Why don't Ford,Chevy,Dodge make DOHC's?
02-04-2007, 06:00 PM
#1
Registered User
Thread Starter
Join Date: Aug 2006
Location: Minnesota
Posts: 130
Car Info: 2006 Impreza WRX Sti/Hawkeye
Why don't Ford,Chevy,Dodge make DOHC's?
Why do they all have SOHC or OHV?? I mean Mustangs only have OHC which is a very weak way to make power. The 3.8L V6 SOHC made only 190hp!! Acura RSX Type S 2.0L I4 DOHC makes 201hp! Why did they abandon DOHC? They know they can do better.
02-04-2007, 07:17 PM
#2
Registered User
Join Date: Nov 2003
Location: Kaneohe, HI
Posts: 160
Car Info: 2004 STi
Ignorance is bliss
Ford has both SOHC(per cyl bank) and DOHC(per cyl bank) on their V-8's. I also believe that most of the duratec V6's that they use now are OHC's. All their 4cyls are DOHC or SOHC, and the used Yamaha DOHC V-6's in a lot of their old Taurus SHO's.
Chrysler runs a number of OHC engines, their 4 cyls began with SOHC in the mid-80's and many incorporated turbocharging.
GM(chevy, pontiac, caddy, olds, etc) still does use many OHV configurations for example a number of V-6's such as the 3800 series I and II as well as all their LSx V-8's. However, they have been using DOHC 4cyls in their smaller cars for over 15 years, lets not forget that the Cadillac Northstar V-8's are all OHC.
Chrysler runs a number of OHC engines, their 4 cyls began with SOHC in the mid-80's and many incorporated turbocharging.
GM(chevy, pontiac, caddy, olds, etc) still does use many OHV configurations for example a number of V-6's such as the 3800 series I and II as well as all their LSx V-8's. However, they have been using DOHC 4cyls in their smaller cars for over 15 years, lets not forget that the Cadillac Northstar V-8's are all OHC.
02-05-2007, 09:19 AM
#3
Registered User
Join Date: May 2006
Location: I was up above it, now I'm down in it
Posts: 5,686
Car Info: New Government Motors SUV!
Would you really consider buying one if they all had DOHC???
Also, the V6 Mustang's intent wasn't to make a lot of power. The V6 makes power much lower in the RPM range (as opposed to the RSX) wich is nice for a daily driver. Even still, Mercedes rocked the SOHC set up till recently and they didn't have any problem making power.
Also, the V6 Mustang's intent wasn't to make a lot of power. The V6 makes power much lower in the RPM range (as opposed to the RSX) wich is nice for a daily driver. Even still, Mercedes rocked the SOHC set up till recently and they didn't have any problem making power.
02-05-2007, 11:08 AM
#4
VIP Member
Join Date: Mar 2003
Location: Phoenix, AZ
Posts: 2,023
Car Info: Subaru Impreza WRX 2002
As Superglue said, DOHC is a tool for getting more power at higher RPMs. I'm not certain the original poster understands the engine design properties of SOHC and DOHC setups. Many domestic motors were also 2 valves per cylinder; you simply do not need (nor could you use) DOHC in this design. The advantage of DOHC is to allow four valves per cylinder and run the motor at higher RPMs as a way of making power. If you are choosing to make power at low RPMs with more displacement, then you don't need DOHC -- totally superfluous. Many domestic engines were still using pushrod designs well into the '90s, which of course doesn't even have SOHC.
Here are a few links to shed some light on this:
http://auto.howstuffworks.com/question562.htm
http://auto.howstuffworks.com/camshaft.htm
It is simply a question of engine design philosophy. Japanese and Euro designers have been working with smaller engine bays and displacements, so DOHC has been the only way to add power. Domestic (and German) engine designers have always had the option to add more displacement, so SOHC is a better and less troublesome to tune option. That's why a domestic 5.7liter powerplant can make less than 190hp; there are some German and UK SOHC V-12 engines that make less than 160hp. Their goal was smooth power delivery over the entire RPM band, rather than peaky power that only kicks in at high RPM.
