High Gear WOT???

[LilPartyBox]

In the end, just don't lull your engines. This creates the low speed, high load condition that is the main precursor to LSPI. This can happen in any gear, not just 6th. Whether your wheels are spinning at 60mph or 10mph, it's the engine RPM and load your foot presents that can cause pre-ignition. In other words, spinning at 1800 rpm at highway speeds in 6th and 1800 rpm around town in 4th presents the same danger when you stomp the gas. The thing to visualize is that you create a high load (stomp gas) at a time when the engine is at low speed, irrespective of mph.

I've reached the point where if i'm approaching a stop sign but can probably just get away with rolling through it and gassing it 2nd gear, I WON'T. I'll come to complete stop (or very close) and rev match a downshift to first to get the engine speed up. A great indicator on our cars is if you hear the symposer make this ugly fart like sound, your lulling the motor and may have just presented it with high load at low speed. Make note of the driving conditions and don't do it again. I owned a speed3 when they were popping rods all over the place and no one could figure out why. LSPI is a very real threat.

Further info on the topic of LSPI and the research oil companies are doing better define/mitigate the occurrence.

https://www.oronite.com/products/lspi.asp
http://www.infineuminsight.com/insight/may-2015/investigating-low-speed-pre-ignition

 

[LedRobster]

Isn't the better advice to never just thwomp it into WOT? I've always found in most situations (not on a FiST, but another boosted 1.6L) that rolling into half to 3/4 throttle progressively to build boost before going WOT is going to give you better acceleration that stomping down. If you're cruising at 70mph in 6th at 3K you can still ease up to 80-90 for a pass in reasonable time without even going WOT or downshifting.

Smooth is fast.

 

[Hijinx]

Isn't the better advice to never just thwomp it into WOT? I've always found in most situations (not on a FiST, but another boosted 1.6L) that rolling into half to 3/4 throttle progressively to build boost before going WOT is going to give you better acceleration that stomping down. If you're cruising at 70mph in 6th at 3K you can still ease up to 80-90 for a pass in reasonable time without even going WOT or downshifting.

Smooth is fast.

 

[IrishST]

Generally speaking I do roll into it and I only ever really go WOT when I'm explicitly trying to go balls to the wall, I just wanted to make sure I fully understood the situation and wasn't accidentally contributing to breaking my car. From this thread, and the recent information posted, I've sort of put this general guideline in my head:

1st - Doesn't matter since we're boost limited (unless you have a tune that removes it of course, then it might be different, but I don't), however WOT from the jump in first is just going to cause a lot of wheel spin so roll/feather first is better anyway.
2nd - Doesn't really matter, see above.
3rd - 2k RPM and above, go for it.
4th - 2k RPM and above, go for it.
5th - Shouldn't need to go WOT, but if I do, try to not do it below 3.5k-4k RPM.
6th - Just downshift or only go half throttle for calm passing.

I think that's a pretty safe approach. Hopefully...

 

[LedRobster]

Soooo it's confusing to apply progressive throttle as opposed to just going straight from partial to WOT in one stomp?

 

[Hijinx]

Soooo it's confusing to apply progressive throttle as opposed to just going straight from partial to WOT in one stomp?

Tell you what, go do some datalogging and report if you find a difference.

 

[LedRobster]

Tell you what, go do some datalogging and report if you find a difference.

Probably my bad for not reading all 5 pages but is the argument here that you should never go WOT (at any RPM) in 6th or that you should avoid going WOT at low RPMs and lugging the engine?

 

[MS67]

Probably my bad for not reading all 5 pages but is the argument here that you should never go WOT (at any RPM) in 6th or that you should avoid going WOT at low RPMs and lugging the engine?

I think the argument, as it pertains to this thread, is to not go WOT while lugging the engine at low RPMs. Now, if you're in the upper RPMs in 6th gear, I don't see an issue going WOT...but if you're going that fast, I think you have other things to worry about.