FRPP 3V ported heads plus Comp Cams Stage 3 Cams

[ratnacage]

I have the stage 4 comp cams and have really enjoyed the added performance they have given my car.

 

On a Shelby or GT? What kind of gains did you get?

[2006GT500]

On a GT. I was at 318rwhp and 325rwtq prior to the cams and dyno'd 333rwtq and 333rwhp with the cams, however I never had a tune done when I added the cams. I think with tuning my numbers would have been higher. However, tuning wasn't necessary with the comp cams put them in and the car fired right up and ran really hard. It was like having a mild power adder. No check engine lights or anything. I know that there was an article in one of the magazines that a guy made 362rwhp with the comp cams and tuning. I would suggest them to anyone. I would not suggest the comp 1's as we installed them in a friends car and I couldn't really tell much of a difference.

[ratnacage]

On a GT. I was at 318rwhp and 325rwtq prior to the cams and dyno'd 333rwtq and 333rwhp with the cams, however I never had a tune done when I added the cams. I think with tuning my numbers would have been higher. However, tuning wasn't necessary with the comp cams put them in and the car fired right up and ran really hard. It was like having a mild power adder. No check engine lights or anything. I know that there was an article in one of the magazines that a guy made 362rwhp with the comp cams and tuning. I would suggest them to anyone. I would not suggest the comp 1's as we installed them in a friends car and I couldn't really tell much of a difference.

 

I went from 306 rwhp to 350 rwhp with the cams, CMCV delete's and tuning. I'll bet with the right tuning you could add another 30 hp.

 

What's the lift on your stage 4's? Mine's 490/500 (I wish I could remember the duration/overlap).

[2006GT500]

Not sure. Do you have a video or sound clip or your crowers? What stage are they?

[ratnacage]

Not sure. Do you have a video or sound clip or your crowers? What stage are they?

 

They're a custom grind but similar to the Comp Stage III. I'll get a video this weekend.

[nachtkriechen]

Actually, I haven't kept this thread updated like I should have. Since that data (April 07), additional tuning has been done which has increased peak tq to 322. Pk HP increased to 342 from 341 - not much there, but the real story is not in the peak values, but in the shape of the curve.....

...here is a more compelling argument.... In stock configuration pk TQ arrives at just over 4000 rpm (around 285 lb-ft). For simplicity, lets look at what happens in 3rd gear with a 3.55 axle: upon shifting to 3rd, rpm drops to 4000 rpm with tq around 282. At this point, tq is just below pk, then headed down towards 230 @ 6000. This means that for the virtually all of 3rd gear, a stock Mustang's rate of acceleration is decreasing. Without regard to the axle ratio, at 4000 rpm, my engine still has not reached its peak tq - this comes around 5300 rpm, thus my rate of acceleration is still increasing at the shift. From 5300 rpm, tq drops to 297 at 6000. So between 4000 rpm and 6000 rpm, in stock form there is net change in tq of -52 lb-ft (282@4000 vs 230@6000), while my car experiences a net change of +2 lb-ft (295@4000 vs 297@6000). This is an absolute difference in change of tq of 54 lb-ft bewteen the two configurations. This is huge and is why you can't just focus on pk values. The shape of the curve is what ultimately determines your overall performance in acceleration. Peak values are great for bragging on Saturday nights, but the proof will be in how the cars accelerate and by how much one beats the other.

 

Now, in the real world with my actual configuration (4.10 axle, 295/45/18's), I'll actually shift out of 3rd at 6250 rpm which will land me at 4700 rpm in 4th. I'll then finish the 1/4 mile at about 5500 rpm in 4th (roughly 110 mph). Between 4700 and 5500, my net change in tq is +3 lb-ft (312@4700 vs 315@5500).

 

So the long and short of it is that while the difference between peak values isn't that dramatic, the difference between the shapes of the curves are. While I'm open to your theory that my overall performance would improve with shorties, I am skeptical only because I wonder, with cams, if shorties wouldn't provide too much back pressure given the much greater volume of exhaust that needs to flow. I'm sure you're correct if we take the cams out of the equation, but I would be very surprised if going to shorties gave me better 1/4 mile performance (with cams).

 

This is a facinating debate - let's keep it going!!

