Originally Posted by bonfire79
thank you for your info, Sir. very glad to hear it.
so, I am getting a gauge as soon as I can. I don't think it is spiking as it sounds and boosts (spools normally, then lets off) but its hard to say. evidently, the VG20ET turbo has this dual function waste-gate where it closes and low speeds and stays open at high speeds, so I don't know if that is causing any abnormal noises or operations. this turbo looks just like a T3 (in my eyes), but it did come off a VG20ET engine, I watched 'em pull it off. and I agree, the smaller, the hotter. there is a T-3 turbo with the exhaust elbow for sale on line that I think I might get while it is available and swap out the TB250.
I'm not 100% sure if the vg20 turbo is smaller or not, I truly can't remember the specs of all of them, but i figured I'd mention it!
the rattling sound is not loud. its very subtle and only occurs when pushed hard and at very high rpms. it doesn't do it during normal take-off boost and normal driving conditions. only when I really get on it.
That would be detonation haha, definitely. When you floor it, you're getting up to 3,500 or 4,000 under boost and your NA ecu isn't compensating enough fuel and can't get enough in there. your timing is lighting off early and the piston gets so hot and the pressures are so high that it causes mini explosions as the piston is traveling upwards. I'm assuming you are running the highest level gas you can get for these tests as well, but I'm tellin you only 2 or 3 runs if it were spiking boost on an NA ecu and you could be looking at needing a complete rebuild.
I am going to adjust the timing down to around 13 like you said and see how it does. it may help with cold start and idling issue as well. I am wondering if the early turbo ECU will react well to that? (states should be at 20 timing for that one). In my personal opinion, even with the turbo ECU I would still run at minimum 3 degrees less timing than was specified for your year engine. The timing goes with the engine first. So if your NA says set it to 20, then you add a turbo, I'd run at MOST 17 ever, 15 would be fine.
I wish I could really capture the sound on it. I might try and secure my GoPro cam in the engine bay and maybe I can get a good audio of the noise. I'm not driving the car daily... just during troubleshooting and testing during my time off.
is there a good (proper to do by myself) way of adjusting the timing at idle? (not total curve, I think I need two people for that)
when I check it, I can clearly see it at 25 but as it idles, the ECU does its little auto-timing computation thing and it jumps all over. I probably need to disconnect my dual fans and aux fan and keep the a/c off to keep it steady. however, the idle-control valve wants to do its thing along with the ECU, so its tough to keep it steady. any suggestions?
To set the timing let it warm up completely, turn everything off like headlights and fans, A/c. then do your best to get it to 15-17. rev it up a few times and let it stabilize. it should still be at the same setting. if it is, tighten up the bolt and you're good to go.
if this is bad detonation and its starts to go, what are immediate signs of failure? will I know it right away, I mean will the engine just blow and start spilling smoke everywhere, or will it just shut down and stop running and not want to crank anymore? just curious.
One case is you'll sieze up the engine from pure heat, then it will unsieze and probably have very little power and blow a ton of smoke, it may never start up again after that. Another situation is blowing the headgasket, a ton of smoke. Sometimes you just blow a hole in a piston or two. other times a chunk of the piston ringland breaks off and messes up the valve on the way out and hits the turbo wheel as it goes through the manifold. Spark plugs can chip off. Rod bearings wear thin under detonation as well.
again, thank you for your info. ready for more...
Also, are you running turbo injectors or stock injectors?? If you're on stock injectors the turbo ECU will be bad bad bad. it runs less injector duty cycle because it is programmed to run the fatter injectors on the turbo model.
If you are on a serious budget, or simply just can't get turbo injectors or anything larger, you'll need something like an RRFPR (also called an FMU) 8:1 or so along with your stock ECU and that will set you up to be safe for up to 8 psi.
Basically if you just make sure you have enough fuel, and you keep the timing low enough not to pop your engine, you are in a pretty safe spot for a VG30, they're super tough. If you get yourself a wideband O2 sensor and gauge (they're around $120 USD~~) and keep it between 11.5-12.5 AFR at anything over 3psi your motor should be OK as long as you don't encounter detonation. It doesn't really matter how you achieve this, it can be with a turbo ECU and turbo injectors(best if you want good mpg, and good driveability). It can be with an aftermarket ECU and big injectors, maybe even a big ol turbo (best if you want a lot of horsepower). Or a stock ecu and stock injectors with an FMU (good if you want to keep it cheap and easy, but you will have to mess and fiddle around a lot, and you can't run high boost, maybe 10 psi).
If you get turbo injectors and a turbo ECU, some people try to stack an FMU on it when you get a bigger turbo. That can work but it's fairly complicated. Here is a website showing a lot of info about the FMU way of doing it: http s://web.archive.org/web/20150218233302/ht tp://redz31.net/pages/fuel/fmu.h tml