Well, here’s the dichotomy of the situation…

• UTEC and boost gauges are not synched, but tee’d to the same line. When I convert psi to inHg in comparing vacuum, UTEC is reading a stronger vacuum by about 9% compared to the other gauges.
  
• UMS tee’d directly off Kinetix manifold, and their psi results are almost exactly as shown in the picture listed above (boost drop after 6k rpms)
  
• Boost gauges are not seeing the same, significant boost drop as graphed. Best I can do is visually record activity on the Blitz and post as a video on here.
  
• AFRs are within normal limits (low 11’s) in the upper range; UTEC not picking up any knock in that range (did pick up some knock there around data line 218 (x-axis) and retarded accordingly, so fuel delivery appears appropriate?

Again, something is happening at 6k rpms and the boost is disappearing somewhere…

So, task list for now, I guess:

• Fab a solid intake;
• Synch all gauges/sensors to ‘see’ same vacuum/boost. How can you calibrate the MAP in UTEC?
• Mechanically verify timing?
• Re-record data.

 

No one wanted to chime in...?

As an update, I fab'd a 3" intake to replace the rubber APS accordion thingie and recorded the data following install. Was also an opportunity to experiment with powdercoating, for which I have a long way to go to perfect that technique...

Below you can see one of the major kinks in the intake before the refab; the other kink was located at the other end of the rubber intake that connects to the intake pipe running alongside the length of the motor. As I was not able to find any mandrel S-bends with a tight enough diameter to work around the power sterring and steering knuckle, so had to resort to a miter saw, modification of the intake pipe, and a lot of puzzle-solving. I was quoted nearly $800 - $1000 by a local shop to fab something similar, and now I can see why, given I invested about 12 hours myself...

The results are impressive... the duty cycle on the Blitz was set at 40, gain at 9. As you can see in the graph below, turbo spools a lot faster, rpms build quicker, and boost taper is not nearly as dramatic above 6k rpms, though there is still some loss. The last two pics are before and after the fabrication, respectively. Set the duty cycle down to 25, which accomplishes 13psi now... though you can still feel the car break up a bit above 6k rpms in 4th and 5th gears.

Still seeking any input about the boost loss above 6k rpm. I also logged other UTEC items if anyone wants to look at the data...

 

i think im reading it right. seems to be better, right?

 

truckloads better, yes. +3psi, spools much quicker, power comes on right now; you can definitely feel the improvement, but would still like to pinpoint reason(s) why boost tapers -1psi afer 6k rpms

 

Boost usually tapers as you approach redline, most singe turbo kits do that, unless you have a really big A/R.

A bigger more free flowing exhaust might help.

-George
GT Motorsports

 

My understanding is the housing that GTM installed has a 1.06 A/R, using the APS exhaust... not sure how much more flow would be necessary to hold 15psi steadily? EGTs are under 1600* F at full throttle

 

Hmmmm. Ill be looking into this on my car shortly.

 

glad to hear, if it was me id live with it.

if only you had bought my custom external WG setup.

 

I got me a GTM version of the same does that count?



If I cannot pin down the cause as to why I can't level out boost above 6k rpms I probably will live with it... the frustration in that tuning around that pressure drop presents as a challenge.

Aside from it breaking up and recording a number of knock events in the upper gears in that range, it drives great.

 

I would take it easy until its re-tuned, or pull some timing if its knocking in the top end now that the intake isn't collapsing. That will change the boost characteristics and you are no in a different area of the map than before.

As I stated, boost dropping of towards redline is normal, the only way to alleviate it is to run a larger exhaust. I wouldn't consider this a problem.

-George
GT Motorsports

 

Try pulling 2 degrees after 6000 to see if maybe your past mbt on your map.

I have to ask, that miged down pipe and dump, was it made by gtm??

sometimes a pressure drop in the top end might be attributed to being out of the compressors efficiency zone. I'm sure it was mentioned but what size turbo and how much power are you making, could you be close to maxing the turbo?

Good luck!

 

yeah thats probably good enough. glad to see its running better.

 

just remembered something else. Some boost controllers that are duty based have an issue with following the torque curve of the motor, due to the volume of exhaust gas changing. we've had issues with the NLR AMS 500 (one of the best EBC's around) having peek boost around peek torque and then declining from there a bit. If your boost controller allows you to taper your boost, do so to raise the top end to correct the issue.
good luck.

 

who did the welds on that open dump mod?

and is this the same car from the BZM vs GTM epic-ness?

 

GTM

the very same...

That I've found, there is no such function on the Blitz

GT35R... power depends on which shop/dyno it's on... as little as 406 at UMS (Dynapack), as much as 501 at GTM (DynoJet)... I mapped the efficiency both before and after (will post sometime this weekend), vastly improved but still leaves something to be desired, thus my interest in resolving the 1 - 2 psi drop from 6000 - 6700 rpms.