 

So, I have a few questions. First things first. Powerplant. Disregarding exhaust and gears, if I plan on getting a GT with a blower, but I want the engine to last, to my understanding you need to stay within the 7-9 psi range. My goal is to have 450 rwhp (or darn near it). Could I accomplish this safely with the 4.6 engine by adding the blower with cams?

 

Secondly. With the prior question in mind, and from what I've read in this thread, it sounds like I might want to go with shorty headers. Is this correct?

 

Thirdly, with the engine and exhaust taken care of, which gearing setup would be best if I only went with the blower, and which would be best for blower and cams?

 

 

Thanks,

 

 

 

- Josh

[ratnacage]

So, I have a few questions. First things first. Powerplant. Disregarding exhaust and gears, if I plan on getting a GT with a blower, but I want the engine to last, to my understanding you need to stay within the 7-9 psi range. My goal is to have 450 rwhp (or darn near it). Could I accomplish this safely with the 4.6 engine by adding the blower with cams?

 

Secondly. With the prior question in mind, and from what I've read in this thread, it sounds like I might want to go with shorty headers. Is this correct?

 

Thirdly, with the engine and exhaust taken care of, which gearing setup would be best if I only went with the blower, and which would be best for blower and cams?

Thanks,

- Josh

 

First things first. The stock engine is safe up to around 450-500 crank HP (I'll use crank HP because when we talk about breaking things, it's all about the power at the engine, not the rear wheels). That's assuming your not beating it to hell at every stop light, in which case you'd eventually destroy it no matter how tame your mods are. With 500 hp as a reference, you then need to "design" your approach to achieve that. Whether you're running 5 psi backed up by cams, heads, CAI, and exhaust, or 10 psi with exhaust, and a CAI - either way you're still relatively safe.

 

Boost: to get 450 rwhp you'll need about 10-12 psi (more fuel and colder plugs too) with full exhaust (LT's), CAI, and of course tuning.

 

Now, here's where people run into trouble; everyone thinks it's about boost pressure, when really it's about total airflow. Look at the engine as a restrictor plate at the end of the SC. Boost is really just a measure of backpressure generated by the SC trying to flow increasing amounts of air through the restriction (engine). So let's say you slap a SC on your completely stock engine and at 8 psi you make about 450 crank HP. You're not satisfied with 450, so you decide to add a full exhaust. Having the bigger exhaust reduces the effective restriction thus total airflow increases and HP increases. BUT - and this is a big BUT - you then notice that the boost pressure has decreased - you were making 8 psi, but now you're only making around 6 psi. Why? Total airflow increased as a result of the reduced back pressure. The reduced boost is actually indicative of higher airflow. The key to understanding this concept is that a SC is driven in direct proportion to engine rpm, so at 6000 engine-rpm the SC is spinning at the same speed before and after the exhaust mod. Since SC speed remained the same and the back pressure decreased, boost decreased even though more air is flowing. This also assumes all other factors remain relatively the same such as air temp, humidity, etc.

 

So the thing that gets people into trouble is they see this reduction in boost and not understanding these relationships, they go get a smaller pulley to get the boost back to 8 psi (they get fixated on boost instead of total airflow/power). In this case, the increased boost is indicative of an increase in total airflow because you haven't changed the engine after the exhaust mod, all you've done here is increase the SC speed without affecting the engine's effective restriction. In doing so, they may exceed the engines design limits and things start to break, then they wonder why they're breaking things when everyone says 8 psi is "safe." Because it's not about the boost alone, but rather the total package and the power it produces.

 

So the short version is this: don't load up your engine with cams, exhaust, CAI and then expect 8 psi to be "safe." With heavy mods like that your safe boost level may be more like 5 psi.

 

Shorty headers: waste of money. Everyone has their own opinion, that's mine. The stock manifolds are pretty efficient as-is. It's not that you won't gain anything with shorties, but the gain isn't worth the price in my opinion. Plus, if you're going with a SC, then you should get LT's to flow that extra air. So, given the choice between shorties and keeping the stock manifolds so I can spend that money on something else, I'll spend the money on something else...maybe a nice neon light kit, hmm (just kidding).

