[Lucid Moments]

continuing from the other thread...




Could you clarify what exactly you mean in this statement? is the implication that the force between the rocker assembly and the lobe on the cam is enough to cause a certain degree of deflection on the lobe itself? And if so, the iron has a greater degree of deflection compared to the 8620 material thus resulting in the claimed power difference between the two materials?

I may be talking out my ass here, but I think BigWorm is on to something. I was talking to Chunky at one point about the 8620 cams and he explained to me that this is exactly why the 8620's make more power. At least if I didn't misunderstand what he was telling me.

 

[ALL MOTOR EM2]

Hey Mike im going to be in Town July 23rd- August 1st.

 

[Davanca]

As I said in the other thread, this website is member supported, not vendor supported. We sell parts and make our living and pay for the website that way, we don't have to whore out to sponsors.

Well you have to expect that K20A.org, is mostly vendor supported. On his site he doesn't have his own online store, like here on crsx. So if he generating money on his site 95% of it is from vendors. Now protecting his vendors on his site is one thing, protect the same vendors on other sites that don't generate money for him is nutswinging. So choosing vendors over his members doesn't hurt him right now. But in the future if he opens up his own web store, the same people he's not favoring, are going to be the ones not buying parts from him. Which will hurt him in the long run when his site starts to generate money from the members.

 

[Lucid Moments]

Hey Mike im going to be in Town July 23rd- August 1st.

Cool give me a shout when you get into town. Your car done yet? You driving it down here?:weeeeeeeeee:

 

[ALL MOTOR EM2]

Nope its not done yet... Im getting antcy... Should be done by August.

 

[?uestion]

Because companies have KNOWN about 8620 for a LONG time now, and if it was really so much better in every way, wouldn't they ALL be using it?

Though I can't recount word for word everything I have been told and every answer I've gotten when I questioned the 8620, the general consensus from EVERYONE that isn't ron that I've talked to said it's pointless. the only cars john at hytech will put 8620 into (unless someone specifically asks for it) is straight up race cars. He'll have to explain to you why but it has nothing to do with power because there is no power difference.

exactly if anyone thinks 8620 is going to add more hp is full of it.

marketing all business do it. :chuck:

 

[VikMan9158]

i didn't think they can make power, a marketing gimmic. But chris did say that the only way 8620 can make power is if it were lighter, taking into account that both cams ahve same specs.

 

[b19coupe]

One reason that cam makers do not use 8620 is cost-machining costs more than the actual raw material.
The benefit of 8620 has something to do with valve train harmonics and valve motion control. Ron explained it to me once, but it was over my head, mostly.
I witnessed back to back dynos of the iron core vs the 8620, and the 8620 was measurably better.

 

[ALL MOTOR EM2]

but is it really worth the extra mark up over the K2's?

 

[HondaTom]

The only point that I could really think of was, that the 8620 stocks might deflect less than the ductile iron.

 

[guu-sama]

but is it really worth the extra mark up over the K2's?

Well, since the Iron Core K2's are no longer made you really don't have a choice do ya now! Unless you are buying a set used...

 

[Islanti]

Are 8620 Cams Worth the Cost?

no.

 

[HondaTom]

Are 8620 Cams Worth the Cost?

no.

I love how so many people know all about 8620 material vs. ductile iron.

 

[NBP RSX-S]

I would be willing to do a back to back comparison of the ductile K2 and the new 8620 k2 but need a reliable source to buy the new ones from and a reliable source to sell the ductile ones to.

 

[Point_particle]

I love how so many people know all about 8620 material vs. ductile iron.

8620 isn't a very "special" alloy, but the process used to produce them is what jacks up the cost

here's some info on 8620
http://www.suppliersonline.com/propertypages/8620.asp

and here is AISI4130, commonly referred to as chrome moly steel (for comparison)
http://www.suppliersonline.com/Rese...ch/Property/result.asp?FamilyID=1&MetalID=20&Chemical=1&Physical=1&Mechanical=1

 

[HondaTom]

Thanks for the site, good info. :thumbsup:

 

[talonxracer]

Nice info on that metal supply site! thnx



My machinist explained the advantages of the 8620 over the ductile occurs at high lift/spring pressures and high rpm as there is slightly less flex in the cam shaft allowing the cam to provide closer to static lift and duration. Slightly more lift and duration will provide slightly more power.

He also said there is also less wear on the cam bearing surfaces.

ALL AT THE LIMITS OF A FULLY BUILT MOTOR.

 

[Kevin949]

I believe that Church Auto tested these cams and the power was a bit more (5to 8hp more) but the big difference was how smooth the transition was going into VTEC. Very seamless transition. I've decided to go turbo, but to justify the cost of the cams is tough for me "personally" but the people that need the best I'd say give it a shot "IF you have lots of money" otherwise stick with the old style. Just my 2 pennies.

Ya, they were done at church. and as an FI guy you would/should be one of the guys that would look into cams MORE than an NA guy. At least, I would imagine (in the K series anyway).

My issue is this, it's not the HP difference that gets me really, because there are WAY too many variables that could have taken place between the original K2 run and the 8620 K2 run to make that 5-8hp difference. The 18ft/lb of torque is what kills me the most. But hell, I could get higher HP and torque readings by lowering my rotor mass on a dynapack (as far as I understand how it all works anyway).

 

[RsxJai]

If it's lighter (less inertia mass) and if its more heat resistant (heat = less power) then it would. Not substantially, but at least a little difference. But can anyone substantiate the weight differences? Or the differences in temperature when the cams are in use? Materials mechanics does say that different materials will provide different powers doesn't it? I'm interested in the post about why "vtec" is a lot more smoother. Same profile, same ramp speed, same everything but material, so why should the transition change? Unless it's smoother cause when it mechanically changes, the 8260 material is just easier to come in contact with than the Iron?

 

[talonxracer]

If it's lighter (less inertia mass) and if its more heat resistant (heat = less power) then it would. Not substantially, but at least a little difference. But can anyone substantiate the weight differences? Or the differences in temperature when the cams are in use? Materials mechanics does say that different materials will provide different powers doesn't it? I'm interested in the post about why "vtec" is a lot more smoother. Same profile, same ramp speed, same everything but material, so why should the transition change? Unless it's smoother cause when it mechanically changes, the 8260 material is just easier to come in contact with than the Iron?

Read my last post, it explains that.

A cam that flexs less when engaging vtec will offer more lift and duration. It has very little to do with weight, but torsional rigidity at temp, the K20 series motors use a solid roller rocker set-up, not hydraulic tappets which reduce the seen and felt cam flex in other motors. A more uniform presentation of the cam profile between cylinders while running makes for a smoother running engine, and a smoother engine can produce more power.

Now as far as the gains with the 8620 K2's, I was "told" by a machinist(who has installed both types of cams fom IPS) that there is minute differences in the cam profile's. This he verified with a degree wheel and measurements.