SterlingEvo

iTrader: (5)

After riding in an Evo with HKS 264/264 I've decided I'm going with that, although not for a while (got Christmas coming up soon ) I've been told that 272's are better for the much higher RPM/speed range, and I'm more interested in low end...

boostfed

iTrader: (2)

What would be the best setup for drag racing. I don't do much autox. at all. I do how ever go to the drag strip on ocassions. I don't care about the idle. if it has a little lope to it that's fine. I just wanna know what setup I need to buy. what are the prices for the other brands: Tomie, jun, piper... I think I'm just gonna go with the HKS cams for the simple fact that it will be a while before I upgrade my turbo. and I figure I can do a little more research on cams before I do a bigger turbo. what are the pros and cons of the 272 in,ex vs 264 in,ex. thanks for any help.

-Chad-

TD05HR

iTrader: (6)

from what u are saying...hks 272/272 is for you man...since u do mostly drag...u dont neet low end power...hks 272 make high end power..and its even better if u ever decide to upgrade turbo...

Mach 8

ok i really want a cam combo that is going to give great torque but also give at least some top end im going to be drag racing but mostly from redlight to redlight and some auto-x.

Thanks,
Jay

Mach 8

What cam combo is most noticable all around in power diffrence

2k4EvoVIII

iTrader: (15)

Look there is no way. I had the HKS 272/272 with the GT35/40R turbo and was having major blow by. I through in the Tomei 260 with 11.5 lift and gained a max of 40ft lbs of torque and top end stayed the same. Lift is what gives you more torque. Duration gives you torque also but at a loss of top end or visa versa. Basically i went from 512whp at 30psi to 689whp at 35psi with the same turbo setup just full bottom end and top end rebuild. By the way you want to talk about compression. WIth the HKS 272/272 i was getting a 125psi compression test and now with the Tomei i get a 145psi compression test. HMM BLOW THROUGH? I will post more details later and get more involved in everything just im at work and dont have time right now.

Chris

MrBubbler

iTrader: (8)

i didnt say anything about tomei and these arent from my personal experiances but with larger turbos some of the guys have not been getting the power they should with the revolvers cams which are high lift etc etc , gt40 i think is testing pipers new cams also but for seem reason most tuners say stick with 272's = / i do however would like to see some back to back testing with tomei because they look like they produce the only other cam i would bother spending money on

boostfed

iTrader: (2)

If you don't mind me asking. How much did the Tomei cams cost and did you have to upgrade the valve springs and retainers. I would guess you had to upgrade your valvetrain, and by doing so did it or does it compromise anykinda streetablity or reliability. I'm not looking to rev my engine much past the stock redline. If I wanna do that I buy another honda and rev to 10K. thanks for any input. it seems you have a little experience with some of these parts. So, I would like to hear your opinion on the matter. please keep in mind that my car is a daily driver car and I have to pass emissions and I'm still making payments on it. So I don't wanna have to go to wild with the car if It's not needed. thanks

-Chad-

2k4EvoVIII

iTrader: (15)

Well ya i did have to upgrade the valvetrain but i was in the middle of a full engine rebuild anyway so i didnt mind (Ross .20 over pistons, Eagle Rods, Fully Blueprinted and Balanced, Balance Shaft Removal, Fully Head ported and Pocket ported, 1mm over Sodium filled Nitrate valves, BR Spings (120 tensil strength compared to 60 stock) Titanium retainers, Tomei Cams, among all the external upgrades. But anyway the BR springs and retainers are the best on the market at this point. As i stated above there are double the strength and are good for 10500rpms redline. I redline at 9500 currently before the turbo drops off. They are much better then the dual spring design and they are a awsome price. When you upgrade the valvtrain it does nothing to the daily driveability of the car and if anything is a safty factor for anybody that has cams. Even though HKS says you dont need springs and retainers i have seen evidence of it being a good idea to get them. Just my 0.02 If you need any help just let me know i would be more then willing to help you.

EDIT** I paid $690 shipped for the Tomei cams

Chris

Ted B

iTrader: (6)

This is the purpose for cam gears. By adjusting the gears, you can dial valve overlap in or out. If we have the duration for both sets at 1mm lift (not advertised duration), I'll bet you I can get both sets to be within a few hp of each other.

