I wonder if this is an issue also on the 1nz...I never experienced any issues whne I put the turbo on the xB. I had suprisingly really good A/F ratios before even tuning on the dyno. The motor never knocked on me either. I never got a chance to pull the head on the block thats in the car right now, but Im curious to check out what the boost has been doing over the past 5,000 miles or so. I had a few passes on cold nights where I cranked the boost controoler up to about 10psi and had spiked up to around 13 psi, it handled it just fine, and never let loose on my once.

 

charles car ran fine on 10psi and up too. just because something runs fine doesn't mean you aren't damanaging it. the modern cylinder head designs that cars have greatly help to contain the spark and reduce detonation. We're not talking about the old Hemi cylinder heads. detonation occurs when you can't hear it, when you can hear pinging, that means you are past the point of no return. the current pistons that most manufactures are using have placed the rings high on the piston. This reduces blow by and helps with the emissions factory that everyone is worried about.

 

we are talking about a completely different motor...I am talking about the 1nz...your right when you say that detonation can occur even when not noticed, I should have made my statement a lil clearer that I have never heard any audible knocks. I have not gotten the chance to look at my internals, but I know that its a different setup than the 2AZ with higher compression, 15 degree offset on the crank and a 75 mm bore, 84.6mm(I think) stroke.

 

Exactly my point. My car ran fine on 10psi, it ran fine on 12psi and it ran fine on 14psi. All good A/F ratio's and the car didn't smoke, for a while. Then I started to notice a little bit when I let out after I'd been in boost. While driving normally, the car acted perfectly fine. In fact, I was sure that my turbo seals were worn until I pulled the engine apart. The problem that I have, is that this isn't just something I've seen on MY CAR. I've seen it on multiple cars. The timing is an issue, its now a proven issue and it needs to be addressed on all the turbo cars or this is going to be an increasingly broad problem for these engines. Im more then sure that I accelerated the problem by running more boost on my car then the majority, but its going to be a problem none the less. That was my intent all along.

Charles

 

sim:

I'm a honda guy. I deal with b16, b18, h22a's. that's the cars i tune and i can talk directly with charles about ring issues and high designed rings on a piston because it crosses all platforms. be it honda, toyota, b18c, h22a, 2az 1nz, etc etc. modern NA engines are not designed to deal with high timing, big boost just due to how thier pistons were inherently designed. pushing out 300-400whp isn't really a problem if tuned correctly, atleast for some honda stock blocks, but it becomes an issue of how much risk do you want to take.

don't get into the mindset of well it happened on a 2az so it can't happen to me. hell get out your compression testor, its a very easy way to see your ring condition. test yoru car, then test a stock car and see if there is a difference.

 

Im not saying it cant happen to me at all. Maybe you misunderstood me, I know that pushing more boost through a N/A designed motor will not yield wonderful results over time. I know what kind of damage can be done with the wrong timing, wrong A/F ratios, but that was not my point. I was running a safe tune @ 6 psi, and even when I would push it further, I would not hear any audible knocking, and my A/F ratios stayed pretty consistent. Of course what I was doing is not healthy for the motor, I knew that since the minute I put the turbo on. Its plain and simple, if it breaks, fix it and make it stronger. Thats the beauty of tuning, the more you break stuff, the more you learn and find weakspots.

 

if the timing is tuned right in the beginning, you won't have to worry if you run 6psi or 12psi. the stock ecu can get a safe A/F that has been proven. but if you don't have something to modify the ignition timing, then you can easily damage the rings by pushing it. in reality, running 6psi vs 10psi really isn't that huge of a difference on the small turbos most are running, its just compensating the tune accordingly.

 

Meaning Of Picture:

The Scion tC will always be ahead of the Toyota Supra

 

 

you mean on top or always a level above? LOL. I wish. Or maybe the tC is a step closer to heaven meaning it will die before the supra. I never even thought about the interpretation of the picture till you brough it up. Hmm. Wow I just realized this post is 10 days late.

 

hey TurboCustomz. Do you know what the tC max speed is (the one limited by gears, not electronically)?

 

No, I would imagine with the stock rev limiter it would be around 140ish. Get rid of the rev limiter and you'll get a few more mph, but its relatively close.

Charles

 

man you guys are scaring me not to get a turbo, maybe ill just go trade my tc in for an rsx type s and drive it stock muahaha ok jk but seriously what would you propose to run 10-14 psi safely on the motor what internal work, what tuning?

 

^^^why do you wanna run 10-14 psi soo bad?? Do you realize that even on 8 psi this car will scream like a bastard.

 

ic like enough hp to beat wrx srt4 and stuff, plus i want to do it jsut for doing it i want to learn how to tune cars to run faster and figured id start with a turbo, stupid question but why would it scream like crazy at 8? stis run 15-17 psi and they sound fine

 

i thought this was power hungry so far every time i post about increasing boost and hp significantly everyone tries to discourage me, when i bought this car i figured it would be a good car to mod up to about 300 whp that was the idea behind going with this car.

 

Im sorry, not trying to come off as an a$$, just trying to save you a lot of headaches in the long run, thats all. You cannot compare a WRX to a tC. The WRX can run up to about 19psi on a stock turbo/block. They are built and designed to handle this type of power output. The tC on the other hand, as strong as it is, will not handle anything close to that without doing proper internal work to the motor. I suggest you go and re read the top statements of this particular thread you are posting in, and you will see that the piston ring lands are the weak link in boosted applications. Too many kids just seem to wanan crank up the boost and are not ready to deal with the reprecussions, and that is why i tried to say that 8 psi will be enough to give you some decent power until you are ready to properly build up the motor to handle the 10-14 psi that you think you want.

 

8psi will get you close to 300whp on the tC. Good luck ever running 15-17psi on this car and keeping it a daily driver. It all comes down to tuning, STi's may run a relatively high boost but they have low CR pistons, are tuned to run on pump gas and still give relatively low emissions. EVO's run more boost than the STi but have less HP, it's all about how you use it. 8 psi on the tC will be more than enough to beat a WRX (not STi) and probably a SRT4.

 

8 psi would put you in contention with an sti. I absoutely murdered a cobb stage two STI when my car was on 10psi.

Like Jmiller has already said. You can never compare a stock boosted car to a stock NA car. Fact of the matter is once you get over 8 psi you should start thinking about internal upgrades and once you exceed 10 psi you're going to need pistons, eventually.

Charles

 

well one the evo has to run more psi seeing as to how it is a 2.0 liter engine vs an sti's 2.5 and it only has like 3 less hp or something, anyways i didnt mean i want to run the stock motor at 10-14 psi i mean i want to get a turbo kit and run it at like 6 or 8 first and have fun with that then while iam doing that upgrade the internals to handle 10-14 psi boost and then run it at that, I was never planning on beating stis on 6-8 boost i know that wouldnt happen with just boost without upgrading everything else sti are monsters my friend owns one, awd, amazing suspension, awesome breaking, 300 hp and tourqe and in nj he hopes for snow during winter times so he can have fun.anyways i guess what my point is that i want to get turbo kit run it at aboutt 6-8 psi and learn on that and upgrade it my question is what would i need to run that safely by safely i mean the car wont start dying on me and acting weird after a year of boost. and then 10-14 psi ill worry after i get to 6-8 first. I want to learn how to tune a car properly not just slap on a turbo and run it at the max psi i want to know what it takes to do it safley and iam going to be putting the turbo on myself with a help of someone who already installed turbos on other cars this is why i was considering the sc it seems like the install is a lot easier and not as complicated with tuning and stuff. I just recently got into modifying cars after I saw a moded rsx s with a turbo done properly, very nice car.