Boss Heads Vs. GT Heads

[Dominic Toretto]

Has anyone noticed a flow chart or have definitive evidence that the Boss heads are worth the upgrade to over the factory GT heads? Curious to see how they would effect power on a standard GT with the regular manifold.

P.S., if this has been explained already on here, shoot me in the face.

-Alex

[TrueStreetTim]

BOSS are mildly ported and flow roughly 5cfm more per cylinder than the GT. Valves are a bit different and the spring rate is a tad better. Worth it to purchase them as a performance upgrade? No. Not IMO.

If someone were interested in something like this I'd recommend putting that money into cams which I think is a better upgrade than heads alone.

[Dan12GT]

^^^ This

[Dominic Toretto]

Excellent response, thanks Tim. I was just looking over prices of NA upgrades. I did notice the cams. I would think though that a cam would perform better with the Boss heads but not sure how much better. Any takes on that?

-Alex

[wbt]

No need for this info.

[KungFuHamster]

There are a few other differences and advantages to the Roadrunner head over the Coyote:

1. Larger exhaust valves.
2. Lighter exhaust valves.
3. CNC ported.
4. CNC'd combustion chambers.
5. Clearanced for running larger lift cams.
6. Different alloy that provides better cooling.

IMO if you are looking to switch over to Boss heads I would go with the CJ cam's at the same time to take full advantage of the port work and the CJ intake to compliment it. While you have the front cover off, billet oil pump gears and Boss timing chain tensioners.

Should have no issues with a reliable 8K RPM N/A motor at that point.what is the main difference between the stock 5.0 and Boss timing chain tensioner?

[TrueStreetTim]

Excellent response, thanks Tim. I was just looking over prices of NA upgrades. I did notice the cams. I would think though that a cam would perform better with the Boss heads but not sure how much better. Any takes on that?

-Alex

If your not worried about the small peripherals that come along with the BOSS heads, porting your stockers is a slightly cheaper, much higher flowing option.

[wbt]

No need for this info.

[blownaltered]

There are a few other differences and advantages to the Roadrunner head over the Coyote:

1. Larger exhaust valves.
2. Lighter exhaust valves.
3. CNC ported.
4. CNC'd combustion chambers.
5. Clearanced for running larger lift cams.
6. Different alloy that provides better cooling.

IMO if you are looking to switch over to Boss heads I would go with the CJ cam's at the same time to take full advantage of the port work and the CJ intake to compliment it. While you have the front cover off, billet oil pump gears and Boss timing chain tensioners.

Should have no issues with a reliable 8K RPM N/A motor at that point.
Seems like putting a blower on it would be cheaper. Would get more power out of the blower as well

[Dominic Toretto]

Seems like putting a blower on it would be cheaper. Would get more power out of the blower as well

Seems like adding two bottles of nitrous would be cheaper. Would get more power out of nitrous as well.

-Alex

[wbt]

No need for this info.

[Dominic Toretto]

It's a lot more difficult to go fast N/A vs. slapping a power adder on. It all comes down to goals.

Fast is relative. I'm good with how fast the car is stock. I'm not looking to build something to be faster than everyone else's car. And basically this thread is just about information gathering. For those people that ARE looking to be the fastest car on the track they might want to know information about both sets of heads as well :)

-Alex

[re-rx7]

Good info in here.

[Grandpa]

Seems like putting a blower on it would be cheaper. Would get more power out of the blower as well
I agree. For the return on the dollar and ease of making power boost is the way to go in my opinion.

These Coyote parts are ridiculously expensive it's mindboggling that it's a Mustang. Reminds me more of the Vette tax than a Mustang! lol. For me, the return on these heads just wouldn't justify the cost for MY goal for my car.

Plus, I LOVE boost!


Seems like adding two bottles of nitrous would be cheaper. Would get more power out of nitrous as well.

-Alex

LOL, never owned a nitrous car before have you?

It's a lot more difficult to go fast N/A vs. slapping a power adder on. It all comes down to goals.

It's certainly far more difficult. Driving ability, suspension set up and weight become far more of a concern. I'd rather take the easy road and just throw boost at it. And of course I couldn't remotely care less about chasing an ET anymore. I have to ignore it and just have fun with the car otherwise it will become a weekly obsession to chase those magical ET whoring out the car and wasting a LOT of time at the track over times that really mean nothing at the end of the day. I look back at that time, I learned a lot, but I can't say I enjoyed it a lot because I obsessed over it so much. It became work instead of just having fun.

[re-rx7]

I loved building the Na hondas as funny as that sounds. To build a fast NA car you really have to know your shit and that particular car to get every ounce of pony!

[Grandpa]

I loved building the Na hondas as funny as that sounds. To build a fast NA car you really have to know your shit and that particular car to get every ounce of pony!

Its all good. Everyone has their things they are into. If that is the challenge you want to give yourself, I say go for it.

[re-rx7]

Its all good. Everyone has their things they are into. If that is the challenge you want to give yourself, I say go for it.

