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UPDATE 8-21-2016: Cam Compare - 20R - see attached Excel sheet.Please let me know if you cannot download and view it.Well, I finally was able to do some mock pulls and transfer the data to an Excel sheet. For those interested, please review and let me know what you think. Gnarls.
I was looking over this again today and I don't think I'd choose anything but a stock cam and exhaust upgrade on the 20r unless I was building the 20r/22r hybrid. Then I think I'd Glen it up with the big nasty LC cam since we have video proof of his truck accelerating like a Celica.The 261C look pretty good on it but the stock cam still kind of smokes it in the drivability area looking at the curve. Funny how that smaller displacement and different head change how it responds to a cam upgrade. I wouldn't have thought it would be much different than the 22r.
Hi 79coyotefrg,I think those specs are off? Isn't the 22 head considered a hemispherical?Interestingly, the Engine Analyzer shows better numbers for the wedge head over the hemi head selection for the 20R.Gnarls.
Tuning exhaust performance is very complex.The cam profile, especially overlap and cam timing, can affect exhaust systems. I imagine most of us that have modified our engines with larger valves, porting and polishing, cam, header, and larger exhaust pipe, free flow mufflers, dont really understand what changes have occurred to flow and volumetric efficiency, and what affects those changes make in the ultimate desire for increase power.Are the headers we buy equal length?
What lengths are best for a 22R and 22RE?
Why does a tri-Y design scavenge better?
Does it scavenge better at WOT or partial throttle?
I believe exhaust tuning has been historically trial and error.
Is the testing done at WOT or a range of RPMs?
There are physical things going on that may not be easily measured or even calculated. Can you measure swirl on a flow bench? Can you measure the pulses at each tube and at the collector? Can you measure the sonic wave caused by exhaust pulses? Can you measure the mass flow at WOT (wide open throttle)?
What affect does increased compression cause?
How about the number of angles and cut degrees on the exhaust valve?
How about the AF mixture wave velocity changes depending upon a lean or rich mixture.
The size of the exhaust tuning from the collector back can be critical to maintaining the performance gained by the header and the cam. Is the tubing mandrel or crimp bent? Does a 2.0 diameter flow better than a 2.5?
Lots to think about and more that I will most likely never completely understand.Gnarls.
Correction:With an inline 4 and a Tri-Y header: cylinder 3 doesn't have much of an effect on cylinder 1 compared to the cylinder it's paired with.The cylinder pairings are 1&4 and 2&3.
http://4wheelonline.com/doug-thourley-tri-y-headers-toyota.224605.0The pairings get weird on V-8s.....The stock manifold is actually a tri-y setup.
Throw a TRD stage 1 and stage 2 in there. (I think they're the same as the crane cams)
I updated the spread sheet. I added engbldr 268 cam and the running conditions for this comparison.I also highlighted with blue the delta in the RPM range for torque and horsepower within 2 numbers. In other words, the peak torque and peak horsepower and 2 numbers either side of that peak number.You can see by the numbers and the ranges that the stock camshaft profile has a nice flat extended range in RPMs for torque.Gnarls.
It's funny that the stock cam seems to do better for the 20r than it does for the 22r. Kind of makes me think they designed the stock cam profile around the 20r and then just decided it was good enough for the 22r and kept using it.
Hi emsvitil,This sheet is for a 20R comparison. Are you asking me to add TRD profiles?Gnarls.
But, they did change the cam when they went to the 22RE
I have a really old Haynes Manual with some cam information and it has the same difference for 20r/22r vs. 22re. The cam I have in. my 22r now is the stock EFI profile because that is all that is available as a stock replacement these days.I measured an original early 22r cam vs. a 22re cam and it did mic out a little bigger on the intake side if that means anything. Biggest difference if this is all true is the difference in the duration intake/exhaust. That has to do something big.
22ret cam specsCode: I EDuration @ .002" 308 336Duration @ .050" 231 212Lift @ stock lash .383" .373"Lift at 0 lash .391" .385"Centerline: 113.5 102.5Seat to seat timing(.002" lift)Opens 30 80Closes 98 64.050" timingOpens -15 32Closes 36 0Overlap @ .002" lift: 106 degOverlap @ .050" lift: -15 deg
UPDATE 11-18-2016I updated the 20R sheet and added engbldr 270 camshaft.The specs I have are:222 degree Duration, 430/430 Lift, 110 lobe center.Gnarls.
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