cams vs. gears
04-13-2009, 09:05 PM
#11
5th Gear Member
Join Date: Jun 2007
Location: Wheeling, IL
Posts: 3,748
I've heard a lot of misinformation here.
Cams are greater than gears in many many ways.
1. Cams give your car physical HP and TQ.
2. Depending on the lift of the Cam, and type, you don't need bigger gears for low end.
3. Cams are a part of building your motor.
4. While having gears and a stall is suggested for a Cam, a Cam alone will give you more than a couple of tenths in the 1/4.
IMO, a mild cam, like Hot Rod Cams, 3.55's and a stall, or just 3.55's will be perfect. Now, if you really want to launch harder, and maybe get a bit more out of the cam, you CAN get a different gear. I.E 3.73's.
Typically, the more aggressive Cam, the bigger gear you will need. I.E Drag Racing Cams need 4.10+
Cams are greater than gears in many many ways.
1. Cams give your car physical HP and TQ.
2. Depending on the lift of the Cam, and type, you don't need bigger gears for low end.
3. Cams are a part of building your motor.
4. While having gears and a stall is suggested for a Cam, a Cam alone will give you more than a couple of tenths in the 1/4.
IMO, a mild cam, like Hot Rod Cams, 3.55's and a stall, or just 3.55's will be perfect. Now, if you really want to launch harder, and maybe get a bit more out of the cam, you CAN get a different gear. I.E 3.73's.
Typically, the more aggressive Cam, the bigger gear you will need. I.E Drag Racing Cams need 4.10+
04-13-2009, 09:37 PM
#13
Mish-ogynist
Join Date: Nov 2007
Location: Helena, MT
Posts: 3,780
+1 the better sound is a bonus.. Cams + install tend to be quite a bit more expensive than gears though.. so if price is taken out of the equation then I would have chosen cams over gears myself.
The reason your percentage gains on the Cams don't seem to work is a stock car at 275rwhp has gained 32 rwhp.. another car with different cams started at 330 and wound up only making 340rwhp.. and a s/c mustang at 430rwhp picked up 25rwhp on blower cams.. so thats why i called your number arbitrary and a percentage increase doesn't apply.
hehe sorry to pick on your sig man.. but it's been bugging me for awhile.. You make good contributions to the forums.
The reason your percentage gains on the Cams don't seem to work is a stock car at 275rwhp has gained 32 rwhp.. another car with different cams started at 330 and wound up only making 340rwhp.. and a s/c mustang at 430rwhp picked up 25rwhp on blower cams.. so thats why i called your number arbitrary and a percentage increase doesn't apply.
hehe sorry to pick on your sig man.. but it's been bugging me for awhile.. You make good contributions to the forums.
Last edited by Mishri; 04-13-2009 at 09:41 PM.
04-13-2009, 11:44 PM
#16
2nd Gear Member
Join Date: Jan 2007
Location:
Posts: 350
FWIW -
https://mustangforums.com/forum/2005...installed.html
My thread on the recent installation of Comp's ***** Thumpr's with Dyno Charts (before and after) as well as seat of the pants impressions. I don't run the 1/4, so no track times, sorry. I would say that the Comp MT's absolutely require a 3.73-4.10 for drive ability.
~Matty
https://mustangforums.com/forum/2005...installed.html
My thread on the recent installation of Comp's ***** Thumpr's with Dyno Charts (before and after) as well as seat of the pants impressions. I don't run the 1/4, so no track times, sorry. I would say that the Comp MT's absolutely require a 3.73-4.10 for drive ability.
~Matty
04-14-2009, 12:59 AM
#17
5th Gear Member
Join Date: Aug 2006
Location: Near Wash. DC Posts: 13,541
Posts: 2,497
Apology accepted. Cams like say the FRPP ones can be a wild card because you get a lot of variation in different cars for whatever reason.
Original post:
The most severe gear switch,3.55-4.10 gives you 15.5% more RPM
A set of average high performance cams give you 13% more top end power as well at 12% more torque. and 2% added low end power and torque.
15.5% more RPM translates to 17.5% more power and 7% more torque based on a dyno sheet of the stock car, though you lose some power on the street because you will be shifting more (I also noticed with certain mods like CMVC delete plates you may even loose torque with gears).
Here's what I have:
Gears:
Max Possible Gain: about 17.5% more power 7% more torque to the ground.
Overall (to 70 mph): about 10% more power 0% more torque to the ground. (assumes .4 second shifts)
Overall (drag strip): about 17.5% more power 7% more torque to the ground.
Cams:
Top End Gain: about 13% more power 11% more torque, to the engine.
Overall (typical average of the useful power band let say staying at 75% rpm): about 9.5% more power 9.25% more torque to the ground.
So cams are much better than gears on the street and gears only even come close if you are very good at shifting because you'll have to shift more with them and are likley to get even more of a loss than 7% of your power unless you are good but gears are better on the drag strip where you go through all of them no matter what you do.
Original post:
The most severe gear switch,3.55-4.10 gives you 15.5% more RPM
A set of average high performance cams give you 13% more top end power as well at 12% more torque. and 2% added low end power and torque.
15.5% more RPM translates to 17.5% more power and 7% more torque based on a dyno sheet of the stock car, though you lose some power on the street because you will be shifting more (I also noticed with certain mods like CMVC delete plates you may even loose torque with gears).
Here's what I have:
Gears:
Max Possible Gain: about 17.5% more power 7% more torque to the ground.
Overall (to 70 mph): about 10% more power 0% more torque to the ground. (assumes .4 second shifts)
Overall (drag strip): about 17.5% more power 7% more torque to the ground.
Cams:
Top End Gain: about 13% more power 11% more torque, to the engine.
Overall (typical average of the useful power band let say staying at 75% rpm): about 9.5% more power 9.25% more torque to the ground.
So cams are much better than gears on the street and gears only even come close if you are very good at shifting because you'll have to shift more with them and are likley to get even more of a loss than 7% of your power unless you are good but gears are better on the drag strip where you go through all of them no matter what you do.
Last edited by Legion5; 04-14-2009 at 01:02 AM.
04-14-2009, 06:06 AM
#18
1st Gear Member
Join Date: Jun 2008
Location: Va.
Posts: 129
I have the FRPP cams,headers, X pipi,FRPP cai with dyno tune and pullies. I had 355 gears and you had to feather the clutch some while taking off in 1st gear. I then added a FRPP 410 gear and it is a perfect match. In my experience you need a better gear than a 355 with the FRPP cams. I gained @20 hp with cams alone. To this date the gear is my favorite mod.