 

Gear selection: select the gear that's going to keep you in the sweet spot of your torque curve and which will allow you to finish the 1/4 mile near the top of either 3rd or 4th (in other words, you don't want to run out of gear 100 ft from the finish). For instance, if you stay with 3.31 gears and install headers and cams, the sweet spot on your tq curve will be above 4500 rpm, but because of the tall gear, everytime you shift you'll be dropping the rpm's down significantly below that so you won't get the full benefit of your mods. With a blower, I don't think you really need to go beyond 3.73, but I've heard of people with 4.10's doing well also (I have 4.10's but I'm NA). So, if you really want to be exact in gear selection, do all your other mods first (assuming you planned on doing them all at once), then choose a gear based on the dyno results and where your ideal shift points are. If you're looking at doing all your mods over an extended period of time, then you really can't go wrong with 3.73's

 

Hopefully between this and my previous notes I've answered your questions without talking in circles too much. I'll be happy to clarify where needed.

[nachtkriechen]

First things first. The stock engine is safe up to around 450-500 crank HP (I'll use crank HP because when we talk about breaking things, it's all about the power at the engine, not the rear wheels). That's assuming your not beating it to hell at every stop light, in which case you'd eventually destroy it no matter how tame your mods are. With 500 hp as a reference, you then need to "design" your approach to achieve that. Whether you're running 5 psi backed up by cams, heads, CAI, and exhaust, or 10 psi with exhaust, and a CAI - either way you're still relatively safe.

 

Boost: to get 450 rwhp you'll need about 10-12 psi (more fuel and colder plugs too) with full exhaust (LT's), CAI, and of course tuning.

 

Now, here's where people run into trouble; everyone thinks it's about boost pressure, when really it's about total airflow. Look at the engine as a restrictor plate at the end of the SC. Boost is really just a measure of backpressure generated by the SC trying to flow increasing amounts of air through the restriction (engine). So let's say you slap a SC on your completely stock engine and at 8 psi you make about 450 crank HP. You're not satisfied with 450, so you decide to add a full exhaust. Having the bigger exhaust reduces the effective restriction thus total airflow increases and HP increases. BUT - and this is a big BUT - you then notice that the boost pressure has decreased - you were making 8 psi, but now you're only making around 6 psi. Why? Total airflow increased as a result of the reduced back pressure. The reduced boost is actually indicative of higher airflow. The key to understanding this concept is that a SC is driven in direct proportion to engine rpm, so at 6000 engine-rpm the SC is spinning at the same speed before and after the exhaust mod. Since SC speed remained the same and the back pressure decreased, boost decreased even though more air is flowing. This also assumes all other factors remain relatively the same such as air temp, humidity, etc.

 

So the thing that gets people into trouble is they see this reduction in boost and not understanding these relationships, they go get a smaller pulley to get the boost back to 8 psi (they get fixated on boost instead of total airflow/power). In this case, the increased boost is indicative of an increase in total airflow because you haven't changed the engine after the exhaust mod, all you've done here is increase the SC speed without affecting the engine's effective restriction. In doing so, they may exceed the engines design limits and things start to break, then they wonder why they're breaking things when everyone says 8 psi is "safe." Because it's not about the boost alone, but rather the total package and the power it produces.

 

So the short version is this: don't load up your engine with cams, exhaust, CAI and then expect 8 psi to be "safe." With heavy mods like that your safe boost level may be more like 5 psi.

 

Shorty headers: waste of money. Everyone has their own opinion, that's mine. The stock manifolds are pretty efficient as-is. It's not that you won't gain anything with shorties, but the gain isn't worth the price in my opinion. Plus, if you're going with a SC, then you should get LT's to flow that extra air. So, given the choice between shorties and keeping the stock manifolds so I can spend that money on something else, I'll spend the money on something else...maybe a nice neon light kit, hmm (just kidding).

 

Gear selection: select the gear that's going to keep you in the sweet spot of your torque curve and which will allow you to finish the 1/4 mile near the top of either 3rd or 4th (in other words, you don't want to run out of gear 100 ft from the finish). For instance, if you stay with 3.31 gears and install headers and cams, the sweet spot on your tq curve will be above 4500 rpm, but because of the tall gear, everytime you shift you'll be dropping the rpm's down significantly below that so you won't get the full benefit of your mods. With a blower, I don't think you really need to go beyond 3.73, but I've heard of people with 4.10's doing well also (I have 4.10's but I'm NA). So, if you really want to be exact in gear selection, do all your other mods first (assuming you planned on doing them all at once), then choose a gear based on the dyno results and where your ideal shift points are. If you're looking at doing all your mods over an extended period of time, then you really can't go wrong with 3.73's

 

Hopefully between this and my previous notes I've answered your questions without talking in circles too much. I'll be happy to clarify where needed.

