bo0oost

I'm in CA on crappy 91 octane gas... I have heads/cam setup that makes 448rwhp/435rwtq.

I need boost! How much boost do you guys think is safe on pump gas, and the stock bottom end?

My setup:

BlackHeads Stage 2 6.0 liter heads
2.02 x 1.55 valves
283 @ .600 intake 239 @ .600 exhaust
Comp Cams Magnum Lifters
Rev Stainless 5 angle valves
Comp Cams Titanium Retainers
Comp Cams 918 Valve Springs
Comp Cams Competition Hardened Pushrods
Comp Cams 226/232 .568/.568 112 LSA Cam
10.8:1 Compression, 7000 redline

Are the heads/cam good for blower? I know that it's generally a nitrous setup.

thanks.

<small>[ November 13, 2002, 02:53 AM: Message edited by: bo0oost ]</small>

Nickn20

with those head flows numbers and cam, those dyno numbers sound inflated, did you dyno at ATP in fremont by any chance? oh your compression ratio is too high for boost, just stick with nitrous, until you can build a forged motor 9:1

smokinHawk

iTrader: (48)

I would agree on not putting boost with that motor, you dont have enough octane at cali for that high of CR and boost, unless your ok with blowing your engine.
even if you get a good tune, with only 91 octane wont work well.

y2khawk

iTrader: (5)

Guys

we all need to remember there are a few "*****" to turn when it comes to boost. It is an overall system that you're dealing with, not a single quantity

CR, octane, boost, and advance are all adjustable.

Assuming a decent setup, you can't turn one up w/o turning one or more in the other direction.

In your case, you've pretty much got octane and CR fixed. So, if you boost you MUST reduce your spark advance.

The disadvantage here is two fold. You'll end up with low spark advance numbers, but the LSx chamber is pretty fast burn and doesn't need alot of advance in the first place. However, you need to make sure you can reduce the advance enough to compensate. But the second issue is finding a blower/turbo/etc that's reasonably efficient at the boost levels you can run. There comes a point where you are so inefficient on the blower and you've lowered the advance so far you can't go anymore.

Specific to your setup, your cam is decent for a blower as far as the durations are concerned. However, the LSA is a bit tight compared to the "normal" recommended. But, it can help you. You end up bleeding off some cylinder pressure with the increased overlap. That gets you somewhat lower effective CR than what your static CR of 10.8:1 says.

The 91 octane will definately be the limiting factor.

smokinHawk

iTrader: (48)

Well let me ask you this, if you were setting up your engine for boost would you raise the compression?
a high CR motor is not generally made for FI. True if you added octane and had less spark advance you would be alright, but will it be worth going to FI, i wouldnt think so.
you could get new 6.0 and not mill them decresing the CR to about 9.8:1 that would work better.

y2khawk

iTrader: (5)

All depends on what your after.....

Pro5.0 guys run BIG boost on BIG CR. Those motors are built for boost, all out race.

I built my motor to get close to what i had before on the 10:1 motor, but on 93 octane. If i wanted a ***** to the wall boost motor, i would have raised my CR higher than the stock 10:1 believe it or not <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> but i'd be running it on C16 at all times.

You'll still make power, assuming the compressor you use can flow enough at low boost or doesn't overly heat the air. But like i said above, they is a point where it just doesn't make sense.

If your dead set on not spending more on the motor, you can get away with it. But don't expect to get too crazy w/ the boost.

smokinHawk

iTrader: (48)

Sure higher CR motors allow turbos to spool faster and ofcoarse produce power at given boost. But most of us cant get c16 at our local quicky mart gas station, so for a street motor and daily driving it is impractical.

so in therory it is possible, but for daily driving impractical, unless you can get high octane real cheap or dont mind the fuel cost.

Fenris Ulf

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by bo0oost:
<strong>I'm in CA on crappy 91 octane gas... I have heads/cam setup that makes 448rwhp/435rwtq.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Bullshit you do, not with those crappy heads and outdated cam. Let's see a dyno sheet <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

bo0oost

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Fenris Ulf:
<strong> </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by bo0oost:
<strong>I'm in CA on crappy 91 octane gas... I have heads/cam setup that makes 448rwhp/435rwtq.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Bullshit you do, not with those crappy heads and outdated cam. Let's see a dyno sheet <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I don't understand.

Can you explain?

VINCE

iTrader: (1)

He is talking about the flow #'s of your heads. If what you are saying is true.. You have the most tq out of anyone on a NA 346ci setup. Your hp #'s are up there too.. Who know's or who really cares.. We need to help you with your boost situation.

MelloYellow

Sounds like the MMS dyno.

Importdestroyer

iTrader: (1)

Yeah we need to adress this question, I am moving to CA in early 04. Right now it runs fine off of 92 but I plan on running the 2.75 (11psi) pulley on my Vortech along with a LS6 intake manifold soon.

I dont know If I can afford to buy Toulene by the 55 gal drum, so we need to resolve this before I swap my pulley too. Im sure theres many other FI guys out there in CA, shed some light on this situation.