7A Exhaust Cam

[chipsenter]

Not bad Mannen

Whats the AR on this Turbo ? Check my results with 7A Cams
We tried both with Racecams and 7A's must say im impressed , we got 1,2 kg's of boost at the same Rpm's with 7A's

Its not a bad suggestion bro.

[meep]

Quick question then.

This is a dyno with my car. Engine spec is as follows.

Stock AAN block.
Stock AAN pistons.
H rods.
ARP bolts throughout.
New bearings and piston rings and so on.
Stock head with stock running gear and cam.

PPF manifold.
Garret turbo charger.
Kompressor: GT40 0.58 A/R, 48 trim
Turbine: GT37 0.99 A/R, 73 trim
1600cc injectors.
Stock s2 wastegate with 1 bar spring.

Dyno is made at 1.9 bars of boost. After that the backpressure starts building up.
I like the powerband so that i dont want to hurt that much but maybe some more power and less lag? Would 7A cams be appropriate for this kind of power or is it just a waste?

Graph


Numbers

[th.b.w.]

Look at the Dyno at Picture 46.......

http://www.s2forum.com/forum/showthread.php?t=22861&page=4

Thomas

[BedaS2]

GT35R ,7A cams ,wosner piston,h rods,11.4s /209km/h drag with bad clutch :-)

[BedaS2]

I have 7A cams...

[BedaS2]

Sorry about my English ,is no good :-(

[Jamo]

There's a thread about with timing plots, ABY cam with RS2 cam wheel I believe was one of the best results or 7A cams

It's a recent thread

[BedaS2]

You know ideal timing for turbomotor ?

[Jamo]

ABY,AAN,ADU have same intake cam...

We know, if you read the post it says timing.

The ADU has different timing due to the Cam wheel trigger being in a different position.

[BedaS2]

ABY,AAN,ADU have same intake cam...

[Bram]

Aaaaaa, there is the data from Pisobiker. I have been looking for that for a long time!
So advancing the 7A cam by 5 degrees would only solve earlier spool-up and not low-end torque?

[Jamo]

I would like to point out some aspects about 3B/ABY/AAN vs. ADU vs. 7A cams:

analizing data I have there are some in my opinion interesting things to consider when choosing among different cam's options:




3B/ABY/AAN:

TIMING:
Intake opens 3° after TDC, exhaust opens 42° before BDC

DURATION:
Intake 202°; Exhaust 213°; no overlap -> intake opens 12° after exhaust closes;

ADU:

TIMING:
Intake opens 13° after TDC, exhaust opens 24° before BDC

DURATION:
Intake 202°; Exhaust 205°; no overlap -> intake opens 12° after exhaust closes;

7A:

TIMING:
Intake opens 7° before TDC, exhaust opens 42° before BDC

DURATION:
Intake 224°; Exhaust 213°; no overlap -> intake opens 3° after exhaust closes;

ADU exhaust on 3B/ABY/AAN:

TIMING:
Intake opens 3° after TDC, exhaust opens 24° before BDC

DURATION:
Intake 202°; Exhaust 205°; no overlap -> intake opens 2° after exhaust closes;

7A exhaust on 3B/ABY/AAN:

TIMING:
Intake opens 3° after TDC, exhaust opens 42° before BDC

DURATION:
Intake 202°; Exhaust 213°; no overlap -> intake opens 12° after exhaust closes;


This means that:

1) as a matter of "TIMING" RS2 cams are designed to give best flowing efficiencyes at lower rpm compared to 3B/ABY/AAN. High rpm efficiency is however ensured by a higher exhaust lift of 9.5mm instead of 8.6mm (and by the higher flow and boost rate of the RS2 turbocharger). I belive RS2 cam settings where designed to have best compromise between low rpm and hig rpm performances.

2) using a 7A exhaust cam with a 3B/ABY/AAN intake cam, timing will be the same but you'll have 10.5mm lift instead of 8.6mm which is a sensible difference in final EFFECTIVE FLOW which will more likely be usefull in the higher rpm. Since timing is not changed there are no changes in efficiency rpm ranges.
Compared to the ADU cam you'll have more high rpm efficiency but will have less low rpm torque.


Marco

Damn good post

[A80Avant]

well obvious difference would be best if i had a remap after the change.safe side of not going lean as well.

[Jamo]

I reckon you may be able to measure the difference without a remap and gtech.

[A80Avant]

i may have to be a guinea pig then.
unless i get a straight answer from MRC or something....or an answer at all for that matter.