[mopar392]

This puzzles me a little bit.

The R/T 5.7 is governed at 145mph while 392ci Chargers (SRT and SP) can go all the way up to 175mph

Both are using 8HP70 transmission with identical gear ratios.
The only differences are Final Drive Ratio 3.08:1 – (5.7-liter) vs 3.09:1 – Limited Slip (6.4-liter) and Overall Top Gear 2.06 (5.7-liter) vs 2.07 (6.4-liter)

I could be wrong but I thought the transmission is what limiting the top speed and engine helps the car to push to that speed.

So the question is, Why the R/T is governed?
For the guys who modded their 5.7, did you remove the speed limiter?

 

[Drew661]

I believe it has more to do with the how the tires are rated

 

[PitchBlack]

Usually the tires determine at what speed the car is governed. I think I saw somewhere the the 6.4 Chargers are drag-governed at 175. In other words, the engine runs out of enough power to overcome wind drag.

 

[mopar392]

So if a R/T 5.7l had more power (let's say another 100-150hp on the wheels) and a higher rating tires (Y or (Y)), the speed limiter can be "SAFELY" removed and only it will be limited by its drag coefficient??

 

[SuperTrooper169]

^ Yep. You can turn the govern off with a tuner too BTW.

 

[gohip2000]

Agreed, you don't need to beef anything up to safely go faster. You just need tires that are rated to handle that speed and a tuner to remove the limit.
I will say, at speeds above 130mph the suspension of a car is often the determining factor in safety on a non-perfect road. You the car will start to feel more floaty and the bumps and dips in the road will feel a lot more pronounced, but if you have a very smooth road, the base, stock, suspension works at very high speed.

My AWD is stopped at 130 because of the tire rating, but I can imagine the handling would start to feel very loose up around 150 as my suspension is very soft.

 

[Ddaddy]

Also remember what the SRT engineers said...

"At speeds over 140 mph, you are flying the car as much as you are driving it. This is where the aerodynamics and performance suspension of the SRT package come into play to keep the car predictable and stable at high speed. We didn't just build it to be able to go that fast, we designed it to do it safely and perform well at those speeds."

 

[B5ScatPack]

why do you want to go above 145MPH on a public road in an R/T (or any car for that matter)? Do you seriously have a death wish?

 

[rob-2]

why do you want to go above 145MPH on a public road in an R/T (or any car for that matter)? Do you seriously have a death wish?

Easy there. Speed doesn't kill, bad driver training, poor conditions and drinking do. He just wants to dream about out running baddies.

Op I will say without suspension work and aero I wouldn't get above 120 too quickly. The SRT feel solid, but other cars I've taken past 130 can feel floaty, developing lift and become unstable. There was thought in that govener

 

[Vogelsong]

Easy there. Speed doesn't kill, bad driver training, poor conditions and drinking do. He just wants to dream about out running baddies.
.
Op I will say without suspension work and aero I wouldn't get above 120 too quickly. The SRT feel solid, but other cars I've taken past 130 can feel floaty, developing lift and become unstable. There was thought in that govener

I will say for there size they are well engineered, better than the 93 5 liter I road raced back in the early 90's.


Anyway, I was letting my R/T STP stretch it's legs shortly after I got it. I was on a 4 lane and all the traffic was behind me, and I had about a visible mile of open road with a slight bend in it. This would be my first time pushing it through a turn.


So I ran it up, entered the bend at 100. At the apex of the bend, there was a little dip in the surface. This was also my first experience with this type of suspension technology. So the car hits the dip, and I gotta say it was the coolest thing I ever experienced. I felt the car drop into the dip, and instead of rebounding, you just felt the suspension make all these little micro adjustments that kept the car solid as a rock. I was impressed, and shocked beyond belief at how the car handled it all in milliseconds.


A few weeks ago, I stretched it out across a bridge. I was at a light, and a
special edition mustang went by that I had never seen before, and I wanted to know what it was. So as I'm sitting at the light it disappears, and I'm thinking as long as no other traffic goes through this light I'll catch him.


Finally the light turns green, and I take off... I caught him about a mile out. When I saw his tail lights about 300 yards out I lifted and looked down. She was at 134 and felt solid as a rock. I would love to get this thing on the salt flats. It just feels like it will pull forever, with no sign of stopping. I can't imaging what an SRT8 feels like.


These are great cars, and I couldn't be happier with mine.

 

[PitchBlack]

Speed doesn't kill, it's the sudden deceleration that's the problem.

But seriously, going 140+ on a public road is nuts. Even Germany has reduced the allowable speed on parts of the Autobahn. There is too much traffic and too many idiots behind the wheel these days. There is no driver's training and people are more concerned with texting than driving. I know my car is capable of very high speed, and from being a former LEO and having a competition driver's license, I have complete confidence in my ability to drive at high speed. But I don't have confidence in the ability of other drivers, the pieces of retread tires on the highway, and any number of other factors that are beyond my control. Things can go south in a heartbeat at that speed. I'm not chastising or trying to be a prude, but speaking from years of experience and from what I've seen.