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There's a limit to the hp in a front wheel drive car???

jet190rs

jet190rs

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Feb 22, 2005
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There's one or two episodes where the presenters were talking about how they believe front wheel drive cars can never surpass 250hp or something. I think they were reviewing a Saab and something else.

Anyway, I don't understand why there's a theoretical limit. Can someone explain it to me or direct me to a website for more info?

Thanks,
Rich
 
There isn't a theoretical limit - at least, not related to the fact that it's FWD. You can tune many cars to produce more than that. Maybe they meant that it's senseless to have more?
 
I thought it was about the Alfa 147 GTA, it has 250bhp.
And also a tuned Mini cooper had like 280hp and Richard talked about that.

Problem is that you get 'torque-steer', if you steer all the way to the left, and press the gaspedal the frontwheels get lots of momentum and will straighten out.

So if you go into a corner and want full throttle the wheels want to straighten themselfs out.

Also, the wheels begin to spin in the corner and you'll have LOADS of understeer.

So would it be smart to have more than 250hp on a FWD car?

You would have to install some electronic anti-skid programs, and that will reduce power, so that's not very smart after all.

Could a mod place this in Questions and Answers? Would make a good topic there
 
it's more of a steering issue than anything else.But then the Focus RS has a very good from wheel LSD.Wonder how much power that can take
 
Jostyrostelli said:
I thought it was about the Alfa 147 GTA, it has 250bhp.
Click to expand...

yes, I remember that too .. but why would anyone want any more BHP than ~250/300 in a FWD car anyways? The car will always want to make a larger "circle" in turns if you push the pedal (circle, if going around and around that is..)

haz
 
Difference is that 500hp on a RWD car can get you through a corner by a little oversteer, you can't get a car fast through a corner with understeer.
 
Thread moved and my guess is grip. High powered FWD cars understeer horribly and get lots of wheelspin.
 
Since I own the saab in question I can say it's more a matter controlling all those horses. My car is the older model than only has 230 hp, but it's still kinda tricky under full throttle. Hit a bump in the road at WOT in 2nd or 3rd and the car wants to either jump into the bushes or oncoming traffic. However, my mom's v6 camry with 190 hp has no fidgityness. I can only Imagine how bad the effect would be with 300 hp.

Torque steer in the true meaning where the car just pulls one direction doesn't happen in modern cars cause of the use of half shafts. However, if the steer load becomes unbalanced it'll start pulling one way or the other depending on which tires took the load. If you apply throttle in a turn, torque steer will try to turn the car tighter up until the point where you light up the inside tire and the front end will wash out.

Here's a really well written explaination of torque steer in the modern sense.

http://www.sportcompactcarweb.com/editors/technobabble/9909scc_technobabble/
 
1) when you have fwd, you make your front wheels transfer power to the ground and steer.

2) when you accelerate your car will be pushed to the ground on the rear wheels (physics) and will have less "weight" on the front wheels. Therefore, the front will have less grip as the rear ones. (also, but this isn't THAT important. Most of the time the rear wheels are wider and will have more grip)

3) as stated before, and referring to point 1, when you push it when cornering you will get understeer because the wheels will start spinning and loose grip. when having rwd, it's not that bad when the wheels are spinning bc the front wheels will still have grip and makes the car able to turn (although oversteer can occur).

Greetz Johan
 
freerider said:
(also, but this isn't THAT important. Most of the time the rear wheels are wider and will have more grip)
Click to expand...

Negative. This is *very* important. Even in a straight line, FWD cars just don't have the traction potential that an RWD or AWD car will have, even with a very stiff rear suspension setup to prevent weight transfer off the fronts. Look at the 60-foot times for all the top drag race cars, and compare FWD and RWD cars.
And what are you talking about with "most of the time the rear wheels are wider"? On what cars? On pretty much anything stock from the factory, all four wheels are the same size, unless they're a very tractionally limited RWD car (I.E. Dodge Viper).
On a related note, it seems that the recent trend is to increase the wheel diameter in the rear an inch or two compared to the fronts.
 
adrianpike said:
freerider said:
(also, but this isn't THAT important. Most of the time the rear wheels are wider and will have more grip)
Click to expand...

On a related note, it seems that the recent trend is to increase the wheel diameter in the rear an inch or two compared to the fronts.
Click to expand...

To save fuel? No...else it would be all 4 wheels right?

Slower acceleration? Higher topspeed?
 
It came with with several cars they reviewed, focus, alfa 147gta etc.

there's no theoretical limit as to how much you can put on the front wheels (fwd dragsters are way above 250hp)

i think most of the issues have been covered here, grip/traction, physics - weight, etc.

so it basically doesnt make much sense to put more then 200-300hp on the front wheels because you will not be able to use to full potential of it even with an lsd, as simple as that.
 
pdanev said:
so it basically doesnt make much sense to put more then 200-300hp on the front wheels because you will not be able to use to full potential of it even with an lsd, as simple as that.
Click to expand...
I wouldn't say that, I can use all of my 230 hp if I so choose. If anything the power is more accessable because you don't have to worry about spinning the car. This is especially true in the wet where a RWD car has to tip-toe around, but I can still fly along and if it understeers I just hafta back off the throttle a little.
 
Don't know if this ep was mentioned but theres also the 147 GTA they tested that was tuned and made 328 BHP. That was TG - 2004.05.16 :)
 
NANANANANANANANANANANANA TORQUE STEER!!!

As said.

1) Torque steer is a bitch even with the most tricked out front ends.

2) When power is being applied, and the front wheels bag up, the car will understeer like a bitch.

3) Weight transfer during accelertion removes grip from the front end.

Anthing missed?
 
Leppy said:
NANANANANANANANANANANANA TORQUE STEER!!!

As said.

1) Torque steer is a bitch even with the most tricked out front ends.

2) When power is being applied, and the front wheels bag up, the car will understeer like a bitch.

3) Weight transfer during accelertion removes grip from the front end.

Anthing missed?
Click to expand...

Yeah FWD powercars sucks!
 
btw, on a side note, this got me wondering, were'nt FWD cars developed to help lower the production/maintanence cost of the cars and not help increase performance?....
 
adrianpike said:
freerider said:
(also, but this isn't THAT important. Most of the time the rear wheels are wider and will have more grip)
Click to expand...

Negative. This is *very* important.
Click to expand...

I know that the size of the tyre mathers a lot, but this was on a sidenote, bc this is not always(bigger tyres rear) and the difference is most of the time very little. Also, most stock cars will indeed have 4 equal wheels, but where talking about sportscars here.

Greetz Johan
 
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