Cam Help
5th Gear Member
Joined: Jan 2006
Posts: 2,760
From:
RE: Cam Help
ORIGINAL: Joel5.0
Here's another area to think about......the heads are limited in flow, but matching peak numbers between camshaft and heads = leaving power on the table...IMHO. Why?.......you have heads that are OK to .500", if you "match" them with a .500" lift cam......for how long will those heads flow at its peak?.....or, for how long will that valve stay open at its peak value with the engine turning 5500 rpms?....wouldn't you want that peak flow earlier, and for a longer period of time to better fill those cylinders?.......just a thought.
Here's another area to think about......the heads are limited in flow, but matching peak numbers between camshaft and heads = leaving power on the table...IMHO. Why?.......you have heads that are OK to .500", if you "match" them with a .500" lift cam......for how long will those heads flow at its peak?.....or, for how long will that valve stay open at its peak value with the engine turning 5500 rpms?....wouldn't you want that peak flow earlier, and for a longer period of time to better fill those cylinders?.......just a thought.
6th Gear Member
Joined: Dec 2006
Posts: 8,007
From: Citrus County, FL
RE: Cam Help
+2
*edit* of course, the length of time the valve stays open at its peak also comes into play. there was a class at the local track where you could only run a cam of something like .480 lift. well, thanks to us having a cam grinder we made a stick that looked like this:
which cam do YOU think makes more power?
*edit* of course, the length of time the valve stays open at its peak also comes into play. there was a class at the local track where you could only run a cam of something like .480 lift. well, thanks to us having a cam grinder we made a stick that looked like this:
which cam do YOU think makes more power?
5th Gear Member
Joined: Oct 2005
Posts: 4,616
From: Ohio USA
RE: Cam Help
With the gt 40 heads, on our cobra, we tried a few cams with the stock 1.7 rollers, and with the 5-speed, stalling at traffic lights was very easy and when engaging the clutch when going over a .520 lift.(streetability and vacum).
But we learned the GT-40 and similair flowing heads liked a split shift favoring the exhaust side, (stock is equal on int/exh), and kept in its power range to top end with .500 -.520 lift. And going larger lift , the power was lost and the heads were holding us back, as far as flow goes.
It was like the cam was trying to put the air there, but the heads could not pull it through and power was lost.
But we learned the GT-40 and similair flowing heads liked a split shift favoring the exhaust side, (stock is equal on int/exh), and kept in its power range to top end with .500 -.520 lift. And going larger lift , the power was lost and the heads were holding us back, as far as flow goes.
It was like the cam was trying to put the air there, but the heads could not pull it through and power was lost.
5th Gear Member
Joined: Oct 2005
Posts: 4,616
From: Ohio USA
RE: Cam Help
September 5, 1996
A Non-Technical Discussion on 5.0 Camshaft Selection
One of the hottest topics of debate lately has been choosing the right camshaft for your 5.0. Camshafts are on the forefront of everyone's consciousness more than any other bolt-on or component, perhaps because people feel it is the heart of the engine. The fact many people fail to understand is that its not the "Heart" of the engine, but just another component that needs to be chosen wisely. Poor camshaft choices are the root cause of why many Mustangs run below their potential. Most often, people are lead to believe that they need a cam to match their recently purchased cylinder head combo. This is the first mistake. Many people don't realize that the cylinder head alone, with its larger valves and intake ports, and reconfigured chamber design shift the power band upward for a typical '85 through '95 5.0 even with its factory roller cam. Often, all that is needed to take further advantage of the new head's flow potential is the extra lift offered by a 1.7 ratio roller rocker. Some shops offer custom ground cams that promise miracles.
Be careful, many of these cams were developed with a sheet of paper instead of a baselined engine and dyno. Some work well with their intended combination and some were only ground to make money. When cam manufactures list an operating range for their cams, the power band is usually shown within a 3000 to 3500 rpm range. The problem with a power band rating is that the cylinder heads and intake have a large bearing on where the engine will actually make its power with that particular cam. We've seen cams rated to pull to 5500 rpm, barely pull to 5000 because of stock or poor heads. However, the power band can extend far beyond its factory rating with a well done set of heads.
The most common problems with a cam change in a 302 is its incompatibility with EEC-IV and a loss of low end torque. We've solved many of the idle problems with custom EEC-IV recalibrations, but tuning alone can't bring back low end torque when the low speed velocity of the intake port is gone due to the big valves, big ports and too large a camshaft. T-5 cars are more prone to performance losses from too big a cam than automatic cars are (providing the automatic's converter is properly chosen). Traditional thinking is that because sticks can launch (stall) anywhere in the rpm band they want to, they can sidestep the problem of lost low end. A T-5 car can in fact launch wherever it wants, but the problem lies in its wide ratio gear selection and its solid connection (no torque multiplication) to the engine. The 1-2 shift and especially the 2-3 shift drop the rpm of the engine too far below where the previous gear left off.
