Folks -- I have noticed since my car was new that the boost does not spike as fast as a friends identical 9. I have used stock setup, 2 MBCs, and now a modified setup where I spike at ~24.5 and taper to 19psi. My turbo appears to hit decent boost, just not as fast as my friends car and I am wondering if my WGA is lazy / opening early / spring is softer?? I hit peak @ 3600 in 3rd gear when doing a WOT run from 2400 rpm....Thoughts??

 

What are his mods?

 

Your next mod should be an MBC. From there you can adjust WG preload up mechanically from the stock 11# to a more responsive 18#. Off hand, your boost spike seems a bit high to me, even on a IX with 93 octane. Are you running 91 or 93 octane pump gas? Do you monitor your boost and EGT's with the Zeitronix?

 

I am a little confused because in your first paragraph you mention spiking to 24.5 and then further down you say you are spiking to 25.5 Which is it? Also,why did you change out your two previous MBC's? Finally, I am curious, what is this "modified system", which you refer to?

From the factory, these cars usually have base boost pressure set at about 11#. That is where the WG will open if you eliminate intercept devices such as MBC's and the factory BCS, or EBC's, bleed valves, restrictor orifices, and etc., and run a hose directly from the turbo discharge nipple to the WG solenoid nipple.

Set at 11 P.S.I.( if it is full open @11#, then it is already partially lifting and open at 8#)the WG flapper valve starts lifting off of its seat at the end of the WG bypass port way earlier , which allows exhaust gases, which should be driving the turbine blades, to instead, escape out through the turbine housing's WG bypass port, thus slowing turbo spoolup.

You can increase the WG preload by shortening the actuator rod. For the street and on pump gas, a preload of about 17-19 PSI is good, and then the final few PSI you dial in with your MBC or whatever boost control device you decide to use.

So, what is this modified system of yours exactly? If you prefer MBC's to EBC's then put whichever you prefer, back on your car and, at least, set preload up to about 18# and you should definitely see improved turbo spoolup and response. At least I think so, FWIW.

 

Hmmmm sorry I don't follow your logic....I have used an MBC and have much better results holding boost up top with the ECU....I had the same 0 to peak boost characteristic with both the MBC, stock BCS, and modified BCS....

I run 93 octane...Yes I log boost etc. with the ZT and am not having problems with knock....So the question is do folks think this is a lazy WG? Should I upgrade to a Forge or FP WG with an 18# spring? Thanks

 

How much do folks shorten the rod? Do you just turn the end a few times? This sounds like an easier / cheaper solution than buying a new WGA...

I put an inline bleeder to the BCS with a #59 hole in it and removed the pill going to the BCS....Right now I am 24.5 psi peak....I was at 25.5 psi peak, but felt it was a bit too much for 93 octane...

 

Yeah, it'd be a more economical idea to tinker around with the stock WGA before plopping down cash for a blingy aftermarket one. At least you can try your stock one. And it should do the job just fine, I think.

Don't go just shortening the threaded WGA rod w/o 1st verifying what your base WG pressure is. To do this you'll need to run a length of vacuum hose directly from your boost reference source to the nipple on the WG solenoid.

 

What manner of boost control is your friend's identical IX with faster spooling turbo using? Does he use the same system of bleeder valves and restrictor orifices that you are employing on your IX? You might wanna try swapping out your setup for his, if his is different, just for comparison's sake. I'm guessing that he uses some more conventional method of controlling the boost duty cycle.

But to answer your original question, in general a too "loose" WGA will make your turbo spoolup lazily, because it allows the flapper valve to lift prematurely, thus venting exhaust gas from the turbine housing, slowing spoolup of the turbine. You can adjust tension by shortening the threaded actuator rod, raising the base pressure of 11# up to a more ideal preloaded 18-19#.

Once the preload is achieved via shortening the actuator rod to 18#, then the last few PSI of boost are dialed in via an MBC or EBC normally. However, in your case, since you have an unusual system of bleedvalves and orifices, it remains to be seen whether you'll be able to safely control the last few pounds of boost between the higher preload point and your peak targeted boost level, without the use of a traditional adjustable boost control device.

That is, will your improvised system w/o MBC or EBC, give you high enough resolution and an effective means of control once the WG preload has been increased? Or does your existing setup only work with a lazy WGA. The problem you might encounter if you increase WG preload significantly, with your present boost control method is an inability to control peak boost, resulting in boost overshoot.

I'd say that if you want faster spool you're gonna have to shorten the actuator rod. And that when you do, you'll be better able to control boost between the new, higher preload setpoint and your max boost level, with an MBC(or EBC). Just my .02.

.

 

^^ Thanks Sparky! Your suggestion makes perfect sense....I will try it tonight or tomorrow, thanks again....

 

cij911, when you finally get around to shortening your actuator rod to 18#, please post back as I am interested to see if you felt a noticeable difference in spool... thanks, man...

 

^^ Will do....I am trying to get VIP to install my O2 housing and make the adjustment today....

Update:

VIP installed the O2 housing and we adjusted the actuator rod (turned the turn buckle 2 rotations)....The turbo hits much harder than before, so I think adjusting the rod helped significantly. Unfortunately I cannot tell you what psi actuates the WG, but it definitely is not as sloppy as before. Thanks to Martin and Soap at VIP ...

 

Ok so after much logging it appears that tightening (shortening ) the wga rod helped a bit, but the turbo still hits slower than most 9s I have seen ....

Peak boost (25 psi) hits at 3600 rpm but hits slowly as if the WG is open/opening...Or the turbo is weak)...

I just dyno'd the car and am making ~315 awhp/ 315 ft lbs...The torque curve is extremely flat from ~3300 - 5600 and the Hp curve seems to flatten a tad after 6100 (my guess is that the UR catalytic converter is killing the top end with this much boost)...

So, my question is when should I be hitting peak boost, are others experiencing this phenom (slow spool) and the flat top end? I am holding great boost throughout so I think my turbo is fine, but would love an 'expert opinion'. Thanks a bunch

 

just dent in the top of your wga

 

[quote=FastAzzEvo;4088148]just dent in the top of your wga[/quote]

I think that FastAzz ^^, means, "dent in," the top of your diverter valve, not your wastegate actuator. Which leads to an interesting point, which is that your diverter valve, may be a bit weak and is bypassing charge air early, thus slowing down your turbo spool. If you wanna test this theory out, all you have to do is pull out your diverter valve and install it backwards. If your turbo spools faster then that your DV is the culprit, and you could benefit from "crushing" the top of the DV in a vise.

It could be also that the shop that installed your O2 hsg., just didn't shorten the wastegate's actuator rod sufficiently. If you want to be boosting 24-25 PSI peak, then your WGA preload should be set up around 18-19 PSI. If they left it(preload) at, let's say 14#, then you could try shortening the rod another rotation.

 

Thanks Sparky! I will try shortening the WGA rod even more as well as look at the diverter valve. If the weather improves, I'll try these suggestions this weekend. Thanks again...