JMortensen Posted April 19, 2006 Share Posted April 19, 2006 I think if you put a splitter on the bottom of a urethane airdam you had better brace the bottom of the airdam. The splitter sticking out the front is going to increase the pressure at the nose of the airdam. I think the aluminum piece between the dam and the radiator is going to help, but I'd run a brace or two or three from the aluminum down to the back side of the splitter. With it braced like that, then if you hit a curb or a parking stone you'd still damage your brace, but not the airdam itself. PS-Note my rubber skirt on my airdam flapping under the car at ~110 mph in the sig pic... Quote Link to comment Share on other sites More sharing options...
bjhines Posted April 19, 2006 Share Posted April 19, 2006 I have aluminum extrusions that brace my (black 240Z) airdam from the bottom in 3 places... I had to slot the mounting points and preload them because any curbing pressure on the dam would break them loose... The blue 280Z lower mounted splitter is braced in several places as well... it also has stiffening ribs riveted to it... they are just not visible in the pictures.... I hit 120MPH regularly...(~70-100 times a month) The car is planted... I have no rear lip spoiler... and I have driven 240Zs over 100MPH without any airdam or rear lip spoiler without problems... I have never pushed one that fast with worn out dampers and stilt high springs.. with wagon wheel S rated tires.. and worn out rubber bushings... The cars are stable at speed if they are well maintained.... the airdam helps me on windy days.. where gusts used to push the car around.. it is more stable on WINDY DAYS.... I would guess that if YOUR car has stability problems above 80MPH.. you have a worn out, used up, unsafe car... get to work on that suspension man... and just lower it a little.. that is what makes a difference.... also try reducing TOE IN.. or even go with a little TOE OUT... the little pissant Xenon airdams are nothing magical... you CAN make them effective.... but they dont do a damn thing but flap in the wind without serious MODS.... The G-nose will help with both drag reduction AND front end lift, AND it reduces the amount of air coursing through the engine compartment... but it makes the Zcar look like a droopy guppy... those things are GAWD AWFUL.... I just traded a Gnose that came on one of my cars.. I traded it and the hinges for a box of old weber parts... LOL... I gave it a good look many times.. there is no way I would drive a car with that weird looking front fascia.... Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted April 19, 2006 Share Posted April 19, 2006 Yeah my urethane airdam has aluminum bracing that runs to the lower rad support as well. The G-Nose is not my cup of tea either. I like the mean look of the open mouth. My 280 was bone stock when I bought it and I drove it alot that way for quite a few years. After 80mph it started to get light. The stock suspension does NOT hold a candle to even the most basic performance shocks, springs, and bushings. Now, even with my pretty basic street performance suspension and braced urethane air-dam I have had mine to 120 on the track and it is totally stable. I am not sure how much faster it will feel stable? I would love to do a full belly pan from air-dam to rear valence but cooling the engine and exhaust would need to be thought out. I am thinking about a rear BRE type spoiler, at this point, purely for looks and experimentation. I do like the pan behind the air-dam idea to get more air to the intercooler. Quote Link to comment Share on other sites More sharing options...
240hoke Posted April 19, 2006 Share Posted April 19, 2006 Hey BJhines, Didnt relise you were on this board or a least never got the connection. I met you at the triad z show a few years ago. I used to have the white turbo 260z. But anyway, I got some pictures of your car at the show noting the front spliter. I just purchased a nice sheet of aluminum and am getting ready to do a similar thing to my 240z along with some ducting, I was gald to see this thread. Anyway hope you dont mind me posting but here are some pictures that might show your overall design better: Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted April 19, 2006 Share Posted April 19, 2006 now I know what to do with the last of my sheet of aluminium that I am making dashes out of. I need to reinforce my urethane air dam... Quote Link to comment Share on other sites More sharing options...
Guest ON3GO Posted April 19, 2006 Share Posted April 19, 2006 what size thickness are you guys using for these alum splitters?? ive had my template done for about a year now but never finished the project up. need to do so. mike Quote Link to comment Share on other sites More sharing options...
