HP JNKEY

Maybe its a little early in the game but has anyone thought about building a bigger more efficient intercooler?
I installed a larger intercooler on my TT 535 and it dropped the intake air temperatures (IAT) to almost ambient (outside) temperatures.
Heat soak is not existent.
Oh, and the car picked up 20rwhp because of it.
Hopefully there is room for one under there.

Chicago1

I don't think it's heat soak the iat's were inline. Its the ecu saying **** You

Blvdbrawler

Would doing that void the warrantee?

TheSmoker

Its not heat soak!!!!

Mdm23

Why do people keep bringing up heat soak? Tuners have repeatedly said the Z06 has no issue with heat soak. Multiple dyno runs show the iat's stay pretty consistent. It appears the car just has a very conservative tune from the factory.

sdtoothdoc

If it was heat soak, then would the aftermarket guys tuning these cars to 600+ RWHP with the factory parts be getting these numbers pull after pull after pull?

JoesC5

So, why does the C7 Z06 have such a conservative tune compared to the Obsolete C6 Z06 and C6 ZR1?

Mdm23

That's the million dollar question. Maybe there's an engine durability concern. Hopefully tuners can chime in with more detailed info. But everyone must consider that these cars haven't even been in the wild for a month yet. Time will reveal what the issues are. People will hit drag strips, more street races will turn up, and Randy Pobst will lap Laguna Seca.

GrampZ

Because that's the central issue.

GM mapped the ECU to pull timing IN ORDER TO AVOID HEAT SOAK.

As timing is advanced, pressure and temperature in the combustion chamber rise together -- which increases heat flow into the head, block, and coolants, which in turn will raise IAT2 temps. (Conversely, as timing is retarded, temps rise much less in the combustion chamber and cylinder, and more in the exhaust flow, as combustion can actually continue there.)

The LT4's IAT2 temps don't rise with repeated dyno pulls (or back to back highway pulls, or with multiple laps around the track) BECAUSE the ECU retards timing to minimize the increase in temperature, especially in the cylinder head and coolants. (I don't know where they are sensing temperature - be it in various locations in the cooling systems, in the exhaust primary just downstream of the exhaust valve, etc. -- only that there are probably several sensors that are sampled, and an algorithm to reduce those data for use by the ECU.)

Unfortunately, having committed to a supercharged engine, it becomes sort of a Catch 22. Maintaining timing advance results in rapidly increasing, and higher temperatures. That itself will result in increasing IAT2 temps, and therefore loss of power. Thus, maintaining full timing advance will cause heat soak, which, over time, will reduce the lifespan of the supercharging systems' components -- such as its integrated cooling system (which in turn will render them unwarrantable for 100,000 miles). Since an extended warranty is crucial to sales (i.e., to old car guys with the money to buy one), GM has apparently opted to reduce performance under sustained peak demand (i.e., via retarded timing) as a trade off to optimize sales.

Of course, air / fuel ratio is part and parcel to the timing / heat calculus, but since everyone has keyed in on ECU and timing, I've left the comments there for simplicity.

One Curve at a time

Very good question...
I had a Nissan 370z that would go into "limp mode" after 5 laps at the track. I added an extra oïl cooler and the problem was resolved!
Could this be also the case for the Z06?

Snorman

I think the first hardware upgrade would be an upgraded heat exchanger. After that the IC reservoir (larger). And finally whether or not an actual upgraded IC "brick" is available.
S.

pcguy2u

PRE-Z06

So instead of thinking of it as pulling timing and reducing power, maybe we should consider it more like an over boost function as Porsche calls it on all the time until things get heated and you don't have that temporary increase of power. Timing is the easiest to use to keep things in line I suppose, but they can also control cylinder pressure via Variable Cam Timing as well. Again people have to keep in mind these 100k mile warrantied engines have to run year around across the US in wildly different weather conditions with varying octane fuel. With that being said, I'm sure GM engineers are going to program to play it safe than sorry.

johnglenntwo

IE Is a car really faster if it has more power, and, less traction?

I remember when some of the tuners got into the ZR1 and said how rich it was. And even though I hadn't heard of going that rich before (11.0 not 10.3) I was sure they new what they were doing and had their reasons!