Auto R34 Pinging On Gear Change

[so_tred]

I've got an auto R34 with the usual mods...full 3" exhaust, fmic, hks evc, safc II & apexi itc.

It was making 200rwkw on 10-11psi. (this was with the apexi itc not installed) the tuner had advanced the timing at the CAS. It was getting a knock during gear change (when pushing it) for a split second (would show up on the safc) had a reading of 150+. Wouldn't knock at any other time.

Long story short, the itc has been installed but the tuner says that it doesn't seem to be changing the timing as much as it says (i'll check this soon) so it was still knocking when I got it back. took the car back again, took timing out from the CAS and the knock has disappeared but the power has gone down to 180rwkw.

I'd like to get it back up to a higher figure. It's just this issue of the standard ecu adding that little bit more timing at gear change on top of it already being advanced. What's my way around this?

Is the itc not the best option? would an e-mange ultimate be better...?

[KiwiRS4T]

I've got an auto R34 with the usual mods...full 3" exhaust, fmic, hks evc, safc II & apexi itc.

It was making 200rwkw on 10-11psi. (this was with the apexi itc not installed) the tuner had advanced the timing at the CAS. It was getting a knock during gear change (when pushing it) for a split second (would show up on the safc) had a reading of 150+. Wouldn't knock at any other time.

Long story short, the itc has been installed but the tuner says that it doesn't seem to be changing the timing as much as it says (i'll check this soon) so it was still knocking when I got it back. took the car back again, took timing out from the CAS and the knock has disappeared but the power has gone down to 180rwkw.

I'd like to get it back up to a higher figure. It's just this issue of the standard ecu adding that little bit more timing at gear change on top of it already being advanced. What's my way around this?

Is the itc not the best option? would an e-mange ultimate be better...?

The auto ecu normally cuts back the timing during gear changes so it shouldn't be that causing the knock. The SITC should be fine for your purpose. Has it been wired correctly? (Full instructions here with my apologies if you already know all this http://www.skylinesaustralia.com/forums/Ap...imi-t80642.html Should be easy to check at idle if you advance the Sitc 10deg that should show up with a timing light. (A bit harder under power). See if you can swap out the SITC with a known good one (seeing that I assume yours is second hand since they are no longer available new to my knowledge).

[so_tred]

I thought it advanced the timing during gear changes? That's just what I understood from somewhere else who I've spoken to. I could very well have been mistaken but it just kind of made sense as to why it would knock only during gear change.

The SITC is wired in correctly (I presume..?) I'll definitely have a look and see if it changing the timing under idle. I guess that will answer the question about whether it's working correctly or not.

edit: it does seem like it retards instead of advances the timing during gear change so there goes all my hope

anyone else have any ideas why it would only be pinging on gear change..?

Edited August 22, 2008 by so_tred

[666DAN]

I thought it advanced the timing during gear changes? That's just what I understood from somewhere else who I've spoken to. I could very well have been mistaken but it just kind of made sense as to why it would knock only during gear change.

The SITC is wired in correctly (I presume..?) I'll definitely have a look and see if it changing the timing under idle. I guess that will answer the question about whether it's working correctly or not.

edit: it does seem like it retards instead of advances the timing during gear change so there goes all my hope

anyone else have any ideas why it would only be pinging on gear change..?

Its probably the SAFC hearing stuff on the change, I can get relatively more noise on a WOT change...it's not knock though, the SAFC may not filter the signal from the sensor well enough and indicates it a high knock instead.

[so_tred]

That's what I was told by the first tuning shop that took it from 180rwkw to 200rwkw.

The only thing is that it never used to get a high reading before.

Could that be explained by the jump in power therefore the transmission being a bit rougher getting into gear...?

If I check the plugs will they show signs of damage if it only happened maybe.. 20 or so times for that split second?

[666DAN]

You need to run it side-by-side with a proper knock detector on a dyno, if they don't hear anything but the SAFC does...ignore the SAFC to the point it's indicating.

With my one '125' is where knock is being heard....I get ~70 at WOT, but on WOT gearchange 100 I'm putting it down to engine noise in general

[so_tred]

Dan,

Do you get those readings on an SAFC or another device?

If it's an SAFC it gives me a bit more hope.

I asked the first guys who tuned it to 200rwkw how they were listening to see if it was knocking or were they just going by the SAFC. He told me that they had a guy in the engine bay with headphones listening & a guy at the back watching the exhaust to see if it blew smoke. I'm guessing they didn't hear a whole lot because he told me to disregard the SAFC's reading at that point.

I'm just afraid if they're wrong then my engine going bang.

I mean, what else is happening at the point where it's changing gears? Over fueling for a split second?..

Edited August 23, 2008 by so_tred

[666DAN]

I'm using a tuned-frequency knock detector, not an SAFC.

Well most of my WOT gearchanges are when the rev-limit is kicking in, so a lot of popping/flaming/overfuelling and ignition cutting going on, normal gearchanges I'm not seeing much of anything

[so_tred]

Mine would tend to get the reading when I wasn't hitting rev limiter..close to it but not quite.. always over 6,000rpm though..

But same, I don't get a reading on 'normal' gear changes. Only full boost, WOT..