what could be a cause for a much higher vtc @ redline

K-Series Programmable ECU installation questions / support issues
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6spd_ek
Posts: 63
Joined: Sat Nov 04, 2006 11:46 am

what could be a cause for a much higher vtc @ redline

Post by 6spd_ek » Wed May 23, 2007 10:31 am

just want to try to get some info - currently car is making peak power with vtc of 35 @ 9000 rpm redline. everyone else has vtc much lower around 20 or so with same cams & header & IM & tb

has anyone ever seen something like this?

my peak is down from where it should be (220/166 on low reading dynapack) - right where is was with stock ITR cams

setup - k20a type R, RBC, HyTech header, Hytech stg1 cams - we double checked cam timing 100 times over (dowel test on cam pickups/arrows on cam pickups, cam gear markings all at TDC which was verified with stick test & crank position markings)

I might have loose packing in a 25" burns resonator (3" inlet with 4.5" O.D) which is being replaced but I need all the info i can get before going back to dyno again - i can't afford anything anymore b/c of this dyno'ing & redyno'ing & dyno'ing again :oops:

Razathorn
Posts: 469
Joined: Tue Jun 14, 2005 12:17 am
Location: Lenexa, Kansas, USA
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Post by Razathorn » Wed May 23, 2007 12:26 pm

Is the resonator a straight through design? If it has louvers, that can be a restriction right there. I've never seen a n/a k20 anything tune out to want 35 degrees after 7500 rpm. It's always 20 - 25, then again, I've never done a cam tune on non oem honda cams. What base map did you start with and how was it tuned before cam angles were hunted for? Was fuel and ignition tuned out on each 10 degree cam increment?

Do you have a datalog and calibration I could look at?

Wayne
2003 black RSX type-s / jrsc @ 12psi / methanol injection / aftercooled

6spd_ek
Posts: 63
Joined: Sat Nov 04, 2006 11:46 am

Post by 6spd_ek » Wed May 23, 2007 12:38 pm

the resonator is BurnsStainless - ultralightweight... no louvers the inside is 3" straight thru (we removed it) to inspect it but we did not take it apart to inspect the packing (which i will be doing shortly)

my calibration is posted in calibration forum (under hytech cam calibration) http://hondata.net/forum/viewtopic.php?t=6358

we originally had ending vtc around 25 with a/f tuned - the more advancement we removed the more power went up (up to 35vtc)

I was wondering if the packing was loose & exh is hitting a 25" long space with 4.5" diameter thereby obstructing velocity if that would be a cause for it liking a higher vtc

obviously i need to do more dyno testing but just wanna have all my ducks in a row b/c I can't afford this anymore (exedy stg2 clutch broke last week :roll: ) BTW we did compression & leakdown & results where 260psi & 0 respectively across the board

6spd_ek
Posts: 63
Joined: Sat Nov 04, 2006 11:46 am

Post by 6spd_ek » Wed Jun 06, 2007 8:56 am

ok - i am going to datalog some runs tonight or tomorrow

but I have some other questions - how can one tell the crank sensor or TDC (cam) sensors could be going bad or malfunctioning without throwing a code?

Garrett_si
Posts: 238
Joined: Wed May 17, 2006 9:49 am

Post by Garrett_si » Mon Jun 11, 2007 7:40 am

Razathorn wrote:Is the resonator a straight through design? If it has louvers, that can be a restriction right there. I've never seen a n/a k20 anything tune out to want 35 degrees after 7500 rpm. It's always 20 - 25, then again, I've never done a cam tune on non oem honda cams. What base map did you start with and how was it tuned before cam angles were hunted for? Was fuel and ignition tuned out on each 10 degree cam increment?

Do you have a datalog and calibration I could look at?

Wayne
I tuned a K20z3 this weekend

and I finished at 30 from 8000 to rev limit

could you help me to see how to reach better power at 20-25 Vtc degree?

I could post the map and the datalog

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