Best Circuit Drivetrain (plus a little intro)

[Smitherines]

A little introduction here, my name is John, and I've been into DSMs for while now, almost 4 years, and after toying around with my 92 Talon, I feel that actually running these cars on the circuit is a great idea. Now I would like to get a car solely for racing, in a year or so, and I was contemplating whether to go FWD or AWD.

Now the downside I forsee running with AWD would be the absence of lateral grip on turns, which in otherwords would be under-steer, but I feel that the AWD system would be prevailant on all the other obstacles put forth by weather, the track, and temperature.

I'd feel that I would prefer to saddle up in a 1g AWD, but what do you guys think? I'd like to see POVs from experiences drivers as well as theories.

Thanks guys.


EDIT: Can the same be said for AutoX?

 

[jtmcinder]

I'm not at all sure why you think an AWD would have less lateral grip. Yes, a FWD can use the power that is sent to the steered fronts to turn the nose, but so can an AWD. And the FWD will run out of front grip when powering through or out of a turn much sooner than an AWD (since tirning and accelerating both "use up" grip). In fact, some people swap in rear-biased centers to reduce the torque going to the front for exactly this reason. In addition, you can't optimize front camber for turning in a FWD and still power down the straights.

So, again: why do you think a FWD will have more lateral grip?

- Jtoby

 

[Smitherines]

Well, I guess I was wrong. Haha, I figured since AWD understeered alot, that FWD was more desirable for RR/AX. How do AWDs fare in AutoX? Is AWD the preferred platform across the board?

 

[jtmcinder]

The thing that makes an AWD understeer applies to FWD at least twice as much. AWDs kill FWDs in autocross (sorry, Kyle, but it's true), all else being equal. That's why a FWD SM car is allowed to weigh about a third less than an AWD SM car ... to prevent all else from being equal.

- Jtoby

 

[Smitherines]

Wow, learned something new. Now the question is, 1g AWD or 2g AWD. As far as I know, the only thing a 2g has over a 1g is the double A-Arms, is that correct? But then the 1g is a cheaper all around car to put together.....choices.

EDIT: May I ask what that certain thing is that makes AWD and FWD understeer?

 

[RusherRacing]

Under-steer is caused by a couple different things. Conditional or fundamental

Fundamental: The front roll moment could be different than the rear roll moment, caused by spring rates, geometry (RC, CG....), swaybars, I don't remember off hand if larger front roll moment causes it or larger rear...

Conditional: Your over stressing your tires. Your tires have a traction circle and a combination of lateral and acceleration/braking load can easily exceed the circle. This is were the AWD comes in, you split the acceleration load on your tires in half because its not just the front doing all the work.

All most every car is setup as fundamental understeer, its much safer. although most people experiencing it in a racing condition are over working the tires.

This is just a brief explanation I am sure others could get much more indepth. There is a section in Drive to Win that does a really good job explaining it. Also the front and rear roll moment is explained very good in How to make your car handle. There are books and articles on the net that can explain it way better than I can regurgitate it.

 

[Slow old poop]

May I ask what that certain thing is that makes AWD and FWD understeer?

Understeer? Naw, an AWD car is neutral. If it's understeering, you are turning in too early. I've had two DSMs and a 3000GT, and none of them understeered.

The only advantage of a 2G is that it's easier to get the transmission out because of the improved trannie mounts. You start road racing, you'll be pulling that trannie two or three times a year for this and that.

I prefer AWD over FWD, simply because it is easier to drive, much more forgiving, and has real advantages on certain courses, especially in the rain. OTOH, a FWD is much lighter and simpler, and Greg Collier did amazingly well with his FWD--better than any of us. He was a national champ, and none of us can match that.

A FWD is tricky to drive, because only one wheel drives, so it handles differently on lefts than it does on rights. On one corner (I forget which one), you can power around like you would in an AWD car, on the other you have to expect wheelspin. That would drive me nuts.

If you are just getting started in road racing, then I recommend AWD because it is SOOOO forgiving and makes it easy to learn. If you are already an accomplished racer, then you might have more luck wih a FWD because of the weight.

