Maybe supercharging
05-19-2002, 11:30 AM
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Maybe supercharging
I have a twin small block application with Kaama drives in my cat.I am taking it out for the first time next week.If I do not get the speed I want I am thinking of blowers.Here is the engine setup.Lunati forged crank and rods and Wiesco forged pistons.Edelbrock aluminum heads Msd ignitions 750cfm Holley and rpm airgap intake.The static compression is about 10.1.I know I would have to change cams to a blower cam but is my compression to high and what blower would be easiest to install.This would be done in the next off season so I want to compile as much info from you supercharger gurus as I can.Thanks Fish
05-19-2002, 08:35 PM
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I am not a supercharger guru, but
I think 10:1 compression is to high unless you plan on running 112 plus octane gas or some kind of alcohol. I think you want to be around 8:1 for a pumped gas blower motor. I am sure some of the others on OSO will shed some light for you.
05-20-2002, 08:39 AM
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Well. First, 10:1 is too high for any kind of real gain for a supercharger, using pump gas.
With a Pro Charger and no t-stat I wouldn't recommend anything more than 3# of boost.
Three pounds will give you an effective comp ratio of about 12:1. You will see a small gain of course, but for the amount you would have to spend to get it...nah.
In a boat I suggest a static comp ratio of 8.5:1 for boost that will be above 5# and up to 9.5 for 5# and under. That way you have a little more power during the cruise.
There are a host of cams that work well with a blower. Yours may be one of them. Check the specs on it and see.
DAVE
With a Pro Charger and no t-stat I wouldn't recommend anything more than 3# of boost.
Three pounds will give you an effective comp ratio of about 12:1. You will see a small gain of course, but for the amount you would have to spend to get it...nah.
In a boat I suggest a static comp ratio of 8.5:1 for boost that will be above 5# and up to 9.5 for 5# and under. That way you have a little more power during the cruise.
There are a host of cams that work well with a blower. Yours may be one of them. Check the specs on it and see.
DAVE
05-20-2002, 05:14 PM
#4
CR vs. Boost....
Hey Dave F,
I'm pondering the same issue with CR. I'm going to be adding a M3 Procharger with the large 504 intercooler on my EFI 540. The CR is currently at 9.25:1 with aluminum heads and I also run at 3600-5000 feet the majority of the time. I'm looking to run 5 lbs with this setup which I believe brings my boosted CR to 12.4:1. This would naturally be at sea level. If say 4000 feet is applied to the mix it drops my boosted CR to 11.6.
This, in my limited knowledge of boost, sounds like 5 lbs. would be safe at sea level or 4000 feet. It seems I could possibly run 6 lbs. at 4000 feet and still be at 12.2.
It seems I've heard that 12.4 is the limit you would ever consider if non intercooled. I would think it would be the limit for intercooled for good longevity.
Am I thinking along the right/safe path??
Any thoughts would be appreciated.
Dave G.
I'm pondering the same issue with CR. I'm going to be adding a M3 Procharger with the large 504 intercooler on my EFI 540. The CR is currently at 9.25:1 with aluminum heads and I also run at 3600-5000 feet the majority of the time. I'm looking to run 5 lbs with this setup which I believe brings my boosted CR to 12.4:1. This would naturally be at sea level. If say 4000 feet is applied to the mix it drops my boosted CR to 11.6.
This, in my limited knowledge of boost, sounds like 5 lbs. would be safe at sea level or 4000 feet. It seems I could possibly run 6 lbs. at 4000 feet and still be at 12.2.
It seems I've heard that 12.4 is the limit you would ever consider if non intercooled. I would think it would be the limit for intercooled for good longevity.
Am I thinking along the right/safe path??
Any thoughts would be appreciated.
Dave G.
