Boss 302R Exhaust Cams

[kevin2970]

Picked these up for cheap and debating whether or not to install... These are the ones with 2mm more lift and same duration as stock. If I'm not mistaken here are the stats:

lift in mm/duration

Stock GT: 12/260 Intake
11/263 Exhaust

Boss 302: 12/260 Intake
13/263 Exhaust

Cobra Jet: 13/263 Intake
13/290 Exhaust

The cams I got are the same spec as the Boss 302 ones listed. 13mm lift and 263 duration. So basically gaining 2mm of lift and I have to clearance my stock heads. Planning on throwing on my LTs at the same time. After getting a Lund revision, how much would you guys expect to gain? How fast would I have to spin? Running stock intake.

 

[Clipboard]

You wouldn't really spin the engine any higher having he stock intake... minimal gain I would think. I would wait until you get a set of intake cams to go with it so you can do it all at once.

Then the boss or cj intake will benefit you much more

 

[Shaun@AED]

Gains would be minimal from the camshaft swap.

 

[redline5.0]

No clearance work is needed for the boss exhaust cams, I didn't have to anyways and mmr who I got them from said they never had to either.

 

[Voltwings]

So if no clearance is needed for the exhaust 13mm lift ... will a 13mm intake cam fit as well? Interesting that there is so much mixed information on whether cams will fit or not.

 

[kevin2970]

Yeah getting a LOT of mixed info... we will see... And thinking about sending my stock intake cams and these ones to JPC for regrinds. Definitely saving up for a CJ setup as well.

And these are going on at the same time as LTs. Heard that having LTs will boost the gains from the exhaust cams... so much hearsay... not enough data on these cams... Well hell they were $120 shipped lol no loss

Also, if I did just do these exhaust cams, it would be the same cam setup as the Boss... most likely going to end up shipping these as a core to JPC.

 

[clinton2003]

from what i understand 11-12 need clearancing, 13-14 dont.

 

[kevin2970]

from what i understand 11-12 need clearancing, 13-14 dont.

That's what I figured was causing all the confusion. Surprisingly little data about differences between 11/12 coyotes and the 13/14s. All I heard was the oil squirter block offs.

 

[Voltwings]

Everyone says they hear it from MMR, itd be nice if a rep chimed in with some input, those guys probably assemble tons of motors and could have some good insight.

 

[Voltwings]

Doing some reading this morning on camshaft lift vs duration and its got my gears turning.

The GT and Boss have the same intake cam, and the Boss has a higher lift exhaust cam, but with the same duration.

GT
Intake: Lift - 12MM (0.472"), Duration - 260 degrees
Exhaust: Lift - 11MM (0.433"), Duration - 263 degrees

Boss
Intake: Lift - 12MM (0.472"), Duration - 260 degrees [Same as GT]
Exhaust: Lift - 13MM (0.512"), Duration - 263 degrees

So basically, what we're seeing here is the Boss CNC heads at work i believe, that the heads are able to benefit from the additional lift because they can flow more. Does this tell us that the GT heads are not able to benefit from additional lift? Ford racing designed the exhaust cam for the 5.0 with the same lift as stock, just a higher duration at 11mm / 290* duration. So basically, we're recieving our additional exhaust flow from duration, and not lift. Was someone over at Ford smart enough to know the heads wouldnt benefit from more lift, or was this simply designed to be a mild drop in cam... Seeing as how Ford racing does not make a drop in Intake cam, i'm willing to bet they knew the limitations of this engine were on the exhaust side, especially seeing how they approached the BOSS and Cobra Jet cam set up.

M-6550-M50BINT (the originally planned Boss intake cam that didn't make it into production, it's used in the CJ)
Lift - 13MM (0.512"), Duration - 263 degrees

M-6550-M50BEXH (the CJ exhaust cam)
Lift - 13MM (0.512"), Duration - 290 degrees


So here we again see the main difference being duration changes in these cams VS the Boss units, and seeing as how the Boss and CJ share the same heads, i'm wondering if that is in fact the case: That we are going to see more gains from duration than lift.

Lets take a look at Comp's cams now:

Stage I
Intake: Lift - 12.5mm, Duration - 260 degrees
Exhaust: Lift - 11.5, Duration - 267 degrees

Stage II
Intake: Lift - 12.5mm, Duration - 268 degrees
Exhaust: Lift - 11.5, Duration - 275 degrees

Stage III
Intake: Lift - 12.5mm, Duration - 276 degrees
Exhaust: Lift - 11.5, Duration - 283 degrees



It seems Comp is kind of confirming what i am thinking, assuming i am viewing this the correct way. Comp has only added .5mm of lift to their cams, but added a fair degree of duration in the stage 2 and 3 cams. What this is leading me to believe, is that there would realistically be little performance difference between the 13mm / 290* cobrajet cam and the 11mm / 290* Ford Racing GT cam on GT heads. Now, here's where it gets tricky... the 13mm lift will allow a higher ramp rate, and the valve will "effectively" be open longer at maximum lift... is this difference enough to make a substantial performance gain?

Lets compare Comp's stage 3 exhaust cam to both units.