As far as lift, the difference in lift between two sets may or may not be advantageous, depending on the flow characteristics of the ports. Unless one can conclusively demonstrate a significant difference in flow between 10.8mm and 11.5mm of valve lift, we're just making the valvetrain work harder and not getting anything from it.

In theory, you are correct that too much valve overlap with a turbo engine is detrimental, but even the HKS 272 set is not what I consider to be a very long duration set. In any case, it's easy to dial out duration with a longer duration set (and get earlier spooling, etc.), but one cannot add duration with a shorter duration set.

2k4EvoVIII

iTrader: (15)

This is true you can dial out overlap with cam gears but then what is the point of the duration if you are dialing them out anyway. Lift is always better nomatter how you look at it. The more air you can get into the engine and out of the engine makes more HP. Now you are right about another point. The pockets in the EVO heads SUCK BIG TIME. THey are almost square looking. Obviosuly not good. But with a good pocket port and 3 or 5 angle valve job that took care of that problem.

Point being that the duration is not the only factor in selecting cams. Infact Duration and Lift are not the only factors. When looking for cams you should look for the following

DURATION
Duration refers to how long a valve is opened in relation to crankshaft rotation. This open valve time period is expressed in degrees of crankshaft rotation. So, a cam specification of 220 degrees duration simply means the cam holds the valve open for 22 0 degrees of crankshaft rotation.

As strange as this may sounds, more duration can be helpful in high RPM engines but not low RPM engines. The extra degrees of open valve time in high RPM engines gives the air flow a little more time to get into (or out of) the cylinder in spite of the piston's stroke. However, at lower RPMs, more duration can cause less power because the valves will be open at the wrong time in relation to the piston's stroke up or down in the cylinder.

CENTERLINE
The cam's centerline specification is used to tie the valve timing to the crankshaft's rotation. This spec is expressed as the number of degrees the crankshaft must rotate from top dead center until the cam has rotated to the peak (or centerline) of the lobe.

The centerline spec and the duration spec can be used to calculate when the valves open and close in relation to the crankshaft's rotation. When the valves open (or close) relative to the crankshaft's rotation is known as valve events or valve timing. Some cam manufacturers will provide valve event information and others only provide duration and centerline information.

Understanding the effects of valve events or valve timing is the real secret to understanding engine performance. For the engine to run at its peak performance, the valves must open and close at the correct time in relation to the piston's position and the crankshaft's speed.

SEPARATION
Separation refers to the spacing between the intake lobe and exhaust lobe on the cam shaft. This spacing (or separation) is expressed in degrees on the cam, not on the crankshaft. So, a 108 lobe separation means the intake and exhaust lobes are 108 degrees apart from each other on the cam shaft.

This spec by itself really doesn't mean anything. If you hear someone else is using a cam with 108 separation, don't think that you should use cams that only have 108 separation!

Separation, just like centerline, is another way to tie the duration to the crankshaft rotation and end up with valve events. This spec is a little more complicated though, because it is in cam shaft degrees and the crankshaft rotates two degrees for each one degree of cam rotation. Also, if the cam has been installed either advanced or retarded, the valve events will be different.

LIFT
The final cam spec to understand is lift. While duration refers to how long the valve is opened, cam lift is used to determine how wide the valve is opened.

If the valves are not opened wide enough, they will cause a restriction for the air trying to enter or exit the cylinder. However, opening the valve past a certain point will not increase the flow to (or from) the cylinder. A good way to demonstrate this is with the garden hose in your back yard. When you first start to turn the water on, the flow increases but after a turn or so, opening the valve more has no effect on how fast the water comes out of the hose.

So as you can see there are allot of variables to picking the right cams out. I think it has been proven that HKS made these cams for a simple upgrade without major work to be had. But if you look into the picture more there is allot more to be had. Also after all my research i should have waiting for the new Tomei cams to come out or just got the Piper cams but i think that 12mm of lift from the Piper is a little too much and you will see no benefit but i also thing the perfect duration is around 265. So the optimal cam profile i would think is 265 duration with 11.5 to 11.8 of lift. Of course soon after i ordered my Tomei cams they introduced the 265 and 272 duration with the profiles i mentioned above. Oh well i have gone through 2 sets of cams and when im ready for the next i will probably get them custom made to my specs of the engine. Im just letting everybody know that i have had the HKS 272/272 and i have had the Tomei 260 and i have noticed a great increase in TQ and HP from switching. Is there more to be had? Yea i think there probably is around another 10-15whp to be had out of some custom cams but right now the price just is not cost effective. Oh yea when i dynoed with the HKS cams i had the gears set to -3/-3 and with the Tomei i had them set to 0/0 and the Tomei picked up lots of lowend but suprisenly didnt lose any top end. So now if i retarded the gears a little "as everybody knows you gain top end" the Tomei's will pick up more top end then the HKS cams did with 12 degrees lower duration. Which tells you that lift really does help IMO. Just my 0.02

