High CR cnc'd 241 vs cnc'd 243?
01-13-2012, 09:44 PM
#41
I went with their "High Compression" 241 port. They told me on a h/c LS1 there's a ~8-12hp difference. The machine work is higher on the HCR 241 because they do more work in the combustion chamber and re-shape the valve angle to give the same PTV clearance as a stock 241 head. I'll have dyno results here shortly.
Jason
Jason
01-16-2012, 09:41 PM
#47
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Also, it has been shown that the cylinder walls wear less with the hotter t-stat. It's pretty small in the real world and probably won't translate into much of a difference in miles driven, but it's still measurable in extreme conditions.
Jason
01-16-2012, 09:47 PM
#48
I run the stock t stat. I like to keep the temps 190-200. With my fan settings it will run 194-203 most of the time in warmer weather. I wanna make sure oil and coolant get up in temp where they should be to burn off moisture and lube the best.
Still not sure what heads to go with hmmm.
Still not sure what heads to go with hmmm.
01-16-2012, 11:30 PM
#49
I went with their "High Compression" 241 port. They told me on a h/c LS1 there's a ~8-12hp difference. The machine work is higher on the HCR 241 because they do more work in the combustion chamber and re-shape the valve angle to give the same PTV clearance as a stock 241 head. I'll have dyno results here shortly.
Jason
Jason
01-17-2012, 01:30 AM
#51
My question is does the higher compression cause any problems? I feel like you would get better gas mileage, no? I'd like to give the 241's a chance for my next build, and maybe an f11 or something along those lines, hell maybe even a tr224 and daily it all day. Never thought I'd see the day where a company could do such good work that it made people second guess the almighty 243's. Props to AI!
01-17-2012, 09:29 AM
#55
My question is does the higher compression cause any problems? I feel like you would get better gas mileage, no? I'd like to give the 241's a chance for my next build, and maybe an f11 or something along those lines, hell maybe even a tr224 and daily it all day. Never thought I'd see the day where a company could do such good work that it made people second guess the almighty 243's. Props to AI!
To get close to yhe edge of compresdion you need to forget about static compression and look at dynamic compression and cranking psi....specially when you start to get bigger cams......8.5:1 dcr is about the max you can run on pump gas in "perfect" conditions (air temp, density, humidity). for example I'm running 12.5:1 scr, but since my intake valve doesn't close until 85degrees abdc I only have about 2.5" of effective compression stroke so my dcr comes out to 8.22:1 which is safe for pump gas under almost any condition with full timing and no knock.
I'm running a 255/263 .624/.624 115lsa cam....if I threw a smaller cam like a 224-228 in my motor I could never run pump gas and I'd have to run race gas to stop in from detonating.
Hope this helped
01-17-2012, 01:37 PM
#56
As long as you don't go too high with your compression it will show gains in power and effeciency ....as long ad you can still pull full timing without knock.
To get close to yhe edge of compresdion you need to forget about static compression and look at dynamic compression and cranking psi....specially when you start to get bigger cams......8.5:1 dcr is about the max you can run on pump gas in "perfect" conditions (air temp, density, humidity). for example I'm running 12.5:1 scr, but since my intake valve doesn't close until 85degrees abdc I only have about 2.5" of effective compression stroke so my dcr comes out to 8.22:1 which is safe for pump gas under almost any condition with full timing and no knock.
I'm running a 255/263 .624/.624 115lsa cam....if I threw a smaller cam like a 224-228 in my motor I could never run pump gas and I'd have to run race gas to stop in from detonating.
Hope this helped
To get close to yhe edge of compresdion you need to forget about static compression and look at dynamic compression and cranking psi....specially when you start to get bigger cams......8.5:1 dcr is about the max you can run on pump gas in "perfect" conditions (air temp, density, humidity). for example I'm running 12.5:1 scr, but since my intake valve doesn't close until 85degrees abdc I only have about 2.5" of effective compression stroke so my dcr comes out to 8.22:1 which is safe for pump gas under almost any condition with full timing and no knock.
I'm running a 255/263 .624/.624 115lsa cam....if I threw a smaller cam like a 224-228 in my motor I could never run pump gas and I'd have to run race gas to stop in from detonating.
Hope this helped
01-18-2012, 05:26 PM
#58
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heres the video i said i would post up and btw truck is untuned and this is a cold start http://youtu.be/PPa3THTDISE
Last edited by twolow02fransen; 01-18-2012 at 05:46 PM.
