chevyboy.520

iTrader: (6)

I know a guy, he would gladly take that turbo off your hands lol.

sprayedenali

iTrader: (11)

I for some reason find it very strange that youre boost is falling off up top like it does... that turbo should flow more than enough to make the numbers you are..... what, if any, boost controller are you running? the S400 turbos are a very high pressure turbo, so they dont really get into their efficiency range until much higher boost levels than you are running, so im wondering if you start telling to controller to make more and more boost if the turbo will get to its happy place and work a little better for you. make sense? and you really should be able to run more than 8*!!! what plugs are you running? i know my 5.3 is almost like apples to oranges with your 6.0 but i had 20* with 100 octane fuel and over 30psi of boost with zero knock. maybe how youre bringing in the fuel has something to do with it....?

smokeshow

iTrader: (16)

I'm a bit confused too. I talked to Jose at FI today, and he was saying I should move the WG reference to the compressor housing because I could be getting bad boost readings from the manifold due to intercooler pressure drops. I'm not too keen on drilling and tapping the compressor, so I think I'll leave it how it is. But he figures I'm getting a 5-6psi drop at the intercooler. Now to me that says the turbo is actually in a higher volumetric efficiency range because its following the map islands better. I don't think the pressure drop at the intercooler is really that high; the company advertises less than 1psi drop since its an air to water setup, but interesting to consider whats happening if it is that high.

I'm running a Hallman boost controller. If I had an EBC I would definitely have tried the 'boost gain' option Its got TR7 plugs at .035. Its definitely no slouch even with only 8° of timing, so the boost drop is likely the biggest culprit. Maybe it likes lower timing..? Its making 600rwhp at 3500rpms so there is plenty of 'under the curve' power

black00chev

iTrader: (2)

I wonder if you are blowing out the spark at all in those upper RPMs, maybe run a little smaller plug gap? Or maybe like someone else said the turbine wheel is choking up top?

smokeshow

iTrader: (16)

If its blowing out the spark I'll have to deal with it lol. The truck ran like *** at .030", not worth it to sacrifice that much driveability. I'm not so sure its the exhaust side. This is borg warners 'small' exhaust wheel, but still large compared to other manufacturers normal sized wheels. Plenty of people putting down more power on relatively tiny exhaust sides.

sprayedenali

iTrader: (11)

i personally dont like getting the boost reference off the compressor housing... you want to know how much boost is in your manifold nt at the turbo, thats almost irrelevant. and from my experience the 7 plugs dont work too well... ive had great luck with TR6s (on a nitrous setup) and now im running BR9es's (or whatever the 9 range non-projected plug is) with a .025 gap and my truck runs fine! it doesnt make a bit of sense but when i had 7s it wouldnt run worth a **** then i went to a 9 with a tiny gap and its fine...? haha. so maybe give them a whirl..?

what are the atual specs on your turbo? what size wheels and everything?

joeyc125

iTrader: (7)

I had trouble keeping constant boost with a hallman, threw it away and used a low pressure air regulator and it stays steady as can be now, and holds my wastegate completely closed until 10psi. It would crack open slightly at 3psi before, and spools a little quicker now too.

smokeshow

iTrader: (16)

I think I figured it out. Like joey said, the Hallman is cracking open like a 'bleeder' type boost controller. All this crap about it being different than the other controllers...bs. Its not holding the line closed until a specific boost level like they say, its bleeding off some of the line's boost that goes to the WG...I can feel the little pressure relief blow air when I pump it up. I rigged up a little pressure tester with a pressure gauge, some rubber lines and a bicycle tire pump lol. Put like 20psi into the line that goes to the WG and quick spool and the QSV actuator isn't budging...so the bitch is stuck closed again. So much for the Hallman helping the quick spool stay shut until target boost...

I'm going to reroute the reference lines today to give the quick spool direct manifold pressure reference and leave the WG solo on the boost controller. I'll post back up with results later

joeyc125

iTrader: (7)

Yeah, with the hallman, target boost was 12, it would go to 12, fall a little top end, spike at shifts, etc. Used the pressure regulator and it doesn't vary more then .5 psi

smokeshow

iTrader: (16)

Do you have a picture of this regulator?

I swapped the reference for the quick spool and it definitely feels better now. Not a HUGE difference, but probably worth maybe another 50hp or so. It fries the tires off up to 75 now instead of 65 Its enough additional air that I'm going to have to retune it, though.