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it was knocking a bit in the transition around boost, so...
on the trip home i just kept pulling timing out of the area where it was knocking, 2500-3000rpm, right around 0 boost, kind of a strange place to do it. i ended up pulling a ton of timing and not really helping.
its a weird place to get knock, and i'm not 100% sure its from the engine either, there are some stretches of road that are bad enough to trigger a knock warning (!).
first order of business was to pull the strut bar, the IC pipe hits it at some time, and that totally could be knock, but it made no difference. i was kind of stuck, i had started with a map that should be fine. as usual i did some reading, and the PFC is weird.
The stock ECU defaults to being rich, and while we think of the PFC as a stock ecu, it defaults to just doing its thing. the PFC is weird, it has a base map, tuned to 14.57:1 afr and then a correction map tuned in a percentage of that (12:1 afr / 14.57 = 1.214). if you look at the correction map, the PFC is tuned to about the same AFR's as a stock ecu, but if you go look at some dyno sheets, it doesn't hit the AFR targets (unless the car is stock maybe).
https://www.rx7club.com/3rd-generati...added-1104322/
the PFC is added to a car with intake, IC and full exhaust and its running right at 12:1, even though the target in the correction map is like 10:5... this got me to thinking that while my turbo is probably smaller, maybe it works really well in the ~2500-3500 area? the PFC is weird, partly due to the different units in different screens. boost is in kg/mm or PIM or voltage depending on the screen you're in. after really looking at the dyno charts i decided just to add fuel by rpm, and in the 3000rpm range adding 15% has helped a bunch. it still has a knock warning, but just barely, so i need to go to 20% and see what it does.
concurrent with that i reset the thing. the PFC does an idle learning thing (i wish it had a flag to tell you if it was working or done..) and i've learned that if the PFC can't reach the targets that are set, it freaks out and stalls and surges and does other strange things. for whatever reason my car with the idle controls off and unplugged idles around 780rpm, so if i leave the idle set to the default 730, it runs bad (it can't hit its target). this time i let it relearn at 800, and it is happy (so i'm happy). the fuel cut settings take a little fiddling, but since the idle relearned at its target rpm its pretty close. also all the throttle transitions are better, the car has really never driven this well, i've made a big step forward in wanting to drive the car.
Re Targets and the PFC, i raised the F/C rpm and the idle doesn't stick as high for as long, i think i'm at 1180rpm Arghx's magic number. i had it lower and the idle was higher, before settling down to 800. weird.
i've done a bunch of testing for the knocking, and its related to engine RPM, at idle knock is zero, but at a steady 3000rpms its like 45, maybe bad lifters?
first thing was to try another knock sensor, for no change
second was that since i need to run a short extension to plug it in, i rerouted it so it goes away from the alternator and ignition
third was to actually ground the shield. these two made a difference, it does read more betters.
next was to take the belt off, no change, so its not the air pump, alternator or water pump.
then i put the stock pulleys back on it, i think that helped a little. in theory more mass helps
i had noticed that the car makes some funny squawk noises when its cold, and while its warm its fine, but if you're under the hood, the brake booster check valves makes a funny noise, so the next step was to disconnect the brake booster, for no change
after that i decided to see what the vacuum signal to the fuel pressure regulator is like, the hose is maybe not as straight as it could be, but its fine
then i took the IC pipes off, again no change, but the BAC valve makes a wooooooooooo noise. i forgot to see if it makes that noise at ~3000rpm but kind of doubt it.
after that i got a big screw driver and touched various parts of the engine and put it to my ear, the knock sensor IS picking up noise, obviously i can't put the trans in gear, push the clutch rev the engine to 3000 AND put my ear to the knock sensor, but it sounds like a trans bearing? or ???
the good news is that when i shook the exhaust it made a rattle, and i found that one of the mounts had a bolt that was tight, but it must have had some junk on the threads because it wasn't in all the way, so the washer that holds the rubber hanger could rattle. cleaned the threads, put it back and the rattle i thought was inside the car is gone, so now its really quiet soooooooo much better!
i switched gears, and i did some leak checking and the turbo failed. when i put it together in the first place i didn't have the any oring or seal between the backplate and the compressor cover, and well its not optional
it actually turned out the carbon seal was bad. i'm also pretty glad i took it apart, the rear bearing was all coked up (its from the 80's...)
i bought the G-Pop Shop kit, and next time, i think i can do better, but the good thing is that the washer/drier make a good workbench
so everything got cleaned up and i would say its actually rebuilt now instead of a bunch of leftover junk thrown together.
i also fixed all the little leaks which is great. it seems like its more responsive, but somehow i have the only S4 turbo on the planet that doesn't boost creep...
car runs really nicely now, its fun
next is some tuning, or more accurately verifying that the ECU is actually hitting its AFR targets
This is dumb, since Wonderus Bread has been rebuilding his turbo, i asked if he could test his the same way i was testing mine. when i went to school the only turbo stuff they taught us, is if it doesn't make choo choo noises its bad, replace it.
