking about the car

And yes he said the added height to the front and rear spoiler would add ALOT more downforce to the car.

 

[cobrar1339]

Specracer, it sounds like the vents must ram a lot of air at speed. The saga sounds similar to the ram air discussions on the Vet forums. They sell a product called Vararam. This intake is known to create a lean effect as well. Some guys report better trap speeds with it as the lean effect boosts power naturally.

The question is how lean is too lean and at what mph does it come into play?. The tuners actually worry about the duty cycle of the injectors on those cars. They don't like conditions they cannot simulate on the dyno very well. When you start out as rich as we do, I wonder if that is only a bad thing under certain conditions , or a good thing under certain conditions. The ram effect on a blown car I doubt is that big a deal, but it is interesting.

 

[Beach-GT]

I ceramic coated my pipes inside and out and additionally put aluminum heat reflective tape on the clam shell just below the vents to reflect heat away.
Runs cool and have had no warpage ploblem with the vents. I'd worry about too much heat affecting the paint on the tail with red hot bare pipes. With the extra space afforded by removing the muffler I've been thinking of adding a small fan to blow the heat out the back and away from the air filter box. This would further reduce the heat in the back when shutting down. An 8 inch thermostaically controlled fan is under $100. :biggrin

 

[AZGT]

I've been thinking of adding a small fan to blow the heat out the back and away from the air filter box. This would further reduce the heat in the back when shutting down. An 8 inch thermostaically controlled fan is under $100. :biggrin

I looked at that too.

One of the smaller fans would fit cleanly over the scooped air inlet on the passanger side, but I put the transaxle cooler which takes up the room.

Also though of putting one in the back to draw air out when the car has been shut off, but did not see a good place that would be away from the exhaust so as to not melt the plastic. I was looking at the Autozone / Pepboys / checker fans (had one that had a thermostatic control).

Better option might be some type of squirrel cage fan like from an A/C unit. More compact, usually metal body and cage. Haven't looked into that yet.

 

[kosupply]

Chip,

Some very interesting observations. I believe that the primary factory at play here is the physical location of the exhaust and tube bends (heat concentration points) of the Accufab. I believe that this is much more a factor than the pulley/tune. Unless you are driving aggressively, the car will operate at 14.7:1 a/f ratio - regardless of tune or OEM set-up. The Heffner (like most tunes) will run leaner and higher HP in open-loop (aggresive driving) mode but will quickly settle down to closed-loop 14.7:1 as soon as you are "off of it". Your around town, stop and go city driving will closed loop and 14.7:1 (unchanged from OEM set-up). I guess what I'm saying is that the Heffner tune/pulley will in fact produce higher temps and more HP but this is typically and higher road speeds with more airflow in and around the exhaust. I think that your highest under hood air temps occur in "normal" driving - especially in stop & go with high ambient temperatures. As such, you pulley/tune are not in play - but the physical properties of your exhaust is still a contributing factor.

I am on my 3rd set of vents with 9100 miles. My first set were warped at 2000 miles....stock car at that point. I was tracking the car some and saw 220 degree temps. Because of the slope of the clam shell, the lowest point of the vents is above the exhaust. I now have the Heffner , Hennessey pulley and tune, quit tracking the car, and the vents on the car have not warped for the last 3000 miles.

 

[Specracer]

Yup, but he told me last year too.....

Thanks again for the shiny silver disc you handed me on Sat.

Andy

Ahh someone was standing there when Mark was talking about the car

And yes he said the added height to the front and rear spoiler would add ALOT more downforce to the car.

 

[timcantwell]

I've had the Heffner Pulley and Tune for 7000 miles, and the exhaust for probably 2500, and no vent warping. That includes some serious high heat desert driving as well as enormous heat and humidity up here. What can I tell you?

You live a charmed life Dave!

 

[Sinovac]

I'm no expert but perhaps metal (aluminum, stainless, etc) isn't the solution. Metal obviously has different thermal characteristics than plastic and if a metal vent really heats up it might not warp but it might get hot enough to damage the surrounding paint. I would think another composite product would be the answer but I can't say for certain. Thoughts?

