Opinions Needed, 10.1 CR & Turbo
03-10-2009, 10:09 PM
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Opinions Needed, 10.1 CR & Turbo I have a 370 ci with 10.1:1 CR, Im going to boost the motor but i can't lower the cr anymore unless i open up the combustion chambers on my head they are 72cc. I know im limited on the amount of boost because of detonation. I heard even with race gas or meth running high compression on a boost is not very efficient is this true? I need opinions on what to do because my motor should be going in soon.
03-10-2009, 10:31 PM
#2
No that's not true. You will need more octane with higher compression, but the power will be there. The alcohol guys run high compression in there FI motors because it works and they have the fuel for it.
Generally speaking the more power it makes NA the more power it will make boosted.
Generally speaking the more power it makes NA the more power it will make boosted.
03-10-2009, 10:37 PM
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That what i was thinking, if I where to have lets say 8.5:1 on 14 psi compared to 10.1:1 14 psi i should be making more power on 10.1:1 but will need better fuel or a meth kit to keep it from knocking. Someone told me that it will make less power since the higher compression creats more heat and make the air less dense even with racing fuel.
03-10-2009, 11:45 PM
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if it is a street car i would try to lower the CR as much as possible . thicker head gasket. and flycut the pistons (it would lower cr but i would ignore this one too many headaches) if you don't want to change them. also get a colder thermostat. 160 degree. but if it is a track car just but some high octane and get it tuned and you will be fine. there are some guys running 13.1:1 compression ratios with big boost. you just have to have the right fuel. good luck
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03-11-2009, 01:28 AM
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11.1 compression 15 psi of boost 93 octane gas with meth. for the track i add more timing and run c10 or c16 race gas and meth just to be safe. use to run 11.1 with 10 psi no meth but safe tune
03-11-2009, 11:08 AM
#12
I would for sure run alc injection system for safety.If you can get e85 that can work great too no higher compression but of course you need to tune for it and get bigger injectors, etc. E85 is THE HOTNESS FOR FI CARS! Wish we had that option up here where I live .Only couple e85 stations on all of Canada. You can also run timing lower if you have higher compression for safety. And its possible although big annoying to make race gas. Mix xylene or toluene available from any local paint store up here to normal gasoline but think not more than 30% or so tylene or xylene to gas ratio.
Lots of turbo guys run this trick to basically get race fuel type octane. I wouldn't do it everyday though its a pain in the butt but for the odd grudge race against buddy or track runs it can work pretty good.
Lots of turbo guys run this trick to basically get race fuel type octane. I wouldn't do it everyday though its a pain in the butt but for the odd grudge race against buddy or track runs it can work pretty good.
03-11-2009, 07:53 PM
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03-11-2009, 08:52 PM
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C16 has a really low RVP (reid vapor pressure) I have tested it with meth and without and my car makes a lot more power without the meth when using c16. VP told me it needs an IAT of at LEAST 100 degrees. Cant get that with meth. Now i Know people run it with cooler IATs but in MY car it slows down
Reid Vapor Pressure RVP
The tendency of the gasoline to evaporate. Specifically, it is the expected pressure rise in a sealed container when the fuel is raised from 40degF to 100degF. Too high of a RVP may cause the fuel to boil or evaporate in the pump, lines or carburetor at a given temperature which can lead to "vapor lock". Too low of a RVP and the fuel will not vaporize and could cause difficulty starting the engine when cold. Low RVP fuels may also vaporize inadequately at high engine speeds, resulting in combustion mis/malfires. Most Racing Fuels have an RVP in the range of 5 to 7.
Reid Vapor Pressure RVP
The tendency of the gasoline to evaporate. Specifically, it is the expected pressure rise in a sealed container when the fuel is raised from 40degF to 100degF. Too high of a RVP may cause the fuel to boil or evaporate in the pump, lines or carburetor at a given temperature which can lead to "vapor lock". Too low of a RVP and the fuel will not vaporize and could cause difficulty starting the engine when cold. Low RVP fuels may also vaporize inadequately at high engine speeds, resulting in combustion mis/malfires. Most Racing Fuels have an RVP in the range of 5 to 7.
