cams for track use only

[Pratas_cup]

hello

im a portuguese and have one saxo 16v (vts) just track use

now is time the update cams, but i have one problem:

what a cams choose.

:wall:

catcames 715? newman PH4? ... ?

:boxing:

the car already has air induction, exhaust system, re-maped, and more.


please help mi choice :clapping:

[Yates]

would those cams not be a little to wild for just cams? unless you uprated internals? not 100% on that tho

i have the catcam 708s and thought they were the wildest cams to use for road and track use? unless your going for more than cams? ie throttle bodies?

[dinga]

tb's and is there not cat 734's ? standalone too

[reg_the_geza]

anything with more lift than 708's and you wont have enough valve clearance with standard pistons, AND it will not idle very well with the standard inlet.
how far do you want to go, if u just want cams them go for catcams 708's. anything more then you will have to change or modify the pistons and then think about t/b's

[Nick_106]

well it depends on how big ur pocket is really, if u want ph4s or cat 715s you will be need pocketed pistons etc, plus tb's ur looking at 2-4k all fitted and setted up!

[Pratas_cup]

In Portugal, is put usually for the 715 with the internals stock until the date without problems!


but with a good electronic

[Pratas_cup]

update!

I decide to newman ph4

FIY the question...

Hello.



I've been browsing your camshaft catalogue and I'm quite interested in your PH4 (CITVTS/280/430) cams for my Citroen Saxo VTS (TU5J4 engine, 1.6 16v).



I have some question though, that I was hoping you could help me with:



- Do the PH4 cams require any valvetrain component change, like followers, retainers, springs?

- Do the PH4 cams require pocketed pistons, or can they be used with the OE ones?



Best regards,



Hello .

The cams will run on the original springs and retainers,and willl run with the original pistons on a standard compression ratio.

Regards

David Newman



Newman Cams

Farnborough Way

Farnborough



:p

[Ryan]

alot here dont use 715s after someone did a few tests and found the 708s to be the 'better' cam.

[Pratas_cup]

let's see if the ph4 approving ;)

[Toad]

alot here dont use 715s after someone did a few tests and found the 708s to be the 'better' cam.

Are Catcam 715's similar to Newman PH4's then? What was "better" exactly?

[Ryan]

Are Catcam 715's similar to Newman PH4's then? What was "better" exactly?

not looked into newmans if im honest.

I remeber when daveP went from the 715s to 708s in his tbd hillclimber, The graphs for this to explain why are on the RR somewhere.

iirc it was that the 708s produced the power with a bigger powerband, lower rpms initially and the 715s barely produced much more.

Ive not checked the graphs for ages though

[Toad]

I heard that 708s give a very small amount of clearance between the valves and the pistons, as little as just a couple of mm? How can you run a wilder cam profile?

[Ryan]

I heard that 708s give a very small amount of clearance between the valves and the pistons, as little as just a couple of mm? How can you run a wilder cam profile?

Im just going on the data from daveP a few years back. Its why most of the RR will use 708s, and its why most people now use racelands and not gmc 4-1s.

[KamRacing]

sounds like the ph4s are similar then in spec to the 708s

[Toad]

not looked into newmans if im honest.

I remeber when daveP went from the 715s to 708s in his tbd hillclimber, The graphs for this to explain why are on the RR somewhere.

iirc it was that the 708s produced the power with a bigger powerband, lower rpms initially and the 715s barely produced much more.

Ive not checked the graphs for ages though

OK, that makes sense.

It's just that if 708s are right on the limit, I can't see how you could run a cam profile giving a higher lift (and the same duration) or a cam profile with a longer duration (and same lift) ... I assume this few mm gap you have with 708s is at the start of the intake stroke, so a longer duration cam profile would mean that the intake valve would be more open at TDC, hence the problem. An increase in lift speaks for itself... If anyone knows how this can be done, let me know, as I'm interested to learn! :)