Aerodynamic aids and 1/4 mile time improvements?

[Guest norm[T12SDSUD]]

Has anybody tried different airdams or any other type of aerodynamic add on and noticed an increase in 1/4 mile times?

 

I have read where supposedly there is little to be gained in the 1/4 mile with aero parts until 140 mph, but I'd like to know if anyone has put an air dam on and then noticed an increase in mph in the 1/4 mile.

 

 

Thanks,norm

[DavyZ]

Norm, I think Don Manzo (dmanzo) installed an airdam on his Z, a 383, 700R4 11 sec car, but I'm not sure how much he frequents the board! If he's the one I'm thinking about, THERE WAS a difference in times. I hope he sees this.

 

Davy

[Scottie-GNZ]

With my trapspeed approaching mid-130s, this is a topic of interest. However, unfortunately I am pretty much stuck with the spoilers I have which were originally installed for road racing to generate downforce, the opposite of what your for high drag racing trapspeeds. The one thing I would strongly recommend is the adition of headlight covers. I cannot vouch for its effectiveness, but sticking out my palm facing the wind is enough to tell me it must be doing something at 125+.

[A. G. Olphart]

Scottie, you are not at all 'stuck' with the spoilers you have!!

 

I'd be more than happy to take them off your hands should you feel the need for a change .

[johnc]

You can see measurable drag reductions at 70 mph. The old Car and Driver test of aero aids on 1973 240 showed that a vertical air dam in front that lets air spill off the sides and keeps it from going under the front was the most effective at drag reduction. In addition, a 7" tall rear spoiler set to a 30 degree angle gave the best combination of drag reduction and downforce. The combination of both improved fuel mileage 1.3 mpg at 70 mph.

 

but sticking out my palm facing the wind is enough to tell me it must be doing something at 125+.

 

And we all thought you were just waving to the crowd as you went through the traps...

[JMortensen]

I'm betting that test was done at stock ride height too. I think you'd get a better result if the area ground clearance area below the air dam was smaller allowing less air under the front of the car and did some simple stuff like sealing the hole between the valance and the radiator support.

 

Jon

[Scottie-GNZ]

And we all thought you were just waving to the crowd as you went through the traps...

That's hilarious :D

 

The reason I said I am stuck with my spoilers is that the outer ends of the 3-piece rear spoiler is actually bonded on the rear quarters.

[Brad-ManQ45]

Nothing a grinder and a little bodywork couldn't cure...

[Sparky]

Does anybody have any Drag measurements for the Gnose bodied Zcars?

I'm curious as to what kind of benefits, if any, you would see from that.

[John Scott]

You can see measurable drag reductions at 70 mph. The old Car and Driver test of aero aids on 1973 240 showed that a vertical air dam in front that lets air spill off the sides and keeps it from going under the front was the most effective at drag reduction. In addition' date=' a 7" tall rear spoiler set to a 30 degree angle gave the best combination of drag reduction and downforce. The combination of both improved fuel mileage 1.3 mpg at 70 mph.

[/quote']

7"! A bit higher than anything I've seen offered.

A little off topic, but what speeds were the BRE racing cars attaining? I'd love to hear more of the history. Was there any aero gains from their rear spoiler, front spook? The early Zs have such an asethetic design, too bad thier aerodynamics are more like a 4x8 sheet of plywood.

John

[jap tin]

I run the headlight covers and the small rear deck spoiler on my Z . I also have a piece of lexan in the grill to help block off air flow there also. No front spoiler or air dam. Runs nice and smooth at 157 mph in the quarter.

[BobsZTwins]

I remember reading some test years ago where a big reduction in cd was achieved by adding headlight covers. The winningest road race Z's all ran headlight covers, must be something to it! Plus, it includes a reduction in radar profile!

[Phantom]

Think G-nose, headlight covers, and underbody panels. The Gen 1 Z's have terrible CD's but a lot can be done to improve it.

[Owen]

What's everyone's opinion on the shape of the front air dam? The aftermarket ones currently offered are curved and look like they would effectively spill air out to the sides. But what about one that was more rectangular in shape, like a Skyline GT-R? I'm just thinking looks vs function here.

Owen

[johnc]

It depends on what you want to do with the air. If you just want to get it out of the way and reduce drag, spill it to the sides and keep it from going under the car. If you want downforce, make it square and vertical so you build a nice high pressure area in front and then put a splitter on the bottom that takes a lot of the high pressure and creates downforce.

 

I'm probably going to be building something for my 240 in March.

[BobsZTwins]

If you want to see a Z that cuts the air about a good as any, check out Andy Flagg's land speed record Z. He went 163.495! Here's addresses to some pics:

 

http://www.scta-bni.org/El_Mirage/ELM%2002/May/photos/pictures/cars/0220.JPG

 

http://www.scta-bni.org/Bonneville/World%20Finals/World%20Finals%2003/photos_BT_17.htm

 

And, yes, it's a 2+2. I think the longer wheelbase is more stable and has less turbulence at the tail. There's a nice article in the 11/02 (I think) Group Z newsletter about Andy and his land speed record attempts.

 

This one managed "only" 150 mph. Maybe the G nose had something to do with Andy's success (duh):

http://www.scta-bni.org/El_Mirage/ELM%2002/Oct/photos/cars/0742.JPG

[Guest zcarjunky]

wow, I had no idea that 160mph was a land speed record for a Z!! How do I enter my Z for the land speed record. I have had it past 150 on several occasions.

 

Maybe I should go for the record!!

[Owen]

It depends on what you want to do with the air. If you just want to get it out of the way and reduce drag' date=' spill it to the sides and keep it from going under the car. If you want downforce, make it square and vertical so you build a nice high pressure area in front and then put a splitter on the bottom that takes a lot of the high pressure and creates downforce.

 

I'm probably going to be building something for my 240 in March.[/quote']

 

Cool! Can't wait to see it. A while ago I think someone photoshopped in a GTR front air dam, also seen a mock up of a Z33 air dam on a Z too, but was thinking the big square front didn't really match the body style. At least not as well as a 240SX/240Z front end body kit that's out now.

Owen

[BobsZTwins]

Regarding the LSR for a Z, there are of course different classes, Andy ran with a Z engine in F (123 to 183cu in) GCC (unblown gas competition coupe), not a built up V8. I've seen Z's running nitro do 200+ in the 1/4 but that would be a little different class! But you have to make a qualifying run in both directions so the car can't be a hand grenade.

[Guest norm[T12SDSUD]]

Bump.