Comp: Exhaust: Lift - 11.5, Duration - 283 degrees

CJ: Lift - 13mm, Duration - 290*

FRPP: Lift - 11mm, duration - 290*

The Ford racing piece has .5mm less lift than the Comp cam, but 7* more duration... i feel without some sort of flow rates or numbers thats fairly arbitrary, but based on what we determined earlier in this post (that it appears these GT heads want more duration than lift) i would argue that the FRPP cam is a very comprable cam to Comps exhaust. The key thing is now going to be trying to determine how much of the Comp cam gains can be attributed to the intake, and how much can be contributed to the exhaust, but thats going to take someone smarter than me to chime in.

 

[Shaun@AED]

The exhaust is under pressure. As soon as the exhaust valve cracks open, if flows a LOT of gas due to the pressure in the combustion chamber. This is why duration off the seat is FAR more important than lift (and ramp rate) on the exhaust side of things.

The Intake lobe on All-Motor applications is a different story. We want to open the valve as FAST as possible to get the airflow moving as there is no pressure helping the air enter the cylinder (unless boosted).

For years my All motor cams had the most aggressive (ramp rate) intake lobe I could make work, and a nice soft (ramp rate) exhaust lobe of proper duration. For boosted applications I run milder intake cams.

 

[Voltwings]

I may be diving into a bit of a grey area here Shaun, but would it be too outlandish to assume that with the added exhaust flow we would pick up more intake flow from the improved scavenging? I realize there are a dozen assumptions, like if our intact tract isn't already maxed out, if our exhaust is optimized, so on and so forth... but I imagine its not seeing as how intake cams alone yield little gains?

Your comments on the exhaust duration of this cam, plus the potential of not having to purchase an intake cam could really make this a killer bang for the buck mod.

 

[kevin2970]

So with a CJ setup and a very aggresive intake cam (maybe my stockers reground by JPC?) would make the process worthwhile? I've heard that cams on the coyote aren't really worth it but I'd like to stay NA for this build.

 

[Voltwings]

So with a CJ setup and a very aggresive intake cam (maybe my stockers reground by JPC?) would make the process worthwhile? I've heard that cams on the coyote aren't really worth it but I'd like to stay NA for this build.

People say "worth it," when you factor in the cost of a CJ set up + cams + install + tune... you could almost have a blower, but I agree. I WANT an N/a build, so im ok spending the money on what I want. Emailing Shaun shortly after I purchased those cams, he made it sound like the intake cams in and of themselves were not worth much, but if he sticks around in this thread I'm sure he could elaborate on that.

 

[Shaun@AED]

I may be diving into a bit of a grey area here Shaun, but would it be too outlandish to assume that with the added exhaust flow we would pick up more intake flow from the improved scavenging? I realize there are a dozen assumptions, like if our intact tract isn't already maxed out, if our exhaust is optimized, so on and so forth... but I imagine its not seeing as how intake cams alone yield little gains?

Your comments on the exhaust duration of this cam, plus the potential of not having to purchase an intake cam could really make this a killer bang for the buck mod.

Yes, in order to make more power with exhaust modifications the intake must flow more as well.
It's all about cam timing and the system as a whole. You cam make the exhaust (as a whole including camshaft) as free flowing as you want, but if there is an intake restriction, beyond a certain point you will no longer gain any power. And vise versa for intake modifications and exhaust restrictions.

At PRI I asked Ford Racing about producing a 290 Intake camshaft to match the exhaust, and that's when they told me they were discontinuing the Coyote camshaft program due to lack of interest. IMO they simply have to wait for demand to grow, and that takes some time as camshaft swaps and tuning these TiVCT vehicles are extremely time consuming as everything is valve event based.

 

[Voltwings]

Damn. Just no easy way out haha.

 

[Shaun@AED]

The beautiful thing about TiVCT is you CAN remove all exhaust restrictions before the intake (or vise versa) without killing power as you can move the valve events around, limiting exhaust reversion. Then when you remove said restriction, modifying cam timing further will greatly increase power.

 

[Voltwings]

I guess I'm just trying to justify tearing my car apart for just these exhaust cams, as opposed to sourcing an intake cam to go with them. It doesn't appear there are any options for the intake side other than custom grinds (assuming 13mm CJ unit wont fit the GT head) which are around $1000 give or take... Doing valve springs, tensioners, pump gears and everything while im in there for the peace of mind is well enough, but if im going to be messing with the cams id like more than 10 whp or something to show for it you know.

 

[Shaun@AED]

I guess I'm just trying to justify tearing my car apart for just these exhaust cams, as opposed to sourcing an intake cam to go with them. It doesn't appear there are any options for the intake side other than custom grinds (assuming 13mm CJ unit wont fit the GT head) which are around $1000 give or take... Doing valve springs, tensioners, pump gears and everything while im in there for the peace of mind is well enough, but if im going to be messing with the cams id like more than 10 whp or something to show for it you know.

Understandable. Unfortunately I have no back to back dyno results from just the 290 exhaust cam swap.

 

[Voltwings]

Fair enough, it sure as hell cant be worse than stock, so i guess i'll just slowly piece things together and we'll find out.