Compression questions blown alky

Hi there im new to the blown alky world. but have picked up an engine from my friend. he used to build and race promod so i trust his build but am just curious. its a 590ci dart big block with a kuhl 14/71. i believe our current static compression ratio is 16:1 and from my research on here nobody is going that high. i believe were going to get around 25 lbs of boost out of this blower. what are your guys thoughts on this and what might be some considerations.

thanks for the thoughts and insights

james

 

Well , I can tell you 16.1 compression is way to much , maybe you misunderstood him , blown Alcohol should be about 11.1 to 12.1 range , would recommend to have
Some that has experience to look at this Engine , 590 ci
Sounds mighty big for a blown engine . Just my advice .
Regards.

 

I did misunderstand it’s 14:1 so I know it’s high but what do we need to do on the fuel side to make it happy

 

ehhh. I am not comprehending why you would not consult your friend that you bought it from on these matters. Seems to me he must have gotten it down the track ok with an no longer produced blower.

 

Lol im just trying to learn, and asking questions to as many experienced people as possible is a great way to learn... i bought the engine incomplete, and the blower seperrate. just a poor kid trying to learn a new science and go fast.

 

I mean cylinder pressure has got to be insane at 50 pounds of boost why can’t you run high compression with less boost. Also cylinder pressures are very high in nitrous applications and you can prevent detonation with the obvious correction of fuel ratio and backing timing off. Say you have idk 14:1 bbc and wanna run say 25 psi. Couldn’t I keep the air charge relatively cool with some extra fuel and back timing off? What other factors are at play that I’m missing

 

I think 14.1 is way to much compression , not really sure what to tell you, I would get in touch with some one that does fuel systems , and get advice from them , all has factors like fuel pump size & nozzle sizes and Barrel valve , ect & ignition timing , I would highly recommend to lower the compression before I ran it , and confirm you compression ratio before I did anything to save time and money .

 

So, here's a couple things i've learned.
I've ran blown alcohol at 9:1 up to 14:1. The tuning window gets really narrow as the static climbs.

It is really hard to screw up on 9:1, it's really easy to nuke it at 14:1.

So, Can you? Sure!

Should you? if you are Les Davenport maybe. I'd drop it to 10-10.5:1, and run it,

 

Thanks for the replies were gonna give it hell at 14. Like I said I know close to nothing in this style of motorsports, but my buddy has been super kind in sharing all his tips and tricks he can with me. Seems like secret society almost lol. I guess we’ll see how it goes.

 

Hopefully your friend sold you good parts like some iron square ports and an Isky 3/4 race cam. Get after it.

 

I forgot forums were social clubs not places of gathering information. Sorry Im In the wrong place to grow my brain. You got some smart a$$ comment but no information talk all the smack ya want. Come play with Rocky Mountain superchargers this summer an you’ll see how my isky 3/4 cam is running just ask for the Volvo

 

It blows me away that you wouldn’t want to share information with someone with the same interests you have? I know my friends an my team are great people and really damn good at what they do. I just figured this forum would be a good place to come at night when i have time to tryn gather some intel on my own. I know I am a total rookie but my Homie isnt. I just want to learn but being as I’m just getting made fun of I guess I’ll do it thee ol fashion way. Thanks for the motivation but not much else

 

we just trying to tell you, that 14.1 compression is way to much , you cant compare with Nitrous motor , BBC likes timing blown alcohol , also if you dont have 1094 dia wrist pins , you asking for problems, I would recommend max of 12.1 compression , from my experience .

 

They are sharing information - 14:1 is way too high.
I would prefer to start out at 10:1 and probably never go past 12:1.
Seems like you want to be told that you have a perfect setup and when people tell you otherwise, everyone else is wrong.
Run the setup you bought if you want - Just remember the advise you were given here when you pick parts of the track.

People on here are way beyond helpful - Just don't get mad at them when they give you feedback that isn't what you want to hear.

 

Mr. blown volvo I cannot see why you think everyone is trying to blow you smoke-Compression in blow alky motors -low 9-to1 high-generally11-1/2-to1-Yes 590 cu.in is bigger than normal and probably won't last long-and yes that Kuhl blower is very old-I think what was given as answers to your question where true .You seem to be sour because no one agrees with what you want to do.You came here in the first place to ask for answers Fuel or timing will not let it live with 25%blower and that high of compression. I for one would not like to be anywhere near that bomb let alone next to it---MIKE KOSKY

 

I really do appreciate the real answers from most you guys I am listening. Thank you kosky and jg kami and Greg for you honest help.

 

I run 11.1 compression, I feel that’s a safe margin & easy
Window tune with the correct fuel system & ect .

 

JG, your name wouldn't by any chance be Sal would it?

Like the others said it is much more cost effective to start in a wide tuning window, 10-11 CR with a safe AFR & static timing to get your feet wet.

These things are perfectly content wasting your money when running well, no sense helping them do it intentionally.

Chris Saulnier - Team Tigges
Mechanic Falls, Maine