 

Wow! Nicely written, Rat! Thank you for the in-depth explanation. I catch on to things fairly quickly, and have always been somewhat mechanically inclined, but, I've never done more than change the oil and plugs and tires on any of my vehicles. I understood all of the acronyms except your "LT" reference to exhaust. I also understood the basic concepts of your explanations, but the specific numbers I'm not 100% clear on. However, I don't think that's entirely necessary at this point for me.

 

When I do buy my GT, I plan on getting the SC at the same time. As far as the cams and everything else, that will be over time. So I'm thinking the 4.10s would probably do well for streetability. After all, Ruf is in love with them, and I've heard nothing but good things about them. That said, what makes you prefer 3.73s? Also, what is the stock GT rear diff at?

 

Thanks,

 

 

 

- Josh

[ratnacage]

Wow! Nicely written, Rat! Thank you for the in-depth explanation. I catch on to things fairly quickly, and have always been somewhat mechanically inclined, but, I've never done more than change the oil and plugs and tires on any of my vehicles. I understood all of the acronyms except your "LT" reference to exhaust. I also understood the basic concepts of your explanations, but the specific numbers I'm not 100% clear on. However, I don't think that's entirely necessary at this point for me.

 

When I do buy my GT, I plan on getting the SC at the same time. As far as the cams and everything else, that will be over time. So I'm thinking the 4.10s would probably do well for streetability. After all, Ruf is in love with them, and I've heard nothing but good things about them. That said, what makes you prefer 3.73s? Also, what is the stock GT rear diff at?

 

Thanks,

- Josh

 

I don't prefer the 3.73's. I only suggested them because 4.10's are a bit much for some people. I love my 4.10's also.

 

LT = Long Tube headers

 

Some of the numbers I used are for illustration. Like I don't know that boost would fall from 8 to 6 psi after installing better exhaust, but what I wanted to illustrate is the principle. I do know that as the engine flows better, boost pressure will drop.

 

I do know that a GT with Kooks headers high flow cats and Ford Racing mufflers, 11 psi intercooled Vortech, bigger injectors and fuel delivery, will do 447 to the wheels. I also have seen a bone stock GT with a Roush charger and Roush plug-n-play tune with 5 psi make 345 to the wheels.

[nachtkriechen]

I don't prefer the 3.73's. I only suggested them because 4.10's are a bit much for some people. I love my 4.10's also.

 

LT = Long Tube headers

 

Some of the numbers I used are for illustration. Like I don't know that boost would fall from 8 to 6 psi after installing better exhaust, but what I wanted to illustrate is the principle. I do know that as the engine flows better, boost pressure will drop.

 

I do know that a GT with Kooks headers high flow cats and Ford Racing mufflers, 11 psi intercooled Vortech, bigger injectors and fuel delivery, will do 447 to the wheels. I also have seen a bone stock GT with a Roush charger and Roush plug-n-play tune with 5 psi make 345 to the wheels.

 

 

Cool! Thanks for the info. 447 HP to the wheels you say? Hmmm....

[ratnacage]

I finally found a way to capture the bass note from these cams - I did it in the garage! Still doesn't do it justice, but it'll have to do.

 

http://video.google.com/videoplay?docid=-8918774062146976212

[nachtkriechen]

I finally found a way to capture the bass note from these cams - I did it in the garage! Still doesn't do it justice, but it'll have to do.

 

http://video.google.com/videoplay?docid=-8918774062146976212

 

Ohhhh mama! I think I'm in love with cams now! Holy crap that sounds good Rat! Especially after the cats heat up, and the idle settles. It sounded great on the dyno too! Now, just add a blower, and you've got "MY" car!

 

So here's a question for you and or Ruff. With the cams alone, do you have to use 93 octane, or can you use 88 or 89 if you "chose" to? Also, do the cams change your fuel economy (not counting lead-foot).

 

Thanks,

 

 

 

- Josh

[ratnacage]

Ohhhh mama! I think I'm in love with cams now! Holy crap that sounds good Rat! Especially after the cats heat up, and the idle settles. It sounded great on the dyno too! Now, just add a blower, and you've got "MY" car!

