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Can anyone tell me the compression ratio for a d17a? I read that it was 10:5:1, is that accurate? Just want to make sure I'm using the correct gas. Also, if all of the sensors were swapped from my old engine to my new one (a2 to a) hypothetical speaking, it should operate exactly the same correct? Vtec engagement and such?

 
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I'll go with whatever the Wiki page says LOL
Wiki says the D17A2 engine is 9.9:1 compression? You SURE the D17A has higher compression??? Wiki shows nearly identical HP and torque figures so I'd kinda expect the compression is the same as A2.

I suppose since it's using a knock sensor 87 octane would be safe enough.
Correct
The computer controls that, and you still use the original computer- right?

 
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To be honest, no I'm not sure the compression is higher, but anything can be stated on the internet. One jdm importer website said it was 10:5:1, another said 9:9, so I'm not really sure. Yes I used the stock computer. There's just something off though. Thought it was just the exhaust not hooked up correctly but I have checked it many times over. I'm not throwing any codes but you know when something is wrong and you can just sense it? Here are the links to those websites.

http://www.jdmsource.ca/products.php...2tat9knnkippk6

http://www.clubcivic.com/forum/threa...or-not.168201/
(Scroll down the thread to #16 post)

 
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I'm gonna go with this unless someone can prove otherwise:
Wiki shows nearly identical HP and torque figures so I'd kinda expect the compression is the same as A2.

If compression was higher, it would have more HP and torque.

HTH

 
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not sure how much is true...

and it's a EU CVT...

http://www.tradecarview.com/specific...cvt_1.7/12155/

 
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Sdaidaji, it also came in the ferio, from what I've read, but regardless the only matching info is the 130hp, so Woo-hoo a 3hp jump! Maybe I will try running higher octane fuel and see where that gets me. As for the noise, I'm thinking it's the different exhaust manifold. The old one was a 4-1 set up and this is a mock 4-2-1. Sounds pretty cool. Something else my mechanic pointed out today that I forgot was the relearn process. Ecu has to relearn my driving and the new engine. Only thing left is the vtec. The swapped the old solenoid from my old engine so it should be functioning properly, and I tested it and you can hear it click, quietly but it does click. So maybe once it's done learning it will be more noticeable?

 
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The only real learning for the PCM is idle speed and fuel trims.

If VTEC wasn't functioning hydraulically you should get codes for it.

 
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I just don't notice it kicking in. I know there's the whole frame of mind that with a SOHC you don't feel it, but I did notice it before. There's also the debate of when it actually kicks in and I'm not going to start that debate again. I used to feel it at 2500-3000 on half petal and 4000 on WOT. Now I don't notice it. Maybe just because it runs smoother then my old one?

 
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Possibly.

I don't notice it on my 12 either. I even drove my car around with the HDS scanner on so I could watch when it kicks on and still couldn't tell it by feel at all LOL.

 
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Alright, I won't worry to much then. I'll get past my 500 mile break in and then go from there. I ran some BG44K through this tank to clean the injectors and stuff but even with that the gas mileage is kinda rough. Next top off I'll run 91 and see where I get with it.

 
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I tried to search in Japanese, but not much luck so far.
Will let you know if I find something. For an old member

 
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Thanks pal!

 
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How about searching in French? LOL
Wiki says the D17A engine was used in Canada too.

 
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Really? If so, it could get some search results. Google and Yahoo don't get hits when written in Japanese (different fonts) but could return hits for French

 
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Well, everything I've found in japanese and french, more in japanese, backs a 9:9 compression ratio. D17a7 packs a whopping 12:5:1. French Wiki didn't have just the A listed, but Jap Wiki did. So I'll just run with that.

 
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woups... Sorry... been having some sleep disorders (was in Europe last week...) and had not done the search yet... Sorry... But it seem you could find the info yourself so good

 
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With all that said, is 9:9:1 high enough to warrant premium? I didn't in the A2, but should I have been??

 
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No. I'd run low octane. 87 octane.

We have other engines running over 10.5:1 on low octane....

Some of the Earth Dreams engines are over 11:1 and running low octane.

 
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I only run premium during the summer, just in case for knocking (sometimes it does)

just for the fun, Max Tierney is running the A7 in his car, if I am not mistaken

 
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The CNG engine? wiki says that's 12.5:1. That seems like a good start for a turbo running E-85.

 
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I had never even heard of the cng engine until researching the d17a. Apparently their sold here in the states. Go figure.