You're going to have that problem with ANYONE that has proprietary lobes. They're exactly that. I can name several that have them. All you can look at at that point are the results, talking to the vendor, and seeing what they say. Either way there's still enough info out there to make a well informed decision.

Geoff will tell you about anything you want to know though and make you feel more than comfortable with the decision you make. I like how he collaborates, and not dictates, where the build goes.

 

The point of going with someone like Geoff, Kip, or Ed@FTI and their product is directly related experience to achieve the best results. So many people have a hard time letting the professional do their job. They don't give up the info because they've worked very hard to get there and don't need the unscrupulous people copying their work.

You know how someone walks up to you and tells you how to do something they have no experience with and you look at them with a "Where in the ....". The right person for the job is just like the right tool for the job. A different tool can do it but not as well or even do it at all.

 

If a buyer truly understands what those numbers mean, and is that in depth with a lobe design, they should break out the lobe catalog and pick out what they want instead of going through a third party to design their cam. Otherwise, those numbers are meaningless to a consumer and they should base their purchase on other factors.

 

In theory, I agree with you. One issue that no one wants to talk about is that just because a catalog lists specifications for a given lobe, when you actually measure them they don't always measure to the specifications that they were advertised at.

 

Like the Comp XFI intake.
I'm new and I know I have alot to learn. Even if I go to, say, the Comp catalog and read the durations at .006, .050 and .200 that's still not enough to tell me how much real overlap I will have or how much vacuum I will generate. Most lobes are asymmetric so those numbers only describe the lift side of the lobe and not the softer closing side. Is this not true ?

 

In the real world, it is plenty accurate enough to estimate that for practical purposes.

I feel like people tend to overestimate what small changes in camshaft duration will actually mean in regards to real world performance.

On that same topic, some of the test that have been shared with me show that aggressive lobes do not produce the additional power that people believe they do either. In my opinion, 90% of the LS stuff in the Comp catalog are too violent for 98% of the applications that people are using them for.

 

What do you consider an aggressive lobe? Fast ramps can make more power if they are used correctly, but the valvetrain has to be able to make it work

 

I would answer this in regards to what I think would represent 90% of the people on here which I would say is street, street/strip or moderate competition. After what has been shared with me, I would personally not choose anything that is more aggressive than an 52-53 .006" to .050" intensity or more aggressive than a 78-80 for .050" to .200" intensity. There is more to a lobe than those numbers for sure, but I used those specs because that is what is referenced in the catalogs that most are familiar with.

From what I saw, more aggressive lobes can generate a few more foot pounds of torque at low to low-mid rpm in the applications mentioned above, but then can become a mess at higher RPMs. Since the guys who typically who are attracted to the more violent lobes are not driving tractors, I think the more violent lobes are a bad choice.

 

Not really. I have seen plenty of cases of lobes being advertised as having 'x' duration at .006" and when they are measured they are WAY bigger than advertised.

There seems to be a fixation on what is going on between .006" and .050". Some folks think faster is more powerful and some folks think faster will tear up parts. Both are probably true to some extent, but unless you actually know the REAL measurements of what you are buying AND have REAL WORLD experience of knowing how far you can push the envelope with speed, just looking in a catalog at numbers or using advice gained on an internet forum will not necessarily give you the results you are looking for.

 

Geoff, I know you are the man who designed the Thunder Racing cams; the TR224 is famous. I was just trying to understand WHY the EPS lobe is better.

In this thread I asked for a cam recommendation. What would you recommend for my car ?

rod70, I'm sorry I hijacked you thread . That piston to valve clearance calculator is in this thread.
https://ls1tech.com/forums/generatio...alculator.html