This is why midrange power is essential during the "recovery" of the gear change. If the low end and midrange isn't optimized a T-5 car can suffer dramatic performance losses during the recovery period because it takes a second to again reach its productive range. On the opposite side of the spectrum, an automatic with a properly chosen torque converter never sees rpm below its productive range, regardless of what gear you're in. If the cam is making good midrange by 3000 and the converter stalls to 3200, you'll always be taking advantage of its power band, not waiting a split second to come into it. We're not trying to say that automatic cars are the only ones that can have large cams, remember this is in reference to 5.0s that are mainly 9:1 compression with T-5s, a close ratio gear box can also make a big difference. Many people choose, or have chosen for them, a cam too large for a low compression (9:1) engine.
This can account for a great deal of the low end power loss when the cam's duration is over 225° to 230° @ .050 on the intake and the N/A engine is not being revved over 6200 rpm. Higher compression will make more torque and horsepower across the entire band, but more importantly it makes a substantial increase down low. The moral, if you have a low compression engine, stay with a very mild cam. Mid to low 12 second ETs are what most 3200 to 3400 lb N/A Mustangs typically look for.
We've found this level of performance easily attained with the stock roller cam or a very mild replacement (less than 215° to 218° @ .050 on the intake) and a properly done set of heads. All too often people pay for an aftermarket cam and run no faster than an equally prepared car with the stock roller cam. Not all combinations can take advantage of the increased valve events. For supercharged cars, the stock cam is good enough for very low 11s and even 10s with good heads. We did it all of the '94 season with a B-Trim Vortech, Edelbrock heads, Tremec, 3.55 gears, with 3350 lbs through catalytic converters. We've made a lot of generalizations and omitted several factors that can alter these rules of thumb, so don't take them as absolutes, but . . . There is nothing wrong with the factory roller cam, in fact, it's a very good grind and capable of impressive performance levels with the right combination of parts. Try to run well with the stock cam before spending the money on an aftermarket cam and the installation. A good cylinder head/intake combo alone will raise the rpm band of the engine without touching the cam, so be careful not to place your shift point beyond the factory 6250 rev limiter.
A good cylinder head/intake combo will run very well with the stock cam and have tons of low end, baseline it with the stocker first so you can see any tangible gains. T-5 cars need lots of low and midrange torque, so steer away from cams that have more than 220° @.050 intake duration if your engine is below 9.75:1. Don't be fooled by promises of dramatic horsepower gains with this or that custom cam, many of them are no better than the less expensive Motorsport or other manufacturer's "off the shelf" grinds.
Be sure to visit the Water Box Archives for more informative articles.
Alternative Auto Performance
51945 Gratiot Ave, Chesterfield Twp., Michigan 48051
Phone: 586.949.7505 - Fax: 586.949.7501
A Non-Technical Discussion on 5.0 Camshaft Selection
One of the hottest topics of debate lately has been choosing the right camshaft for your 5.0. Camshafts are on the forefront of everyone's consciousness more than any other bolt-on or component, perhaps because people feel it is the heart of the engine. The fact many people fail to understand is that its not the "Heart" of the engine, but just another component that needs to be chosen wisely. Poor camshaft choices are the root cause of why many Mustangs run below their potential. Most often, people are lead to believe that they need a cam to match their recently purchased cylinder head combo. This is the first mistake. Many people don't realize that the cylinder head alone, with its larger valves and intake ports, and reconfigured chamber design shift the power band upward for a typical '85 through '95 5.0 even with its factory roller cam. Often, all that is needed to take further advantage of the new head's flow potential is the extra lift offered by a 1.7 ratio roller rocker. Some shops offer custom ground cams that promise miracles.
Be careful, many of these cams were developed with a sheet of paper instead of a baselined engine and dyno. Some work well with their intended combination and some were only ground to make money. When cam manufactures list an operating range for their cams, the power band is usually shown within a 3000 to 3500 rpm range. The problem with a power band rating is that the cylinder heads and intake have a large bearing on where the engine will actually make its power with that particular cam. We've seen cams rated to pull to 5500 rpm, barely pull to 5000 because of stock or poor heads. However, the power band can extend far beyond its factory rating with a well done set of heads.
The most common problems with a cam change in a 302 is its incompatibility with EEC-IV and a loss of low end torque. We've solved many of the idle problems with custom EEC-IV recalibrations, but tuning alone can't bring back low end torque when the low speed velocity of the intake port is gone due to the big valves, big ports and too large a camshaft. T-5 cars are more prone to performance losses from too big a cam than automatic cars are (providing the automatic's converter is properly chosen). Traditional thinking is that because sticks can launch (stall) anywhere in the rpm band they want to, they can sidestep the problem of lost low end. A T-5 car can in fact launch wherever it wants, but the problem lies in its wide ratio gear selection and its solid connection (no torque multiplication) to the engine. The 1-2 shift and especially the 2-3 shift drop the rpm of the engine too far below where the previous gear left off.