 

[AZGT]

I'm no expert but perhaps metal (aluminum, stainless, etc) isn't the solution. Metal obviously has different thermal characteristics than plastic and if a metal vent really heats up it might not warp but it might get hot enough to damage the surrounding paint. I would think another composite product would be the answer but I can't say for certain. Thoughts?

We'll see.

I have top and side metal replacements in the works (prototypes).

I had already thought about heat, expansion, etc.

If they work, I will check them with the infared thermometer and see if they have any more heat than surrounding areas.

 

[shesgotlegs]

"He also did a cool air mod by blocking the engine bay air inlets and removing inner clamshell baffles. 100% cool air intake. Installed "

What is the story on having the screen there, was there an air flow issue of some kind the air box or MAF did not like?

Are the balles behind the screen or in the air box?

What is the downside of blocking these?

At the rally Steve Stillen mentioned that his GT race car at one time had problems at very low speed whereby the engine would stall when being moved around the lot - something to do with cross wind / air pressure change. It was determined that his very early car didn't come with baffles from Ford but definetly needed them.

On another note if anyone noticed, his clam shell underside was finished in carbon fibre and not painted black carbon fibre like our cars. He said it was because Ford didn't want anyone potentially complaining about imperfect looking carbon fibre.Too bad.

 

[Arm]

My car is bone stock and the passenger side vent was warped within the first 1200 miles. I always left the clamshell open to cool off after a drive.

And speaking of warpage, I think the clamshell itself is slightly warped on the passenger side also. Anyone else experience this? :frown

 

[AZGT]

Update

Just to keep everyone posted, I have 3 prototypes in the works for replacements for the top clamshell vents. :banana

One will be a more or less direct replacement. Two of them will be a more retro style option.

The sides will also have a couple of options - one essentially a replacement, and then some modifieds.

All will be made of aluminum, so NO WARPING. :thumbsup (Warp is only good if you are Captain Kirk - wait a minute, these will be the "No Kirk" options :biggrin).

As I get some rough inital pieces, I will post some images to get an idea of forum impressions. Some of the idea may "fly", some may not.

Stay tuned.

 

[Spirit]

Will Do

As I get some rough inital pieces, I will post some images to get an idea of forum impressions. Some of the idea may "fly", some may not.

Stay tuned.

Thanks for the update. :thumbsup

Looking forward to seeing what you have come up with.

By the way, I enjoy staying tuned. :lol

 

[Sinovac]

Just to keep everyone posted, I have 3 prototypes in the works for replacements for the top clamshell vents. :banana

One will be a more or less direct replacement. Two of them will be a more retro style option.

Might there be a Mark II scoop on the horizon?

 

[SteveA]

My car goes in for a replacement set on tues. The plan is to remove them when I get home and replace them with the warpped set for everyday use. It would be very cool if one of these aftermarket options goes into production and I could just junk the bad set.

 

[Kip Ewing]

vents in carbon?

Anyone up for vents in carbon?

I had planned to get to this one, eventually, but it looks like there is immediate need.

It would be pretty tough to do a carbon version of the original louvered vent.

My intent has been to do something in the spirit of the flat panel with the oval slots some of the original race cars had.

Interested parties PM me and I can start planning.

Oh yah, get ready to see something cool for the car's instruments sometime next week...

 

[Ed Sims]

carbon fiber

Kip - Can't wait to see what you have for us next!

Shesgotlegs - The CP car Millen is using had the CF engine shell liner of a standard weave while our GTs have a less expensive CF. They are a mixed/loose fiber but not painted. It is CF but almost could pass as plastic. Is this right Kip?

Ed

 

[Kip Ewing]

Carbon

Greetings Ed

The car that Millen has is a very early car. Not sure what the number was.
A very few of the early development cars had inner clamshells that were from a 2x2 twill weave carbon. The regular production cars used a unidirectional fiber carbon. I can't recall why we went that way in production. That would be one for Bill Clarke to answer. Usually the reason is to use the fibers most efficiently for a given load path. It doesn't look as cool, though... The Z06 fender is a unidirectional fiber, but it is painted.