so while its simple and comes right apart i really don't know how its supposed to go or anything like that. after some back and forth, i noticed that i had the carbon seal installed
BACKWARDS.....
so i yanked the turbo flipped the seal around, put it back together and boost response is WAY better. it hits the same boost, around 6psi, but instead of being laggy, its pretty instant.
i also ditched the gasket between the compressor and backplate and went with sealant, it kind of looks like that is how the factory did it.
the seal and the collar were like that, so the sealing was being done (or not) by that little lip on the spacer. also the whole thing was too tall, and the turbo didn't spin right
with the seal the right way, the flat bit on the thrust collar does the sealing and it spins much nicer
so sorta happy, the end goal is to have a car that is FUN, and the quick response is pretty neat. i guess this was a step backwards, but the forward progress was pretty big!
this was going to be a totally different update, next is to resume leak testing the intake, so far its been like a colander..... and then the parts i overnighted from Japan came in
so i yanked the turbo flipped the seal around, put it back together and boost response is WAY better. it hits the same boost, around 6psi, but instead of being laggy, its pretty instant.
i also ditched the gasket between the compressor and backplate and went with sealant, it kind of looks like that is how the factory did it.
the seal and the collar were like that, so the sealing was being done (or not) by that little lip on the spacer. also the whole thing was too tall, and the turbo didn't spin right
with the seal the right way, the flat bit on the thrust collar does the sealing and it spins much nicer
Glad you got it sorted out I actually broke my (brand new) carbon seal by putting the little collar UNDER the backplate before installing it. Which was especially foolish as I took video of the disassembly for later reference, then failed to actually watch it before putting the turbo back together...
Out of curiosity, do your new bearings from Gpopshop also not have the groove on the outside? I don't think it actually matters, but I noticed it when putting the new ones in.
Out of curiosity, do your new bearings from Gpopshop also not have the groove on the outside? I don't think it actually matters, but I noticed it when putting the new ones in.
yeah they are just plain, not sure if it matters, but i like the groove ones better.
next time i'm just buying somewhere else, i've found the bearings and the seal at amazon, for like $20... 410775-0001
carbon seal is 409695-0000.
yeah they are just plain, not sure if it matters, but i like the groove ones better.
next time i'm just buying somewhere else, i've found the bearings and the seal at amazon, for like $20... 410775-0001
As far as I can tell the bearing itself also spins freely in the bore, which means that the groove shouldn't matter because the different oiling holes are rotating around anyways. But I also like the groove better, it's a bit of an unusual choice to not have it. Although all the aftermarket bearings I see online also omit the groove.
The service I got from Gpopshop was great and the price is not bad all things considered (since you also get a new thrust bearing, o-ring, collars, snap rings, hardware, etc). I'd buy again, although international shipping is killing me (my fault for breaking the carbon seal).
My wheels are weird. had i known they were weird i would have gotten something else
The Volk GR-C's are neat wheels, but just about every part for these wheels is special, which makes finding replacements or missing parts really hard.
The wheels, in a 5 bolt pattern are 5x100, and they use an adaptor to make them 5x114, which is weird. 5x114 to 5x100 is a tough thing to find, usually people are going the other way. (they are out there though)
i had found some spacers, at great expense, but a few months ago a full set in the correct offset (probably) with the hub centric rings came up for sale.
this lot in fact;
i had the presence of mind to realize that i'm the only person on earth who was interested and bought them, and after many months (since November?), i got em
the adaptors and stuff were exactly what i wanted, but the little wheel spacers have to be
The most JDM Part ever
Its a 1mm wheel spacer. its almost like a prank....
so of course i put them on, and i took some great pains to make sure the witness marks lined up
so the car went from 13mm in the front and 27mm in the rear to 14mm all the way around.
the wheels were a little too far out in the rear and i was hoping it would help turn in but honestly i can't tell a difference.
the hub centering rings helped though, so it was worth doing.
The wheels, in a 5 bolt pattern are 5x100, and they use an adaptor to make them 5x114, which is weird. 5x114 to 5x100 is a tough thing to find, usually people are going the other way. (they are out there though)
i had found some spacers, at great expense, but a few months ago a full set in the correct offset (probably) with the hub centric rings came up for sale.
not much to report, the funny bit. when i put the PFC in, it was really obvious that the intake temps were kind of high, and after looking at the space i put this piece of cardstock in between the radiator and filter.
i wasn't expecting much, but it dropped intake temps like 10c!
i mentioned it to my race car buddy, Mr Lo, and he gave me a piece of the stuff he used on his S2000. i don't know what its called, but its 2 thin sheets of aluminum with plastic in the middle
its really easy to work with, and really light, so its great there, but i think it raised intake temps 10C!
