Cat Cams - What are your thoughts?

[Pesch]

Hello folks,

I'd like to have your input on "off the shelf" profile Cat Cams propose:




They are all for 4 bearing cam tower.

These are an affordable option for European customers but I cannot really relate their profiles to any well known supplier in US.

Does any of you ever used their products? They are quite famous in the hot hatch rally car world here in Europe.

[Peter M]

If you convert there valve lift figures to inches, average your lobe angles to get lobe centres and print off the specs from the Dougherty Cams website you'll be able to see how they compare in terms of duration, lift and lobe centres to the factory cams and the common performance cams that often get referenced on these forums. This should at least allow you to categorise them.

[m42racer]

Comparisons mean nothing. You cannot compare how a cam affects an engines performance just by lift and duration.

The design is so important as many off the shelf cams are copy and paste designs that induce huge harmonics into the valve train.

Before you even think about choosing a cam, you need to use the air flow the engine flows, the engine sizes, piston clearances, CR, etc., to determine the cam design along with the engines use.

[Steve@Rennsport]

Originally Posted by m42racer

Comparisons mean nothing. You cannot compare how a cam affects an engines performance just by lift and duration.

The design is so important as many off the shelf cams are copy and paste designs that induce huge harmonics into the valve train.

Before you even think about choosing a cam, you need to use the air flow the engine flows, the engine sizes, piston clearances, CR, etc., to determine the cam design along with the engines use.

OH so very true.

Its not like ordering an entree off of a restaurant menu.

[Pesch]

Here's a table I made quickly on those proposed profiles:


I filled-up a profile request for the configuration I plan:
- 66 x 90
- 10,5:1
- twin plugs
- type of use, rallye

Waiting for their proposition

[Peter M]

Originally Posted by Steve@Rennsport

OH so very true.

Its not like ordering an entree off of a restaurant menu.

So Steve, how else would you "short list" them for further consideration?

Surely culling based on lift, duration and lobe centre gets you into the ballpark?

I'm asking as I'm keen to learn more.

Thanks
Peter

[Tippy]

Originally Posted by Peter M

So Steve, how else would you "short list" them for further consideration?

Surely culling based on lift, duration and lobe centre gets you into the ballpark?

I'm asking as I'm keen to learn more.

Thanks
Peter

You're correct IMO, if you are sticking with ballpark figures.

[m42racer]

Originally Posted by Peter M

So Steve, how else would you "short list" them for further consideration?

Surely culling based on lift, duration and lobe centre gets you into the ballpark?

I'm asking as I'm keen to learn more.

Thanks
Peter

You are right in your idea. The cams lift and LSA will give you a ball park idea if it will even fit with no other changes to the engines internals.

However, and unfortunately, most "off the shelf" cams sold by the well known suppliers are "cut and paste" or bad copied designs that will give you the lifts and duration's required but also supply a huge amount of camshaft harmonics into the valve train, killing performance.

Most have never experienced the difference as the "norm" is all that has been supplied and used for years. Ask people like "Steve of Rennsport" and others of his caliber about the differences. These shops design their own and its parts like this along with the included engineering that make these shop's engines perform at a different level.

You get what you pay for and in this situation a whole more you didn't account for.

[Tippy]

How much performance are these off the shelf grinds costing us in power?

[m42racer]

Originally Posted by Tippy

How much performance are these off the shelf grinds costing us in power?

Depends upon the engine and the cams used.

You can be sure that the harmonics built into many of the "cut and paste" cams causes the cam timing to go in the tank and the engine performance to drop off dramatically.

This can never been seen unless monitored on a Spintron or an engine dyno with cam position measuring devices. I have seen where the cam position changed over 8° due to harmonics.

[Tippy]

8° is a lot! Wow!

[lvporschepilot]

I've never used Cat Cams Porsche camshafts, but I have used their valve springs which they actually have custom made by PAC racing springs in the US. Their springs are awesome but very difficult to get to the US as none of the EU distributors who have them want to ever ship stuff to the US. Use Dougherty's springs, they are every bit as good anyway.

As for their cams, I have used at least 6 sets for various Ferrari engines and they are brilliant. Their Ferrari cam profiles are the business, very aggressive ramp speeds and very good quality. Cat aren't really known for their Porsche stuff, more so their tuner 4v stuff is their bread and butter.

