Cam Design (Or lack thereof) for the MZR DISI

Since you can theoretically push the IVC event later with more boost...I'm now curious if the simulator will show similar results with and without full VVT advance. If VVT top end HP is still higher than non-VVT, the difference should be less...in theory.
As stated several posts ago, I typically run 28psi on the CS turbo...BUT it's out of breath with the mods I have. I'm betting larger cams and "slightly" better flowing head may limit my boost to mid/low 20's.

I'm guessing you're using DynoSim for these? If I had a copy, I would literally lose sleep playing around with that program night after night.

 

IVC close helps with higher RPMS and is boost agnostic, IIRC. As I'm sure you're aware, boost and flow are not the same thing; increasing flow tends to reduce boost, again, depending on the setup.

 

That's what I'm saying. Larger cams and some mild port work will increase flow...which will lower my boost since the turbo is already nearly maxed out. My 3-port WGDC at 6500 is 90%+ trying to hold 28psi.

 

Well I doubt your WGDC is going to go down any...You'll probably drop boost at the same WGDC and keep the power you're at. If you have a compressor map, might want to check it and see how it effects efficiency.

 

Keep in mind @Fstrnyou wants to do all of this..... For 360whp

lol I like where he's going with the cams but the +2mm valve's...

 

Nothing really wrong with going efficient. You wind up with better MPGs too (if you can keep your foot out of it). I also agree that larger valves are unwarranted for anything less than max effort every last HP counts racing.

 

I'm with you on one of your earlier thoughts though that essentially the cams and bowl work will get 90% or more of anything we'd realistically want or be able to obtain.

Also didn't realize the CS cams may actually do most of what I'd actually want. Combined with a 2.5 bottom end things could get interesting.

 

One thing to keep in mind about going larger displacement is that you're going to reduce the powerband and efficiency of the existing head. I'm guessing you want a billion torque and diesel gears...?

 

Hehe

.

 

The only way I can convince myself that it's not a crazy idea to upsize the valves is that I would be using all new valves anyways and it's not much more to get the larger valves.
And what's a little more grinding to open up the valve seats when I'm already in there doing bowl work?
The need to cut the piston tops will depend on some careful measuring first.

 

The thing is though, that larger valves don't make the head flow more; headwork does. If the head can outflow the valves, then yeah, larger valves make sense (or if you want every last HP for racing applications).

Unless you're shooting for the moon, it doesn't make sense (and if you are, you'll see greater net benefit with a more aggressive cam profile anyways).

 

To be fair, that's a bit of a misquote. My estimated 360whp limit right now is fueling related because I'm lacking a decent number of significant parts for PI. My target has always been 450whp...but ONLY because that's what CS advertised as the limit for their turbo.

But now that I'm down the rabbit hole and a turbo is a lot easier and cheaper to change later than an engine, I was thinking of making the engine package everything it could be while I can so that IF/when I upgrade the turbo, the engine will be ready for it. That's assuming it doesn't lose compression first.
[doublepost=1558232155][/doublepost]Okay....here goes.
I pulled in the IVC 6 degrees...but IVO is 12 degrees sooner, thereby making duration 6 degrees longer. I kept overlap still relatively low at -12 degrees @ 0.050" by advancing the exhaust cam timing a few degrees to account for the earlier IVO event which brings the EVO to 50 degrees BBDC. Even at 50 degrees, most of the combustion work has been done by that point. There isn't much piston movement (cylinder volume expansion) those last few degrees so there shouldn't be much torque being given up. I could be way off base though too.

Intake Duration 230/270
IVO 20 BTDC (0.005"), 0 TDC (0.050")
IVC 70 ABDC (0.005"), 50 ABDC (0.050")
IV Lift 0.413"
Lobe C/L 115

Exhaust Duration 218/258
EVO 70 BBDC (0.005"), 50 BBDC (0.050")
EVC 8 ATDC (0.005"), 12 BTDC (0.050")
EV Lift 0.378"
Lobe C/L 121

 

speaking of sounding like a diesel should hear my car.(2.5 swap)
not to completely necro a old thread but what do you think of running an aftermarket exhause cam (since all the duratec exhaust cams are the same) with a stock intake or reground intake cam + 50* vvt gear. with upgraded springs ofc

was looking at crower exhaust cam which 258/272 duration @.050 212/230 with .296 lift gross lift of .532

for intake no clue on this end and doing some research other than just using 1 of the 3 cams for the car(kelford,cs,piper, i dont include sp63)