to bre or not to bre, that is the ?

[Carl Beck]

Hello zhead240 (everyone):

I'm coming to the thread a little late... but if you haven't decided what to do yet... I will add a few comments that might provide a little more information to help your decision.

I have a couple of 72 240Z's myself. The one I drive most of the time is pretty much stock from the perspective of the body, drive train, color etc. However I have added a few bolt-on options that improve the driving experience, without permanently altering the body; so if at any time in the future, I or any future owner want's to return it to ""pure stock".. it can be easily done.

There is no question in my mind, if you plan to drive your Z at freeway speeds, the addition of the BRE Spook (Front Spoiler/Scoop) is a must have.

According to tests done by Car & Driver back in the early 70's the stock 240Z generates 140lbs of lift on the front tires at 70mph. This contributes greatly to that feeling of front end wonder.. you feel in a pure stock 240-Z.

The BRE Spook generates 105lbs of downforce (ducted type), or 115lbs of downforce (unducted type) at the front tires. This all but cancels the lift.. and has the added advantage of directing additional cooling air into the radiator. The effects of the BRE Spook can be measured at 35mph.. so you don't have to be going 70mph to benefit.

Chris wrote:

>.....snipped...

>....Furthermore, the Japanese cars came with spooks and spoilers. So did

>the European exports. Consider that the front spook is worthless without

>the rear spoiler.

>......snipped...

Car & Driver also tested the factory front spoiler and found it to be all but ineffective. It only protruded down about 3.5" and had no significant effect on reducing lift. Additionally the BRE Spook covers the area between the front lower finisher panel (valances) and the lower radiator core support.. enclosing this area had the added effect of preventing air flow around the bottom of the radiator from the grill area.. thus directing/forcing more air flow through the radiator.

Adding only the front Spook is actually very effective. You will find it locks the front end down to the road at speed and provides far more stable tracking which makes the 240Z far easier and more enjoyable to drive for prolonged periods. (it eliminates that feeling of front end wonder).

Adding the BRE Spook to the front, adds downforce to the front, which in turn pushes the nose down. This then causes the rear of the car to be pushed up.. in other words it adds lift to the rear. The lift at the rear wheels on the stock 240Z at 70mph is 35lbs, adding the BRE Spook to the front increases the lift on the rear wheels by an additional 20lbs. The additional lift at the rear is hardly noticeable... and all but gone if you are packed for a road trip.

Nonetheless - adding the BRE Rear Spoiler (which is about the same as the Nissan OEM type) adds 75lbs of downforce to the rear at 70mph.... which completely cancels the 35lbs of lift on the rear wheels in the stock Z, or the 55lbs of lift at the rear, on a BRE Spook equipped Z. For higher speed road racing you might want to add the rear spoiler... or if you just like the look..

Dave wrote (related to the rear spoiler):

>the spoiler isn't going to help with the fumes...might make em worse.

Car & Driver's Tests and my personal experience would tend to indicate that the opposite is true. Adding the rear spoiler moves the turbulent high pressure area, normally present and pushing directly on the rear of the Z.. which is caused by the Kamm back design... farther to the rear of the car. This reduces the positive pressure that is pushing the exhaust fumes into the cabin in the stock Z... So adding the rear spoiler will, in theory reduce the exhaust fumes normally pushed into the cabin. This has been born out by my experience as well. (it's not a cure-all but it will help).

To properly mount the BRE Spook.. you do have to drill about 7 small holes in the front lower finisher panels. If you remove the Spook, it is doubtful that you would notice these, without close inspection. Nonetheless, if that bothers you, simply buy a used set of finisher panels, have them painted to match the car along with the Spook, and save your stock panels to reinstall, should you ever want to return the car to its pure stock look.

I also agree with the recommendation to buy the Spook from Classic Datsun Motorsports. Les had the original Interpart molds used for the remanufacturing of the Series II BRE Spooks.

hope this helps,

Carl

Carl Beck

Clearwater, FL USA

http://ZHome.com

[26th-Z]

"Car & Driver also tested the factory front spoiler and found it to be all but ineffective. It only protruded down about 3.5" and had no significant effect on reducing lift."

