SP - Luke's rockers are a quality shaft rocker so changing the ratio is not on the table. I would like to change out the springs then I have a Custom Cam in mind using a newer Lobe profile I would like to see used. Otherwise, I agree the Voodoo's are not a bad choice. He is not after a heavy idle either so the wider LSA helps reduce overlap and calms it down at idles while widening the torque curve. I will do a few calcs see where it should sit.
Ive got a set of those Trickflow springs here which would be ok for an XE lobe as well, they are about 145 I think and they are really a PAC spring, if Lukes caps are the right size quick to swap them out.
They are 150 lb at the seat and would be perfect. I have been thinking about the Cougar was thinking I might need them. If he wants them that is fine by me.
Well interesting exercise. Very quick calcs though it was interesting.
First (and a key assumption) is the heads. I am assuming they are the Brodix Track 1 heads (standard) which flow (according to the web site).
0.200 0.300 0.400 0.500 0.600 0.650 0.700
Intake 124 172 212 241 255 260 261
Exhaust 100 129 153 166 176 179 180
So a 363 needs a lot of air. I chose 6000 RPM peak HP. You can see the intake flow is not great compared to other heads (at it uses a 2.08 valve) though the exhaust is good relatively to the intake which is nice. Because the heads do not flow so well then to peak at 6000 you will need far more duration than I was originally thinking (because I use TFS TW 11R 205 as my base for this sized engine). Any way, you would need a camshaft with 235@50 and 600 thou lift on a 110 LSA (or slightly tighter). The balance of the port flow you could use a Single pattern camshaft but I would add in some split because of the restricted headers (need at least 1 3/4 primaries).
Just for the record the TFS 11R 205 head with its 298 flow at 500 thou would mean the Voodoo at 221 intake duration would work well and no need to raise its lift. I would still want it on a 110 LSA.
Any way, that was a fun exercise.
BTW: The lobe I would suggest comes in at 629 lift using the 1.6 ratio rocker. You would need different springs alright.
Edit: Found these flow numbers for the heads - very different to the Brodix web site.
I agree totally with him - but a 205 E-Street is quite a different beast (flow and turbulence) to a 205 AFR or even a TW 205. All of these heads would need different cams to be optimal. A known formula engine is easy as all of the parts are being purchased as a matching set to produce a known result.
In this case, there is a consideration for changing the cam - nothing else - while the rest is being reused. There are levels of constraints, e.g., 195 Brodix head with 135lb Springs, EFI, while Intake flow is fine being a ITB induction. He also does not want a rough idle.
I will someday think of something clever to say.
Last edited by boofhead on Mon Jul 18, 2016 8:17 pm; edited 2 times in total
Ok good to know the head details so we are not guessing. So looking at the small Voodoo;
Intake duration 221 degs
so you need 260 CFM to fill the cylinder at 6000 RPM. This can be provided by the head if the cam has 550 thou lift. Which is provided by the cam at 1.6 rocker ratio. So all good to go though it is right on the limit for a 6000 RPM peak.
If I was doing a custom I would go just a little longer in duration and a tighter LSA. In any case, it should work out quite well.
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