CNK Pistons.
02-28-2003, 05:47 PM
#11
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I see now...Jumps from HP and WHP so much. I got confused.
258whp I am sure is not over 300crank hp.
But no one will really know, unless the engine is taken out and dynoed.
But I would think if the transmission was eating more then 40hp it would melt. but thats for another post.
so what are you exactly guaranting the piston at?
300hp or 300whp?
258whp I am sure is not over 300crank hp.
But no one will really know, unless the engine is taken out and dynoed.
But I would think if the transmission was eating more then 40hp it would melt. but thats for another post.
so what are you exactly guaranting the piston at?
300hp or 300whp?
03-01-2003, 12:00 AM
#12
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He stated that the pistons are rated to handle 300 crank HP. Chris has had these pistons over 300 WHP, but he doesn't say that they are rated to handle that nor does he reccomend it.
On a side note, I believe that Bat's transmission IS eating a bit more than 40 HP. If he only had a 15% drivetrain loss, at 300 HP, he would be making 255 WHP. At those HP levels, I think that he is probably losing closer to 18%. But, you are correct, there is no way to prove it except to yank the engine. Manual trannies can eat a lot more than 40 HP and not melt as well.
On a side note, I believe that Bat's transmission IS eating a bit more than 40 HP. If he only had a 15% drivetrain loss, at 300 HP, he would be making 255 WHP. At those HP levels, I think that he is probably losing closer to 18%. But, you are correct, there is no way to prove it except to yank the engine. Manual trannies can eat a lot more than 40 HP and not melt as well.
03-01-2003, 01:25 AM
#13
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I personally think like Shadohh; I don't think the transmission could handle a power dissipation of 40hp. Remember that this lost power must go somehwere; it is mostly converted to heat. Do you think Bat Lard's transmission is acting as a BIG heater? wink I don't remember the forumulas on top of my head, but it would certainly produce a lot of it if 40hp was converted to heat.
Also, it's not correct to note tranny lost as a percentage, especially when you go FI (or anything that boosts your car by a fair amount). The reason for that is that at 140hp you may be losing ~12%, which is about 15hp (I'm only taking tranny lost in account, not all the parameters), but it doesn't go linearly from there if you go up to 300hp. At 300hp, it will probably be closer to 20hp than 40hp.
My 2$ (remember, I'm paid in CDN cash... wink )
Also, it's not correct to note tranny lost as a percentage, especially when you go FI (or anything that boosts your car by a fair amount). The reason for that is that at 140hp you may be losing ~12%, which is about 15hp (I'm only taking tranny lost in account, not all the parameters), but it doesn't go linearly from there if you go up to 300hp. At 300hp, it will probably be closer to 20hp than 40hp.
My 2$ (remember, I'm paid in CDN cash... wink )
03-01-2003, 01:52 AM
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for those of you that are having a hard time understanding the drivetrain losses, think of it this way: the mass of the parts in the drivetrain that need to be turned (gears, driveshafts, etc...) is fixed. for the sake of arguement, let's assume that there are 4 kilograms of mass to turn in the drivetrain, whether you're making 140 or 300 hp at the crank, the same amount of energy is needed to turn the 4 kg. i'll look through my phisics notes later today and post the heat difference between the tranny eating 20hp and 40hp...we just went over energy and heat.
03-01-2003, 05:12 AM
#15
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Guys ---
The pistons are rated at 300HP -- CRANK HP --- the reason I do this is because most manufacturers in this country that provide power fgures on their cars found in the local magazines are always rated at the crank --- this is because manufacturers don;t use chassis dyno's, instead engine dyno's.
I followed suite.
The pistons are rated at 300CRANK HP --- which is + - 240WHP at a loss of around 17 - 19% ---- lostbouys car has a d/train loss of exactly 17%, then again different size wheels and tranny oils will give you different losses. You can work on around 17 - 20% losses for cars with stock wheels and tires up to 17 inch babies. In fact my personal tiburon has the exact same losses as Lostbouy.
OH - before I forget - this was calculated on a dyno doing a coast down test.
The pistons are rated at 300HP -- CRANK HP --- the reason I do this is because most manufacturers in this country that provide power fgures on their cars found in the local magazines are always rated at the crank --- this is because manufacturers don;t use chassis dyno's, instead engine dyno's.
I followed suite.
The pistons are rated at 300CRANK HP --- which is + - 240WHP at a loss of around 17 - 19% ---- lostbouys car has a d/train loss of exactly 17%, then again different size wheels and tranny oils will give you different losses. You can work on around 17 - 20% losses for cars with stock wheels and tires up to 17 inch babies. In fact my personal tiburon has the exact same losses as Lostbouy.
OH - before I forget - this was calculated on a dyno doing a coast down test.
03-03-2003, 12:33 PM
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how much is a set of your pistons? what are the comparisons/differences vs. the turbo pistons on www.kspec.com?