Now that the octane here in california has dropped to 91, I am concern if it will be enough for a higher compression engine. As it has been stated before, it is benefial to have higher compression when running aggressive cams (ie. toda b or toda c), but will 91 octane be sufficient for some one that lets say has TODA B's & JDM ITR PISTONS? May be some of you can tell me how can I determine how much octane is needed for the different compressions?

Thanks

 

You will be fine with the jdm pistons. the compression is still pretty low with those.
We are running ctr pistons oon 92 octane. No problems.

 

what would be considered about the max that we can go for compression?
I can have custom rods and pistons made, but I have no idea what specs to go with. Is it even worth upgrading on an otherwise stock motor (stock cams)?

yoshi - who can use some help in this area

 

What would you say would be the highest compression I can have with the 91 octane?

 

Anymore input?


[Modified by BLITZ, 3:20 PM 8/23/2001]

 

I've heard of guys runnng a little higher than 12:1 on the street. Gotta run bigger injectors and definitely have your ecu tuning done.

 

Thats with 91 octane?

So I may be able to get away with higher compression, using 91 octane, than the JDM ITR PISTONS. May be the CTR's?

SGT: you mentioned you are running the CTR pistons on 92 octane with out any problems. Would the 1 octane difference give me any problems? I may consider the CTR pistons.

 

I dont think the *1* octane will matter, but you may want to pickup a
J&S version 0 just in case if you decide to go that route.

 

True, I was just thinking the same thing.

Thanks

 

Yoshi: EP GONZALES may be able to answer your question. He has a similar set up.

 

i forgot, what CR will JDM pistons in our car yield?
I'll just get the pistons made similar to that

 

Why do they only have 91 in Cali, seems a bit strange to me!!!!

Sam

 

shouldn't it be 11:1? just like the JDM ITR?

 

correct. 11.1:1

 

According to this, https://honda-tech.com/zerothread?id=61228


The ITR pistons are 11.1. Some said the CTR pistons were 12.2 or 12.5 & http://tiiite.b16a.com/pistons.htm said the CTR pistons are 11.6 or more.

 

I think we have 91 octane instead of 92 because the refineries can produce more gasoline in California..That's what I heard!

 

Has to do with emmision standards for CA. I think it was H-T member dustin that had posted this link recently:
http://rely.net/~dustin/fueloctane.html

 

So will the "1" octane difference hurt my ITR? How about 100 octane(racing fuel), does it make a huge gain in power?

 

How high of compression can one run with no mods to the OE ECU, retaining 16 deg timing, on 92+ octane, and remain "ping" free during Southern summers?

 

I would have to say 11.8:1~12.3:1 would be safe ...but it also depends on pistion prep to less sharp edges in the combustion area the less likely it will ping...But then again what do I know