4 pattern cams

[Thom 6,651]

Just been reading an article on comp cams 4 pattern cams, baisically the outer 4 cylinders vavle events are altered to compensate for the difference in runner lengths on single 4 barrel intakes

http://www.dragzine.com/tech-stories/comp-cams-new-4-pattern-cam-boasts-advanced-nascar-technology/

What are your thoughts on them?

[gerg 10,871]

To me it's a band-aid fix, just like balance shafts in engines that have inherently poor balance. Still, sounds like a novel approach to a problem that can't be otherwise solved with single-carby manifolds. One would assume that it's purely race-oriented and tuned for max efficiency at high-rpm, and low-speed cylinder balance is not important. The article itself is great on technical detail, very impressive.

[slydog 7,873]

I do know of some speedway guys doing this with in lines running a single carby.I guess you would run em back to back on a dyno and see what happens to find out for sure.

[gerg 10,871]

I had that exact idea after reading this! Crossy inlets are a perfect candidate for this kind of thing. Would like to hear/feel the difference some time.

[slydog 7,873]

You can move the carby around a bit to try to get a more even burn on the plugs and or run different heat range plugs to suit each cyl.

[ando76 4,354]

I know of one roller cam crossy that is going back to 'single' pattern roller cam from multi pattern.  The engine builder is a well known Queenslander and I like his thinking.  Could also have a bit to do with the balanced inlet that the engine runs now. 

 

With advances in electronics (individual cylinder timing) I think the days of multi pattern cams are just about gone but hey I been wrong before today. 

[Trev Vaa 1,185]

got an email a month ago about this from comp saying they were releasing these. then again last week or a week before with the press release.

the theory makes sense, and they're pegging it against their own products in dyno testing, that's ballsy.

 

while adjusting timing aids the fuel mixture issue in single carb it doesn't stop the lean out caused by fuel vaporising on a longer intake runner.....

this is a bandaid fix as said, but hell if it works as well as they claim, then why not give it a shot?

nothing is going to work as well as ITB EFI but if you can improve i say i'm all for it.

windsors are inherently bad for this issue, scott and i discussed it breifly at AFD this year in regards to his XW.

[slydog 7,873]

GM and Donny don't have fuel vaporizing issue's with there Windsor's as they jet to suit.Pretty well anyone who "owns" a healthy Windsor would already be doing so I'd suggest.But the problem is still there on even on blown cars that have a butterfly per inlet valve.That said the fix is already known and for $3 per jet compared to a new cam and lifters @ minimum I know what I would be doing.

 

This style cam can and would suit Nascar and such with there throttle body EFI and base plate carby combo's for different tracks but I think Comp are years behind what the well traveled Windsor fan has already accounted for.I'm sure Roush,Joe Gibbs and such would have some "very" trick manifolds that already compensate for this aswell.

[Clevo120Y 815]

The theory is sound and works BUT the amount of data needed to get it right is huge. You have just as much chance of finding a suitable single/dual pattern cam profile as finding an off the shelf "scatter" cam that suits your engine.