So I took the C10 to the dyno today and the outcome wasn't what I expected. Motor is a 2001 ls1, forged rods & pistons with a 70mm turbo. 96 ar, jgs50 waste gate, Speed inc Tu1 cam, dual springs, 60# injectors, 255 walbro pump, meth injection and a boost referenced fuel pressure regulator. On the previous dyno session with the top port on the gate vented and the bottom port to the compressor outlet I was able to get around 8psi on the spring. I wanted to be around 10-12 so I decided to try out an air regulator. I hooked the top port of the gate to the inlet on the regulator. Outlet on the regulator to a tee feeding the bottom port on the gate and the compressor outlet. I had the regulator completely open thinking it would use the spring pressure only and I could adjust to my goal of 10-12#'s of boost. Well....the first pull on the dyno at 4krpm blew the silicone boot and piping off of the throttle body. We walked to the front of the truck to see coolant leaking but couldn't see from where. All hoses ect were in place. Grabbed an inspection mirror and saw Coolant on the radiator in between the fan blades but only on one of the fans, and leaking straight down. After looking around I noticed a big gash where the intake elbow probably smacked it. I'm thinking it forced a bolt holding the fan on the shroud to puncture the radiator possibly. Only logical reason it would be leaking in the middle of the radiator like that I think. After review he said the map read around 200kpa if I recall. He said it was equal to about 15 #'s. I removed the regulator out of the equation and put it back to how it was the first time. Top vented bottom to the compressor housing and he got on it but not very hard because of the leak and it showed the same as the first Dyno tune session, about 8 pounds. So did I have the regulator hooked up wrong? This is the diagram I followed. Now I'm out of a radiator and more downtime FML. It did make 470 whp and 550 tq @ 4k though, before it popped off. Any input is greatly appreciated.

 

The very last sentence in the picture you posted says "Allowing no pressure to the top port will give you your lowest boost". If you loosened it all of the way up, you allowed pressure to the top port, meaning there was equal pressure on both sides of the diaphragm. This is basically the same thing as not running a pressure line to your gate at all.

Would've been easier to get a cheap manual boost controller and putting it inline with the line going to the bottom port.

 

I would think the outlet of the regulator would face towards the gate as the tee from the compressor housing is the boost source. By the directions you supplied turning the regulator all the way counter clockwise should close it not allowing any boost to the top of the gate. This would give you boost at gate spring pressure. As you turn it clockwise it will allow boost to the top of the gate adding to the gates spring pressure and raising your boost.

 

That's what my intention was, just as it would be connected to an air compressor. Turn it clockwise (+) to increase pressure and counter clockwise for less. I was under the assumption if I hooked it up per the diagram it would run off of the spring pressure (8#'s) with the regulator turned all the way out, then turn clockwise to increase to desired boost. It hit 15# @3800 rpm then blew the coupling off.

 

if your boost referenced, watch afr closely. imho the 255 isnt going to cut it.

 

You don't think the 255 will be fine at 10#'s with meth injection?

 

A single 255 with msd boost a pump, and hot wire kit with 60 lbm Injectors and meth got me 610 to the tires several years back but fuel pressure was dropping.

OP did you drill a small hole in the line down stream of the regulator if not, air most likely leaked past the regulator and was trapped in the line between it and the top of the diaphram which would have caused your over boost issur. I've never seen a air regulator that could hold pressure back unless there was a flow path. Get your smallest drill bit and put a hole in the line down stream of the regulator.

In order to test it put a tee in the line and install a pressure gauge in the line between the regulator and the waste gate make sure that the hole is already drilled. Hook up your air compressor to the inlet of the regulator with the regulator backed all the way off, start turning it clock wise and watch the pressure gauge you installed. As you turn the **** pressure will start to rise and will stabilize on the gauge. Every 1psi increase here will be 1psi more boost. Shoot for 4 to 5 psi to achieve you goal then remove the tee and gauge and let it eat.

 

Not all regulators are the same, or operate with usable pressure ranges.

So unless you have exactly the same one the person is using....dont expect it to behave the same.

A simple bleed valve is hard to beat for what you want to achieve, plumbed in-line with the single line to the lower port only.

 

with the money you have spent in other areas, why not use an aem tru boost or similar controller?