The added weight of AWD is a major consideration, because it affects everything: Stoptech doesn't make a brake kit for AWD cars (its FWD kit doesn't work, because it can't handle the extra weight); the turbo motor is the same in both cars, so the same mods apply, but it stands to reason that a FWD car will be faster than an AWD car because it weighs less; finally, all the extra weight puts extra stress on everything.

My crew chief said (over on the Iowa Speedway thread), "What an evil mistress turbo all wheel drive cars are. The maintenance is high and when things go bad....they go BAD. But the great times are just unbelievably high." That sums it up pretty good. In any case, DO NOT try to road race a FWD or a AWD DSM unless you really understand the mechanicals, can fix everything yourself, or have a bunch of knowledgable friends who do know all that stuff and love to go to the races with you and fix stuff when it breaks.

I still vote for AWD but I can see somebody like Elvenhome kicking my butt with his FWD car one of these days. It would be because of the weight, you see, not because he is an experienced circle track driver and better than me (I am lining up my excuses already).

 

[Elvenhome21]

Thanks for the complements, But I hope to have the GSX done before nasa or October MFBA so we can really have fun and race.

 

[Smitherines]

Haha, this is awesome. I feel that it may in my best interest to start with AutoX for a couple reasons. The most important, is that its very local, and it allows me to find my cars limits, and get to learn how to drive better, without dropping 1000 for the day.

I appreciate all of your help, and it wasn't a wasted effort, trust me. Maybe I'll see you guys on the track one day.

 

[Slow old poop]

Haha, this is awesome. I feel that it may in my best interest to start with AutoX for a couple reasons. The most important, is that its very local, and it allows me to find my cars limits, and get to learn how to drive better, without dropping 1000 for the day..

$1000 for a day? Where'd you get that number? It's more like $150 for a day, $300 for a weekend. For example, it cost $275 to run the two-day NASA event at Iowa Speedway this past weekend. The most expensive is Road America, where it's $400 for the weekend.

Go to http://www.roarracing.com/tracklocator.php, find tracks in your area, find an HPDE event (usually put on by the Porsche or BMW club), and check it out. Sometimes you can find a track day midweek, which can be $100 for the day.

There is nothing wrong with starting with autocrossing. It is a noble sport, but you will be demolished by dudes who take that stuff very seriously. It will be embarassing. Don't lose hope because a turbo-shitbox whups you by 10 secionds.

OTOH, it has little to do with road racing. You will be running in 1st and 2nd gear on cold tires, cold brakes, and getting 3-4 one-minute runs on a Sunday. If you tried an HPDE, you would get 4-5 20 minute runs at WOT in 4th and 5th. Let's see, what's the better deal? Three minutes in 1st and 2nd for $25 vs nearly TWO HOURS of track time in 4th and 5th at $150?

Autocrossers are a wild bunch of guys, and are very, very good at what they do. I know I couldn't beat a top autocrosser in my class. But I am not sure I would want to.

 

[asian312]

I'm with Rich...take it to the track

Honestly though, why not saddle up and try both out for yourself. Both are very different in setup and execution, but equally fun and challenging in their own respects. It's also alot of fun to have friends or a community you can 'click' with. It's not all about straights and corners, for me a large enjoyment comes from the people I meet and things I learn.

 

[Smitherines]

I figured 1000 after tires, brakes, gas, admission fees, inspection fees, and whatever else is required.

Hmm, Slow Old Poop...that link seems to be a search for RC car tracks, .

And what engine setup would be the best? 2.0, 2.1 destroked, 2.3 stroked, or 2.4?

 

[asian312]

Once again, depends on organization and class if your going to race. If your car is in good mechanical shape (aka can survive rush hour traffic, wheel bearings are ok, and has no leaks) then your track ready. One of the biggest mistakes new comers make is throwing money at their car thinking they have to make it a race car. Street tires (with the proper speed rating) and low horsepower setups are key ingrediants to learn on. If you have the urge to upgrade anything, do brakepads. Other than that just maintainence and hit the track.

 

[Slow old poop]

1. I figured 1000 after tires, brakes, gas, admission fees, inspection fees, and whatever else is required.

2. Hmm, Slow Old Poop...that link seems to be a search for RC car tracks, .

3. And what engine setup would be the best? 2.0, 2.1 destroked, 2.3 stroked, or 2.4?

1. If you have to tow 250 miles with a trailer, stay two nights in a hotel, and get a room and meals for your crew, then you are close. If you day-trip to a nearby course, then it's not so bad. For a day-trip, it should be $150 entry plus travel. For tires, a set of Toyo Prox RA1s will last an entire season. Rotors are $19.99 at Autozone. A set of Carbotech Panther Plus race pads will last for several events.

