I collected some Durametric data back in August, when it was really hot. Collected some more today, when the air temps are a lot lower. The figure shows results for 4th gear pulls. Torque and hp are about 5% lower on the hot day.

Looks like intercoolers are in my future!

jon

 

jon, what IC's you running. what other stuff do you have on the car. Boost pressure? etc. did you measure AFR's and timing?

 

Dennis,

Sure, I measured all of that stuff. I'm one of Kevin's boys.

Stock 996 TT intercoolers, Milltek exhaust. Stage 2A (K16/997GT2)

The lambda's were about the same, 0.73 vs 0.74. Mass air flow is higher at the lower temperature (maxed at 1366). Boost is a bit higher too. Timing doesn't seem much different. IAT's were running up to 60C under boost back in August.

Jon

 

I'll share some information, maybe a little off topic but interesting.

In 2003 we setup our 996tt with a double jacketed Y Pipe and IC sprayers. We injected CO2 into the jacketed wall on both sides. It came in the Y Pipe, exited the Y Pipe and was then routed to sprayers on the intercoolers.

We also had sensors set up on both sides of the ICs and a controller that monitored inlet and outlet of the IC as well as providing the delta.

The delta was hugh when the ambient air temps were 90 degrees F. Surprisingly, it was either 65 or 70 degrees F ambient (I can't remember), the delta was all but non existent. As the ambient dropped from 90 to 65/70 the difference in the charged air delta became less and less.

 

Interesting enough when I had the stge 2a, I switched from stock IC's to my B6's and I gained about 2 mph trap speed. And did not loose any speed over 2 hours of doing runs.
D

 

what boost did ultimate Motorwerks on Stage 2A ? 1,15bar

 

1.3 bar at 91 octane

 

This makes sense... with stock intercoolers back in August, I was seeing IAT over 60C after a pull in fourth gear. Better intercoolers should decrease that and help top speed.

 

The highest boost in the data above was 1.24 bar. I've never seen 1.3, and don't really want to with my current configuration. There is more performance available from these turbos, but I don't have the fueling to get there with stock fuel pump, rails, and injectors.

Max boost and peak hp aren't very good indicators of performance. The load/hp-rpm curves tell you what your car is laying down. Someone sent me a Durametric data file from his car, which is shown below compared to mine. Note that the max hp is the same for both, but the curves from my car are higher over the entire usable rpm range.

IMHO, these curves are what people should be looking at when they compare tunes and turbos.

Jon

 

very good performance at this boost and temp....your AFR`s made with a 5bar FPR

 

I have found that H20/Meth Injection helps a lot with internal temps, and keeps them down at higher boost levels.

SWR

 

Correct, I do have a 5 bar FPR.

Interesting side note... We had to detune a little back in April because the Injector duty cycles were getting to be too high (105% in some cases). Later discovered a leak in the fuel pump hose, and am now back to the original tune duty cycles max 90%.

Jon

 

Very usefull info about I/C's Jon,thank you very much.I need better I/C's but still saving for them.Hard times.

 

it is a great advantage to have aftermarket IC.....and you gain more if your ECU is progammed to this IC, a little more timing ore AFR are possible...more efficient engine.... as we can see in your thread

Winfried