So, a member here and I were talking about the cobalts low compression. Without much details I assumed that this is why we're boosting so much. Back in my Honda days, boosting what the cobalt does is car suicide.

But from what I understand higher compression is better to an extent. So wouldn't it be better to just add maybe a 10:1 ratio instead of all these other mods while keeping the same stock parts?

I'm not car savvy this is all just uneducated talk, but if someone can educate me that'll be great.

Thanks

Well like the RSX compression ratio is like 11:1 and I hear people boosting like 5 PSI and getting like super high gains. It seems like a higher ratio reacts better to mods. Correct me if I'm wrong, but doesn't that seem more efficient?

 

I'm not car savvy either when it comes to Hondas, but this is my opinion,
Say it with me, direct injection, direct injection, direct injection. This is why you can run the boost relatively safe on our higher compression motors. I believe the new Taurus sho is running like 10.1 compression (might be 10.5:1) ratio with dual hair dryers on the ford direct injection.

11:0 compression ratio @ 5psi is a time bomb waiting to happen on pump gas. Unless you like to run some type of alcohol/meth/water injection and super high octane fuel all the time or equivelant I couldn't see your average person driving around on just 93 octane with out severe knock on something like that. I think it would have to have one bad ass tune.

 

So why can't my cobalt be 10:1? I heard the cobalt is 9:1

 

LSJs were 9.5:1, I believe the LNF is over 10:1.

The K20 in the RSX you mentioned is also a much more efficent motor out of the box, so when you pump a given amount of air in, it makes more power. They are getting nearly 200whp out of almost stock N/A 2.0L engines, boost setups can be around 500whp on a stock block at under 20 psi.

 

LNF is 9.3:1 i believe Joe.

 

They went down?

I dunno, LNF's are boring

 

Yup, i just know it's lower than the LSJ

I agree, LNF's make power too easily.

 

The LNF is 9.2:1

https://www.cobaltss.net/cobalt_ss_turbocharged/

 

There you go. I was close.

And the only way to up your compression is to either;

A. Shave your cylinder head (not recommended) or,

B. New aftermarket pistons.

 

Wikipedia says it's 9.2:1

That's quite high for a factory turbo engine considering many FI engines generally have around 8.0:1. A turbo is essentially an air compressor. So, instead of going through the trouble of swapping pistons, why not just increase boost?

 

Thinner head gasket, but the stock one is only .027" thick, so there is not much room there

 

If you pour some water into the spark plug holes, you can up your compression ratio. Let us know how that goes.

 

lmfao

 

You can stop up the cats, too.

 

Actually, you'll bend the rods a little and lower the compession

Did that when we hydrolocked my boy's accord. Twice. Still runs like a champ, but i'm betting the compression is lower now. I tell him to boost it, but he won't

 

He asked for higher compression ratio with stock parts. I'm just here to help answer that question

 

You'd be very very suprised they do this on a daily basis I have a friend on 12psi T3/T4 60 trim RSX. The car is daily driven on 93 octane and sees no knock whatsoever. Hondata makes life easier. timing is key.

 

Interesting,
What power is he putting down, because a lower compression engine will let you run more boost and timing with less detonation. I mean seriously if hes getting timing yanked out the butt using 93 octane, then hes not going to be close to running what the setup is capable of compared to a low compression motor running more boost.
I'm by no means an expert on hondas, I do known they have a huge aftermarket available, just kind of applying logic from when I had my DSM and my current mitsubishi turbo project.

 

Yeah, the LNF is 9.2:1 .

There was a thread a while back about people asking about running more boost versus upping the compression ratio. After some research we found that it was better to run less compression and more boost than more compression and less boost.

That being said, you would be best off going larger turbo, to take advantage of the larger flow and cooler air at that psi. It would also help to do some work on the head/manifold to free up some flow.

I wouldn't advise boring to get more power, because there just isn't that much material to bore without weakening the sleeves. I would also advise again stroking it, because that would also be upping the compression ratio while also increasing friction.

 

He made 347hp and I think like 260tq once the tune was done and timing was conservative but not to a point where the car ran like crap. The tuner even said he could of had another 5 degrees in it, not to mention the car spools so quick.

Its not uncommon to add a little bump in compression to pick up some ponies but there other benifits as well. Quicker spool up, off throttle response increased.

 

the lack of compression is why most turbo 4cyl make zero tq... i know of a ton of people who have done B18B motors in hondas with over 10:1 compression and turbo... car made 300hp on 93 pump gas and made 300tq as well... its all in the tuner. 9.2:1 is okay for a turbo but its actually pretty freaking wimpy for a direct injection motor...

look at what all of the supra guys are doing now... look what all of the guys on TheTurboForums are doing now... if they are fast its high compression and turbo...

 

Higher compression engines make good power when boosted but it has to built well. Hondas run low boost because the engine components aren't beefy enough. Hondas are well balanced engines that's what makes them smooth and drivable. If you have a high compression LSJ/LNF, the drivability will suffer.

 

Considering a higher static CR is interesting, but think about how touchy our cars are with respect to knock retard. Do you really want to go through the trouble of making it high comp/high boost and deal with that tuning, when you could just get a higher flowing turbo and have far fewer headaches?

On a side note, there are plenty of pump gas turbo/sc'ed LE5s out there with 10.4:1 compression. They make relatively good power on low boost.

 

Not to mention few have messed with other tuning options outside the of the usual 3. Where as most of the other cars mentioned are usually running some sort of standalone fuel management not restricted by the parameters of the te stock PCM.

 

Ok so one of you people that think running more compression will be ok on the stock LNF do it and come back and let the rest of us know how good it went

But don't come back in here with some weak sauce crap like going from 9:2.1 to 9:5.1 (that would be to easy) I want to see some 10:0.1 or higher.