Probably a real dumb question but ....

-
MOPARMAGA

MOPARMAGA

" The other hard member"
FABO Gold Member
Joined
Aug 20, 2019
Messages
10,532
Reaction score
11,277
Location
Yakima Wa
Is it ridiculous & is it possible to turbo charge an engine with near 13.1 compression?
I'm very inexperienced in boost, one could say a dummy.
Engine is 471 with two 850s on a tunnel ram.
It makes about 690hp & 667 ft lbs n/a.
Just wondering what you guys would do ?
 
Last edited:
MOPARMAGA said:
Is it ridiculous & is it possible to turbo charge an engine with near 13.1 compression?
I'm very inexperienced in boost, one could say a dummy.
Engine is 471 with two 850s on a tunnel ram.
It makes about 690hp & 667 ft lbs n/a.
Just wondering what you guys would do ?
Click to expand...
There's easier ways to window your 471. :rolleyes:
 
Interested in the answer, blown or not the CR should remain 13:1 so I imagine you should be able to, probably with the right fuel.
 
Wow! Never thought that far out of the box as I was allways schooled boosters like turbo or blower want 8-1 or 9-1.

Imagine 13-1 just the smallest amount of boost would go a long way at a given rpm.
Calculate that fuel mixture. Wow!
Syleng1
 
I tried it with methanol and blew the head gaskets between every bolt on the first hit and they were multi-layer steel. We now build most engines with High boost with the heads o-ringed. Every diesel done here is o-ringed. I'll go get some pictures I believe there is over 10 in the shop right now. Big blocks are O-ringed and cross bolt mains like a hemi or the block with spit up through the mains. Just got one that was split.
 
Oldmanmopar said:
I tried it with methanol and blew the head gaskets between every bolt on the first hit and they were multi-layer steel. We now build most engines with High boost with the heads o-ringed. Every diesel done here is o-ringed. I'll go get some pictures I believe there is over 10 in the shop right now. Big blocks are O-ringed and cross bolt mains like a hemi or the block with spit up through the mains. Just got one that was split.
Click to expand...
Yikes
 
It’s the same situation you run in to with an NA engine. You just need enough octane for the combination. And you are correct 100LL will NOT be adequate. 13:1 with boost is methanol territory. And it’ll be awesome. I recommend not doing it because once you do you’ll never build an NA engine again, and you’ll be poor. :lol:
 
TT5.9mag said:
It’s the same situation you run in to with an NA engine. You just need enough octane for the combination. And you are correct 100LL will NOT be adequate. 13:1 with boost is methanol territory. And it’ll be awesome. I recommend not doing it because once you do you’ll never build an NA engine again, and you’ll be poor. :lol:
Click to expand...
Lol, thanks...Im already poor maybe it will make me chase money more like I did when I was a addict lol
 
Would E85 work? I know a dedicated E85 build shoots for some pretty high compression ratios but no idea if 13:1 + boost is too high.
 
I have been plannjng to add a belt blower or turbo to my red 66 charger. It is 11.5ish to 1 and even with a fat cometic gasket I'd be in the danger zone on race gas.

I was told to stay under 10.5, preferably 9.5:1 under 15 lbs of boost. My understanding through research is that high compresion and/or anything beyond ~1 bar creates a very narrow tuning window on gasoline. The two big boost guys I know run methonal.
 
DionR said:
Would E85 work? I know a dedicated E85 build shoots for some pretty high compression ratios but no idea if 13:1 + boost is too high.
Click to expand...
In a very light race car with deep gears and an excellent intercooler you might be able to make it work on low boost. But where’s the fun in that? At that compression you need better fuel.
 
Jeremiah said:
very narrow tuning window
Click to expand...
That’s the deal right there ^^^. The window gets very very small as you go up in compression and/or boost and it’s not for the first time tuner. Really it’s not worth it to try and make power with a lower octane fuel. You end up crippling it with timing to make it live.
 
Oldmanmopar said:
I tried it with methanol and blew the head gaskets between every bolt on the first hit and they were multi-layer steel. We now build most engines with High boost with the heads o-ringed. Every diesel done here is o-ringed. I'll go get some pictures I believe there is over 10 in the shop right now. Big blocks are O-ringed and cross bolt mains like a hemi or the block with spit up through the mains. Just got one that was split.
Click to expand...
What was the combination you tried it on? Small block? Big block? Hemi? Turbo? Supercharged?
 
Do as I say and not as I do, I know but I have my reasons.
EC0093D0-B403-4F3F-98DD-5FD66253B6F0.jpeg


DFAB6EBD-4B4D-48D8-84C2-43EA294996FE.jpeg


FE1381A8-3441-4C20-A256-5AD36B739949.jpeg

This is my 9.2:1 489 twin turbo big block Chevy. Runs on pump gas 91 octane, non intercooled, blow through carb, in my boat. It makes around 800 at 7psi and idles like a stock big block. If I could get e85 at the dock I’d run that. If I could fit an intercooler I’d run one. But sometimes you make compromises and those compromises will limit output. We hit my power goal pretty easily and didn’t see any reason over complicate it. Start with a goal in mind (hp) and pick a fuel to run, then set the compression to the fuel. Then turn the boost up till it makes the power you want.
 
You must log in or register to reply here.
-

Back
Top