That is a correct statement only regarding Car & Driver's article. There are other tests, including Nissan's that convey different results. That's why the cars were fitted with the devices to begin with. Car & Driver, as well as BRE / Interpart, recommend both devices - front and rear.

"The additional lift at the rear is hardly noticeable... and all but gone if you are packed for a road trip."

That is a subjective statement that cannot be substantiated. What does it mean? Every time you want stability in the rear end at speed, you put a couple of concrete blocks back there?

[Ron Carter]

Les Cannaday, Classic Datsun 760-940-6365

That is where I got my front and rear BRE spoilers.....

[Carl Beck]

That is a correct statement only regarding Car & Driver's article. There are other tests, including Nissan's that convey different results. That's why the cars were fitted with the devices to begin with. Car & Driver, as well as BRE / Interpart, recommend both devices - front and rear.

Hi Chris:

Please provide the source of the "other tests" including Nissan's and/or publish their results for us, I would very much like to read them.

C&D wrote of the Factory Front Spoiler:

..."Unfortunately, the Datsun Spoiler hangs down so little that it isn't very effective. Our tests showed it developed only 35 lbs of front down-force and no measurable improvement in gas mileage. The 3.5 inch vertical dimension is simply not enough to block a substantial amount of under-car air flow."

Secondly, BRE sold both the front and rear spoilers, so of course they would recommend them both. Both BRE spoilers are effective, as I reported from the C&D article.. I'd recommend both BRE spoilers, if the person wants them both.

Recommending them both, for specified reasons (total drag reduction, total down-force etc.), does not in any way imply that the front spoiler is worthless without the rear, nor that they are both "required" in every case.

Your original statement however: "Consider that the front spook is worthless without the rear spoiler." is, I believe, simply incorrect.

"The additional lift at the rear is hardly noticeable... and all but gone if you are packed for a road trip."

That is a subjective statement that cannot be substantiated. What does it mean? Every time you want stability in the rear end at speed, you put a couple of concrete blocks back there?

Actually it is a conclusion, based on both personal experiments (one 72 Z with both front and rear spoilers, a second 72 Z with only the front spoiler)... and supported by the quantitative data provided by the C & D article. Additionally, I told you how to substantiate it for yourself - ie. pack for a road trip.

20 lbs of lift is completely offset by 20 lbs of down-force, no matter if the down-force is supplied by air pressure or additional weight. I seriously doubt that anyone driving their Z on the highway at 70 mph would notice any difference in handling when their fuel tank had 9 or 12 gallons of gasoline... for example.

What does it mean?... It means that adding only the front Spook to a 240-Z, adds 20 lbs of lift to the rear wheels... there is no need to add the rear spoiler in an effort to offset that additional lift, because 20 lbs of lift on the rear wheels has no noticeable effect on the handling of the car. The car handles perfectly well on the highway at 70 mph, plus or minus 20 lbs of lift at the rear.

On the other hand, as everyone who has added the BRE Spook will attest, adding it to the front of the 240-Z does have a very noticeable, positive effect on the handling of the car at highway speeds.

FWIW

Carl

[HS30-H]

For the attention of Mr Carl Beck:

Sorry to poke my nose in here, but I wanted to catch Mr Beck's attention on an active thread that he is participating in.....

Carl, have you seen this thread:The First Z Pace Car?

Some relevant, pertinent and ( I think ) interesting information in there for you regarding Z Pace Cars.

Perhaps you would like to use some of that information to update your own pages re Z pace cars on zhome.com?

Don't forget my credit, will you? ;-)

Hijack over.

Cheers!

Alan T. :classic:

[26th-Z]

Not a problem, Alan. We are getting off the topic and loosing ground on factual information anyhow. My suggestion to Patrick was simply do both the front spook and the rear spoiler. Not just one. I don't have time to argue my reasons.

