Car Question

Glitchny

Diamond Member
Sep 4, 2002
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Having an argument with someone and need a definitive answer.

Do cars come with restrictor plates to make sure the car cant go over a certain speed?
 

Glitchny

Diamond Member
Sep 4, 2002
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Originally posted by: Pacfanweb
Not restrictor plates, but many cars have their top speeds governed by the PCM.

what is the PCM? and what are restrictor plates used for then?
 

olds

Elite Member
Mar 3, 2000
50,124
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Originally posted by: Pacfanweb
Not restrictor plates, but many cars have their top speeds governed by the PCM.
Powertrain Control Module

 

Nocturnal

Lifer
Jan 8, 2002
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Are you talking about rev limiter? Then yes, a car cannot rev over say 8k RPM otherwise the rev limiter kicks in.
 

alkemyst

No Lifer
Feb 13, 2001
83,769
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There are no restrictor plates on mass produced cars I believe....

The PCM (computer) has a set limit on top speed, normally governed by the tires (it will never be more than the speed rating of the OEM tires on the vehicle).

There is also usually a rev limiter to protect the engine, but the speed limiter works outside that.

 

Actaeon

Diamond Member
Dec 28, 2000
8,657
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Originally posted by: LAUST
Restrictor plate limits HP

Rev Limiter limits RPM (My Redline is at 6000rpm my rev limiter is at 5900rpm) once I hit 5900 the engine will cut out like it does when you hit the...

Top Speed Limiter is programmed into your PCM/ECU and it cuts you off by speed, stock mine cut at 100mph but I have programmed mine to 124mph now (H tire rating)

What kind of car is that?

100mph is rather low for stock.

My little Saturn SC2 is 124mph/6750rpm (6500 redline) limiter out of the factory.
 

LAUST

Diamond Member
Sep 13, 2000
8,957
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Finding H rated tires for a full size 4x4 isn't that easy ;) (285/70/R16)
 
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geno

Lifer
Dec 26, 1999
25,074
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Do cars come with restrictor plates to make sure the car cant go over a certain speed?
Restrictor plates go in Carbeurators, and the only use of them that I know is in NASCAR.

Speed limited is done by the ECU (the engine's computer) nowadays.
 

Jombo

Golden Member
Aug 19, 2001
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the cars are speed limited by manufacs to make sure you don't go over the speeds rated by the fitted tires.

tire speed rating

you car maybe capable of pulling faster than 130, but if your car has h rated tires, the manufacs would limit the speed to 130 to make sure the driver won't run the risk of blowing a tire going over the rated speed.

higher speed ratings aren't always a good thing either, since the compound composition of the tire on higher speed rated tires tend to wear out faster..

as for putting in restrictor plates on a stock car, what manufac in their right mind would drop their horse power/ torque rating to limit the car's speed?
 

johnjbruin

Diamond Member
Jul 17, 2001
4,401
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yeah. most cars have speed governors so you dont take it over the max speed (say supported by the tires it comes stock with etc.)
my car has the limiter at 146mph. now you might ask how do i know this :Q
 

Ronstang

Lifer
Jul 8, 2000
12,493
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Originally posted by: TommyVercetti
I have heard of some cars which do that. I know the RSX has a speed limiter on its top speed.
Sure does....it is called lack of horsepower and more importantly torque.

 

johnjbruin

Diamond Member
Jul 17, 2001
4,401
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Originally posted by: Ronstang
Originally posted by: TommyVercetti
I have heard of some cars which do that. I know the RSX has a speed limiter on its top speed.
Sure does....it is called lack of horsepower and more importantly torque.

haha. doesnt the W(eak)-tec kick in ;)
 

Ronstang

Lifer
Jul 8, 2000
12,493
18
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Originally posted by: johnjbruin
Originally posted by: Ronstang
Originally posted by: TommyVercetti
I have heard of some cars which do that. I know the RSX has a speed limiter on its top speed.
Sure does....it is called lack of horsepower and more importantly torque.

haha. doesnt the W(eak)-tec kick in ;)
Hey....get it right. It's V(Vrooooooom)-Tech

 

johnjbruin

Diamond Member
Jul 17, 2001
4,401
1
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Originally posted by: Ronstang
Originally posted by: johnjbruin
Originally posted by: Ronstang
Originally posted by: TommyVercetti
I have heard of some cars which do that. I know the RSX has a speed limiter on its top speed.
Sure does....it is called lack of horsepower and more importantly torque.

haha. doesnt the W(eak)-tec kick in ;)
Hey....get it right. It's V(Vrooooooom)-Tech

for just the sound and no go right? ;)