 

So here's a question for you and or Ruff. With the cams alone, do you have to use 93 octane, or can you use 88 or 89 if you "chose" to? Also, do the cams change your fuel economy (not counting lead-foot).

 

Thanks,

- Josh

 

There's really no point in tuning for less than premium fuel if you've gone this far, especially if you plan on throwing a blower in the mix. My MPG went from 24/18 to 22/13. I suppose I could get maybe 15 in town if I tried.

[nachtkriechen]

There's really no point in tuning for less than premium fuel if you've gone this far, especially if you plan on throwing a blower in the mix. My MPG went from 24/18 to 22/13. I suppose I could get maybe 15 in town if I tried.

 

This is true. I suppose if you're going to own a performance Mustang these days, you'd better plan on having a fuel economical vehicle as well. Oh to live in the 60's, muscle-car (and gas) heaven.

 

 

 

- Josh

[RUFDRAFT]

I've never figured MPG before in this car because I can't do anything to change it!

 

But - for the hell of it, I'll keep track for the next two fill-ups and see what I get.

 

It will be about a 50/50 mix of sustained 62 mph and city driving.

 

I "get on it" maybe once a day for 3 gears.

 

It's funny how many people ask me what I get. I usually tell them it doesn't really matter.

 

To me, it only matters when you buy the car and read the numbers.

 

I didn't buy this one for mileage!

 

And - I run a 93 octane tune. After spending the money on the engine - I want all I can get when I need to get all I want! :happy feet:

[nachtkriechen]

I've never figured MPG before in this car because I can't do anything to change it!

 

But - for the hell of it, I'll keep track for the next two fill-ups and see what I get.

 

It will be about a 50/50 mix of sustained 62 mph and city driving.

 

I "get on it" maybe once a day for 3 gears.

 

It's funny how many people ask me what I get. I usually tell them it doesn't really matter.

 

To me, it only matters when you buy the car and read the numbers.

 

I didn't buy this one for mileage!

 

And - I run a 93 octane tune. After spending the money on the engine - I want all I can get when I need to get all I want! :happy feet:

 

Good point, Ruff. I just wonder how much longer we'll be able to enjoy our V8 babies. From what I've been hearing, the trend with oil prices is not only going to continue, it's going to increase. With China competing with us for the largest consumers in the world for petrol, they say that oil reserves are coming to their peak, which means we'll be cresting the reserves soon, and oil prices will only skyrocket. It's sad, but, in our life times we may see the end of the gasoline engine, at least the way we know it now. Soon it may be nothing but hybrids.

 

 

 

- Josh

[RUFDRAFT]

That's why I drive mine every day.

 

I feel for those who follow us.

 

They'll watch documentaries on our cars.

 

Very sad.

[Secondo]

Ruf look at your car's guages, scroll through the info it'll have the MPG there.

I drive mine daily too with 87 octane stock tune and it reports 19 MPG!!

[nachtkriechen]

That's why I drive mine every day.

 

I feel for those who follow us.

 

They'll watch documentaries on our cars.

 

Very sad.

 

I've got a friend that graduated "Art Center" in Cali. a few months ago. He's in Transportation Design, and was considering design jobs from GM, Honda and a few other major companies (how would it be to have jobs looking for you?). He's been telling me about this stuff, and the direction the automotive industry is taking. I told him that it's the most depressing thing to me, to think that soon, we may never hear the growl of a Mustang V8, or a Ferrari 8 or 12 cylinder again. He's been trying to cheer me up by telling me the upcoming "electric" Sports cars have a whine that sounds like a jet engine, and that they out perform gasoline engines, hands down. I told him, it's just not the same.

 

It's not all about performance, it's the entire experience. It's the smell of the gasoline and exhaust, the growl of the engine, the feel of the engine vibration through the car, and the connection with the engine and car you "feel" coming into a turn, hit the brakes, blip the throttle, and hit the RPM dead on for the down shift and power sideways out of the turn. Or, how about the visceral exhilaration from that 4.6 screaming at the top of its lungs and the smell and sight of the gargantuan smoke plume from your burnout! You're just not going to get that with an electric car.

 

But... I digress.

 

 

 

- Josh