Exactly..... in that application over 7K it starts to make sense. IT'S PART OF THE DESING!!! That is not the OP's application.

 

How are they different? Serious.


Nothing to argue with there.... FINALLY!!



I understand what you are saying. Today's new cam profiles, especially ROLLER cams, have very aggressive lobes and very high lift. I'm running .602 lift myself, which, by todays standards isn't even that much.

However, as it relates to the OP, I don't see it being necessary. My point is that Rev Kits were reccomended for an application that does not need them, specific to the OP. Now, if we want to talk about engines like VetteOz mentions, then yes, that's a different issue, but I am fairly certain that is not the intent of the OP. In fact, I have not seen anyone ask him about his cam profile, correct me if I'm wrong, as it relates to the necessity of a rev kit.

I am not arguing the need for a rev kit in particular applications, I am debating the necessity of it in THIS application

I get it, just see above. Like I said, my cam has a very fast ramp.

Again, i agree. However, my point is design the best valve train design possible for the combinatoin, use the right springs, the right push rods, etc.... THEN go to a rev kit. If you don't have the basics down first, you're artificially fixing a problem.

I think where there's some space between us is that we're having less of a technical discussion, because there really isn't a lot of room for that it is what it is. What I am talking about is strictly PROCESS. If an engine REQUIRES a rev kit to run right, then it wasn't designed right in the first place. The Rev kit is strictly INSURANCE like I said. Not a replacement for good design.

Now, I would expect that you could argue that a Rev Kit is PART of a good design, and that position has merit, however, I would sustain that it is more important to get the basics right then add the kit, rather than mask flaws in execution.

I think what you will find is that if the execution is correct, that rev kits are not really necessary in a lot of applications as it relates to this specific build, and many of the builds on this board. Should we NOT strive to help people build the best possible combination of parts rather than promote band aids for poorly designed valve trains?

Maybe I'm idealistic, stubborn, IDK. But I would much prefer to discuss the right way to do things, then come to the conclusion at the end of the day if something like a rev kit was needed. The alternative is to just seek out cool parts and slap them together whether they are appropriate to the application or not.... Just sayin.. Basics, basics, basics.

I agree on the techincal points, see above on the process points. You are assuming that the valve train is designed correctly, I am not. I hold the position that in many of the combinations on this particular board, the reasons valves get out of control is faulty design, not the requirement of a rev kit.

As you know, I left those choices in the hands of Musi. I don't think many people on earth have the ability to question his decisions. Yes, that can be debated, but he has the pedigree to back it up. And money was not the issue I told him to do it right, not cheap, given the application of course. He knew I wasn't coming in for a $60,000 motor, he knew what I wanted and he built it accordingly.

It's a 240/246 112 LSA on a 108 Centerline. Lift is .602 with .1.6 rockers.

Power is all the way to 6500 RPMs which is exactly where I wanted it. The limitations of the valve train are 7000 so I wanted some margin in there told him to make it come off at about 6500, I'm at 64XX give or take. It kinda peters off, doesn't fall like a stone.

It's a 1206 port matched lightly ported Miniram and 215 CC heads. FOR ME the combination works just the way I wanted it to.

So basically, I have an aggressive cam, high lift, and run it to 6500 RPMs before slightly losing power, and that was with a 1/2 assed tune about a year ago.

And I don't run a rev kit. My AFR at WOT was 10.0 Maybe less, thats as far as the wideband would read. Now with the new ECU and tuning I'm getting that AFR to 13.X I expect to run the power closer to 7000. We'll see what happens. I'm cleaning it up as we speak and will get the tune dialed in by the end of October, I hope.

Then I'm taking a break.