Higher Compression

[jewelproject]

Is it possible to raise the 8.8:1 compression

To something a little higher without

Tuning a pt6?

Plan to use bisi stage 1 cam and Upgrade the springs and retainers

[deevergote]

Sure. You can run a JDM H22A with 10.5:1 compression on a PT3. I mean, it's not a great idea... but that ECU will run a higher-compression engine. Run 91-93 octane gas to reduce the chance of detonation.

How do you plan on raising compression?


Honestly, though... to get the most out of your cam and increased compression, you are going to WANT to tune the ECU properly. You'll see more power gains. I don't suggest tuning a PT6, though. It's not as impossible as it once was, but unless you're knowledgable when it comes to tuning, I'd stick with a P06.

[Jack93prj]

Hey Deev sorry to thread jack, besides our classifieds do you know where I could get a pt6? I have been looking but people are asking lot for them

[Jack93prj]

Also bisi sells its 9:1 piston and connecting rod for not to expensive. That would give you your compression and reliability of bisi. and if you get some head work done and tune the ecu you would put down some nice NA numbers

[The G-Man]

Also bisi sells its 9:1 piston and connecting rod for not to expensive. That would give you your compression and reliability of bisi. and if you get some head work done and tune the ecu you would put down some nice NA numbers

You get get a piston/rod combo for pretty cheap, but it is also going to take a lot more work than just installing those two items to make them perform well and reliable.

[Joey GT-R]

While he's installing the Stage 1 Cam. He should get Bisi's High Comp Valves. They will raise his compression roughly to 9.3:1. I'm not sure why he's so adamant about not getting a P06, PR4, or P75 ECU when that route has already long been paved.

[Jarrett]

Based solely on his only post in this thread, I don't believe he's adamant. He's just not fully aware of other options.

Unless you're swapping an A1/A4 to an A6 or using the A6 cam and intake on the A1/A4, there's really no reason to use a PT6 at this point. IABs can be added to the P06 and P28 so all that's left is chipping the ECU and tuning it. It's not cheap, but modifying cars never is.

And the suggestion to get the Bisimoto 9:1 piston and rod kit is a little off base. While it is .2 points higher in compression than factory it's not considered an NA setup. Go with a piston that will put you in the 10.5-12 range if you're truly shooting for a nice NA build.

[Jack93prj]

Based solely on his only post in this thread, I don't believe he's adamant. He's just not fully aware of other options.

Unless you're swapping an A1/A4 to an A6 or using the A6 cam and intake on the A1/A4, there's really no reason to use a PT6 at this point. IABs can be added to the P06 and P28 so all that's left is chipping the ECU and tuning it. It's not cheap, but modifying cars never is.

And the suggestion to get the Bisimoto 9:1 piston and rod kit is a little off base. While it is .2 points higher in compression than factory it's not considered an NA setup. Go with a piston that will put you in the 10.5-12 range if you're truly shooting for a nice NA build.

What he said.... but would you be able to dd the car on 10.5 in the F22? I mean could he use 93 octane with out worrying about detention? Deev was saying something about it, but that was on the h22, and they come stock with high compression and could handle it easier.

[Joey GT-R]

12.5:1 and under is perfectly drivable in any application. Anything past that requires extensive tuning and/or race gas. Judging by what the OP said, he's probably not looking to go anywhere near that.

[Jarrett]

12.5:1 is NOT okay in any application. Can it be made to be okay? Sure.

A gasoline internal-combustion engine is about 30% thermally efficient. That means it can only turn roughly 30% of the energy gained from gasoline into useful heat energy. The rest is soaked up by the metal components of the engine. When you increase the compression ratio you are significantly increasing the amount of heat that the engine will create due to the increase in intensity of of combustion. If we say that only 30% of this new heat will be used then where does the rest go? Your engine components. Do not overlook the cooling system on a high-compression car. Radiators with an additional capacity are a minimum. Lower-temp thermostats, better fans and other things should be considered as well if 12.5:1 in a street car is desired. None of those things are even close to impossible. But you cannot make a general statement that says that any motor will be fine if tuned on 12.5:1. What about a turbo engine?




Edit* this was typed on my phone. So if any of you out there think the inability to communicate at the minimal orangutan levels because you're on your phone is valid, you're wrong.

[Joey GT-R]

You're killin me man, lol......Must I be so specific?

The radiator and slim fans could definitely help out, but I wouldn't go so far as to say they are a requirement. Too many cars run around N/A with neither. Especially the popular "F23 Stroker Kit" for the H22. Would I check fluid levels very often? Probably. Water/Meth would be a nice addition as well.

And there's no need to mention turbo since he isn't going that route. But there are race only applications that do run compression ratios in the 11-12s with small to mid size turbos. But again, it's not relative to his post.

[gloryaccordy]

12.5:1 is high but there are a lot of cars in the 12:1 range on pump gas

The real measure of compression though is dynamic compression which takes the effects of valve timing into account. On a stock cam dynamic compression would be pretty high... going with the Bisi would open up duration longer and lower it a little

http://en.wikipedia.org/wiki/Compres...pression_ratio

[Joey GT-R]

Agreed. And if you're running compression that high, who wouldn't throw some cams in to make the most out of that power? Since he is already on the path of installing a Bisi Stage 1, I believe he'll be fine. He'd be even better in fact if he saved a little more money and went Stage 2.

[Jarrett]

I think we're taking two different view points on this. What you're telling him is that he should be fine because it's been done many times and often without the supporting mods I listed. My angle is to try and give a more complete picture of the changes that will be going on. The OP is just some random guy on a forum and I wouldn't want him, or anyone else reading this, to act without knowing all of the variables.

As for my comment about turbo motors:
It was mainly me supporting my argument that was contrary to your absolute position. As an honorary member of the Jedi council it is my duty to respond with oppositions to absolute statements as they are indicative of Sith behavior.

[deevergote]

We're going WAY out of the OP's original focus here! Perhaps we should chill until he replies. Though I guess I did technically answer the question as far as it can be answered in my initial reply... without more info from the OP, there's nothing left to do but discuss further options.

Also, since "tune a PT6" was mentioned, I assume he meant a P06... either that, or he knows NOTHING about tuning an ECU, down to what ECUs are readily tunable...