Honda / Acura K20a K24a Engine Forum banner
1 - 18 of 18 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter · #1 ·
Hey guys I would like to know whats the highest compression you could run on a k20a or a k20a2 dynoed on k pro on 91 octane. I'm also talking about not taking out any timing so the motor runs at full potential. I'm located in bay area cali and was also wondering if there is a reputable tuner for k pro on k20's near here. Thanks guys.
 

·
Registered
Joined
·
107 Posts
The stock compression on a k20a is the safest on 91 octane.. any higher than that is sketchy.
 

·
Registered
Joined
·
565 Posts
91 octane for a K20A. I run mine on 106 and hope to go to 110-112 this week.. Octane is power..
Provided you tune for it it is fine.. BUT if you tune for 96-98 you wont be able to run 91 safely. But if you tune for 91 you can throw anything in it.. Although it wont run to its full potential..
If you have the option of a higher octane use it.. More octane means more power, more power means better mileage, better mileage means its cheaper-cost the same to run higher octane than lower octane.
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #5 ·
Well see the thing is I have talked to so many people about c/r's and its always different. I have called DSR which is a reputable dyno tuner and they say they could run 12.1 compression on a b series, and not have to take any timing out of and run it on 91 octane. Never asked about a k20 yet. But I also hear from engine builders that you shouldn't go much beyond 11.5:1 which is k20 stock compression as we all know. I'm just trying to get info on highest compression possible and run 91 octane. I mean im far off from a k20 swap but it doesnt hurt to learn more. :D
 

·
Registered
Joined
·
25 Posts
Would you feed your son poor quality food? Now take the same concept and use it for your engine. The higher the octane the better. As for the compression ratio if your not going to play with the engine for max performance then you should just keep the stock compression it's good enough anyways.
 

·
Banned
Joined
·
320 Posts
Yeah but 91 octane is the highest available at the pump in Cali, unless you find one of the rare 76s that sell 100. It makes it pretty difficult to drive the car anywhere far if you can't run pump gas. Although you could always put in a 25-gallon fuel cell and... :rolleyes:
 

·
GoldStar
Joined
·
2,657 Posts
i understand where you're coming from. a lot of people that are from different areas don't realize that 91 octane is the highest we can get at the pump here in cali.
correll said:
The stock compression on a k20a is the safest on 91 octane.. any higher than that is sketchy.
you could get away with 12:1 if your ecu is tuned right. but you may run into problems on a hot day.
 

·
Registered
Joined
·
25 Posts
Your lucky enough around here we don't even get 91 Octane.
 

·
Banned
Joined
·
320 Posts
oh and remember that you can usually run higher compression if you are running cams that have more overlap as that reduces cylinder pressures...

I am planning to run 12:1 compression on my build, I don't think it will be a problem but we may have to run less-than-ideal timing - you will always be able to run more timing with higher octane...
 

·
Registered
Joined
·
191 Posts
it realy depends on your elevation too, i live at 5,ooo feet so i can run crazie compression. i ran +14:1 on my last b series motor with huge cams and i could daily drive it just fine on regular unleaded. and on 91 at 3/4 throttle with stock cams. but at sea level i would have to run 100 octain with the big cams.
 

·
Registered
Joined
·
10 Posts
Don't listen to some of these fools. Just putting higher octane gas in your car does not create power. In fact if you put in too high of an octane you will lose power. Did you know that higher octane gas is harder to combust? Yes that's a fact. If you tune your car to run on a higher octane gas then you can advance timing further and make use of higher compression. Also if you run too high of a compression on a car that needs to run on 91 or 93 you will have to retard the timing. There is a delicate balance. If you run the compression too high you will have to retard timing to the point that the power gained from compression is negated or you even lose total power.

I would say for a street setup either stay where you are at 11:1 or get a toda or spoon head gasket and let that bump it up to 11.4:1. No need to run it higher than that on street gas.
 

·
Registered
Joined
·
6 Posts
Discussion Starter · #13 ·
pints99 said:
Don't listen to some of these fools. Just putting higher octane gas in your car does not create power. In fact if you put in too high of an octane you will lose power. Did you know that higher octane gas is harder to combust? Yes that's a fact. If you tune your car to run on a higher octane gas then you can advance timing further and make use of higher compression. Also if you run too high of a compression on a car that needs to run on 91 or 93 you will have to retard the timing. There is a delicate balance. If you run the compression too high you will have to retard timing to the point that the power gained from compression is negated or you even lose total power.

I would say for a street setup either stay where you are at 11:1 or get a toda or spoon head gasket and let that bump it up to 11.4:1. No need to run it higher than that on street gas.
Yea your right pints. One time I bought 100 octane for my hatch now with a d16z6 with stock 9.2:1 compression and it felt like it was going slower, then I talked to one of my homeboys about it who runs like 13.5:1 compression on a built b series and he said yea that won't make any power with your stock compression. But yea I guess the best thing to save money would also to leave a k20a at stock 11.5 compression, but I know on bigger cams higher the compression is better and yea I was wondering with like 12.1 with like crower or toda cams since u can get away with slightly higher compression could this compression run on 91 octane. Well like I said earlier I don't want to run to the point where I have to take timing out of the motor. But ok thanks for all the info guys. :up:
 

·
Registered
Joined
·
107 Posts
pints99 said:
Don't listen to some of these fools. Just putting higher octane gas in your car does not create power. In fact if you put in too high of an octane you will lose power. Did you know that higher octane gas is harder to combust? Yes that's a fact. If you tune your car to run on a higher octane gas then you can advance timing further and make use of higher compression. Also if you run too high of a compression on a car that needs to run on 91 or 93 you will have to retard the timing. There is a delicate balance. If you run the compression too high you will have to retard timing to the point that the power gained from compression is negated or you even lose total power.

I would say for a street setup either stay where you are at 11:1 or get a toda or spoon head gasket and let that bump it up to 11.4:1. No need to run it higher than that on street gas.

This is true... you want to run the lowest octane possible. On a stock K20a you want to run 91-92...
 

·
Banned
Joined
·
320 Posts
If we are going to get into a big discussion about octane ratings I wrote a whole essay on it a while ago I will have to dig it up...
 

·
Registered
Joined
·
10 Posts
You can tune anyhting to run on anything. The question is will you be making power. If you have to retard timing to much to make your octane gas work with your compression you might lose power. If you're going to have to run on pump gas everyday I don't think anything over 12:1 is for you.
 

·
Banned
Joined
·
320 Posts
pints99 said:
You can tune anyhting to run on anything. The question is will you be making power. If you have to retard timing to much to make your octane gas work with your compression you might lose power. If you're going to have to run on pump gas everyday I don't think anything over 12:1 is for you.
you brought up a good point here. everyone I know who is running high comp (12 and up) in a street car did so because they have tuned the car seperately for race gas, so that when they go to the track they can fill up with race gas and switch to a different ECU map (using hondata or AEM ems). if it's a pump gas only car theres not really much sense in going any higher than 11.8ish... above that you end up pulling so much timing out that it's pretty pointless as you don't really get any more power. in my experience with b series motors I have found that high compression motors will tend to detonate on 91 octane at high load in the lower rpm (going up a slight hill at around 4000 in 5th gear, say) even when you have the timing retarded a lot. I don't know if the K will be the same or not...
 
1 - 18 of 18 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top