which cams!!!!!!!!!!!!!!!!!!!!!

[trackslag]

right guys need best info here on cams, the cams in question are 7a/rs2/s2(stock)
with the 7a/rs2 cams is it the extra lift that gives better power or the fact the they change the timing BTDC and increases the power. On paper a turbo engine would work better with higher lift of the inlet side not on exhaust side eg more air/fuel faster there for faster and greater bang!!!. i need to know abit more about over lap and changes in timing, i think this maybe where some of this extra power people getting with the exhaust cam changing. there must be some techies on here with the info............

[Bram]

Use the search please. This topic and question keeps coming back for so many times now. I think cam choice is also a sticky somewhere.

[Rusty]

There have to be a dozen threads on this with lots of info...

Personal choice as ever, I'll be trying a 7A inlet at some point on the stock k24.

[Ruffiano]

Here are some dyno results that 034 had, same car same dyno, different cams:

[trackslag]

yes have found loads of info on exhaust cam changing, have just spent last 5 hours reading it BUT!! very little info on changing inlet cam. which is more important than exhaust on a turbo engine, this has been done for years.

[S2central.net]

I'm NOT the expert on camshafts - it is somewhat a specialised area and only the best engine builders will advise what is best for your application - and that will not just come from 'paper' exercises - it will come from real world experience. The latter is where most of the knowledge on here comes from.

Some general views of mine -

1 - Camshafts with overlap are not good for turbo engines - no need for 'scavenging'

2 - Stock 3B/ABY/AAN camshafts have been used widely in many a 400bhp engine to good effect

3 - A higher lift exhaust cam provides most bang for the buck on the S2... This gets the turbo spinning faster - in order to make boost quicker/earlier... which is a more efficient way of getting more air in than increasing lift on the inlet cam. Note the RS2 has exact same inlet camshaft as 3B/ABY/AAN but the cam pulley retards it by 10 degrees. The RS2 has a higher lift exhaust cam.

4 - It has been proven by many that 7A inlet cam has benefits in S2 applications in the high rev ranges - it flows more air up there - but it is less useful at low/medium revs.

For a K24 based trackday special, I'd say 7A or RS2 exhaust cam is a good choice, but leave the inlet alone.

[S2central.net]

To clarify point 3 - the 7A inlet ONLY has power gains at high revs... the 3B/ABY/AAN inlet cam makes more mid range torque on the same engine.

[trackslag]

do you have any part numbers? for rs2 cam and timing gear?

[Rusty]

RS2 exhaust cam is also shorter duration and different timing to he S2 one. Also, the stock turbo turbine will cause quite a lot of back pressure, so there's only so far you can go with exhaust cam, hence wanting to try just the inlet, something that works well NA and not seen it done before on a k24 car.

[S2central.net]

I have a spare 7A cam you can have for a fair price anytime ;-)

I personally feel it will not be that useful on its own - though with experimentation on a variable pulley might show some surpises - like if the mid range loss could be cancelled out and just provide gains at high end would be something. I just feel the 7A EX cam provides more immediate potential for added oomf - agreed that benefit may not be fulfilled on the K24 though.

[S2central.net]

do you have any part numbers? for rs2 cam and timing gear?

YOu'll find it by searching here - I posted a spreadsheet with part numbers of many camshafts and their main datapoints.

[S2central.net]

Here it be...

[Rusty]

Had one in the cupboard for over a year thanks. Just need to find the energy to fit it. Adjustable timing gear would be nice but blows the budget somewhat...

[Flat on my back]

Had one in the cupboard for over a year thanks. Just need to find the energy to fit it. Adjustable timing gear would be nice but blows the budget somewhat...

No it doesn't...:mischeif:

[trackslag]

thanks for replys im sending the info i get to an engine builder who is very good with cams, he used to be only importer of cat cams, mat at QEP. im planning on running a GT3071R with over sized vavles and flowed head.