Procharged z06. Throttle Only ~60%

[doc350]

Just recently finished putting together a '15 z06 with a baby can and a Procharger conversion. I'm working on getting the MAF dialed in, but the throttle body is only opening to ~60%. I have tried raising the DD tables to extremely high numbers, but there is no change.

I did notice in the log that my Delivered Torque maxes out at 868Nm (640 ft/lbs). Is this just an upper limit of the 2.24 scanner?

I think part of my issue is starting with MAF tuning rather than getting the VE dialed. Would this affect the throttle?


z06_procharger.hpt
z06_pc2.hpl

Edit: When the car was stock (w/ a CAI) I got 100% throttle, so there is something limiting it....

[Ben Charles]

When I get home later I'll take a look...

I always seem to fix 100% throttle issues with the DD/peak tq table...

Yea that limit is the max the scanner shows, but the Ecu uses values above that

[doc350]

Yeah, I typically do it the same way. I bumped the 100% row in the DD to 2,000 just as a test and nothing changed...

It seems that the VE is off enough with the cam that is in the car that it is throwing something off. I switched over to tuning the VE instead of the MAF and things have started improving. Not perfect, but improving.

It seems like even with VE turned off, it still has an effect.

[RickClarke23]

That's not high enough in the DD tables

[Higgs Boson]

Is your DD table in kilowatts or axle torque?

[doc350]

DD is in kW. I raised the value in the 95 and 100% rows to double what it is in the tune I attached, and there was no difference in the throttle.

I started playing with the Airmass Torque Coefficients and making them LOWER seemed to help, but not completely. So now my question would be, how do these relate to DD and Peak Torque? I don't want to make drastic changes without understanding what they might effect.

My thought is that since the centrifugal supercharger makes less torque at lower RPMs than the roots style that was originally on the car, it's not asking for as much torque so I get less throttle. Does that make any sense?

[Higgs Boson]

Can't view tune on this computer.

First, put everything back to stock regarding airmass, tm and dd tables. make sure all your torque limits like axle torque, tcc torque, etc etc are all maxed out. make sure your brake torque multiplier is 1.0 not 0 since it's a multiplier. there is a good chance you are being limited by something other than DD or PT......

next try to imagine what your car should make....800 rwhp? 1000 rwhp? whatever. let's say 800 rwhp. That is 975 at the motor (give or take whatever).

kilowatts is 1.34 X HP so you want your DD 100% row to be 1500 across (for now).

let's say stock DD is 600. 1500/600 is 2.5

multiply your Peak Torque table by 2.5 in the area where you are having a throttle closing issue.

leave airmass stock for now.

adjust accordingly DD and PT.

If there is one issue I am not having, it's throttle closing. my airmass tables are stock.


if these changes don't work, you have a limiter still active somewhere else. you also need to make sure to tune the GMVE table.

[veee8]

The M7 ZO6's will do this with the stock blower once you start changing pulleys.

[doc350]

Can't view tune on this computer.

First, put everything back to stock regarding airmass, tm and dd tables. make sure all your torque limits like axle torque, tcc torque, etc etc are all maxed out. make sure your brake torque multiplier is 1.0 not 0 since it's a multiplier. there is a good chance you are being limited by something other than DD or PT......

next try to imagine what your car should make....800 rwhp? 1000 rwhp? whatever. let's say 800 rwhp. That is 975 at the motor (give or take whatever).

kilowatts is 1.34 X HP so you want your DD 100% row to be 1500 across (for now).

let's say stock DD is 600. 1500/600 is 2.5

multiply your Peak Torque table by 2.5 in the area where you are having a throttle closing issue.

leave airmass stock for now.

adjust accordingly DD and PT.

If there is one issue I am not having, it's throttle closing. my airmass tables are stock.


if these changes don't work, you have a limiter still active somewhere else. you also need to make sure to tune the GMVE table.

Thanks Higgs, I'll give that a go.

This is certainly the first car I've had these issues with, so I was trying some different things to see the effect.

[Higgs Boson]

That's a great point, the boost tables in the TM tab also must be tuned.

[Jmiles_86]

kilowatts is 1.34 X HP so you want your DD 100% row to be 1500 across (for now).

let's say stock DD is 600. 1500/600 is 2.5

multiply your Peak Torque table by 2.5 in the area where you are having a throttle closing issue.

Hi Higgs, I tried your process and I still seem to be getting the throttle closing as soon as I get into WOT. No matter what I do, throttle closes to 62% then 80% then full throttle over 4000rpm.

[Ben Charles]

Try lowering peak tq ONLY now and retry

[Jmiles_86]

Try lowering peak tq ONLY now and retry

Can you let me know the reasoning behind this? Wouldn't lowering peak torque actually decrease throttle opening?

The weird thing is after 4000rpm no matter what I do to the DD or Torque it will always open 100%.

Tried increasing the torque, but PE enrichment would enrich later on, again at 4000rpm.

[Ben Charles]

If peak tq vales are too high for the tq model then you need overly high DD values.... Haven't been able to look at the tune, just going off what I have seen and experienced...

Had a car with what I thought looked fine on the DD that did something very similiar, lowered peak tq and the car went 100% throttle

Give it a shot, remove it with a decent change and see if throttle changes

[Jmiles_86]

If peak tq vales are too high for the tq model then you need overly high DD values.... Haven't been able to look at the tune, just going off what I have seen and experienced...

Had a car with what I thought looked fine on the DD that did something very similiar, lowered peak tq and the car went 100% throttle

Give it a shot, remove it with a decent change and see if throttle changes

I'll give it a shot tomorrow. I haven't been able to drive the car on the road yet, worried the dyno might be actually limiting the ETC% opening?

[Ben Charles]

What speeds are you doing the pulls??

[Jmiles_86]

What speeds are you doing the pulls??

all of 5th, from 120mph up to 160mph

[Higgs Boson]

Ben, with that logic, maybe leaving Peak Torque Stock is the best idea and raising only DD is the way to go....

JMiles, I didn't realize you were getting 100 throttle in the upper RPMs and just had closing issues down low. Anyways, I am interested to hear the results of lowering PT.

Ben, does the result come from lowering the whole table or just the affected area?

[Higgs Boson]

Yes, there are plenty of limiters in the boost tab. That's one thing I don't have to deal with since I have an LT1 OS which is NA. Boost to my ECM is just cfm, basically. :-)

[doc350]

Ben, with that logic, maybe leaving Peak Torque Stock is the best idea and raising only DD is the way to go....

That's typically the way I go, or at least I try not to go too high with Peak Torque. This particular car is giving me fits....

Yes, there are plenty of limiters in the boost tab. That's one thing I don't have to deal with since I have an LT1 OS which is NA. Boost to my ECM is just cfm, basically. :-)

Now that's an interesting thought. With the Procharger, I got rid of the factory boost solenoid, so I have largely ignored the factory boost tables. I think there is a good chance you are on to something there...