240Z TwinTurbo

iTrader: (25)

I don't mind an argument, but you went straight to insults.

240Z TwinTurbo

iTrader: (25)

I fabricated one of these for my buddy in August 2003 when he was running a GT4294r on his 280Z. It was made from Inconel and Hastoloy X and was a PIA for me to machine. I posted on this previously...

https://www.evolutionm.net/forums/8273276-post29.html

http://forums.hybridz.org/index.php?...1&#entry753679

With all of that said you should first run a twinscroll setup to aid in spool.

sparky

iTrader: (1)

So, we can theorize all day but we aren't getting any closer to solving the OP's problem. His turbo setup exhibits slow spool. So......?

That Tomei turbo is a notoriously slow spooler considering it's relatively limited power producing potential. If you review the pertinent threads on this forum you'll conclude that since its inception tuners had a hard time making this thing spool quickly.

Let's be honest there are several stockframed options that both spool quicker and/or lay down better power numbers. The usual suspects are in no partcular order: the HTA Green, BBK-Full, HKS 7640, HTA 71, MAP EF2 and etc.

sparky

iTrader: (1)

I wasn't trying to insult you. But now I realize that I offended you. Please accept my apology. My remark about, "getting real," must have done it. I realized, but too late, that I was implying that your statements were unreal.

I hope you don't take it personally. I want to clear it up though. It is just that I never liked or used nitrous injection. I realize that other people have had great results with the stuff. It is just that for me nitrous injection seems potentially risky and extreme. It is just my personal conviction about using that motor drug though. Personally, I am afraid to even use meth injection on a gasoline engine, only feeling "safe' with meth in diesel applications.

So, please believe that it was nothing personal. I realize that my comment was, at best bit**y. In fact, I had gone back and attempted to edit my offensive post before you got a chance to read it. But, obviously, I was a bit too slow about at editting my remarks.

Again, I am sorry if I offended you, 240Z TwinTurbo

fromWRXtoEVO

iTrader: (18)

You should be doing a leak test first, then check individual components specially the turbo flapper, the flapper connecting rod to the waste gate solenoid and the solenoid itself.

Many components "freeze up". Thing can go wrong from a leak on a TB to a BOV open to a crack on the hoses to a dent or whole on the intercooler etc.

Carlos

Randal

Got it will do

Randal

Yes that is what I thought and others have told me as well, the M7960 is a slow booster. I am not interested in nitrous tho. Thanks for your help

240Z TwinTurbo

iTrader: (25)

I appreciate your response so no problem. I ran 125shot for several years on top of 20psi of boost with no issues. Therefore, I personally do not think it is "risky" or "extreme." Once I install the Curt Brown 10:1 2L bottom end I may add nitrous.

sparky

iTrader: (1)

So, does the Tomei M7690 have a TS, or an undivided turbine housing. If it is undivided then that is probably the main reason that this turbo in general has always been known to exhibit such lethargic spool, right?

unihappytime

Its a TS, see pic of the gasket that came with the turbo:



I'm also finding this thing slow to boost, and with a complete stock engine, this thing can't hold high boost.

I use a HKS EVC V (the one before the color screen), found out that setting it up to run like a stock turbo is hard, let alone any extra boost with my set up...

sparky

iTrader: (1)

As a first step, check everything that Carlos suggests above. Once you have discovered and corrected any boost leaks then as a practical matter we should move on to optimizing, or improving spoolup on your present setup.

The M7960's WGA is almost identical externally to the factory IX WGA. There is no way of knowing just from external appearances if they are the same internally with respect to spring rate and the diaphragm. But for our purposes it does not really matter as the Tomei WGA is adjustable. So, we can get on to the task of checking wastegate spring pressure and adjusting preloaded tension in an attempt to improve the spoolup on your particular setup.

Are you game for this? You'll just need a couple hand tools and a willingness to scrape your knuckles. First go down to the autoparts store and buy a couple feet of 4mm rubber vacuum hose and a few zipties or hose clamps.

Since you have a MBC do a simple preliminary test: Back the adjustment knob on your Hallman out all the way counterclockwise to full-soft(-). That is , the lowest possible boost setting attainable.

Take your car out for a spin and do a WOT run in 3rd or 4th gear. Check the peak boost level indicated on your boost gauge. Report back. It should be somewhere between 8-12 PSI. But we need to know.

Once you have done that test and noted the boost reading then you can move on to disconnecting your MBC. Pull off the MBC hoses at 1)the boost reference source(j-pipe nipple or IM/DV "T"), and, 2) the WGA cannister port.

Install a short length of the 4mm hose that you purchased between the nipple on the j-pipe and the nipple(port) on the WGA cannister.

Remove the exhaust manifold heatshield. Cover the radiator fins with a square of cardboard. Loosen the backup nut behind the turnbuckle on the threaded end of the actuator rod. Pop the cotter pin out that holds the turnbuckle onto the flapper valve's pivot arm. Pry the turnbuckle away from and off of the pivot arm using a flat blade screwdriver.

Rotate the turnbuckle inward, clockwise. First try three complete 360 degree rotations. You will have effectively shortened the overall length of the actuator rod. This "preloads" the internal spring inside the WGA. Keeping the flapper valve shut down onto its seat longer and counteracting the force of the exhaust pressure within the turbine housing which acts on the face of the flapper valve to lift it off its seat at a ratio of at least 2:1.

Once you have reconnected the turnbuckle/actuator rod assembly back up onto its home on the flapper valve's pivot arm then take the car out for a spin again and do a WOT run. Compare the new boost reading to the first one that you did.

For the meantime leave the WGA/discharge nipple hose hooked as above and the MBC disconnected. You probably will need to go back and add still more preload after the initial adjustment.

sparky

iTrader: (1)

Working from side-by-side photos of the M7690 and a stock IX turbo I deduce that the WGA's on the two units appear to be virtually identical with respect to actuator rod length, bend angularities and mounting bracket orientation.... Nearly identical.

I would be tempted to try either a Forced Performance HD 25 PSI, or 18 PSI IX actuator instead of the original Tomei unit. The OP might be better off with a 25 unit since he is running 29 PSI peak pressure.

Has anyone out there with an M7690 turbo tried replacing the original WGA with a FP HD unit? I wonder if it would just be plug-and-play.

sparky

iTrader: (1)

See my post number 26 above. Since you have an EBC you would need to disconnect that and plug off any unused boost/vacuum hoses. Then route a length of 4mm rubber hose directly from the nipple on the compressor discharge of the turbo to the nipple on top of the WGA. Then we can go about increasing WG spring pressure to try and get your turbo to spool faster.

sparky

iTrader: (1)

Unihappytime: What DV/BOV do you have on there now? The stock cat isn't helping your turbo spool any faster either.

meckert

iTrader: (11)

OP--what are the cam gear settings? Think you mentioned you had cam gears as well.