That all said, Dougherty is IMO the best on the planet for Porsche 911 camshafts with literally every corner of the globe using his stuff, so why go anywhere else.

[Pesch]

A pair of Cat Cams camshafts for a 911 can be get for about 900$ thus the interest in their products.
For European customers, it isn't cheap to get a hand on US made products, you can add shipping +10% Custom fee +20% VAT...

The way to go is maybe to get custom grind specific for each build, I'm waiting their proposition.

They seem to know what they are doing as they also develop cams and followers package to target 300hp @ 9000rpm on a 2.0 Renault rallye NA engine.

[Nux]

Originally Posted by Pesch

A pair of Cat Cams camshafts for a 911 can be get for about 900$ thus the interest in their products.
For European customers, it isn't cheap to get a hand on US made products, you can add shipping +10% Custom fee +20% VAT...

The way to go is maybe to get custom grind specific for each build, I'm waiting their proposition.

They seem to know what they are doing as they also develop cams and followers package to target 300hp @ 9000rpm on a 2.0 Renault rallye NA engine.

Pesch,

Did you end up using Cat Cams for your application? I'm European based, and would like to have a "local" cam shop.

[safe]

Originally Posted by Nux

Pesch,

Did you end up using Cat Cams for your application? I'm European based, and would like to have a "local" cam shop.

You don't have any local cam grinder in Denmark? My experience is that there is knowledge around, just not on the internet. Otherwise the Germans aren't bad, just hard to get information when you don't speak the language. Mittelmotor for example has a lot of stuff and can probably help if you contact them. Their website is just exceptionally useless...

[Nux]

Originally Posted by safe

You don't have any local cam grinder in Denmark? My experience is that there is knowledge around, just not on the internet. Otherwise the Germans aren't bad, just hard to get information when you don't speak the language. Mittelmotor for example has a lot of stuff and can probably help if you contact them. Their website is just exceptionally useless...

Hi Magnus

As you know, Denmark is tiny (population 5.5mill in total), so naturally we don't really have any Dougherty's , Steve's , Wayne's, Sal's or Al's (just to name a few). I find it difficult to find REAL knowledge here - and the very few capacities that we do have, are very busy and/or retired from the air cooled porsche world.

So by local I mean in Europe . I speak German ok, but at the prices Mittelmotor take for their stuff, I would rather use Dougherty.

Do you have any good experience with shops in Sweden or Germany (besides Mittelmtor)?

[racing97]

Pesch, you have provided Cat with everything except the Induction details I suggest you do and also the RPM band you would like to run. This is all anybody over here does the nature of the Hemi head and the CORA or cam on rocker arm limit many of the mystery profiles that are touted on the Internet. You could also ask them if they are asymmetrical which means the ramps on the opening side of the lobe are different than the closing both I an E which is the proper way to make these cams. (asymmetrical lobes give symmetrical lift) You will find the profiles that the cam company recommends that you replace the valve springs are cams that have ramps that differentiate from stock Porsche profiles, they will through trial and error develop along with some software. they don't show the velocity curves because of its proprietary nature, those graphs would show you why the spring is important. Also Schrick Camshafts make very good products and have many years of experience.
You will be fine
It sounds like you will be in good hands
Regards

[safe]

There are some shops here that does cams for saab, volvo, opel, etc. Mostly for rally cars, but I think they would have experience with Porsche too if you ask them.
In England you have Tuthill and 9miester.

I have a set of cams in my 3.2 from Dougherty, they gave me exactly 10 hp LESS than stock, less hp and torque everywhere. I have since retimed them against his recommendations and regained most but with slightly different exhaust.
I my 3.6 I have a set of cams from FVD they gave a solid 30 hp (a bit peaky between 4-6000) verified it other engines too.

So I have mixed results...
If I would buy a new set of cams I would try to come up with my own design. Not the easiest but I think it would be really rewarding.

[lvporschepilot]

Pretty sure Dougherty supplies camshafts to a couple English and German suppliers who brand them as 'their' cams.

[racing97]

If you want to delve into cam design you can look at the PDF and the reference to Gordon Blair and a pretty good simulation program that might help you visualize some aspects.
Prof Blair & Associates Home Page - Published Articles
https://www.destaco.com/assets/docs/en/servicemanuals/CAMCO_Cam-Design_Moon-Book.pdf

About: Vannik Developments (software)

regards