Chris

Ted B

iTrader: (6)

Chris, thanks for cutting and pasting the theory. I'm quite familiar with cam theory, having designed and implemented my own sets of custom roller cams in Chevy V8s almost 20 years ago. By no means do I know it all, but I do understand that cam timing is a multidimensional subject.

The purpose of duration extends further than the causes and effects of overlap. Keeping the valves open longer (to a point), can be beneficial, depending on how the lobe centers and centerlines are set.

In short, you can use only as much lift as the headflow charts indicate. If the flow data indicates only a few % difference in flow from one valve lift to another, there is little to be gained. Furthermore, if you know how to compute the area under a bell curve, you can determine exactly how a cam profile will behave if and only if you have ample basis for comparison. This is why more lift beyond a certain point does not necessarily yield more power (but is harder on the valvetrain), and advertised duration numbers are of little value whatsoever.

One cannot say that "265" is the optimum duration. 265 doesn't mean anything. FWIW, the Piper 265 set has as much effective duration as the HKS 272 set! Again, this is why advertised duration numbers are useless. One needs to know duration at 1mm lift for effective duration.

Finally, one such instance of advancing the HKS 272s to +2/+2 revealed no real loss of top end. The downside to advancing the cams is a greater tendency to develop preignition.

boostfed

iTrader: (2)

I just don't know if it's worth the extra cost. 150 dollars more for cams over the HKS, then valve spring and retainers are another 275. then cost installation. would you have to remove the head to do the valve spring and retainers. It seems like you would. if so that's gonna be even more cost for the installation. plus if I'm gonna remove the head I'm gonna install new head studs. I know there's a bit more power difference in there between the Hks and the tomei. but for a mildly stock engine. is it worth it. I'm just trying to be reasonable and see if the price difference is gonna be worth is or cost effective. that last post was very informative. thanks again.

-Chad-

2k4EvoVIII

iTrader: (15)

Hey your welcome for posting that anytime i can help. Anyway HKS measures there cams "i forget the name maybe you can help me with that one" but the way they measure them is not a true measurment. I know for a fact the Tomei, Piper, Jun cams are measured in the correct manner.

Now i would be more then willing to throw my Tomei cams into your car and we can do back to back dynos to see what happens if you want.

To answer the other question honestly if you dont have plans to do major work then HKS or JUN (most aggressive cam at 1mm lift" is the way to go for you. I never said that they are not good cams infact i loved mine when i first got them. All im saying is there is more to be had of course you are going to be paying to get that extra maybe 10whp. But hey people spend $10K on a dragbike to go 2 tenths of a second faster. Ever bit counts in a drag race.

Im sorry somtimes i forget peoples needs are different from mine. I have a bad habit of once i start somthing to get it done to its optimal performance nomatter the cost. "HENCE ALL MY DEBT....LOL" But at least im having fun doing it.

Back to the topic I was not doubting your knowledge in anything and im sorry if you took it that way im hear to provide information to people that need it and if you dont need it then dont reply go on and add what you want to add and call it good. And actually i can provide information saying what the best cam profile would be for my engine "but that is not the same case for everybodys engine of course becouse of setup" but with the way i set this engine up at 9500rpms and 35psi the longer duration will kill me on top end. So after some flow marks and all this mathamtical crap we came to the conclusion that the setup i mentioned would be best for my setup. Enough said.

NO DISRESPECT INTENDED! THIS IS ALL GOOD INFORMATION FOR THE COMMUNITY!!

Chris

Ted B

iTrader: (6)

I'm glad you posted that cam data. If only everyone took the time to read and try to understand it.

I have the duration at 1mm lift for the HKS cams, but not for the JUN and Tomei cams (anyone?). If I did, I could give an accurate picture of what to expect from these cams in comparison to any other cam set for which I had the same specs. Additionally, I wish I had actual head flow numbers at different valve lifts from anyone with a flowbench. With this info, one can make fairly reliable predictions.