Why do 4WD cars tend to bog down in a launch start?

[Skygrasper550]

i know there are a lot of variables and other things to consider, but what's the most common reason for this?

 

[1241Penguin]

Simply put, too much grip.

 

[speed junkie]

They bog the same way that RWD cars bog when its driver does a lousy job of launching it. Yes, the 4WD car will have about twice as much potential grip in a launch but with a proper driver behind the wheel, it won't bog.


At 0:55 seconds...

 

[niky]

And too little power.

 

[Keef]

Simply put, too much grip.

And too little power.

Nopes.

The reason they bog is the one Speed Junkie cited. Yeah, they have a lot of longitudinal grip, and new ones are often electronically limited to an rpm with too little power to churn the wheels.

But the driver is still in charge of managing the throttle and clutch on launch. If he doesn't do it right then it will bog. Sometimes you have to finesse these things.

 

[Dennisch]

Well. Try launching a 4wd Justy with a 1.3. You will not succeed. You will bog.

 

[niky]

Let me specify... Too little power at the engine speed you are at when you let off the clutch.

You can launch an STI quite easily. just spin it to 5k or so, to a point where you're making enough spin to overcome the tires, then slip the clutch to launch it. Anything less and it will bog.

A Justy, probably redline before you drop the clutch. If I recall, the proper lainch rpm given to get a 1 second 0-30 mph out of a Fiat Panda 4x4 is said to be at redline...

 

[Ridox2JZGTE]

Fit shoddy tires at the rear would help a bit and at least a heavy duty clutch or twin plates for easier launch.

 

[sumbrownkid]

Well. Try launching a 4wd Justy with a 1.3. You will not succeed. You will bog.

I have a question.

Why would one want to launch this car, other than into a car crusher?

 

[Dennisch]

I have a question.

Why would one want to launch this car, other than into a car crusher?

Actually, once you have some speed into the vehicle, it handles like it is on rails.
And in the mud it is great fun too, as long as it isn't knee deep mud.

 

[sumbrownkid]

Actually, once you have some speed into the vehicle, it handles like it is on rails.
And in the mud it is great fun too, as long as it isn't knee deep mud.

Nice.

My neighbor used to have a Justy, and it was so dilapidated that he had to use a screw driver in place of the keys to start the car.

 

[Watt2159]

The RWD fan in me is going: CUZ AWD SUX LOLZ XD

But the rational person in me is going: It's probably because its trying to get the most traction on all four wheels as possible, take the TCS system off, and it might make a difference.

 

[C-ZETA]

Yeah, pretty much as has been said above. You need to time all the variables above right to avoid a bog start. If you do get it right, you're off the line before you know it.

 

[gt4rulez]

Fit shoddy tires at the rear would help a bit and at least a heavy duty clutch or twin plates for easier launch.

i've got a twin plate in my GTR and i have to say that doesnt mean it can be launched easeally. i think it actually makes it a bit harder to control since about 3 to 5cm of movement in the clutch pedal means the clutch is fully engaged or not at all.

if you dump the clutch it will bog, even if you use launch control, wich in my case actually builds up some boost (even though it has been set very lightly to avoid damage, and it needs some further setting up), but it just has too much grip with 4 265 wide sticky tires. in 1st gear even with 493hp powering the wheels it wont loose grip.

its actually quite hard to get a good launch, but once its rolling it beats pretty much everything in its path:tup:

 

[Skygrasper550]

Simply put, too much grip.

And too little power.

LOL no wonder fitting Racing tires to a stock Mitsubishi Lan-Evo in GT5 to improve its standing start launch doesn't work

really appreciate all the replies. Well for me, I thought it had something to do with the AWD system managing power to all four wheels. Or is that another factor? Because when I try to do the same thing in a RWD that is at the same class as the Lan-Evo (FD RX-7, for example), obviously it doesn't bog.

 

[niky]

GT5 and real life are not 1:1.

That said, you can bog a rear wheel drive car in real life, as speed junkie has said. It's just much easier not to.

 

[Ridox2JZGTE]

i've got a twin plate in my GTR and i have to say that doesnt mean it can be launched easeally. i think it actually makes it a bit harder to control since about 3 to 5cm of movement in the clutch pedal means the clutch is fully engaged or not at all.

if you dump the clutch it will bog, even if you use launch control, wich in my case actually builds up some boost (even though it has been set very lightly to avoid damage, and it needs some further setting up), but it just has too much grip with 4 265 wide sticky tires. in 1st gear even with 493hp powering the wheels it wont loose grip.

its actually quite hard to get a good launch, but once its rolling it beats pretty much everything in its path:tup:

I see where the problem is, the wide sticky tires , the clutch slip is also important, as is the rev when you launch in a GTR. The RB26DETT with that much power, I suggest to try between 7500 - 8000rpm and side step the clutch or allow little slip, while going full throttle, it should launch when rev drops to 5500rpm or so.

Side step = rev up close to limiter and dropping the foot off the clutch completely when launching. This might be hard on the drive train.

Or you can do a preload launch if you don't want the sudden jolt on the drivetrain = Bring it to 7-8k rpm, hold handbrake and let go the clutch slowly until you feel the car is about to lurch forward.Drop the handbrake, and launch with full throttle while allowing some slip on the clutch.

I don't think R32-R34 has launch control, if it's about the R35 - auto, then there's no clutch to worry about.

 

[HELLAFLUSH240SX]

^This, if you are asking why they bog down in the game, it could be a different story.Who knows what the factors are for GT5 since it isnt exactly accurate in all portions of these things.

 

[MCNAGTROC]

mine has no bog at all w(ith the right surface)..it comes off the line at almost 4100 rpm and i get 1.58-1.62 60 ft times with it


only time i get bog is when too much spin is detected from a less than idea surface