[oldman]

It is a sickness, I still have my heart set on a sheet metal intake...I'd sell my soul for it. I do like the idea of dual injection and I know the MSD can also take injectors.

[TJay74]

Originally Posted by PRAY

So the BOV surging pressure won't effect the stock TB? Seems that the surge on the TB blade will be the same until it is corrected.

My guess PRAY is the air turbulance going over the throttle blade. I will know in a couple of hours as I have a OEM stock TB and am going to swap it over and test out my theory.

[PRAY]

Originally Posted by TJay74

My guess PRAY is the air turbulance going over the throttle blade. I will know in a couple of hours as I have a OEM stock TB and am going to swap it over and test out my theory.

I have since revamped my TB porting and now leave the TB blade bar alone. I think with the blade being flat there is nothing to break the air and it can cause a flat hit on the blade. I did reconfigure the actual porting though as to not lose any of the benefits from the porting. They flow virtually identical. This is by far the weakest blade motor I have ever seen from GM. Any little air variance to it and it freaks out. None of the TB's before this have been this sensitive. I have things I do in the tune to lessen it's sensitivity now as well.

[DapperDan]

I am also having the same surge and have a ported TB , is it ok to swap back to the stock TB without doing anything to the tune?

[TJay74]

Originally Posted by DapperDan

I am also having the same surge and have a ported TB , is it ok to swap back to the stock TB without doing anything to the tune?

I am gonna say yes, at least I did today. BUT.... It didn't fix the issue at all. I am still seeing surge, my log runs are confirming that something is going on airflow related. On steady state drives the MAF and MAP are showing large spikes and dips.

It is continuing to lead me to thinking it is the BOV causing the issue.

[Chevy71]

Originally Posted by TJay74

Eureka...!!! I found the culprit today.

Well after talking to a friend this morning who had the same issues on his car which is the same car as mine with almost the same mods we think we found the culprit and the reason. We both have a custom ported throttle body on our cars. I spoke with Procharger yesterday and they said the BOV is causing the surging issue due to the standard BOv is only 1.5" and the Race BOV is 2". They said the car is seeing BOV surge that is making it past the BOV and into the intake because I am over the limit for what the standard BOV is designed to handle.

This is where the TB is fitting into the equation. Not only is the TB ported, the TB blade arm was thinned down as well. When I am at steady state cruise the TB blade is partially open, when the surge of air hits the throttle blade the air changes the TB angle and the ECM freaks out as it isnt expecting the TB angle to change and in turn it is adding timing advance to control the expected torque change. This explains why it only happens at part throttle steady state cruise as the blade is only partially open.

Moderate throttle all the way up to going WOT doesnt affect it as the blade is fully open and level in the airstream so the blade angle isnt changing.

When I get home later I am gonna change back over to my stock OEM TB and see how the car does.

I can tell you it will do it with the stock TB as well. Mine was giving me this same issue, so I did some real redneck sh!t (I'm only proud of it in certain company.). I ran a few data logs with desired pedal position, actual, and TB position along with timing, HP fuel, Boost etc.. I could see hiccups in the data, but also wasn't certain how precise the data was with the sensors on the car, as well as pin pointing the surges on my data logs to compare them to "normal" state driving. I thought it was a tune issue and wanted to prove that. My tuner told me almost right away it was because I was asking too much of the bypass valve and I probably needed to put the race valve on. This is where the redneck stuff comes in, I called myself from my wife phone on FaceTime, then duct taped it on a support bar above the BOV so I could see it in real time while I was driving. My buddy watched the video and I watched the road. Every time that surge would come on the arm on the BOV was moving. I unhooked the valve and took it for a quick easy ride.. sure enough no surge at all. I ordered the race valve the next day. Still haven't put it on though haha

[DapperDan]

I have the race valve with the exact surge stated by the Op I was thinking he was on to something with the ported TB guess not

[oldman]

I heard the race valve needs the tank to be welded?!

[DFW1LE]

Originally Posted by PRAY

You're out of control.

Oldman looking to be in 800-900 whp range, I see a fuel system upgrade in his future.

[Chevy71]

Originally Posted by DapperDan

I have the race valve with the exact surge stated by the Op I was thinking he was on to something with the ported TB guess not

DANG IT! I was thinking/hoping that was the fix for this.

[Chevy71]

Originally Posted by oldman

I heard the race valve needs the tank to be welded?!

Where at and do you know why? I haven't heard this.

[TJay74]

Yes there is welding needed to be done in order to fit the Race valve or even a Tial. The standard exit on the I/C is 1.5" and has a 2" long extension that projects off of the I/C. in order to put a larger BOV on you will need to cut the existing flange off, then enlarge the hole on the I/C and then weld a new 2" flange back on the I/C so you can run the larger 2"/50mm BOV.

[PRAY]

Not the ported TB. Thanks for the update.

[JANNETTYRACING]

Originally Posted by TJay74

Who all has a D1SC on their manual SS?

I got mine installed, car runs great so far. Only one slight complaint, I am getting a little surge at light throttle steady cruising state. Anyone else with a M6 seeing this with their D1SC.

The shop said they see this on the M6 cars, the A8 cars dont get it as much due to the converter. They said when they swap a Z06 over from the LT4 blower to a Procharger they run a different Surge (BOV) valve to keep from having the issue on those cars.

We both agree that it is some sort of torque management causing the issue.

Anyone else have any suggestions or has been able to adjust for this?

Thanks in advance... Todd

The D1SC is a big supercharger and it needs big bypass to eliminate surging and light throttle.

The blower moves air based on Engine RPM but you are in control of the throttle blade opening.

You have a large amount of air backing up in front of the throttle blade but the blade is barely open, this is what causes the Slinky effect or Surge.

Move to the Race bypass or add a second bypass to the Drivers side or Hot side of the intercooler and your surging will go away.

I prefer to run 2 as it can have more volume than 1 large one.

On my YSI Camaro I run 2, 50mm Tial Q valves with 1.5 psi springs.

Ted.