Boss 302R Exhaust Cams

[Sean@LethalPerformance]

Voltwings, this should be an interesting read for you if you haven't seen it already.. Its on a roadrunner, but it's a good breakdown on what we have and what we're looking towards in the future. I might just pick up these ford racing coyote exhaust cams (11/290) just to have a pair myself, can't be a bad idea when they're just $151!!! The thing is, when it comes time to do the cam job, it probably only makes sence to throw an intake cam in there even though it's not yielding as much power as the exhaust side, because I'm sure you're paying right around the same labor.

http://www.mustangandfords.com/how-...02-bolt-on-upgrades-haul-natural/viewall.html

The also compare two different intakes for the cj, frpp (102mm) vs PBTH(4.5") interesting to see where they differe.. Lower end tq with the ford raging one and a little higher end with power by the hour intake

 

[Dizzyscure1]

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.

Worth is all up to you, I've seen many times the Comp Cam Stage 3 NA's gain 45-50rwhp, should be a few dynos on here just take a look see.

 

[redline5.0]

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

When I was having m engine built I was worried about the clearance issues but had none. The engine builder also had a 11gt head that we looked at and couldn't see why it would need to be clearanced.....looked the same as my 13gt head. MMR are the ones that told me no clearancing would be needed to run the boss cams and there not sure where the rumor got started. I got my boss exhaust cams from mmr for 99 bucks too and was already going to have them out for springs anyways and figured why not.

 

[kevin2970]

Hm that's weird. I remember seeing a thread somewhere else where a guy showed how he clearanced the heads for these specific cams... We'll find out when we crack her open I guess lol and I got them from MMR as well for $99. $120 shipped.

 

[redline5.0]

Hm that's weird. I remember seeing a thread somewhere else where a guy showed how he clearanced the heads for these specific cams... We'll find out when we crack her open I guess lol and I got them from MMR as well for $99. $120 shipped.

This was pulled from that thread you were talking about, but my 13gt head and the 11gt head we looked at were both already notched in that spot from the factory.....stupid me forgot to take pictures of my head. Maybe some of the first heads in 11 were not notched in that spot?

 

[Voltwings]

I guess its fairly simple to just pop off the valve cover and see if that area is notched.

 

[kevin2970]

Yeah someone please sweat it out for us and let the rest of us know lol it's 110 deg out here in AZ and it isn't any cooler in my garage LOL

 

[redline5.0]

This is what my head looked like as well as the 11 head that was at the machine shop.

 

[Voltwings]

I think we're looking at different sides of the head here, but unless I'm mistaken, these are distinctly different... I'll try to pull the valve cover off my '13 this weekend and compare.

 

[Voltwings]

well, it doesn't look like my heads have the machining to clear the 13mm cams :cryying:

'13 base model M6

 

[kevin2970]

WTFF lol Why do some have it and some not lol

 

[redline5.0]

It looks fine and just like mine. It is notched where the lifter and rocker meet which is where you would have a problem if there was one.

 

[Voltwings]

And yours cleared the 13mm cams? Maybe I really wasn't able to get my head in there enough, but the rocker looks damn close to that little shelf / ledge as it is...

 

[redline5.0]

Yes mine have been find, no issues. If i get bored ill snap a pick. also I'm not sure if the lifters are fully pumped up with the engine off, mmr mad it sound like they were not unless the engine was running.

 

[Voltwings]

ok then... I may pull the trigger on those 13mm intake cams then. Fingers crossed.

 

[Voltwings]

Since we've already got quite the cam discussion going here, i figured i'd dig this thread up instead of starting a new one.

My original plan with the Ford racing exhaust cams (11mm / 290) was to do a mild build by just installing them on their own, or possibly pairing them with a Ford racing intake cam (13mm / 263). That being said, i (potentially) have the chance of snagging a set of used comp cams, and while those gains are proven i have a feeling the CJ cams may be the better combo.

Comp Stage 3
Intake: Lift - 12.5mm, Duration - 276 degrees
Exhaust: Lift - 11.5, Duration - 283 degrees

FRPP
Intake: Lift - 13mm, Duration - 263 Degrees
Exhaust: Lift - 11mm, Duration - 290 Degrees

The Ford racing intake cam has much less duration, but the higher lift and ramp rate will create some artifical "duration" in and of itself... I forget if it was earlier in this thread, or in emails, But Shaun frrom AED made a very valid point about the exhaust cams; the exhaust is under pressure, so the longer duration is good to get all the pressure out. So while the FRPP exhaust cam has less lift than the comp cams, it does have an increase in duration. Basically i understand how lift / duration effect power, but in a case like this where theres so much give and take (especially on an engine without a lot of cam tuning information) its really just a hard call to make. The Comp cams are proven, but something tells me that Ford Racing combo could be a pretty potent pairing.

 

[PACETTR]

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.

Just trying to clarify doing some research, but doesn't the piston moving down in the cylinder create negative pressure (vacuum) which draws the air in? Makes valve timing critical on an n/a car. You can actually increase velocity, even with ports that are "too big", by slightly delaying the valve opening, which (I think) makes the increased ramp rate even more critical, as there would be less duration to work with...?