Increasing high speed stability

[CanadianTalon]

Does anyone here do stuff like the texas mile? I'm looking into doing some of this full mile drag racing stuff with my talon, but I'm scared as hell of the car getting all light on me and loosing control at 160+ MPH. I already have sway bars, strut bars, tein coilovers, big brakes, it's getting a cage as we speak, and I'm going to splurge for some CCW wheels. I have pretty much all the bases covered, now I just need some stability. I was thinking of making a carbon kevlar lip for the nose of the car, maybe an undertray of aluminum to keep the air flowing smooth under the car, and then a drag race type wing off the back of the car. Here's the best picture I could come up with to describe what i'm thinking of. Adds a lot of downforce without adding much drag. Any other suggestions?

 

[ACM]

Try the YahooGroups DSM RoadRace list, there's a lot of expertise there on high speed driving. Also some of the DSM-AutoX list members are road-course users. Me - I'm a wuss, I don't go over 70 - in 2nd, at least.

Charles

 

[Jason99DSM]

I cant imagine goin 160 in my dsm.........that would be sweet

 

[DSMeclipse4G63]

I did 135 in my dsm bone stock(I was very foolish) and it held up perfectly. I mean the car felt very stable and very solid. For going 160 in a safe condition like at a race course I would say springs, shocks, sways, bushings, wheels and z tires would be more then enough. Strut bars are good pieces but they stiffen the suspension and make a car jittery on bumpy turns. I have also heard things about high speeds and dsm's having the slight tendency to lift in the rear, so with that said a front lip and rear wing would be good as well as safety stuff like a helmet and cage. other then down force you have everything you need to go that speed.
Andrew

 

[cait sith]

I cant imagine goin 160 in my dsm.........that would be sweet

DSM's are gear limited to 157 miles per hour in fifth gear at 7250 rev limiter.

 

[the_anti_honda]

how are they gear limited? i have had my speedo buried at 170mph 7900-8000 is my tac really that off?

 

[wret]

Look into hood vents. Cars get light at high speeds due to air pressure build up underneath. Be careful with belly pans. I understand they can make this condition worse if not fabricated correctly. Have you seen the commercial for the Lexus or Mercedes with a dimpled belly pan? That's the ticket, or a big bulge, which you don't have clearance for. A flat pan would increase lift though.

Then put on some tall, narrow tires like 205/60/16’s and you should lengthen your gear ratios enough to get you to 160.

 

[RACER-X]

Yeah between 135 and 145 GSX handle fine at 155mph I noticed my front end feeling light like it was being lifted. If you get the VR-4 5th gear and cams you can easily go past 155 and into the 160's + with mods of course ( a stock or lightly modded dsm wont cut it) so down force will def. be needed.

 

[14.5 drift]

Word to the hood cowl. All that air being forced through your bumber is directed straight down out of the bottom of the car creating a pressure pocket under the car, but with a hood cowl that air is released out of the hood and relieves SOME but not all of the pressure. The pan, depending on your bumber and it's aero chracteristics, should definatly improve this situation if not eliminate it altogether. Almost all cars have upforce from under there cars, created by this pressure pocket called newton, but with a cowl and a proper pan you can turn the pocket of pressure into a vacuum that sucks the car down, creating more down force. To do it right if there is not some else already doing it tried and true, you would have to test in a wind tunnel to do it right, and to be sure your setup is doing any thing at all.


Not as effective as doing boththe plate + cowl, but the cowl alone will relive pressure and improve engine cooling and aero,

 

[ldstang50]

the cowl hood is an awesome idea. and he is right about the air pressure. if you can't get a cowl hood, a cheap quick thing to do is to take your hood off and put washers on the hood studs. this will raise the back of the hood and allow some pressure to be released. i would also think under body diffusing would be a good idea. being able to dissipate the air underneath the car and have it suck the car down vs pushin it up would be of great help in high speed stability. i would also check into your power steering. I'm not sure if it completely disengages at high speed. If it doesn't you will have some oftly jittery and touchy steering at those speeds

 

[jtmcinder]

the cowl hood is an awesome idea. and he is right about the air pressure. if you can't get a cowl hood, a cheap quick thing to do is to take your hood off and put washers on the hood studs. this will raise the back of the hood and allow some pressure to be released.

Buzz.

The area right in front of the windshield is a high-pressure area. If you raise the back of the hood, more air will end up under the car.

Don't believe me? Tape some string there and see where it points.

- Jtoby

 

[PaulPDX]

Make a simple skirt/air dam under the front bumper out of thick rubber mat or abs plastic that extends the entire frontal width of the underside. This will force air to go around rather than under the car. The air speed differential directly under and around the car will create a vaccum.

Aside from aerodynamics, you may also want to look into gearing. Magnus dog tranny?

jtmcinder is right. If you raise the hood, more air will be drawn into the engine bay from front and under. Air is like fluid. It will take the path of least resistance. Think.

Belly pan is a good idea but should be combined with an effective air dam. To prevent mishaps (ala NASCAR a few years ago), you should devise some hinged flaps in the hood to allow air to exscape and reduce your chances of flipping should the car become airborne. Think in terms of an airplane wing... and how you could turn the car into a wing that creates negative lift (downward pressure).

 

[cait sith]

how are they gear limited? i have had my speedo buried at 170mph 7900-8000 is my tac really that off?

You honestly think that the DSM speedometer is that accurate at 100+ MPH?

 

[PaulPDX]

You honestly think that the DSM speedometer is that accurate at 100+ MPH?

7... 5... 7... close enough. 7 sounds better though.

 

[paul s]

I have taken my talon to 170mph(270km/h) several times and the car feel pretty stable..I have G/C coilovers, rm sways, konisYellow,bushings, braces and good tires/wheels..I did notice that unless you have your allignment set properly(toe especially) the car will feel like its all over the road..

 

[14.5 drift]

Paul


you sir essentially have my dream car. Nice work!!

 

[paul s]

Thanks..^^