If you look at a dyno plot of that Mustang V6 vs. the Acura powerplant, you would see exactly what I am talking about. The Mustang motor puts out flat torque from 1,000 RPM to 5,500; the Acura is as weak as a golf cart until 3,500 and doesn't hit peak torque before 5500. Peak HP is worthless, it is the RPM in the normal driving range that matters.
Here are a few links to shed some light on this:
http://auto.howstuffworks.com/question562.htm
http://auto.howstuffworks.com/camshaft.htm
It is simply a question of engine design philosophy. Japanese and Euro designers have been working with smaller engine bays and displacements, so DOHC has been the only way to add power. Domestic (and German) engine designers have always had the option to add more displacement, so SOHC is a better and less troublesome to tune option. That's why a domestic 5.7liter powerplant can make less than 190hp; there are some German and UK SOHC V-12 engines that make less than 160hp. Their goal was smooth power delivery over the entire RPM band, rather than peaky power that only kicks in at high RPM.
If you look at a dyno plot of that Mustang V6 vs. the Acura powerplant, you would see exactly what I am talking about. The Mustang motor puts out flat torque from 1,000 RPM to 5,500; the Acura is as weak as a golf cart until 3,500 and doesn't hit peak torque before 5500. Peak HP is worthless, it is the RPM in the normal driving range that matters.
Last edited by meilers; 02-05-2007 at 11:10 AM.
02-05-2007, 11:28 AM
#5
Registered User
iTrader: (11)
Join Date: Feb 2006
Location: top of Mt. Hammy
Posts: 2,097
Car Info: 413whp/461wtq
Originally Posted by meilers
As Superglue said, DOHC is a tool for getting more power at higher RPMs. I'm not certain the original poster understands the engine design properties of SOHC and DOHC setups. Many domestic motors were also 2 valves per cylinder; you simply do not need (nor could you use) DOHC in this design. The advantage of DOHC is to allow four valves per cylinder and run the motor at higher RPMs as a way of making power. If you are choosing to make power at low RPMs with more displacement, then you don't need DOHC -- totally superfluous. Many domestic engines were still using pushrod designs well into the '90s, which of course doesn't even have SOHC.
Here are a few links to shed some light on this:
http://auto.howstuffworks.com/question562.htm
http://auto.howstuffworks.com/camshaft.htm
It is simply a question of engine design philosophy. Japanese and Euro designers have been working with smaller engine bays and displacements, so DOHC has been the only way to add power. Domestic (and German) engine designers have always had the option to add more displacement, so SOHC is a better and less troublesome to tune option. That's why a domestic 5.7liter powerplant can make less than 190hp; there are some German and UK SOHC V-12 engines that make less than 160hp. Their goal was smooth power delivery over the entire RPM band, rather than peaky power that only kicks in at high RPM.
If you look at a dyno plot of that Mustang V6 vs. the Acura powerplant, you would see exactly what I am talking about. The Mustang motor puts out flat torque from 1,000 RPM to 5,500; the Acura is as weak as a golf cart until 3,500 and doesn't hit peak torque before 5500. Peak HP is worthless, it is the RPM in the normal driving range that matters.
Here are a few links to shed some light on this:
http://auto.howstuffworks.com/question562.htm
http://auto.howstuffworks.com/camshaft.htm
It is simply a question of engine design philosophy. Japanese and Euro designers have been working with smaller engine bays and displacements, so DOHC has been the only way to add power. Domestic (and German) engine designers have always had the option to add more displacement, so SOHC is a better and less troublesome to tune option. That's why a domestic 5.7liter powerplant can make less than 190hp; there are some German and UK SOHC V-12 engines that make less than 160hp. Their goal was smooth power delivery over the entire RPM band, rather than peaky power that only kicks in at high RPM.
If you look at a dyno plot of that Mustang V6 vs. the Acura powerplant, you would see exactly what I am talking about. The Mustang motor puts out flat torque from 1,000 RPM to 5,500; the Acura is as weak as a golf cart until 3,500 and doesn't hit peak torque before 5500. Peak HP is worthless, it is the RPM in the normal driving range that matters.
Thread
Thread Starter
Forum
Replies
Last Post
dropkick_muppet
Car Lounge
5
12-20-2003 09:40 PM
IS2Scooby
Hawaii
9
10-04-2003 04:22 PM
