ericwilloughby

Yeah man, its just a spring. Not like an electronic boost controller. I can hear mine start opening at 5-6 psi but it settles on 10. A little higher than that as I go through the gears. I like that though. It lets me tune richer as the gears go higher. I.E. It fuels by the 166 kpa boost column in 2nd gear but uses the 171 or 175 column in 3rd..

So what was the pressure drop through your intake system?

Even if you had an inaccurate gauge, it wouldn't change the fact that your numbers were different...know what I mean.

ericwilloughby

Don't expect perfection on this either. The MAP is on the front of the manifold and I had by boost gauge on the vacuum lines at the rear. I was seeing a 2 psi difference at times so I moved my gauge to the evap solenoid connection on the front of the manifold and voila. Same reading...don't sweat a few psi difference.

JAX04

iTrader: (17)

well eric, i never checked the pressure drop through the system, i mean, its 2.5 inch from turbo to innercooler, then 3" from the innercooler to the TB. I dont think im making near enough power, or air for this piping to be holding me back yet.

I noticed today that spool took FOREVER! before i was cracking my wastegate by 32 to 3400 RPM. Today, it seemed way slower, Only changes that were made was a 12" downpipe after turbo. 3" diameter and its a straight shot with two very small bends, and i re-referenced my wastegate. Now, i did forget to block off the turbo reference point, but seriously, and 1/8th hole couldnt be causing that much spool issue. (could it??)

i read through zombies post about back pressure, im 2.25" from both headers to where the factory makes its catback connection, then its 3" from there to the turbo, and EVERYTHING is wrapped tight. (2 pipes at a diameter of 2.25 inch is not a 4.5" pipe, its closer to a 3.xx pipe. So with all that said, im still in a good posistion as far as exhaust size. Thinking back to HVAC class and my flow charts that i have.)

Today, i didnt crack my wastegate till 4k or a little higher, NO clue what happend. And it still only built around 3.5 to 4 psi. So it would seem if:

1. My 3" dump pipe is killing me, but seriously, how could it be. not sure.
2. that port on my turbo killed me that bad, again, dont see how it did,
3. ****, i dont know. Im going to change the spring, close the port, if that doesnt help, ill explore flaring my 3" x 12" long tail pipe to about 4" or 5".

Not sure, but it is a pain. Lucky for me(a noob)---

Zombie, eric, and people of the like have paved the way and can offer good insight to my issues.

Ill report back after i block off port, and change spring.

Also, eric, my map sensor is located at the same place my gauge is, the back of the manifold right next to the factory MAP location.

It took us for ever to get our MAP offset correct, hell, it took us 2 hours to get the car out of the driveway after installing the 2bar OS.

Zombie

iTrader: (2)

the T61 should have a 3" V-band so you should be fine with a 3" exhaust after it as long as you don't have something like a 90 degree bend closer than 6" after the output. If you do, that could be an issue.

When you said headers, you really meant manifolds right?

a 1/8" hole is a bigger leak than you think it is Shows you how important fixing leaks are. I'm lucky, my friend 1320 made my new cold side piping, only it only uses 4 couplers, turbo to ic, ic to tb and it's all 3"

Don't get discouraged yet, it takes time to work all the bugs out. I've had more bugs in my setup than most, but we were learning along the way and didn't have a map to follow.

When you get your setup right, that t61 should spool almost instantly at anything over 2500 rpms.

JAX04

iTrader: (17)

oops, i did mean manifolds. absolutley. And i was completely wrong, i did have that thing 1/8" hole plugged. It has a piece line on it, with a bolt in the end and ziptied down. Its not leaking.

So, with all that said, i cant figure this out now. I just got done putting my 10lb spring in the gate, and thought for sure id atleast hit 7psi, WRONG. Hit hit a solid 4.5 close to 5. end of story, gate never opened, and it didnt build anymore boost. AFR was around 11.5 and leaning out, so i backed out, and we have a whopping 24 degrees of timing up there right now, it is strong as can be. Im not sure,

I can tell you this, i know my AFR is decent, maybe ill have my tuner command it to 10.5 in that area we are at, and remove my tail pipe and see what happens.

Before i had my tail pipe put on, which was Saturday, i was able to hear my little snail starting to spool up at like 2300 rpm. It had a nice solid whistle. Now, im at 3k and have to listen really hard to hear that thing.

here is my tail pipe

sbcgenII

iTrader: (1)

Is that your wideband in that last pick? Are you tuning off that? Whats the boost at the turbo itself when the gate doesn't open? You might wanna check your back pressure also.

