GTR Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
8,804 Posts
Discussion Starter #1
I gave the car some beans tonight - she is running VERY quick this week. I wonder if it's the recent tank of gas I got (probably not), but the car is now producing a single HUGE knock spike at 7500rpm in 3rd gear (keeping me from going to 4th under boost), 1st was 38, the 2nd 56...I haven't seen knock values remotely that high on my current engine build. Through 2nd gear and 1.88bars boost the knock graph stays around 20 and flatlined, then in 3rd rises a bit then spikes.

Maybe I got some crappy gas. Maybe I need to pull timing.

Anyways...I checked my oil pressure peak value because I noticed the needle swing hard while revving. Turns out that at over 7500rpm, I am pushing over 9 bars of oil pressure (aftermarket gauge in stock sender position)...is it possible to have too much oil pressure? Is my Tomei simply flowing mad amounts of oil near redline, or should I start worrying myself over this high pressure being indicative of reduced flow just when it's needed most?

Oil pressure normally hovers at 6 bars off idle and pretty much straightaway starts bouncing off the 7 bar relief valve in normal low-boost driving. Keep pushing and the oil seems to hold the relief valve open and climbs to 8 bars, then 9, then 9.8...
 

·
Registered
Joined
·
411 Posts
at least its high and not low lol. prob just a stuck relief valve or a bad sensor. doubt theres a blockage somewhere since its not always high
 

·
Registered
Joined
·
1,122 Posts
too high can be just as damaging as low pressure

i recon one of 2 options here

1, a blockage some where in the oil system (maybe some sludge in the pickup pipe or similar)
2, a faulty sensor/ wire fault

is there a manual pressure guage you can temp fit and go for a run, just to compare the two readings (this will either confirm or rule out a faulty guage)
if there the same, id recon a good oil change and new filter, when you have the sump plug out and it's fully drained pour in a cup full of clean oil and get under the car with a clean container and catch the oil for inspection (will flush any crap out that is still in the sump), this will tell you if there could be a blockage (oil will be very thick to the touch)

i wouldent recoment useing the car too much till you get to the bottom of it, there not exactly cheep to rebuild (as im sure you will know)

hope ive help'd mate and good luck
oh and keep us posted if you find the fault


alex
 

·
Registered
Joined
·
6,794 Posts
Toby.

Have you ever posted a thread where you HAVEN'T had a problem with your GTR? :eek:

Maybe it's long overdue a good mechanic to sort out all of the "issues"? It sounds like it could be a real nice car when it's running 100%.

:)
 

·
Registered
Joined
·
1,206 Posts
mate everyday it's a new problem ..try not to be so anal about everything you'll drive yourself crazy ..!!
from your previous posts it seems you are always altering the map i just wonderd why ?
i like most people on here (i imagine) have never felt the need to touch the map ...the car can't possibly run different from one day to the next
i live in a very hot country like you and my 32gtr runs perfectly well in the scorching hot weather ..you need to get the car mapped on a rolling road or live road mapped then leave it alone . just my 2 cents !!
 

·
Registered
Joined
·
8,804 Posts
Discussion Starter #7 (Edited)
Toby.

Have you ever posted a thread where you HAVEN'T had a problem with your GTR? :eek:

Maybe it's long overdue a good mechanic to sort out all of the "issues"? It sounds like it could be a real nice car when it's running 100%.

:)
it's an old car. I am a perfectionist.

yeah there are little niggling things, but tonight I went out with some mates, beat a Carrera GT three out of three times, thrashed a Murcielago LP640 once, but by several car lengths, and twice beat by half a car length a Novitec Bi-Compressor F430. All standing start 400m drag (don't worry Trev, we found an abandoned street and the road was barricaded off before we started). Someone had some timing gear, and my car pulled 0-160kph in 6.82 seconds - best out of the group. We're all amateur enthusiasts, so factor in our non-professional skill level compared with journalists or test drivers. (and for the love of god, I am not tooting my own horn, willy-waving, or whatever here - just reporting my evening and results, OK??? If you don't like it or think I'm a braggart, go take a 650bhp Skyline (not exactly rare nor expensive) and some mates with exotics, and you'll get the same goddamned results ffs)

So you have to understand where I'm coming from when my car has "issues" :chuckle: - it runs perfectly 100% by most measures. If I didn't constantly log all my telemetry, I would never notice a lot of things I talk about. I'd just be driving along and be blissfully unaware.

But when you're making 650bhp via turbos, power varies significantly from climatic conditions, and can be largely compensated for my map adjustments. I can feel when I'm down 30bhp, and I like being able to bring the car back to full power without breaking the det threshold I maintain.

I am remapping my car for the summer. I only have a winter and spring map. Sure, if I lived in Greece or San Francisco, one map does it all. But the weather changes in Seoul are extreme enough to require a different map each season; the change in air density is enough to warrant adjustments to the boost control as well (I keep track of peak AFM voltages versus boost pressure). Anyways, my car was off the road last year, and the map for the previous engine obviously doesn't work for this engine as well. So this year is mapping time, and I should be all set for next year.

And yes, a map can be endlessly perfected as perfect power versus knock settings vary according to humidity and air temperature, which obviously varies from day to day, hell, even day and night! Race teams remap for track conditions as a matter of course; I'm not so much being anal as I am practicing and improving my ability to map.
 
1 - 7 of 7 Posts
Top