Thread: Thoughts on a full race motor setup

Coheed, I have degreed in all of these factory honda cams ( US and Japan Market cams) D15,16, B16, B18, H22, F22, F20c, F22c, K20a, a2, z1, z3, K24a2 you name It. I have also degreed in about 12 other sets of aftermarket cams for the K series motor and probobly 6-8 sets for each other engine type alone. I have degreed in sr20ve, sr16ve, sr16ve N1, Frankin STG3, STG4, 2 sets of Kelford cams, 7 sets of custom grinds and so on. This is all by the camshafts intalled in the motor with a degree wheel and dial indicators.

I can tell you the numbers that you are looking at and trying to compare is not going to get you anywhere.

1. you need to compare at the same lift and duration points
2. you need to compare the same type of valve train components compare 100%
3. the Honda K series motors use Roller rockers and not flat follower rocker arms so you can compare specs all you want between a sr20ve motor and K20a and the K series can have less duration from .004" to .050" lift but will make way more power because the roller rocker setup can open and close the valve much faster, more aggressively and be able to control valve motion accurately. Thus more area under the curve and more power.
4. you can only compare overlap for a set of specs on paper but that doesnt mean thats how the cams are run in the motor, but for "0,0" specs you still need to compare at the same duration/lift points. the B series cams that are 235/240 deg duration is at 1mm ( .0394") of valve lift at that duration point. so that 25 deg of overlap is at being compared at 1mm valve lift, not advertised duration when the valve lifts off the seat.

-Ted

Ted, would it be ok to round off .0394" to .040" if you do not have a mm. dial indicator? Would it have a effect on cam timing?

^^^^ exactly what I was thinking, but I would like to see the specs of the VE cams vs the B series cams at the same lift etc. I know you can't compare these cams directly against each other etc, but it would give us an idea on what we need to improve on to have a set of cams made that is the best for both worlds. why can't we have a cam with big lift and duration without making any sacrifices?

Since you have done a lot of testing on these cams maybe you can enlighten us?

The VE head flows better than the De head, but you can get in the same ballpark with just S4 cams in the DE. When is the ve gonna get a 12mm lift cam that makes good midrange and top end? Would the 20V cams be decent for a turbo engine? I think the Lift on the N1 cams is great, but the duration makes it only good for an NA motor or maybe an 11K race engine. If I want the best compromise of engine power down low and mid range and still have a crazy top end, which cam is best by looking on paper?

I will try to test these VET cams against the stock ones as soon as I can, but I figure while I am in there I should replace the springs for the higher revs.

What can we do to compete against the hondas?

The VE, DE and can be compared to all the other honda cams directly EXECPT the K series cams because they are a roller rocker. They can achieve very aggressive ramps and valve velocities because of the roller design.

A SR16VE N1 Exhaust cam has about 330 deg duration at .004" lift at the valve. that is a big duration cam. HOWEVER it has one of the smoothest ramps of any camshaft out there and because of its profile, depending on the exact stock VE valve spring harmonics, you may be able to rev to 10,000rpm on stock springs before valve float may occur. The N1 cams have 250 @ .050" Exhaust and 249 @ .050" IN duration. the IN is about 305 Deg @ .004" lift. The Civic Type R cams are about 299 @ .004" and 237 @ .050" IN and 291 @ .004" and 229 @ .050" at the valve. Now all of these cam measurements are dependent on correct valve lash. Such as HOT valve lash because that is the clearance that the engine runs with. If in doubt measure with "0" lash first then at cold specs and again at Hot specs.

Getting NA drop in cams for the VE is not a hard thing to do. Getting them to make power is. The head may flow more than a good B series head, but they have the better intake manifold design. I just did some port work on a B16A cylinder head tonight and with a 5 angle valve grind and very nice ports ( street head) its flowing about 275cfm @ .500" lift. I have flowed several stock VE heads ranging from 238-277 CFM @ .500" lift. The draw back is the intake manifold. Because of the VE's intake manifold ( even the SR16VE N1) we get a low pressure area forming in the middle of the intake runners because they are a slight reverse taper. So you have to design cams around this "drawback" for them to work and make power. The N1 cams are designed for a 1.6L motor, but with that head design and intake manifold as well. So the best way to start with a drop in cam is with the N1 profile and actually modify it from a short stroke/ long rod motor setup ( 68.7mm, 144.6mm rod 2.10 R/S) to a long stroke short rod setup ( 86mm, 136mm rod 1.58 R/S). Because the piston Dwell time is higher on a short stroke motor, the valve timing events are different for max performance opperation at high RPM compared to a Long stroke motor with higher piston speed. Thus why you need to tweak the cam gears on N1's to get the most power out of them. I do know how to "modify" the N1 cams for drop in power over the stock cams but I do not have new camshaft blanks to do so with. I do agree with the stock P12 SR20VE Low cam lobes for starters with any new cam design at this point because they have short duration and high lift for great cylinder fill and high cylinder pressures. N1 Cams do have the potential to make a lot of power on a higher RPM motor with the right cylinder head setup, but it still comes down to the right intake manifold.

Because all of the current "performance parts" are designed around the SR16VE motor I believe that there is better performance potential AT THIS TIME to build a motor centered around a 1.6L 68.7mm crank. You can go with a bore as large as a 94.5mm if O ring'd and with a 1 layer Steel head gasket, but 92mm seems safe from what is out on the market. This setup would yield a 1,827cc motor with potential to make solid power to 10,500rpm or so and make well over 200whp.

I have made a few camshafts for turbo setups with 282 @ .004" lift and 258 @ .050" and 12.6mm lift max. Same profile for IN and EX. I have made 3 of these setups, 1 with larger small lobes, and have shown great results. At this point the std sr20ve cams are great for turbo power. Since there are no "better" cams for "most people" to use for turbo, I would suggest getting head work done instead. If you can achieve a 20% increase in flow, then at a 2.0 Pressure ratio, you can achieve 40% more power theoretically. This means if you are making 300whp @ 15psi and you make a 20% increase in air flow across the board ( average) then you should go from 300whp to about 350-360CFM with the same parts. now this does assume a lot of variables are going to remain constant which ofcourse they are not such as turbo compressor flow, turbine flow, turbine pressure drop. But that is just to give you an idea.

I found a few Dyno sheets to compare a few turbo setups that I have spoken about before. I should be able to upload them tomorrow.

-Ted

I do this myself actually to make life easier. .0005" is "about" .01mm. The Porsche motors that I build are usually within .01mm but a few of the newer GT3 engines are within .001mm which is .00005" roughly.

-Ted

I do this myself actually to make life easier. .0005" is "about" .01mm. The Porsche motors that I build are usually within .01mm but a few of the newer GT3 engines are within .001mm which is .00005" roughly.

-Ted

Wow a lot of knowledge now dropped in on this thread. Ted

The dash is becoming the place to be for technical information. Still missing a few posters though.

where abouts are you from mrslappy?

also with your turbo grinds you made, what low lobe set ups did you use? Also was there much of an improvement from standard sr20ve cams?A;so where in the rev range was the biggest improvement? And what sizes turbo was on the cars used for the cam swaps?

Maybe it would be a good idea for a company to do a intake manifold and cam package together for NA. That way they can design the best intake manifold then design cam specs around that then sell together as a package for a big jump in power. I have seen big jumps in power from home made intake manifolds even with the current available cams

CA18 bluebird, MrHappy Slappy is from America.

He is the man.