Im in no way denying that a supercharger and or juice is a easy way to get alot of power. NA is very expensive once you ad it all up but cheaper if you think of it as part by part. Alot of people have a hard time spending 5k plus on a supercharger. Even if I had it I would feel somewhat guilty buying it because thats alot of cash that could be used for something else.

[Dominic Toretto]

LOL, never owned a nitrous car before have you?


Nope. Does it cost ~$8,000 for parts and labor and tuning for a nitrous setup though?

-Alex

[BERT]

Nope. Does it cost ~$8,000 for parts and labor and tuning for a nitrous setup though?

-Alex



Depends on how many bottles you go through :D

[Dominic Toretto]

Im in no way denying that a supercharger and or juice is a easy way to get alot of power. NA is very expensive once you ad it all up but cheaper if you think of it as part by part. Alot of people have a hard time spending 5k plus on a supercharger. Even if I had it I would feel somewhat guilty buying it because thats alot of cash that could be used for something else.

Looks like building a stout NA application would cost more and definitely yield less power, as to be expected. Just funny people think they can slap on a blower, run 8lbs of boost all day and night on a stock bottom end and expect it to be as reliable and cheap as doing the same thing with an strong NA build.

These motors are pretty new. So I don't trust anyone that says, yes you can add 50% horsepower on a stock bottom and and race it all day and expect the stock pistons and rods to be just fine. That's just dumb. Once I see people doing that upwards of 60k plus miles on a blower setup with stock internals, I'll consider it. Until then, it's just a dumb assumption.

-Alex

[Dominic Toretto]

Depends on how many bottles you go through :D

People here are not considering longterm usability, clearly. So a bottle of nitrous always wins in the power/dollar argument.

-Alex

[re-rx7]

550 to 600 seems to be pretty reliable. Ford racing offers a kit thats is covered on a 1yr 12k mile warranty IMO that says something. IT really comes down to how the owner treats the car.

[Grandpa]

Nope. Does it cost ~$8,000 for parts and labor and tuning for a nitrous setup though?

-Alex

A GOOD nitrous kit can cost as much as some blowers. Add to that constant bottle refills at $45 bucks a pop which is a never ending expense.

Add to that a nitrous set up isn't always ready. It needs to be armed, good bottle pressure which means you need a good bottle heater and remote valve opener. That's if you want a good street set up.

You can do it on the cheap for a track like the old days heating it up with a torch of course and a button, but that's kinda ghetto now in the day and age of tech we have now.

[re-rx7]

A GOOD nitrous kit can cost as much as some blowers. Add to that constant bottle refills at $45 bucks a pop which is a never ending expense.

Add to that a nitrous set up isn't always ready. It needs to be armed, good bottle pressure which means you need a good bottle heater and remote valve opener. That's if you want a good street set up.

You can do it on the cheap for a track like the old days heating it up with a torch of course and a button, but that's kinda ghetto now in the day and age of tech we have now.

Good nitrous kit I.E all the goodies prolly around 1500 new.

[Dominic Toretto]

550 to 600 seems to be pretty reliable. Ford racing offers a kit thats is covered on a 1yr 12k mile warranty IMO that says something. IT really comes down to how the owner treats the car.

And for those that want to be able to beat on their cars reliably daily, they will have to fork over more to build the bottom end to handle the abuse.

I like driving a fun car often. Not just 3 days out of the month. To me it's not very fun to have a fast car that you have to pamper because you're scared a rod will break. So for those that do enjoy that, hey cool. I just know I wouldn't. So in my eyes, the cost of a successful blower setup includes a built bottom end.

-Alex

[Dominic Toretto]

Good nitrous kit I.E all the goodies prolly around 1500 new.

Exactly. A lot LESS than the price of just a uninstalled blower.

Someone provide a link showing the price of a full nitrous install costing about $8,000.00.

-Alex

[Grandpa]

Looks like building a stout NA application would cost more and definitely yield less power, as to be expected. Just funny people think they can slap on a blower, run 8lbs of boost all day and night on a stock bottom end and expect it to be as reliable and cheap as doing the same thing with an strong NA build.

These motors are pretty new. So I don't trust anyone that says, yes you can add 50% horsepower on a stock bottom and and race it all day and expect the stock pistons and rods to be just fine. That's just dumb. Once I see people doing that upwards of 60k plus miles on a blower setup with stock internals, I'll consider it. Until then, it's just a dumb assumption.

-Alex

I'm pretty sure that anyone here that is looking to make good power isn't planning on the stock motor to get them there in the long run. It's pretty much a given at that power level that a motor build is in the plan at some point which is why you see so many people buying blowers that are bigger than the stock motor can handle, but being able to crank up later on a built one. Room to grow so to speak.

[re-rx7]

And for those that want to be able to beat on their cars reliably daily, they will have to fork over more to build the bottom end to handle the abuse.

I like driving a fun car often. Not just 3 days out of the month. To me it's not very fun to have a fast car that you have to pamper because you're scared a rod will break. So for those that do enjoy that, hey cool. I just know I wouldn't. So in my eyes, the cost of a successful blower setup includes a built bottom end.

-Alex

My car is basically stock right now, I do not beat it everyday. Hell, Id be lucky to redline it once a week. LOL I think my motor would last a long time even at 650 LOL. This is all hypothetical though lots of factors.