Crap luck on the dyno for sure, but with any new build we are going to be chasing things down and making refinements... I am chasing issues myself right now after about 20 perfect dyno pulls, lol....

 

Do you have a bleed valve you would recommend and a diagram on how to hook it up?

 

Any valve that gives you an easily adjustable leak really. I've used plastic fish tank valves which cost almost nothing, to various brass/alloy ones.

Really, take your pick.

All this MBC stuff are just more expensive versions of the same, so choose one of them.

All you're doing is introducing a small leak into your existing line to the lower port on the w/g. This means the gate will open much later as it thinks there is less boost in the system.

Whilst I havent used anything like it for almost 15 years, these sorts of things were once popular....and can still work for many. These tend to have a check valve type affair so it also restricts boost getting through for a few psi, to try and help prevent the gate cracking during initial spool.

http://www.ebay.com/itm/NXS-MANUAL-B...RZReOU&vxp=mtr

http://www.ebay.com/itm/1-30-PSI-ADJ...RYZXmg&vxp=mtr

But really, you could probably find dozens or maybe hundreds of similar items.

Some old info.

http://www.autospeed.com/cms/article...ntrol&A=107770

 

what's the difference between a bleed valve/MBC and the air pressure regulator I used. Pretty sure they do the same thing.

 

The big difference is the failure potential. With his way, you can't ever boost above the spring in the gate, even if the bleed fails. With your way, if the regulator fails you will basically have a closed gate. I prefer to take the risk, but I am AWARE of the risk in plumbing to the top port.

 

Hi C-10, YES WRONG.

Connect the regulator to the Manifold Pressure AND the FPR ALSO.

Lance

 

if you didn't want to boost more then the gate spring allows why would you want/need a mbc? My current spring will only get me to 8 #'s. I would like to be more in the 10-12 # range. Can I double the spring or shim the current one to keep it simple?

 

By lowering the pressure to the port that OPENS the gate, you open the gate later. This gives you more pressure than your spring is advertised for. By adding pressure to the port that keeps the gate closed, you are getting a "theoretically" unlimited amount of gate pressure. They both can do the same thing, but the limits and potentials for failure are vastly different. While changing springs or shimming something IS an option, the fact is that the simplest adjustable option is lowering "or bleeding off" pressure from the bottom port. Every other option has a potential for a more problematic failure.

 

I'm not even a fan of manual boost controllers. I feel like every set up should use an electronic boost controller and a super light spring. The ability to manage boost accurately on the fly is super nice. And the main reason I always use one is if it overboosts the ebc will kill all boost and save your set up. Happened on my SRT twice. The first time I had a manual boost controller blew off a reference line and went straight to 45psi blowing ring lands. The second time I had a ebc set at 26psi blew another line off spiked to 28 then killed all boost. Saving my engine. Now i no longer use zip ties for boost lines but those small hose clamps where you screw them tighter on all of my set ups. Never had an issue since.

 

ok I'm confused how to hook this regulator up. Can someone draw up a diagram for me please or post a picture.

 

Ok so you have your waste gate. There's a spring inside of it in your case I believe it's an 8lb spring. Now there's a port on the top and the bottom. When air goes through the bottom port it pushes on the 8lb spring. Once the air pressure on the bottom exceeds 8lbs it pushes the spring open and limits boost. Now you can put a valve on the bottom that bleeds pressure so when the turbo is pushing more than 8psi some of that air gets bled off so the valve only sees 8psi even though there's more in the system. Now you have the port on the top. It's job is to push the spring down. So if you supply positive pressure to it it adds to your 8psi spring. So if it sees 5psi up top you have a total of 13psi in the system before it opens. 8psi spring + 5psi from the top port. By putting a valve on the top port you can control how much additional psi gets put on the top of the valve holding it closed.

 

I have absolutely no idea what regulator you used, so how would I know ?

If you wish to use that style of regulator, and AGAIN I state they are not all the same. This old article covers some options.

http://www.autospeed.com/cms/article...art-1&A=111348

http://www.autospeed.com/cms/article...art-2&A=111350

Any differences will be down to the internals and operation of whatever control valve you use. IMO it is hard to beat the simplicity of a basic taper seat type manual bleed valve.

But the others can serve useful purposes too.

And NEVER connect the FPR signal line to any line that leaks. ie that of an EBC or MBC etc.