Carl, how about if we just agree to not talk about automotive aerodynamics. I'm really not up on the fine points luggage influence. In the mean time, you might go back to your Z Car magazines and read the articles Ben Millspaugh, Phd,. Aerospace, wrote in 1995. That would be good reading for anyone who is interested in Z car aerodynamics.

Thanks

[Alfadog]

i like the look of a air dam and spoiler, but i just can't bring myself to drill holes in her.

Hi Zhead! I think the spook looks good too, but with such an original car IMO I'd probably leave it be. That said, if you decide to individualise it with a BRE spook/rear spoiler then I'd agree with what some people have already mentioned - shop around and buy the best quality parts you can! That cherry of a car deserves no less.

[HS30-H]

26th-Z,

Its a shame the thread will peter out, as I have been scratching my head in wonder at how a static loading ( luggage ) can effectively be compared with an aerodynamic effect. Wouldn't that be comparing apples with bananas? And wouldn't spring, damper and ARB rates have a bearing on the effects of static and dynamic loads, and on aerodynamic effects?

Carl asked you to produce any of Nissan's data to 'prove' their findings, but I'd agree with you that if Nissan put spoilers on some cars then they had a good reason to do so. But wouldn't we expect Nissan's research data to be in Japanese rather than English? I can't imagine that being of immediate use.......

And why does Nissan's rear spoiler so often get referred to as the "BRE" rear spoiler?

[26th-Z]

Yes, the subject involves several other issues such as pitch-roll-yaw and drag. From what I read, the Nissan rear spoiler was designed and placed to destroy lift by separating the accelerated boundary layer of air traveling over the hatch. I don't think it has anything to do with the rear suspension exclusively. There was data available from Jim Cook Racing lab work conducted in the late '70s which points to the same conclusions. Suffice to say that the S30 produces lift causing instability and that the BRE combo spook / spoiler is a real good "bang-for-the-buck" solution. The setup closely mimics the Nissan solution and even though it produces more drag, it probably helps with cooling better. I'll reiterate my point and that is the combination of equipment gives the best results.

[Ron Carter]

And why does Nissan's rear spoiler so often get referred to as the "BRE" rear spoiler?

Because it was sold through Brock Racing Enterprises in the United States. :stupid:

[Carl Beck]

For the attention of Mr Carl Beck:

Sorry to poke my nose in here, but I wanted to catch Mr Beck's attention on an active thread that he is participating in.....

Carl, have you seen this thread:The First Z Pace Car?

Some relevant, pertinent and ( I think ) interesting information in there for you regarding Z Pace Cars.

Perhaps you would like to use some of that information to update your own pages re Z pace cars on zhome.com?

Don't forget my credit, will you? ;-)

Hijack over.

Cheers!

Alan T. :classic:

Hi Alan:

Great Stuff... thanks for the contribution...

I'll put a draft up on the Z Car Home Page, send you the URL via e-mail (is it still the same as it was?). You can review the draft.... send corrections/edits as you see fit (copy/past plain text in e-mail will do, or if you can do the html coding that is fine also).. and once it meets your satisfaction... we'll link it to the main index.

If you have color images, or higher resolution images that you would like to use.. just e-mail them to me (I have no limit on size of files on my e-mail and high speed connections etc.).

kind regards,

Carl

Carl Beck

Clearwater, FL USA

http://ZHome.com

beck@becksystems.com

[HS30-H]

Because it was sold through Brock Racing Enterprises in the United States. :stupid:

Hello Ron!

What happened to me being on your 'ignore' list then? I didn't think you'd be able to see anything written by me any more, let alone quote it.

Personally speaking, I've never used the 'ignore' function - so I don't know exactly how it works.

Regarding the 'BRE' ( actually Nissan ) rear spoiler, thanks for your input. It is interesting to me that a Nissan designed and manufactured part would take on the 'BRE' accreditation simply because 'BRE' sold it in the USA.

Did this happen with all the other non-'BRE' manufactured products sold by 'BRE', or was it just the Nissan rear spoilers? Or was it just mis-accreditation on the part of the general public?

All these questions asked with the presumption that you can actually see what I have written......

Cheers,

Alan T.