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Using your calculator, my current setup with 84mm bore, 85mm stroke, 5.233" rods, 9:1 compression, 50* ABDC inlet valve timing, and 40 PSI boost, I get
7.96 dynamic compression ratio
29.62 effective boost compression ratio.
That is already significantly over your 18:1 sane numbers.
If I ran 12:1 and 35 PSI boost:
10.57:1 dynamic compression ratio
35.74:1 effective boost compression ratio.
That's beyond where I would be comfortable. Kudos for boosting "All of it".
At 20 psi you're at 18.77 dynamic with the same above info. Again just my target on race gas or E85 in a highly stressed environment. YMMV. In for results.
e85 does knock/detonate with enough craziness thrown at it, so there's that.
and then there are the physical load limits you mentioned
Yeah, I think I have octane to spare right now. At least for how I use the car, which is street and drag.
Originally Posted by k24madness
That's beyond where I would be comfortable. Kudos for boosting "All of it".
At 20 psi you're at 18.77 dynamic with the same above info. Again just my target on race gas or E85 in a highly stressed environment. YMMV. In for results.
My spring pressure for wastegate is 30 psi.
So if you consider 18:1 safe for track, and I have gotten away with 29.62:1 effective compression ratio, that is quite a difference. Do you think you could run more boost, or more compression on your setup?
I know this thread is about high comp and e85 but there is also some good info about high(er) boost levels and e85. I want to add some timing to my map but a lot of timing tables that Ive found are all for lower boost numbers.
I hit 22psi at ~4700rpm and it tapers up to 25-26psi by 7250. E85, stock 9.5:1 pistons, stock rings, stock head.
My current WOT, full boost timing numbers are highlighted in the picture. Could I safely add 4-5 degrees in all the cells?
no such thing as a definitive answer to that. assuming you don't start knocking, and don't stop picking up significant power per degree of timing, you might. I have on several cars in the past
09-06-2017, 07:51 PM
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