240hoke Posted April 19, 2006 Share Posted April 19, 2006 I scored a sheet from a guy that does alot of aluminum work, Im not certain on the size but its looks like about 18ga. Im going to be using 90 deg angles rivioted on like ribs for extra strength. Im actually going to have ALOT left over, might could cut a few of these things out. Quote Link to comment Share on other sites More sharing options...
bjhines Posted April 19, 2006 Share Posted April 19, 2006 The blue 280Z is not mine...... that belongs to a fella in the Triad z club who runs with us at the THSCC/Triangle Z Club track events series... His name is Roddy... There are 3 guys in that Triad Z Club group who have a variety of fabrication skillz... Roddy(owns the blue 280Z) welding and machine specialist Mark(owns a BEAUTIFUL flared Yellow 240Z) Paint and finish Tom( owns a 90's 300ZX Maroon) Tom has a MONSTER 240Z in progress.. I mean this car is going to be a MONSTER!!!!!!!!!!!!!!!!!!! No expense spared... and I hear it is close to completion... My car is the Black 240Z in the first pics with the upper plate... I also have a MONSTER $20K+ 240Z V8 project in the works.... ready by next season... I used ??? cant remember exactly... 0.090 plate... not quite 1/8" thick... The trick to doing this is to make the plate fit the car... I did not find templates useful.. this is the second plate I have made to fit 240Zs... the first one...welll... may it RIP.. along with the car... I tried to salvage the first plate and the airdam.. but they fit differently on each car.. the urethane is just too flimsy and stretchy to fab it up off the car... The first step is to cut your plate to fit inside the front clip.... get it to fit (includes 2 bends for 1/2" step up) and bolt that sucker to the lower radiator support... make your siffening ribs/braces and install them too... leaving the front lip rough cut longer than it needs to be... Then get your flexible airdam in the right shape and in the right position.. level it across the bottom and get a good look to make sure it is in the right position... tack a few wood screws through the plate and into the airdam to hold it correctly in postion under the plate.... then trace the front lip of the plate to match the V profile of the upper part of the airdam.... Remove the plate and cut the front edge to shape... use a long file to straighten the edges and clean it up... layout your holes for the front edge fasteners and predrill them all (get them as close to the edge as you can.. but look at the inside of the urethane... if you get them too close to the edge you will come out in the thicker fillet of extra urethane in the front edge of the airdam).... For the brake ducts I cut small plates of aluminum that would bolt to the bottom edge of the brake duct openings... I used wire to hold a 3" duct hose to that plate... then I used expanding foam sealant to fill the gaps... let the foam puff out... then when it skims over but is still flexible collapse the foam back into shape with your fingers.... it will make a nice HARD fillet... Quote Link to comment Share on other sites More sharing options...
240hoke Posted April 19, 2006 Share Posted April 19, 2006 Hahaha ok sorry. I have met roddey and mark. I also know Drew i guess that would be mark's nephew up here at NCSU. i think he made some carbon hoods for mark and some others in Triad. Anyway sorry for the mix up lol. I see now. Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted April 19, 2006 Share Posted April 19, 2006 my sheet of aluminium is .063 which is 1/16" which is 20 ga. Aluminium guage thickness for aluminium is different than steel thickness Quote Link to comment Share on other sites More sharing options...
bjhines Posted April 19, 2006 Share Posted April 19, 2006 Here are some shots to see where I cut and notched it.... There are a fair number of notches and tweaks to get it tight.... you could simplify this by removing horns, grill center support, etc.... Here are some better pics of the brake ducts This is a COOOL looking rear diffuser that Darius has been working on I think that for it to work it would have to come much closer to the ground... but it is a neat idea... It could be made to work if it was easily removable for trailering... Quote Link to comment Share on other sites More sharing options...
bjhines Posted April 19, 2006 Share Posted April 19, 2006 Here is a picture of my car and my tow vehicle at the track a few weeks ago... Here is the back of Roddy's car.. and you can see Mark's yellow 240Z in the right hand side This picture has all 3 Triad members cars in it... notice Tom's unfortunate tirewall damage on the maroon 300ZX... Quote Link to comment Share on other sites More sharing options...
ZROSSA Posted April 19, 2006 Share Posted April 19, 2006 Bugger, Just lost 15 mins of typing. http://album.hybridz.org/showphoto.php?photo=6307&cat=500&ppuser=8086 This is the nose cone I have made. If you look around my photos you will see the undertray thats attached to it. It runs flush from the front of the nose cone to the engine crossmember . Its made out of two layers of glass with a foam core and two more layer on top of that. Very light, stiff and strong. http://album.hybridz.org/showphoto.php?photo=6311&cat=500&ppuser=8086 The car is still in paint jail. Spot primeing and sanding when ever I can get to it for the last month. Work and a new addition to the family have really cut back on zeddy time. Douglas Quote Link to comment Share on other sites More sharing options...