i think my next step is to replace the air temp sensor, probably with a faster one and probably in the intake elbow. i think my setup may have a bigger temp swing than the stock stuff, it should anyways, i've got the biggest intercooler you can fit in the car...
part 2, the wheel spacers didn't make a difference, but the hub centric rings did! (i think my beef with the handling is now just the steering effort, its too high)
part 3 i've just been slowly tuning it with the commander. i got my tuning laptop out, and its OLD, all the batteries are dead and can't seem to figure out a way to get the tuning software onto it! so i've just been tuning with the commander, and its turned out that the engine is noisy, but it after that the knock actually was knock. i've actually heard it. its also turned out that my setup seems to be quite efficient at low boost? to get the AFR's where the target is i'm adding 17% fuel in boost. its kind of weird that in vacuum it hits the AFR target right on the nose, but tip into even 0 boost and it was super lean. so i've got AFR's where they should be (about 11 at 6psi), and then its still knocking a little so i've been pulling timing and i'm getting there.
its odd how the PFC map is fine on a stock FD (my friend did 342rwhp on it!) and my car is just way off, even though i've got a stock engine/intakes a worse turbo, small exhaust at less boost.
i'm debating weather to put colder plugs in it, or to keep pulling timing.... or both i guess.
i mentioned it to my race car buddy, Mr Lo, and he gave me a piece of the stuff he used on his S2000. i don't know what its called, but its 2 thin sheets of aluminum with plastic in the middle
Seems to be some sort of signage material. Alumalite is a popular one for DIY aero devices, but that uses a corrugated plastic core instead of solid
i had a brain-wave last night, and took the 10psi timing row, and put it to the 6psi row, and things seem better, fewer knocks, there are still a couple of bad cells, but most of the map actually runs great
the back of the envelope says i'm making about the same hp as a stock FD, 6855rpm, 11:1 AFR, 6psi, 75.8% injector duty... 88c water temp, air temp was ~25c, but it was like a 5c night. 21mpg too, so i'm close
another cheap way to drop IAT would be to wrap your charge piping with header wrap. just get some of the no name stuff on amazon. that aluminum loves to soak up heat.
another cheap way to drop IAT would be to wrap your charge piping with header wrap. just get some of the no name stuff on amazon. that aluminum loves to soak up heat.
yeah that would work too. i should take a picture, the problem is kind of obvious. i put the Taurus fan all the way to the right, and bolted it to the radiator with the stock holes. on the left i made brackets, but there is ~2" of radiator not covered by the shroud, which is just going right into the intake/ic pipes...
so i finally got the Laptop, Datalogit, and FC Tweak up and running and the car has never run better.
of course i've run into the usual problems, FC Tweak gets mad at me because my logs aren't long enough, but like our roads are so bad the USB plug falls out of the computer!
also the computer is annoying, as they tend to be. one of my logs was cut short because the computer just went to sleep. the setting in the thing was for it to stay on for 5 hours, but i guess 5 hours in computer time is like 18 minutes....
the other thing it likes to do is to not use the USB driver for the USB cable, and instead use some default one that doesn't work. its semi random too, so once in a while i just have to delete the driver, and then it goes oh this one? my DD computer is a Mac, and like this kind of nonsense just isn't a problem. when you plug stuff in it just works.
the car really has never run better, and i'm being like the worst tuner ever, i just take a log, and hit the auto tune button and just approve everything, lol the FC Tweak does some filtering of the knock data, and the PFC is logging knock in the 100's, but the highest i've seen in the FC Tweak is 41 (it pulled 1 degree of timing from 1 cell, lol). i must have a mechanical issue somewhere, although not sure where. i'm wondering if its like the springs in the clutch disc or something.
in other news the i've now tested the cardboard intake shield, the alunite one, and nothing, and the cardboard has done best. not sure if its the shape or that the aluminum conducts heat or what
Since i had to piece the interior together my door panels were from a convertible, and this was ok because they were door panels, and they were even the right color.
but it did bug me that they weren't the "correct" T2 ones to match the seats. they pop up for sale on YJA pretty frequently, but it was always the shipping that was gong to be the trouble.
the size limit is 1.05m and the door panels are just about 1m, so its really close.
these guys popped up and i did some measuring and some thinking and just bought them. i think the pair were $67? or $87? cheap!
they get to Buyee and i get an email, hey your junk is here shipping is $584, let us know what you wanna do.
i asked if they could rebox them, and they said sure but it will be 500Yen ($3.88), sure
shipping drops to $150 each and a few days later i got this:
then this:
the car was totally in an accident (maybe a while ago, the left door panel had glass in it! and the light was not working)
the pics don't really convey how much the interior is "just right" now, but it is.
my buddy gave me the Colin Chapman biography, the Lotus symbol you see down there, and so far its done a lovely job of holding the tuning laptop....
11-17-21, 08:53 AM
