25/30 Cam Timing

[AngryRB]

Hey this might be silly idea but Im curious, what if you did a comp test , then did the adjustments would the right adjustment raise its compression the highest?

Edited March 18, 2015 by AngryRB

[Ben C34]

Hey this might be silly idea, but what if you did a comp test , then did the adjustments would the right adjustment raise its compression the highest?

Its not as simple as that.

Overlap will lose compression when testing like that, but raise the dynamic compression ratio higher in revs and make more power. Cam shafts and timing are crazy technical, mixed with black magic and heaps of guessing and testing to get it optimal.

Also depends what characteristics you are chasing.

[XKLABA]

Hey this might be silly idea but Im curious, what if you did a comp test , then did the adjustments would the right adjustment raise its compression the highest?

A comp test tests part of the dynamic comp ratio but only tells you half the story, simple advancing the intake cam alone will give you a higher psi reading simply becuse it closes the intake valves sooner increasing the compression stroke lenght increasing the volume that gets compressed into the same area and due to the cranking speed used to do the test changes the VE

The best way to test and tune cam timing changes is on the dyno where you can see the slightest changes in a controlled repeatable evironment

[iruvyouskyrine]

Okay so it goes back on the dyno to play with cam timing on Tuesday.

I think I will just start by doing what GTRPSI said as that should give me a good basis to work from.

Any other ideas/feedback appreciated [emoji4]

[lcxu105]

Results?

[iruvyouskyrine]

Result was spending 6 hours chasing a missfire that proved fruitless. Cam timing didn't even get touched unfortunately.

[AngryRB]

spot of bad luck hey, 6hrs is alot, any ideas what it could be?

[iruvyouskyrine]

Well if bet my left nut it's not electrical. Did absolutely everything myself and tuner could think of but still no avail. Thinking it could be a leaky injector seal or something similar.

Out of rego at the moment anyway so I haven't touched it yet.

Missfire started at 5500rpm and continued from there. Still make 340kw on 17psi with a safe tune to account for missfire only revving to 5500.

[Piggaz]

Valve float?

[iruvyouskyrine]

Jez did question it (running standard cams/springs/etc) but we both felt it was electrical in nature and tried to pursue that. Ran out of time in the end but will go back and try and suss it out.

What other ways does valve float manifest itself?

[Piggaz]

Try running it up at lower boost and another run with more boost early on. If it makes it to say 7000 rpm without the "miss" and then when you give it more boost it happens at say 4800 rpm, good chance it's that.

I've had the same issue on my own car and it turned out to be float. Sounded like a missfire.

[iruvyouskyrine]

With 7psi gate spring it make 295kw on 14psi revving to 7krpm. I then put a 14psi spring in and went back for retune and minimum boost we could run was 17psi and it started missfiring, another thing, it seemed to get worse with heat soak, the more runs back to back the earlier it would start doing it.

[dave1200]

sounds like coil packs or plug gapping issue.

What gap are you running?

[iruvyouskyrine]

Tried 2 known good sets of splitfires, and brand new BCPR7ES starting at .8 and working down to .55

Definitely not an issue with ignition. Started at 14.3V and dropped to 13.8V when miss started.

[AngryRB]

Hope you get it sorted, i'm looking forward to seeing what the beast puts out, 340kw's is great so far

[iruvyouskyrine]

Getting some D585's and a 5 port boost solenoid and going back for retune so hopefully should have some results soonish with a bit of luck.

[AngryRB]

how will you determine 4degrees on the intake cam?

Do you think the stock cams will do much being adjusted, im thinking the RB30 would love more beefy cams as you have higher comp and a bigger pump..

Edited January 9, 2016 by AngryRB

[iruvyouskyrine]

By moving it the same amount as the exhaust cam, I have marked the standard intake cam gear so have a reference to work with.

Yes aftermarket cams would make considerable difference I would imagine. But my standard baby neo cams seem to be doing quite well at the moment. Trent from chequered tuning has made over 400kw on standard neo cams so not looking like they will be a restriction.

Plus $700 buys a lot of tyres so the dollar/fun ratio isn't high enough for me to justify spending that much on some wobble sticks. [emoji4]

[AngryRB]

Will be interesting to compare our graphs later on, how much boost you planning to run or do you wanna max out the SS?

[lcxu105]

Any updates on this yet?