This is why midrange power is essential during the "recovery" of the gear change. If the low end and midrange isn't optimized a T-5 car can suffer dramatic performance losses during the recovery period because it takes a second to again reach its productive range. On the opposite side of the spectrum, an automatic with a properly chosen torque converter never sees rpm below its productive range, regardless of what gear you're in. If the cam is making good midrange by 3000 and the converter stalls to 3200, you'll always be taking advantage of its power band, not waiting a split second to come into it. We're not trying to say that automatic cars are the only ones that can have large cams, remember this is in reference to 5.0s that are mainly 9:1 compression with T-5s, a close ratio gear box can also make a big difference. Many people choose, or have chosen for them, a cam too large for a low compression (9:1) engine.
This can account for a great deal of the low end power loss when the cam's duration is over 225° to 230° @ .050 on the intake and the N/A engine is not being revved over 6200 rpm. Higher compression will make more torque and horsepower across the entire band, but more importantly it makes a substantial increase down low. The moral, if you have a low compression engine, stay with a very mild cam. Mid to low 12 second ETs are what most 3200 to 3400 lb N/A Mustangs typically look for.
We've found this level of performance easily attained with the stock roller cam or a very mild replacement (less than 215° to 218° @ .050 on the intake) and a properly done set of heads. All too often people pay for an aftermarket cam and run no faster than an equally prepared car with the stock roller cam. Not all combinations can take advantage of the increased valve events. For supercharged cars, the stock cam is good enough for very low 11s and even 10s with good heads. We did it all of the '94 season with a B-Trim Vortech, Edelbrock heads, Tremec, 3.55 gears, with 3350 lbs through catalytic converters. We've made a lot of generalizations and omitted several factors that can alter these rules of thumb, so don't take them as absolutes, but . . . There is nothing wrong with the factory roller cam, in fact, it's a very good grind and capable of impressive performance levels with the right combination of parts. Try to run well with the stock cam before spending the money on an aftermarket cam and the installation. A good cylinder head/intake combo alone will raise the rpm band of the engine without touching the cam, so be careful not to place your shift point beyond the factory 6250 rev limiter.
A good cylinder head/intake combo will run very well with the stock cam and have tons of low end, baseline it with the stocker first so you can see any tangible gains. T-5 cars need lots of low and midrange torque, so steer away from cams that have more than 220° @.050 intake duration if your engine is below 9.75:1. Don't be fooled by promises of dramatic horsepower gains with this or that custom cam, many of them are no better than the less expensive Motorsport or other manufacturer's "off the shelf" grinds.
Be sure to visit the Water Box Archives for more informative articles.
Alternative Auto Performance
51945 Gratiot Ave, Chesterfield Twp., Michigan 48051
Phone: 586.949.7505 - Fax: 586.949.7501
5th Gear Member
Joined: Oct 2005
Posts: 4,616
From: Ohio USA
RE: Cam Help
ORIGINAL: FullAuto
Cliff's Notes?
Cliff's Notes?
http://www.alternativeauto.com/
We do offer the most experienced, practical, down-to-earth technical backing in the industry for 5.0, 4.6 and 351W Mustangs. We build impressive power and tune with driveability and reliability in mind, not the highest possible peak horsepower number that puts the car on the ragged edge of engine safety. Every car that leaves our shop is extensively tuned to offer the absolute best in driveability and performance with “reliable†power production. Our customers do not leave frustrated or disgusted like so many others because of driveability problems or poor work. Our product line reflects our dedication to providing quality performance, there are many items that we refuse to sell or install because of their poor quality or failure to deliver. Customer satisfaction is more important to us than making a profit by selling inferior parts. At Alternative Auto Performance you’ll find more than just excellent, Ford trained mechanics, we’re craftsman, and every vehicle that leaves our shop reflects this attention to detail and pride of workmanship. We’ve been serving the Mustang performance community since 1990, testament to our quality and ability in an era of so many fly-by-night “performance expertsâ€. A Vortech Supercharger dealer since 1991, you will not find a shop with more experience and knowledge. Isn’t it time you quit looking for the lowest price, and started looking for the best service and the most experienced support?
Thread Starter
6th Gear Member
Joined: Feb 2005
Posts: 5,205
From:
RE: Cam Help
Well can we get back to my thread question about which cam to use for my car. This car is going to only be a street driven car and wont see higher then 5500 rpms anyways. I want acam that will have bottom end torque not high HP since it will only be street/highway driving. This car is going to be my DD. This the original cam that I picked out going to do this or should I look at the TFS stage 1 cam?
