|
|
comp 2 high for 91 oct?
#530274
11/18/09 09:57 PM
11/18/09 09:57 PM
|
Joined: May 2006
Posts: 388
wine valley
cudaben1968
OP
enthusiast
|
OP
enthusiast
Joined: May 2006
Posts: 388
wine valley
|
im rebuilding a little 4 cyl engine and was looking at using the stock style replacement pistons that will give me a compression rating of 10 to 1, but for a few bucks more i could get it up to 11.4 to 1. is this street-able with 91 octane? it will be a daily driver and gets lots of abuse / use. The engine has a knock sensor that will pull out timing till the knock goes away, but i don't want it to have to pull a ton of timing and kill performance. I know a thicker head gasket would help but then i lose some quench... so is 11.4 to 1 ok?
Half measures availed us nothing. We stood at the turning point.
-Alcoholics Anonymous, The Big Book
|
|
|
Re: comp 2 high for 91 oct?
[Re: cudaben1968]
#530275
11/18/09 11:01 PM
11/18/09 11:01 PM
|
Joined: Oct 2004
Posts: 8,165
Left Coast
BobR
master
|
master
Joined: Oct 2004
Posts: 8,165
Left Coast
|
Quote:
im rebuilding a little 4 cyl engine and was looking at using the stock style replacement pistons that will give me a compression rating of 10 to 1, but for a few bucks more i could get it up to 11.4 to 1. is this street-able with 91 octane? it will be a daily driver and gets lots of abuse / use. The engine has a knock sensor that will pull out timing till the knock goes away, but i don't want it to have to pull a ton of timing and kill performance. I know a thicker head gasket would help but then i lose some quench... so is 11.4 to 1 ok?
Iron or aluminum block/heads?
|
|
|
Re: comp 2 high for 91 oct?
[Re: HotRodDave]
#530279
11/18/09 11:26 PM
11/18/09 11:26 PM
|
Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
HotRodDave
I Live Here
|
I Live Here
Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
|
Probably a Honda since no mopar ever came with aluminum block and head and DOHC. No one hot rods a toyota. It could be a nissan but few people hot rod those either.
It depends on the cam timing and quench, also a Honda has a very efficent combustion chamber, kinda like a hemi. Many newer motors work wonders when it comes to compression, my dads geo-metro has very high compression and short cam timing and will blow 200 PSI on just about any compression tester but it runs fine on 87 octane.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
|
|
|
Re: comp 2 high for 91 oct?
[Re: HotRodDave]
#530280
11/18/09 11:59 PM
11/18/09 11:59 PM
|
Joined: May 2006
Posts: 388
wine valley
cudaben1968
OP
enthusiast
|
OP
enthusiast
Joined: May 2006
Posts: 388
wine valley
|
it is a honda, i have talked to a few engine builders in my area and they all say different things.... but none of them really speaclize in imports. mainly they do the super rare and powerful sbc...  the stock motor actually runs 10.2 to 1 and it ran just fine one 87, say about two 10ths lost in the quarter but nothing major. (when its running in the high 13's whats a few tenths???) what about with adjustable cam gears?
Half measures availed us nothing. We stood at the turning point.
-Alcoholics Anonymous, The Big Book
|
|
|
Re: comp 2 high for 91 oct?
[Re: cudaben1968]
#530281
11/19/09 12:47 AM
11/19/09 12:47 AM
|
Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
HotRodDave
I Live Here
|
I Live Here
Joined: Jan 2005
Posts: 12,419
Kalispell Mt.
|
If your building a honda motor for a hot rod you are probably going to bigger cams, bigger cams are more forgiving of compression. You will be fine with that much compression.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
|
|
|
Re: comp 2 high for 91 oct?
[Re: HotRodDave]
#530282
11/19/09 01:50 AM
11/19/09 01:50 AM
|
Joined: May 2006
Posts: 388
wine valley
cudaben1968
OP
enthusiast
|
OP
enthusiast
Joined: May 2006
Posts: 388
wine valley
|
im actually sticking with the stock cams, the car ran high 13's in a close to 3000 lb car, it burned a bit of oil. so i figued i'd put new pistons and rings in yes overbore too... its now going in a car weighing close to 1000 lbs less at just over 2000 lbs. hoping for a bit more power would like to see 200 at the front wheels. o well, maybe ill just get a thicker head gasket.... thanks guys
Half measures availed us nothing. We stood at the turning point.
-Alcoholics Anonymous, The Big Book
|
|
|
|
|
|
|
