Why do people dyno their car with higher octane?
12-09-2002, 03:35 AM
#31
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Its wierd, when I run on the street, I never have a problem with hitting 20psi which is what I try to tune by, but after a few pulls on the dyno, it ends up not going past 17? I'll keep working on it
12-09-2002, 04:30 AM
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Maybe you are not having enough air flow across the intercooler, your engine is detonating, and your ecu is retarding timing or not allowing boost to get top 20.
Not knowing your setup I am just throwing ideas.
Not knowing your setup I am just throwing ideas.
12-09-2002, 06:04 AM
#33
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Originally posted by bill strong
Maybe you are not having enough air flow across the intercooler, your engine is detonating, and your ecu is retarding timing or not allowing boost to get top 20.
Not knowing your setup I am just throwing ideas.
Maybe you are not having enough air flow across the intercooler, your engine is detonating, and your ecu is retarding timing or not allowing boost to get top 20.
Not knowing your setup I am just throwing ideas.
I agree with Brian, I am a little of both when certain situations arise
12-09-2002, 06:58 AM
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Re: Why do people dyno their car with higher octane?
Originally posted by 16g-95gsx
Just curious, as Josh's post reminded me. It seems to me that all the cars that use a dyno always add higher octane fuel to their car and THEN tune it. Is it just me or does this make no sense at all? Yes adding the higher octane will resist knock, but if you are tuning to the threshold anyway like I would hope you are doing, then it wouldnt make any difference whether it was on 100 or 93 octane, since you were teetering on the borderline anyway. I just find it funny that all these people always dyno their car with slightly higher octane and tune it that way, because the moment they get off that dyno and get regular gas in their car, they will begin to knock like a bitch and power will decrease significantly. Anyone here have any thoughts? Sorry this wasnt an attack against you josh, I dont want to make it out to be like that. This thought was actually brought about by my friend with his supra going to tune it on the dyno, but the owners of the shop that were going to tune it said for him to put some 100octane in the tank for the dyno day, and I argued with my friend saying hell no dont do it. Your comment just reminded me thats all.
If you are going to make power claims for a daily driver, then tune and dyno on just plain 93oct. That's my thought for the day.
Just curious, as Josh's post reminded me. It seems to me that all the cars that use a dyno always add higher octane fuel to their car and THEN tune it. Is it just me or does this make no sense at all? Yes adding the higher octane will resist knock, but if you are tuning to the threshold anyway like I would hope you are doing, then it wouldnt make any difference whether it was on 100 or 93 octane, since you were teetering on the borderline anyway. I just find it funny that all these people always dyno their car with slightly higher octane and tune it that way, because the moment they get off that dyno and get regular gas in their car, they will begin to knock like a bitch and power will decrease significantly. Anyone here have any thoughts? Sorry this wasnt an attack against you josh, I dont want to make it out to be like that. This thought was actually brought about by my friend with his supra going to tune it on the dyno, but the owners of the shop that were going to tune it said for him to put some 100octane in the tank for the dyno day, and I argued with my friend saying hell no dont do it. Your comment just reminded me thats all.
If you are going to make power claims for a daily driver, then tune and dyno on just plain 93oct. That's my thought for the day.
So yes, on a dyno:
hotter air + 93 octane = less boost and more detonation.
hotter air + 110 octane = little more boost and less detonation
Originally posted by 16g-95gsx
Very unlikely, most likely the fuel map for the 93oct will closely resemble the fuel map for the higher octane, just it will allow for less knock, and hence higher boost.
Very unlikely, most likely the fuel map for the 93oct will closely resemble the fuel map for the higher octane, just it will allow for less knock, and hence higher boost.
So in conclusion, put a dyno in a wind tunnel and do all the tuning your heart desires, and lower your drag coefficient too.
Or get an air to water intercooler.
12-09-2002, 07:08 AM
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Re: Re: Why do people dyno their car with higher octane?
Originally posted by V8BRICK
Or get an air to water intercooler.
Or get an air to water intercooler.
another good intercooler would be NOS... back in the old days of the 1980s that is what we used NOS for. It works really well as an intercooler.
12-09-2002, 07:59 AM
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i think you answered your own question, air to water is expensive. it's also pretty heavy. it's complicated. it takes up a fair amount of room. it loses efficiency as you use it...
Looking at the IC core chart in my turbonetics catalog, my air to air core is 88% efficient at 20mph, pressure drop at 20psi is only 0.6 psi. seems pretty good to me.
marshall
Looking at the IC core chart in my turbonetics catalog, my air to air core is 88% efficient at 20mph, pressure drop at 20psi is only 0.6 psi. seems pretty good to me.
marshall
12-09-2002, 08:21 AM
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Originally posted by 16g-95gsx
Very unlikely, most likely the fuel map for the 93oct will closely resemble the fuel map for the higher octane, just it will allow for less knock, and hence higher boost.
Very unlikely, most likely the fuel map for the 93oct will closely resemble the fuel map for the higher octane, just it will allow for less knock, and hence higher boost.
maybe you missed the part where I said...if you use C16: 116 octane leaded