2. Try these instead:
http://chasinracin.com/track-locator/
http://www.na-motorsports.com/Tracks/
http://www.raceindustry.com/racetrack_locator.php

3. Keep it bone stock. Tires and brakes are the only mods you should make. What you need is SEAT TIME, so spend all your cash on entry fees and instruction. After you've done this for a season, pick a race class and modify accordingly.

 

[mavisky]

The main advantage to fwd is weight. That's about it. Everywhere else the awd will trump me.

 

[asian312]

The main advantage to fwd is weight. That's about it. Everywhere else the awd will trump me.

Dont let Greg hear you say that WTF

 

[mavisky]

Well if you think about it, for a road racing car the single biggest improvement is going to be weight as far as the car's potential is concerned. Reducing the weight of the car instantly improves acceleration, deceleration, cornering grip, and transitional abilities.

The only area I'm worried about with the awd's is slow corner exit acceleration, and even then it's gotta be pretty slow.

 

[Elvenhome21]

For me at road america the awd would be better 2 fold, because if you have anything bigger than a stock turbo and open diff, you are going to be running into traction issues coming out of the corner. The next part is coming into the corner and doing all of your braking before turn in and using the throttle to overcome the notorious push in the middle and exit of the turn (because then it acts like RWD with the front tires gaining grip because they are only turning and doing marginal acceleration, instead of all of it).

 

[asian312]

The only area I'm worried about with the awd's is slow corner exit acceleration, and even then it's gotta be pretty slow.

Not so sure on this one. Maybe its a difference in line but corner exit is where my AWD excels. It's corner entry that I have to give up the speed. Stab breaks, get the car rotated, throttle to kill the push as Elvenhome21 stated, and then its a full throttle rocket to the next corner.

This may apply differently to auto-X.

 

[Ludachris]

FYI, for info on tracks in your area, click the Regional link up in the top navigation, choose your region. On the left hand column you'll see a link for Tracks.

 

[schemauer]

There are lots of qualifying questions that should be asked before making suggestions in this thread....

I've driven open track events with a stock FWD Laser back in the early 90's, then a stock AWD Laser, then a AWD Eclipse from new (stock) to a point where it ran mid 12 sec 1/4 miles. Now I use the Archer Talon - FWD - for track days. I've also driven my BMW 540 - RWD on Road America.

First of all I'm not a big autocross fan. There are a few things to be learned there, but for the most part the car will handle much differently on a slow autocross course vs open track. Setup is different. Lots of prep and screwing around for a few short runs.

If you're going to run close to stock horsepower or only 50-100 hp more a properly set up FWD car will be fine. You'll need to play with the rear sway bar to dial out the inherent understeer. My Talon has only basic mods and I cannot get any wheelspin out of any corner on a road course. It also has an open diff. The FWD cars are also much lighter and easier to work on and less expensive overall to run.

With higher hp an AWD car will help make the power useable, but you've got more "stuff" to break and a heavier car to get around the track.

Higher hp also will be harder on the brakes - you'll also need to consider this. On a stock hp car the stock brakes can be adequate. Use good pads and cooling ducts.

If you just want to have fun with a realiable car, get a FWD and set it up properly. If you plan to go for mega-hp then you may want the AWD platform to start with.

 

[mavisky]

Agreed, I'm not comparing my car to cars like slow old poop with their strokers and huge turbos. Were my car making that kind of hp I'd be at an even bigger disadvantage. With the car the way it is now my best shot is to take each corner as deep on braking as possible and use the car's weight to its main advantage. It rotates very well midcorner with this new setup and I know that with a little more camber my cornering speeds will be through the roof. The main reason I didn't upgrade to the awd was the extra drivetrain parts wear and tear.

The fwd is nice and simple and a good spring, shock, swaybar setup will make all the difference in the world when it comes to handling. I'll be doing a writeup of my new prototype suspension after my May 20th autox. Soon after it should be available to the general public.