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Is this boost to high?

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Old 01-08-2007, 05:22 PM
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Default Is this boost to high?

I have gotten my boost controller hooked up and acting right finally. I currently have it set so I see a total of #15 and 11.1 AFR with Meth.

My motor is forged 346, 6.0l heads, Stealth II cam, and my CR is about 9:1.
I know my weak spot right now is my tranny wich is a stock 4l60e with shift kit and 3400 stall.

This thing almost scares my now. I have never felt it pull so hard.

I just wanted to know all the people out here that are running these kind of boost levels if this sounds ok.
Old 01-08-2007, 09:00 PM
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Are you at 9:1 or 9.8:1 like it says in your sig? I will tell you I built my motor to run at 15 psi, but I'm closer to 8.5:1. I assume your no seeing any knock, and you afr is steady, but I would definitely keep an eye on that stuff.

What kinf of #'s did you put down?
Old 01-08-2007, 09:07 PM
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is the sensor before or after the turbo?
Old 01-08-2007, 11:57 PM
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It might be a little high, I would probably run 12 max but it really depends on your comp ratio. If it's 9:1 then I'd say you're fine, if 9.8:1 then you might be about as far as you'd wanna go. There's a lot more air going in that thing with that T70 as well. You gotta be making some great numbers...I want to know
Old 01-09-2007, 12:25 PM
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The wide band is before the turbo.
Does anyone have a formula for CR
I know the stock motors are 10.5:1, And when I redid my motor I added the 6.0l heads which I was told would drop me to 9.5:1, and I also added the -9cc pistons.

I thought I was somewhere between 8.5 or 9.0 on the CR.
Old 01-09-2007, 01:19 PM
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I found a CR calculator and it comes out to be around 8.75:1 with stock gaskets.

That still shouldnt be too high for #15 boost should it?

Yesterday when I was testing it I wasnt getting any KR so that is good. And at 11.1 AFR I dont think I want to lean it out any more. I also do not want to run out of Meth.
Old 01-09-2007, 06:02 PM
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Be careful about trusting wideband readings before the turbo under boost. Mine tended to peg as rich as it would read at 10#'s of boost when I had it before the turbo. I knew this wasn't right, so I move it behind the turbo. It turns out the 9/1 readings under pressure were actually closer to 12/1. I don't know the exact reasons, but pressure really skews the readings.
Old 01-09-2007, 06:18 PM
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Originally Posted by gametech
Be careful about trusting wideband readings before the turbo under boost. Mine tended to peg as rich as it would read at 10#'s of boost when I had it before the turbo. I knew this wasn't right, so I move it behind the turbo. It turns out the 9/1 readings under pressure were actually closer to 12/1. I don't know the exact reasons, but pressure really skews the readings.

What he said....

get that bung plugged and put one in your downpipe.
Old 01-09-2007, 06:29 PM
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I have the AEM wideband kit and the wire that came with it I have already used all of it. I guess I can extend the wire to go all the way back. I guess it just needs to be installed where the exhaust exits the turbo.

I spoke with Rick at Synergy motorsports and he was telling me they did a back to back test and they did not see any difference with the reading on a sts kit weather it be in front of the turbo or after.
Old 01-09-2007, 08:08 PM
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I didn't see a noticeable difference on low boost at 5#'s, but a substantial difference appeared at 10#'s. I'm curious what boost they tested at, because the pressure ratio between intake and exhaust means that the exhaust pressure is dramatically higher with even a small boost increase.
Old 01-09-2007, 08:55 PM
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15lbs should be no problem with your setup.Timing will play a roll too.I would expect it to top out at 14-16 degree's.

I would build that tranny and add another fuel pump for safety.
Old 01-09-2007, 09:50 PM
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FWIW, I recently dynoed my car, and the wideband is in the y-pipe (before the turbo), and I saw a .1 difference in afr from my wideband, and the tailpipe sniffer. That was only at 5 psi though.
Old 01-09-2007, 10:58 PM
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I have been thinking about going to a dual fuel pump for safty reasons, is there a good kit out that makes it easy to go dual?

And does anyone here think I should put in a set of TR8 plugs. Im running TR6s right now.
Old 01-09-2007, 11:08 PM
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for yr fueling needs - http://racetronix.com/

or

if u wanna get nasty - http://www.nastyperformance.com/FuelSystems.html

or

you can build your own... lots of choices.
Old 01-10-2007, 12:18 AM
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At your HP level, the only thing tr8's will do is make you change plugs more often when they foul out. Sparkplugs that cold are pretty much a full race only option. Some people who have way too much time to caress their sockets may disagree.
Old 01-10-2007, 06:38 PM
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Originally Posted by gametech
I don't know the exact reasons, but pressure really skews the readings.
Its temperature more so than pressure, but both do affect them.

NTK sensors arent as bad, but the Bosch ones defo are affected.
generally you dont want the sensor to go over 1300-1400degF

Before the turbo will be way over that.



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