So how is the 18:1 maximum calculated please. I have looked on .turbobygarrett.com but still unsure.
Edit.
Sorry to bother you. found it on Alfa Romeo site. Thanks
So how is the 18:1 maximum calculated please. I have looked on .turbobygarrett.com but still unsure.
Yeh, sorry selfish of me, did not think of it.godlameroso wrote: ↑23 Apr 2018, 13:08For anyone else, geometric compression ratio is merely volume of CC with piston at the bottom of it's travel, vs the volume of the piston at the top of it's travel. That means the volume of the CC with the piston at BDC cannot be higher than 18 times the volume when the piston is at TDC. In other words if the cylinder volume with piston at BDC is 266.66...cc, then cylinder volume with piston at TDC cannot be lower than 14.811cc.
OK got it, thanks for thatgodlameroso wrote: ↑23 Apr 2018, 14:16I wish I could radius by hand, not easy, I'm limited to only angle grinding. I give myself some margin on the valve install height when I put in a new seat, then get to crackin' or butchering the crap out of the valve seat, depending on who you ask. I go first for the 45 and get my 1 degree margin to the valve face, then I do my other angles, then finish off with another 45 cut. Some people like to put two angles after the 45, but it doesn't make too much of a difference in my experience. For me, and I guess for some others, the most important angles for flow come before the 45(higher up the port). But for a F.I. drag car most of the fast Honda guys go O.S. valves on the exhaust and push the limits on the valve install height to get the widest seat possible.
It is, if we consider geometric CR of 18:1 plus dynamic compression increase from 4 bar, even with Miller/Atkinson you're looking at insane dynamic CRs, which I'm too dumb to calculate but I'm guessing 27:1 wouldn't be out of the question.Big Tea wrote: ↑23 Apr 2018, 17:24Yeh, sorry selfish of me, did not think of it.godlameroso wrote: ↑23 Apr 2018, 13:08For anyone else, geometric compression ratio is merely volume of CC with piston at the bottom of it's travel, vs the volume of the piston at the top of it's travel. That means the volume of the CC with the piston at BDC cannot be higher than 18 times the volume when the piston is at TDC. In other words if the cylinder volume with piston at BDC is 266.66...cc, then cylinder volume with piston at TDC cannot be lower than 14.811cc.
This is the page I found interesting.
http://www.autocomponenti.com/boosted_t ... d_tech.htm
Well that would depend on how the plug is designed...godlameroso wrote: ↑24 Apr 2018, 01:32Speaking of spark, I wonder what kind of gap they're running, .016"
.016" on typical plugs sometimes @30 psi @ 10.2:1 and a whole lot of E-85.MrPotatoHead wrote: ↑24 Apr 2018, 02:04Well that would depend on how the plug is designed...godlameroso wrote: ↑24 Apr 2018, 01:32Speaking of spark, I wonder what kind of gap they're running, .016"
But if it’s your typical plug I would say around 0.024”
That’s where I run on high boost engines.
I never have to run that low with good coilsgodlameroso wrote: ↑24 Apr 2018, 03:21.016" on typical plugs sometimesMrPotatoHead wrote: ↑24 Apr 2018, 02:04Well that would depend on how the plug is designed...godlameroso wrote: ↑24 Apr 2018, 01:32Speaking of spark, I wonder what kind of gap they're running, .016"
But if it’s your typical plug I would say around 0.024”
That’s where I run on high boost engines.
Honda distributors will push 1,000hp on a single cam if you will it.MrPotatoHead wrote: ↑24 Apr 2018, 03:23I never have to run that low with good coilsgodlameroso wrote: ↑24 Apr 2018, 03:21.016" on typical plugs sometimesMrPotatoHead wrote: ↑24 Apr 2018, 02:04
Well that would depend on how the plug is designed...
But if it’s your typical plug I would say around 0.024”
That’s where I run on high boost engines.
... bad for marketing to call for diesel enginesMrPotatoHead wrote: ↑24 Apr 2018, 00:10It's pretty simple - they want the engines to be Spark Ignition not Compression Ignition.