JIM73240Z Posted April 20, 2006 Share Posted April 20, 2006 try looking at this page. http://e30m3perfomance.com/myths. it has a great section on splitters and venturis. it is on the bmw race cars but still good reading. jim Quote Link to comment Share on other sites More sharing options...
jeromio Posted April 20, 2006 Author Share Posted April 20, 2006 I would guess that if YOUR car has stability problems above 80MPH.. you have a worn out, used up, unsafe car... get to work on that suspension man... and just lower it a little.. that is what makes a difference.... also try reducing TOE IN.. or even go with a little TOE OUT...I am certain that my car could benefit from some professional suspension tuning. However, it does have stiff springs (coilovers), new shocks (Tokico), is lowered and rides on performance tires (235/45/17 SP5000). Before the dam (but after all susp. mods), the car was, IMO, not very stable above 80MPH. 100MPH was scary. With the dam, 80 is cake. With this mod - whatever function it is serving (air direction or dam stability) - it is even more stable at speed. Interestingly, my rear susp. used to be a total mess. There was a severe toe-in condition, I suspect a mis-aligned spindle pin bore from the factory. This condition didn't really bother me in the dry. But a little bit of water on the road and the car was completely un-driveable above 30MPH. I've since fixed it and it's fine in the rain, but I really am hard-pressed to find a difference in the dry. However, this dam, in both of its "stages", has produced very noticeable results. Quote Link to comment Share on other sites More sharing options...
240hoke Posted April 21, 2006 Share Posted April 21, 2006 I have my suspension set up pretty mild for the street, basically stock settings, a little more negitive camber and a little more caster. I have no aerodynamics work except a xenon from lip, which is not reinforced with a splitter right now. The fastest Ive had my car is 125 or so and it is very solid. I feel the same as others, if you are having issues at 80-100 there may be some other issues you need to look at. My car is lowered about 3" and has 250/275 springs, with illuminas I had my old 260 to between 150 and 160 a couple times, who know how fast it really was since i was using the stock tach. Over 140 WAS scary, i would say in the z cars i have driven things start to get scary in the 130-140 mph range. Quote Link to comment Share on other sites More sharing options...
spotfitz Posted April 21, 2006 Share Posted April 21, 2006 I had my old 260 to between 150 and 160 a couple times. Over 140 WAS scary' date=' i would say in the z cars i have driven things start to get scary in the 130-140 mph range.[/quote'] I've had my 260 up to 120 or so acouple of times in the last 8 years, at 3 a.m. on a road I know well and no one in sight, but even then you come up on someone pretty quick! Not the best time to do it concerning the po po, but I was not in much danger of hurting anyone but myself and possibly a guard rail. This is just one of the reasons why I try to keep it on a track now. It was very light in the front end, even with the Xenon air dam. This was with questionable stock suspension and non Z rated tires. Z rated tires, no pun intended. Or was there? Suspension is not a concern now and I've yet to drive it that fast since the reconstruct. The scary(or funny how ever you look at it) was this little Honda going past me very slowly, just SCREAMING along. To bad I reached my exit as I noticed him... Quote Link to comment Share on other sites More sharing options...
Phantom Posted April 21, 2006 Share Posted April 21, 2006 All I know for certain is that my '77Z, in stock form, got really light at around 105. With the MSA 4-piece Aero II kit and a small 1-piece rear spoiler it is now solid to at least 120. The Aero II front air dam is not closed in behind but it does direct a significant amount of air around the car rather than under it. Closing that area off, as Jeromio did, should yield some improvement by further reducing the amount of air that can flow under the car. Unless significant venting is done at the hood, however, any additional cooling air flowing through the radiator will end up going out under the car. Quote Link to comment Share on other sites More sharing options...
Clifton Posted April 21, 2006 Share Posted April 21, 2006 good idea jeromio. i know what you mean about float. years ago i had my 260 up to 132 mph on the highway and the front wheels would touch down every 100 feet or so. not the kind of thing you want to be doing for long. Were you drinking? I've been over 140 many times, 150 a few times with no spoiler. and no wandering or wheeling at all. I think alot of this wandering/floating is on Z's with bad alignments, shocks, and soft stock springs. Quote Link to comment Share on other sites More sharing options...
Phantom Posted April 21, 2006 Share Posted April 21, 2006 Well Clifton - I guess you must have a 1:1,000,000 Z. Aerodynamic instability of the S30 at speeds over 100 is a well documented behavior. Mine has new ball joints, new tie-rod ends, urethane bushings, 4-wheel alignment, european spec springs, and gas struts. It runs at stock ride height - not lowered. I've encountered the problem in both of the S30's that I've owned and the thing that seems to have made the most improvement it was the aero kit. Quote Link to comment Share on other sites More sharing options...
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