What compression would be ok for about 12#'s of boost on street fuel, around here thats 93oct ??

I was gunna run 9:1 comp and 12#'s of boost on my 412 but wasnt sure how it would be on street gas.

 

intercooled or not?

not intercooled 12# 8:1 (and your probably pushing it)
intercooled 12# 9.5:1 or 10:1

Here is a chart from procharger

 

Innercooled foresure. Thinking on the ATI twin Intercooled listed here actualy.

Looking at your chart maybe I'll run 14#'s

 

That chat is a joke! I've run 12psi on 9:1 motor, on pump gas w/26d advance.

-- Joe

 

Are you running an intercooler?

are you saying that that the numbers are on the low side?


I'm sure the numbers fall under the catagory of "reliable" like it says up top of the chart with a safety factor built in. They are going to give themselves a bit of cushion so that they don't have people comming back to them and saying 'hey look I just blew my motor using your info'.

 

weve done 14lbs with 9:1 static on pump gas. Your camshaft will play a big part on your ign. timing.

 

My setup sofar is a 412 Stroker motor with, JE forged pistons, eagle 4340 6"rods, 4340 stroker eagle crank, splayed billet main caps, ARP hardware, hv pump, AFR 190cc heads, ProMagnum 1.6 RR

Comp cams Retro Roller 276/288 dur 224/236 @50 dur .502/.520 lift (w1.5RR's) 113LSA cam

 

Was that intercooled?

 

yes

 

I'm saying this numbers maybe acurate for 1 compressor, out of a dozen or so manufacturers. What plays the biggest role is output temps.

NO I dont have an intercooler. With my A-Trim I saw 8psi with 170-200f mat temps, and full timing. The S-trim got me 12psi boost, with lower mat temps (around 115f) and full timing.. Static compression is around 9:1.

I've been told the prochargers have excessively high output temps. The S-trim seems fairly reasonable. Perhaps folks with other compressors will chime in.

I think the ATI hype is simply, you can't run much boost on their units WITHOUT an intercooler. And personally, I'm not into the 10 feet of plumbing.

-- Joe

 

So then are you running on pump gas, or do you have to run race gas? If you had the exact same setup, except with a YS compressor, you would be able to make the same boost w/ less rpm correct? If so, then it would create less heat than the smaller one correct? I was just wondering if you can run higher boost w/ a larger supercharger without having detonation if everything else stays the same, or if there is a flaw in that idea somewhere?

Ben

 

Running on pump gas. Keep in mind, this is boston, nor miami, so the outside temps are not too crazy.

I talked to Vortech about that. The y trim creates more boost at less rpm, and is more efficient. My S-Trim is around 70-73 % efficient, compared to the a-trim that was barely 60%. I'm using a stock bottom pully (litterally, a stock fbody pully on the bottom is what they use), and a 3.33" top pully, which puts 6k shift points around 50k on the impeller. On a honda civic it would be 20psi, on my 355 its around 12ish.. (well that was with TPI, I imagine the singleplane would show less boost).

-- Joe