Start Of My 1.8l Turbo System

[SonicBoy24]

I thought our CR was 10.5:1

 

[River_Rat]

I thought our CR was 10.5:1

You are correct. The CR for the 1.8 is, indeed, 10.5:1. Perhaps Preloader forgot that he was posting in the 1.8 thread. The 1.4 does have 9.5:1 CR.

 

[Preloader]

Hahaha. I forgot where I was...... 1.8 n/a thread. But if you're going to boost 12psi or less I'd stick with the 10.5:1.

 

[$ub$onic]

Heck old 6.9 idi diesels has 22.5 -1 compression and the banks turbo kit would run them at low pressure

 

[River_Rat]

too slow

 

[Preloader]

Lowering the CR would lose you a little low end power in an exchange for safer power at higher boost in upper RPMs. I guess if your goal is all out performance and you plan to build up the internals anyway, dropping to 9.5:1 could be desirable.

 

[mitdr774]

My plan will be to drop to about 9.5-10:1 CR with forged rods and pistons. We already have forged rods, but I suspect it was done to keep the same strength requirement but reduce mass. I doubt a stock 1.8 rod will hold up to about 300 crank HP. I would say I am still at least a year away from attempting a build due to saving up to make it happen and researching what parts I want and where they will be from. Some parts will have to be custom parts.

 

[SonicSteve]

Hahaha. I forgot where I was...... 1.8 n/a thread. But if you're going to boost 12psi or less I'd stick with the 10.5:1.

And as im sure everyone is well aware... At the 1.8s CR boosting 10 psi is a major difference...whereas 10 psi on the 1.4 and you guys would be like, well this is lame. 8-10 on the 1.8 should be pretty crazy as it is...

Since i still havent found a ton of info on our engines... the crank is nodular. Rods are forged I beams... Pistons hyperutectic? And does anyone have any ideas on a swappable piston?

2012 Sonic LTZ HB White 6Au 1.8l now Free

 

[$ub$onic]

I have been looking for a cheap or blown 1.8 to tear down but have not came across one. Well I did once but did not have the money at the time to get it.

At this time there is no internal upgrades out.

Personally I would start with 4-6 psi and go from there. Work your way into it.

 

[SonicSteve]

I plan on doing my tune live on a dyno even if i have to trailer to bnr or trifecta.. that way people who are experienced can watch over the progress whike not grenading it... As well as live tuning is the most precise and will yeild the most results

On the 1.8 for cheap... Join the club man. If you locate one that u dont want or find a goldmine in a junk yard pm me lol

2012 Sonic LTZ HB White 6Au 1.8l now Free

 

[$ub$onic]

Everyone wants 8-900 plus shipping for one.

My plans are to have the stock head flow tested for cam lift measurements

Then port it and do the same that way we have best lift measurements for both.

Then I'm going to have the cams redone and more then likely go to the port and polished head .

 

[barch88]

shouldn't be too hard to find a 1.8 motor cheap, probably 70% of sonic owners have the 1.8 - but you wouldn't know it being on this forum, haha.

 

[$ub$onic]

shouldn't be too hard to find a 1.8 motor cheap, probably 70% of sonic owners have the 1.8 - but you wouldn't know it being on this forum, haha.

Your looking at $800+. Then shipping on top of it. That's on average anyways

 

[barch88]

Your looking at $800+. Then shipping on top of it. That's on average anyways

When you think about it, that's not a lot...spend nearly that on headers/downpipe, and exhaust system alone if not more.

 

[$ub$onic]

When you think about it, that's not a lot...spend nearly that on headers/downpipe, and exhaust system alone if not more.

Very true but I don't have that to blow on a engine to tear apart to get specs for parts to spend more money on

 

[SonicSteve]

Well. I think the main issue here is we have new vehicles... In otherwords... The parts from wrecked ones are scavenged immediately for a higher dollar amount just to fix the cars that are a daily for the random joe.

However. 800$ is the going rate no question about it... Whoever gets theit hands on one first i hope they have calipers and a set of mics to give everyone some great specs... If i get my hands on one i promise ill give complete specs top to bottom.

Thirdly. I intend to build a 1.8 so i will come across one. And considering the money spent on bolt on gear.... That gear is something that has almost no effect on performance... In other words... Having full exhaust on a stock motor vs a built motor... You still have the same potential there... You dont ever change it.. that is a one time investment to have a "performance" exhaust. However, building an engine and swapping it in is a whole other topic. Considering the initial investment and all the parts for it. Were looking at more money for something that is not a single investment.

2012 Sonic LTZ HB White 6Au 1.8l now Free

 

[2THEXTRM]

Not a turbo related question, but Is a 50 shot of nitrous not an option with the 1.8L?

Sent from my XT1080 using Xparent Skyblue Tapatalk 2

 

[SonicSteve]

Single 50 shot shouldnt kill the motor. But id rather be tuned to accept a denser charge 24/7 rather than a standard tune plus a 50 shot every now and then. The motor will take it im sure but the ecm wont adjust fast enough to increase injector, cam and timing for the nos. I may be wrong someone else can chime in. But thats my knowledge on the idea

2012 Sonic LTZ HB White 6Au 1.8l now Free

 

[sx sonic]

Another member has run a 50 shot of NOS. Blew a gear thru the transmission case.

I'm with SonicSteve, turbos generally aren't as abusive to the engine and drivetrain per a given output as the explosive burst of power from NOS; or even the exponentially greater stress upping the rev limiter has on the bottom end.

 

[$ub$onic]

For a car you drive on the street I'm not a fan of nos.

For a dedicated drag car I'm all for it.

Everytime you press the button you risk a catastrophic failure and that is to much of a risk on the street for me.


The f17 is a rather weak trans compared to the m32. This is also the reason I'm not going for a a s/c or a t/c until I swap in a m32. In a automatic I'm almost positive you will be fine with a positive pressure upgrade. Not sure about nos