Cam combo what's best?

[Jamo]

???? Just taking a proper look now they both have the same part number so how can the grinds be different?

They are not, it's the RS2 cam wheel which is different it advances the cam 10 degrees.

[GazzaG60]

so are you planning on useing adjustable wheels jamo. on cams or maybe just belt?

[Jamo]

I've got one for the belt, not planning on using ones on the cams, don't trust them after reading on motorgeek what happened if the bolts came loose!

[JP]

They are not, it's the RS2 cam wheel which is different it advances the cam 10 degrees.

OK that's interesting info that means the RS2 cam wheel could potentially be used (assuming change of waterpump etc..) to manipulate the other combinations of grinds to optimise overlap.

[Jamo]

No change of water pump required it's a direct fit to the ABY the difference is the hall sensor trigger wheel at the back is in a different position.

BTDT

But I have the proper fukky adjustable Dahlback wheel to do this as you can advance or retard with the wheel the inlet.

[JP]

OK been looking at the cam profiles listed by jamo. Assuming all figures are correct then the following assumptions can be made using an engine simulator with 1.4 bar of boost on a K24.

For all out top end power and an increasing torque curve through the rev range i.e. track car I would say a combination of 2 x 7A exhaust cams would be very nice as the peak torque and hp are within a gearshift change.

For a combo that gives the flattest torque curve across as much of the range as possible you'd go for ADU intake and the 7A exhaust.

And the best all rounder for peak figures is running the 7A exhaust with the standard AAN intake.

The ADU cams irrespective of the simulation I throw at them will not produce max power or hp instead they are offering lesser power but more spread out over the rev range in the form of flatter curves potentially making for the most street friendly car if pub figures are not what you are after.

As I don't have 2 7A exhausts I wont be able to test that result however based on what two 16v KR exhausts do I'd say it's a pretty safe bet. AAN with 7A I've already tested So I'll compare it to the standard ADU setup and if I can figure out how to time up the 7A exh with the ADU intake I'll give that one a go too. Although I can't ever see that being a cost effective means of tuning

[Bram]

I think I can agree with your findings, as my belly feeling tells me the same about these combinations of cams. I do not had a chance to really test them in practise, so some more evidence would be great! That is also the reason why I choose the ADU cams for best streetable driving. These Porsche engineers must have had that in mind when they started working and modifying the S2 Avant towards RS2 specs. What about the NM cams?

Can you share this engine simulator software insights with us, or how does this work? Can you simply enter the cam data from Jamo's post or do you have to enter different data?

Cheers

[Bram]

For a combo that gives the flattest torque curve across as much of the range as possible you'd go for ADU intake and the 7A exhaust.

How will this combo do in the HP department? Will it provide higher HP figures than a dual ADU combination?

[JP]

Program is desktop dyno, you input engine configuration, headflow, turbo spec and cam profiles. It will then project a power curve based on it's simulation software. I used to use it when playing with chevy v8's and found the hp projection to be within 5% when playing between 400 and 600hp. With turbo cars I've never managed to get acurate hp projections but the shape of the curve seems to always be a good representation of what's to be when playing with cam profiles.

If someone can get me the following data on the K24 turbo I'll try and program it a bit more accurately and post up some screen shot results of the different combinations of cam profiles for future reference.

turbo flow in cfm
intercooler efficiency in %
Pressure ratio
maximum boost
surge flow of turbo in cfm
turbo efficiency in %

[Rusty]

Can you tell me how bad a 7A inlet and ABY exhaust will be please

[Jamo]

The 7A cams they don't produce as much low / mid torque as the ADU and ABY and they increase lag. We have dyno plots to prove this however they pull harder once on boost.

[JP]

still doesn't explain why my dyno plots on my motor showed quicker spool up and more tq and hp through range on a standard chip and a 7A exh cam over the AAN?

Give me a couple of minutes just editing some simulated plots I've put together this morning (joys of kids half term ). Will carry on doing some more through the day.

[Bram]

Program is desktop dyno, you input engine configuration, headflow, turbo spec and cam profiles. It will then project a power curve based on it's simulation software. I used to use it when playing with chevy v8's and found the hp projection to be within 5% when playing between 400 and 600hp. With turbo cars I've never managed to get acurate hp projections but the shape of the curve seems to always be a good representation of what's to be when playing with cam profiles.

If someone can get me the following data on the K24 turbo I'll try and program it a bit more accurately and post up some screen shot results of the different combinations of cam profiles for future reference.

turbo flow in cfm
intercooler efficiency in %
Pressure ratio
maximum boost
surge flow of turbo in cfm
turbo efficiency in %

This one?
http://www.proracingsim.com/desktopdyno.htm

I also found another tool:
http://www.motionsoftware.com/

[Bram]

Seems like Dynomation can analyze a few things:
http://www.proracingsim.com/enginesimfeaturetable.htm

[JP]

Here we go, I've done 12 so far. The first 4 jpg's are based on the exact measured flow figs pulled on a standard AAN head vs that of the flow figs on my stg1 head from. Each simulated with all 4 standard cam configurations. The turbo specs have been read from a compressor map and then slightly tweaked to make the standard curve look the most realistic.

I've noticed straightaway that the simulator wants to shift the power curve higher up the rev range than real life. However as this error is a constant across all the results the cam changes are still comparable to each other.

First of std vs stg1 head on standard AAN cams




Next std vs stg1 head on ADU cams



std vs stg1 head NM cams



std vs stg1 head 7A cams




std head AAN vs ADU cams




std head ADU vs NM cams




std head NM vs 7A cams




stg1 head AAN vs ADU cams




stg1 head ADU vs NM cams




stg1 head NM vs 7A cams



All of the configurations respond equally well to simple headwork on the simulation which is reflected by the dyno results in my other thread. The differences in top end power between the cam sets is less significant once the head has been breathed upon as the flow figures in the lower lift ranges have been brought up to those similar of the higher lift values.

The ones that I found most interesting though are these two. I've taken the standard AAN cams and retarded them 10 degrees using the ADU pulley and compared them to the ADU cams with the ADU pulley.

With both the std and stg1 head flow figs the AAN cam comes out ontop.

Std head AAN cams 10 degree retarded vs ADU




Stg1 head AAN cams 10 degree retarded vs ADU




When I get a chance I'll start doing simulations by combining the various cams.