Zombie

iTrader: (2)

That DP should be fine. You are chasing some other sort of leak, either exhaust or cold side.

JAX04

iTrader: (17)

yes, that is my wideband, and yes we are tuning off of that. Just like every other rearmount car out there. Or atleast the ones that dont want skewed readings.


i had an Epiphany lying in bed last night. I think i have a pretty nasty bottle neck within 2' after my turbo (coldside). If you look in the pic that shows the piping at the turbo, it makes a hard 90* bend to go arount the differetial. Its crush bent, and let me tell you, it is crushed.

sbcgenII

iTrader: (1)

Was thinking your o2 was closer to the turbo and tailpipe that it actually is. Try checking the boost before the bend and see where the boost is at. If the bend is a problem you could weld in a larger diameter one to make up for it. Do you have a boost controller hooked up yet? What A/R is your exhaust housing?

JAX04

iTrader: (17)

yeah, was actually just on mandrel bends.com looking at there "welders kit" and thinking i may just get the ones i need and have my fabricator replace all my crush bends with mandrel bends. Or try it my self.

I was thinking i may try to measure the pressure before and after the bend., seems like id have to weld in a 1/4" pipe bung in two places to really get the idea, then i could plug it when done.

lilgcts-v

im curious to see what this thing puts down on the dyno, i would love to do a build like this for my V

ericwilloughby

Wait man wait. There is a simple test to determine your backpressure in the cold side and you've already done it. Reference the wastegate off the compressor housing and compare that boost, measured with a gauge on the manifold, to the boost you get when you Reference the gate off the manifold. The difference is your cold side boost loss. Even with this immediate 90 degree hose bend out of the turbo and a crushed bend just after that I had about 1 psi loss.



I think you are having a gate problem? Bench test that sucker with an air compressor to see if it is working right before you redo pipes.

JAX04

iTrader: (17)

eric i completely forgot our systems were pretty much the same with exception that we are on opposite sides. lol. But what will a bench test do on a wastegate, its designed to work with exhaust pressure as well???

with the 10lb spring, i didnt open the gate, it just didnt build past 5lbs. I think my first step should be to get my pipes air tested for leaks, Cold side and hotside. Then work on figureing out why i lost 1000rpm spool time somewhere.

ericwilloughby

It may not show you anything. Just check to see if it is closing all the way. Even if you had some MAJOR leaks on the cold side that turbo should provide boost. Are you getting up on the wastegate, is the gate controlling boost just not at the desired pressure? Or is it not making enough boost to even need to open the gate? I'm thinking the latter. And you've got to have a gate problem.

Take the reference hose off the gate and run it. Be careful and quick off the peddle if necessary. And then take the whole darn gate off and block the hole......

JAX04

iTrader: (17)

well, i didnt take the refrence off, but i did change from the 7lb spring to the 10lb spring. and basically now, i just dont think its opening. It stayed at 4.5 to 5lbs, but wouldnt go farther. I do have the little round ring in the gate like im supposed to.

ill remove the reference and try that.

JAX04

iTrader: (17)

What about the BOV?????? Im using a greddy type RS bov, and had a lot of trouble getting it actually work. Infact, i had to back the spring almost all the way out to get it to open.

Is it possible that i couldve softened it up too much and its too weak now??

ericwilloughby

Only if the diaphram is busted. Boost helps hold the BOV closed, and when you let off the vacuum helps to open it. Good thinking though. If that diaphram is busted it may be leaking a lot of boost there. Air compressor test that thing too. Remember to keep the pressure <20

JAX04

iTrader: (17)

im going to give it a look tonight, means i gotta remove my good old front bumper, DAMN, i just love removing the bumper on this car

for anyone that didnt know yet, the turbo im using (updated first post) is a tiny little turbonetics 60-1 with a itty bitty .68 hotside. T4 divided. So, lol, i shouldnt be having any trouble spooling this too the moon and running out of steam with the quickness.

ericwilloughby

Before you go taking anything apart just put some air on that hose, BOV and wastegate, and see if the diaphram is busted.

JAX04

iTrader: (17)

will do eric. thanks man. still trying to figure out how im going to test the hot side for leaks. im thinking about hooking an air test setup on the outlet of the turbo (exhaust side) and taking my rockers loose so all the valves close. Then i could just test everything at once.