whats it worth in HP.......11.3:1 to 12.5:1
#7
Its a 100% street car.....will never see a drag track......weekend warrior, fun car. Maybe 2,000 miles a year.
I'm having a 441ci built...I was wondering if its worth it to go higher compression than the typical 11:1 or 11:3.1, and go 12.5:1 or maybe even 13:1....since using full time race gas is no issue for me. 101, 110, E85..whatever.
I also want to be able to spray a 200 shot though.....is 13:1 too high for that much spray?
Because to have what amounts to possibly 50 more HP (10% more from 11.3:1 to 13:1 cr) for N/A driving....why not......
.
I'm having a 441ci built...I was wondering if its worth it to go higher compression than the typical 11:1 or 11:3.1, and go 12.5:1 or maybe even 13:1....since using full time race gas is no issue for me. 101, 110, E85..whatever.
I also want to be able to spray a 200 shot though.....is 13:1 too high for that much spray?
Because to have what amounts to possibly 50 more HP (10% more from 11.3:1 to 13:1 cr) for N/A driving....why not......
.
Trending Topics
#9
They trailer it a station to fill it when it gets low.
***Can an engine set up for E85 also use 110...with no changes?
.
#10
Depends on the cam. Keep your dynamic compression ratio down with a big cam and you can get away with a lot. I'm running about 11.8 to12:1 static CR with pump gas, 24 degrees of timing, no knock. Because of my cam my DCR is only 8.5:1.
#12
Isn't it safe to say with 800 RWHP the car would have 8 second potential...IF it was set up for drag racing?
.
#13
Old School Heavy
iTrader: (16)
Here is an article with a chart from Popular HotRodding that illustrates the diminishing benefits of adding compression.
Read more: http://www.popularhotrodding.com/tec...#ixzz1aUhiazku
The above chart is not perfect either. More of an example of the diminished returns. The dance is: static compression, dynamic compression and volumetric efficiency. Those factors all together produce the final answer. Because of this, I always temper theoretical ideas with real world experience. I look at what other racers have been successful with in comparison to the theoretical data as a double check.
#14
This is not correct. It is not a simple percentage per point of compression. The gains diminish as the compression increases. There is a much larger increase from 8:1 to 9:1 then there is from 12:1 to 13:1.
This is true to a degree. This also is not a simple formula. Once the engine comes into it's range of volumetric efficiency, the cam is no longer bleeding off pressure. In fact, it is increasing it. DCR is a helpful tool, but it is only part of the equation.
Here is an article with a chart from Popular HotRodding that illustrates the diminishing benefits of adding compression.
Read more: http://www.popularhotrodding.com/tec...#ixzz1aUhiazku
The above chart is not perfect either. More of an example of the diminished returns. The dance is: static compression, dynamic compression and volumetric efficiency. Those factors all together produce the final answer. Because of this, I always temper theoretical ideas with real world experience. I look at what other racers have been successful with in comparison to the theoretical data as a double check.
This is true to a degree. This also is not a simple formula. Once the engine comes into it's range of volumetric efficiency, the cam is no longer bleeding off pressure. In fact, it is increasing it. DCR is a helpful tool, but it is only part of the equation.
Here is an article with a chart from Popular HotRodding that illustrates the diminishing benefits of adding compression.
Read more: http://www.popularhotrodding.com/tec...#ixzz1aUhiazku
The above chart is not perfect either. More of an example of the diminished returns. The dance is: static compression, dynamic compression and volumetric efficiency. Those factors all together produce the final answer. Because of this, I always temper theoretical ideas with real world experience. I look at what other racers have been successful with in comparison to the theoretical data as a double check.
Another question: If I do go 13:1 does that mean 110 octane minimum?
.
#15
Old School Heavy
iTrader: (16)
I'm just wondering if the approximate 50 HP increase from 11.3:1 to 13:1 will be worth having to use race gas or E85 full time. Whatever the increase is will just be a bonus because running the race gas or E85 is absolutely no problem at all.
Another question: If I do go 13:1 does that mean 110 octane minimum?
.
Another question: If I do go 13:1 does that mean 110 octane minimum?
.
#16
I have no experience with E85. But, 13:1 definitely means racing gas all the time. Another resources is your cam manufacturer. They will also give you their compression recommendation for a given cam or vice versa. The whole thing is about volumetric efficiency in a given RPM range and cylinder pressures. The volatility of the fuel and the burn rate have to be a good match for your set up. You want to match your cam and compression closely. If I were in your shoes, I would consult the cam manufacturer and start talking to the guys on YellowBullet.com. It is a rough crowd, but that is the best place I know of to share practical experience with people running racing fuels and E85 on high compression set ups.
.