Ask AJ Hartman - Aero Questions

[JP X]

I sealed the top of the bucket with clear lexan. It was pretty simple. But also on my '16 S550 the grille were the air inlet is has a lot of the hex holes blocked off. I felt that was not good so I opened them up with a drill and a dremel grinder. I figure more air is better. I still have no idea why Ford would block that off.

I hadn't thought of that. You probably prevented me from asking another question next week.

 

[302blown]

You'll probably want to seal the top of the airbox but not a huge deal.

Engine perspective: Air entering the grill is ducted to the air box, at WOT the fresh air will be ingested into the engine, at idle/cruise the unused air will go out the vent, sealing the airbox will net some tiny amount of positive pressure but likely not much hp gain.

Aero perspective: the vent will be evacuating airbox air instead of air from the back of the radiator, so a tic of cooling to be had if its covered.

 

[Paul McWhiskey]

I have the GT350 airbox currently but will be installing the closed top GT500 airbox very soon. I did not realize much change in the AIT with the open top and did have my filter get quite soaked when the car sat in a good rain storm with the front end pitched downward in my driveway. I agree that the "ram" from the front inlet with a closed box will be nothing to negligible, but I hope that I can get a few degrees less AIT since the 350 box does not seal well against the hood even with added sealing.

 

[JP X]

Sunday project: done!

 

[Ewheels]

@AJ Hartman
Is there much of a benefit from cutting this portion out? I imagine it creates drag by acting like a parachute. (Ignore the trailer hitch, I'm removing that anyway.)

 

[TeeLew]

Hey, AJ, check this out. I think I might have a couple ideas for you. These are 350R Magneride Struts. I'm using a 3" ID spring and a shock body/perch off a King desert damper. The upper perch is a Hyperco Wobbly-top. If you Dremel the dust cover retaining ears off the bearing, this fits absolutely perfect. I've got probably 15-20k miles on it.

 

[AJ Hartman]

Hey, AJ, check this out. I think I might have a couple ideas for you. These are 350R Magneride Struts. I'm using a 3" ID spring and a shock body/perch off a King desert damper. The upper perch is a Hyperco Wobbly-top. If you Dremel the dust cover retaining ears off the bearing, this fits absolutely perfect. I've got probably 15-20k miles on it.

View attachment 84922View attachment 84924View attachment 84923

Cool for sure. But your missing the biggest advantage of my setup in that it can be installed in about an hour or two on an unmodified strut with just basic hand tools.

 

[TeeLew]

Cool for sure. But your missing the biggest advantage of my setup in that it can be installed in about an hour or two on an unmodified strut with just basic hand tools.

I didn't realize we were competing. You win.

 

[AJ Hartman]

I didn't realize we were competing. You win.

I don't think we are. Theres advantages and disadvantages to just about everything.

 

[TeeLew]

You were asking about the top spring perch and the bearing. Here's the way I made it work. I did mine for me, not production, so there are obviously going to be differences in our approach. To have your initial response be an unfavorable comparison of the two is a little disappointing. When I saw your approach, I thought it was a really cool idea.

You might be better off going for springs with a shorter height to get your static ride back if you want to go much stiffer than 350#/in. That's on the low side for track duty, IMO, but it's about all you're going to be able to damp if you're on the base Magneride struts. The 350R/500 struts and shocks make significantly more force and can take more spring. You've got plenty of real-estate where you're putting your spring on the diameter, but not a lot on the length. The longer the piece of wire you can use for any spring, the better they tend to be in terms of rate consistency. 2.5/3.0 barrel or 3" OD straight spring would be easy gain if you're looking for a little extra load capacity/travel.

 

[AJ Hartman]

You were asking about the top spring perch and the bearing. Here's the way I made it work. I did mine for me, not production, so there are obviously going to be differences in our approach. To have your initial response be an unfavorable comparison of the two is a little disappointing. When I saw your approach, I thought it was a really cool idea.

You might be better off going for springs with a shorter height to get your static ride back if you want to go much stiffer than 350#/in. That's on the low side for track duty, IMO, but it's about all you're going to be able to damp if you're on the base Magneride struts. The 350R/500 struts and shocks make significantly more force and can take more spring. You've got plenty of real-estate where you're putting your spring on the diameter, but not a lot on the length. The longer the piece of wire you can use for any spring, the better they tend to be in terms of rate consistency. 2.5/3.0 barrel or 3" OD straight spring would be easy gain if you're looking for a little extra load capacity/travel.

I originally tried 6" springs but they would go solid like 1/4" before the internal bump stop and with the shim stack to maintain ride height (or adjustable perch like I showed in my video) there just wasn't quite enough room. I'm sure with some tinkering and what exact spring a 6" could maybe work but it would be tricky. So 7" it is and since the perches themselves are not adjustable like yours, about 400lbs is about all you'll be able to do with my kit.