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I’ve been playing with the MBC in line to the bottom of the WG. I set it to the same ish psi that I was using for the 8psi and it seems to be working. I hit 157.3kpa right on the nose at 1/2 TPS %. I cranked the MBC down another turn and hit 160kpa but still around 1/2 throttle. The MBC is bleeding boost to the bottom of the gate forcing it to run on spring pressure alone.
I’ve been playing with the MBC in line to the bottom of the WG. I set it to the same ish psi that I was using for the 8psi and it seems to be working. I hit 157.3kpa right on the nose at 1/2 TPS %. I cranked the MBC down another turn and hit 160kpa but still around 1/2 throttle. The MBC is bleeding boost to the bottom of the gate forcing it to run on spring pressure alone.
You have a pic or drawing of how you have everything hooked up and plumbed?
I have attached 2 pics. The diagram is exactly how I have mine plumbed. My MBC instructions showed it going to the top of the WG, when I did that the adjustments for increasing boost was backwards.
Thanks. Work must have blocked the pics. Have you tried moving the source to the intake instead of the turbo? In the spirit of experiments want to give it a try and report back any difference in boost?
Thanks. Work must have blocked the pics. Have you tried moving the source to the intake instead of the turbo? In the spirit of experiments want to give it a try and report back any difference in boost?
i did that a while back. I made no changes on spring (no MBC) and went from the compressor housing to the intake and it made the exact same boost basically. Might have been off like .2kpa. This was at 6psi I believe. The good news is that the MBC is working as I can only make 6psi off this spring with boost running to the bottom port on the WG. It was making 8-9psi with the MBC installed. I don’t really need a lot more, I want like 10psi which it just blows the tires off anyways at 8psi so... I might just crank it up a few turns and see what it gives me.
I bet if you remove your exhaust and just dump your down pipe your boost will nearly double. You have a 5.3 with ported heads, a decent size cam and the nnbs intake so your engine is setup to flow. Then you installed a small turbo with a small turbine housing and a full 3" exhaust. I bet if you measured back pressure it would be super high. This is why its not a quick spooling setup.
I'm sure back pressure is higher more about the turbo sizing than the exhaust size. A 3" exhaust/DP will support something like 800whp. Sure I'm loosing a little by running a full exhaust but its needed on the streets. I have a 3" electric cutout but Its not really needed and Ive heard too many people complain bout rattles/leaks or failures. So you think being in boost by 3k is not quick spooling? I also blame the 3" crossover
Just an update. Dual springs in WG netted 25-27psi cracking pressure. Logs show 12-12.5psi boost and boost gauge peak recall saying 14.5psi! Only got to 78% TPS but tire spin is a problem. Ordered some new 275/45r18 MT streets and yanked my tires off the car tonight. Going to swap the 275/40r18 sumimoto htrz IIs for these and hope for some good street traction.
Not sure about boost at this point. Stall is like 3k which is when boost starts so it spins the tires unless I roll into it then I can go heavy and not loose traction. Boost still starts like 3-3500 and builds slowly but I blame traction and me not being able to get on it!
is 15psi safe on 93 pump at 15-16* with 750cc 50/50 or 70/30 wiper fluid and 11.5:1 AFR?
these 275 DRs look wider and they are about 1” taller than the 275 sumimotos.
You should pull a couple degrees since you don't actually know what max boost is yet. You're going to load the motor more with those bigger tires, have traction, and still haven't been WOT.
You should pull a couple degrees since you don't actually know what max boost is yet. You're going to load the motor more with those bigger tires, have traction, and still haven't been WOT.
How much should I pull timing?
This is my timing table.
Decided to get a AEM tru boost gauge so I can control boost pressure when I want it and it gives me boost cut to save the motor. I will reduce the current WG dual springs to either the single spring which netted me 4-5psi or a slightly larger 8psi spring which should net me max 6psi. Then let the tru boost increase boost accordingly.
Tru boost installed, boost cut set to 15psi. I pulled the dual WG springs and installed an eBay 8psi spring which was slightly stiffer than the 12psi spring that came in my gate that netted me 5psi of boost or so. So hopefully I get 6-8psi and I will let the tru boost do the rest. Need to play with the duty cycle of the solenoid but have it at 30% for boost A and 50% for boost B just doing initial setup.
05-09-2018, 09:15 PM
