Why does the throttle only open 60-70% under a hard pull?

[Dinosgt]

Hello Folks:

I am now getting dangerous, due to my recent acquisition of an Ngauge. I have been doing some datalogging, and have noticed something interesting, and I was hoping that the bright folks on this board could help me understand if there is an issue or not.

It seems that I almost never get 82 degrees (full) throttle in my car when running it hard. I have included 3 graphs - the first from a recent short pull in third gear (rpm vs throttle) and the second and third graphs are a recent, 2-3 pull (rpm vs throttle, and RPM vs timing). Although not included here, I have other graphs, which all show good/rich AFR (10.3-11.1), and knockR of -1 to a max of .75, air temps were IAT1 at 63 degrees, and IAT2 ranges from 106 in the beginning to 120 at the end.

Is this normal? The car runs hard, (you can see it gets loose at high RPM in second), but if the throttle isn't opening all the way, is there more on the table?

FWIW the car is a stone stock 2013 GT500.

Many thanks for any insight anyone can provide.
:beer:

 

[JAJ]

Perfectly normal. It's not percentage, it's degrees of throttle opening angle. Zero is throttle closed (it sits at an 8 degree angle when it's shut), and 82 is wide open.

 

[Dinosgt]

Perfectly normal. It's not percentage, it's degrees of throttle opening angle. Zero is throttle closed (it sits at an 8 degree angle when it's shut), and 82 is wide open.

My apologies, I meant "degrees" vs "%". Yes, you are correct - however it just seems odd to me that the car almost never sees 82 degrees (full) throttle, instead it creeps up as RPM increases. Wouldn't the car make more power with a WOT at all times?

Thanks again for any insight...

 

[Casper cobra]

I have seen your issue in stock like your car and it seems the factory tune have some TQ management issue (may be) . try to data log in 4th gear to avoid wheel spin and see if it differ.

 

[JAJ]

...it just seems odd to me that the car almost never sees 82 degrees (full) throttle, instead it creeps up as RPM increases. Wouldn't the car make more power with a WOT at all times?...

That's a different question! First, in any engine, airflow is power. In a positive displacement blower forced induction engine, maximum airflow is controlled by the displacement volume and rotation speed of the blower. A TVS2300 moves 2.3 liters of air every revolution, and the pulley ratio determines how many times it rotates for every rotation of the crankshaft. This means that once the throttle blade is "open far enough" that the throttle is no longer limiting air flow into the blower, opening the blade further doesn't increase airflow or power.

 

[Ray Lucca]

The N Gauge sounds really interesting. Looks like you have Data-logged the stock tune running on So Cal 91* "Premium"..
Assume you bought it from Van, did you also receive the 13-1 Tune?? If yes how about loading it, Data-logging it and send it to JL for evaluation... See what the changes are, and post up your findings. Good Luck...

 

[Dinosgt]

The N Gauge sounds really interesting. Looks like you have Data-logged the stock tune running on So Cal 91* "Premium"..
Assume you bought it from Van, did you also receive the 13-1 Tune?? If yes how about loading it, Data-logging it and send it to JL for evaluation... See what the changes are, and post up your findings. Good Luck...

Thanks. Indeed I am running the Socal swill we have the pleasure of paying 80 cents a gallon more for with less octane than the rest of the nation. I typically mix it with VMP 101 at the pump but I am told that is a no no for some reason (not sure why).

I didn't get the 13-1 tune from Van - I asked for the "Stock" Lund 93 tune, which I have yet to load. Still datalogging and learning, while gathering the cojones to void the warranty...

Thanks again...