[Grandpa]

Good nitrous kit I.E all the goodies prolly around 1500 new.

LOL, hell no! $1500 for a ghetto set up maybe. If you want a plumbed intake, remote valves, bottle heaters, good solenoids,lightweight bottles, progressive controller so you don't blow tire every time you hit the WOT switch etc.

I almost snorted coffee out my nose at that one! Fuck that hurt. lol

[Grandpa]

Exactly. A lot LESS than the price of just a uninstalled blower.

Someone provide a link showing the price of a full nitrous install costing about $8,000.00.

-Alex

A Paxton can be had for $4400 bucks. Don't take to an extreme to suit your argument. lol

[re-rx7]

LOL, hell no! $1500 for a ghetto set up maybe. If you want a plumbed intake, remote valves, bottle heaters, good solenoids, progressive controller so you don't blow tire every time you hit the WOT switch etc.

I almost snorted coffee out my nose at that one! Fuck that hurt. lol

The Nx kit is 700 I believe. Bottle warmer, purge kit, ect. Theres a new kit out that has the progressive controller, rpm switch and everything built in for like 1300.

[wbt]

No need for this info.

[re-rx7]

LOL, hell no! $1500 for a ghetto set up maybe. If you want a plumbed intake, remote valves, bottle heaters, good solenoids,lightweight bottles, progressive controller so you don't blow tire every time you hit the WOT switch etc.

I almost snorted coffee out my nose at that one! Fuck that hurt. lol

I just priced a NX kit, purge, warmer, opener, for 1550. Add a window switch and controller and your looking at 2k roughly.

[Dominic Toretto]

I'm pretty sure that anyone here that is looking to make good power isn't planning on the stock motor to get them there in the long run..

I can bite on to that idea. At least with that, you can see how long a stock one will last at boost and figure out the weak points of the internals.

My car is basically stock right now, I do not beat it everyday. Hell, Id be lucky to redline it once a week. LOL I think my motor would last a long time even at 650 LOL. This is all hypothetical though lots of factors.

Me personally, I'm going to give it a few years to see what developes from people that have spent the money and effort. I don't want to make their mistakes :D

-Alex

[Grandpa]

I'm hoping there will be a ZR1 in my garage in a couple of years! lol.

[re-rx7]

Me personally, I'm going to give it a few years to see what developes from people that have spent the money and effort. I don't want to make their mistakes :D

-Alex

Exactly. When the Kseries honda came out everyone was bitching about how the motor was weaker then the Bseries. Now 450-500 on stock internals is a well known fact. Just like the S2000 making 600whp on stock bottom ends is reliable. The record for that stock long block is 700whp.

[Dominic Toretto]

Something else to consider, and it really does come down to setting up goals....if you decide to put together an N/A build short to medium term and long term want to put a power adder on the car, use parts that will work for both applications so you aren't buying twice or three times. Examples would be:

Exhaust
Suspension
Driveline
Tires/wheels
Electronics
Oil pump gears
Damper
etc....

Build the foundation first then whatever you decide to do down the road will compliment it.

Excellent advise. I would think the main difference would be piston choices for different compression for an NA and boosted application though.

-Alex

[Dominic Toretto]

Exactly. When the Kseries honda came out everyone was bitching about how the motor was weaker then the Bseries. Now 450-500 on stock internals is a well known fact. Just like the S2000 making 600whp on stock bottom ends is reliable. The record for that stock long block is 700whp.

Exactly. That's why I references the F22C. I believe that car comes with forged crank and rods stock. So you can boost it and not have to worry about the bottom end failing for a good while.

-Alex

[re-rx7]

Exactly. That's why I references the F22C. I believe that car comes with forged crank and rods stock. So you can boost it and not have to worry about the bottom end failing for a good while.

-Alex

When they first came out people were saying that since they were high compression 350 whp was the tops before you needed a build. Now look at them today! Crazy! I knew people that blew them up back then at 300whp lol!

[wbt]

No need for this info.

[re-rx7]

It's all relative to cylinder pressure.

Less boost, more compression.
Less compression, more boost.

These platforms are 11:1 and they seem to handle a decent amount of boost.

From a piston standpoint....I prefer to run a flat top or dished piston vs. a pop-up as I think you get a better flame pattern resulting in more efficient fuel burn however that is a sacrifice in compression. In the pushrod days you could overcome that by decking the block and milling the heads. Not going to happen with the OHC stuff.

And fuel type?

[wbt]

No need for this info.

[Dominic Toretto]

My rule of thumb is run the least amount of octane without detonation as possible. What that means for each combo depends.

Some will get away with 93, others are stuck with MS109, e85, etc...

Could you elaborate more on this please? I don't have as much knowledge on this as I should so just asking one of the experts here :)

-Alex

[re-rx7]

Could you elaborate more on this please? I don't have as much knowledge on this as I should so just asking one of the experts here :)

-Alex

HE is looking for the most complete combustion cycle. By using the least octane needed for the burn he is insuring that there is a complete combustion for optimal efficiency.

[wbt]

No need for this info.