Yargk

https://en.wikipedia.org/wiki/Confirmation_bias

KareemGT4

I went with dundon race headers... stock tune stock plenum.

Before under 5k rpm the car felt weak, and it opened up like a vtec at around 5k!

Now the power is available from 3k all the way to redline, I definitely feel it.

I also uploaded a dyno chart on the dundon headers thread.

cox1974

Please post it here...

GT4_Driver

The a-Workx GT4 that was tested in SportAuto had the following features:

Akrapovic Titan exhaust
200 cell HJS headers
BMC air filter
Software
Allegedly 420 hp and 455 NM torque.

The acceleration from 0 - 200 km/h was like the series GT4 SportAuto had tested before (14.4 sec). The acceleration from 60 - 160 km/h was even worse than the series GT4 - in each gear.

Very disappointing. My guess is that subjectively the acceleration appears to be better (in particular because the car is louder), whilst the difference in reality is, in fact, not existing or very small.

jmartpr

Please read the exact precious post to yours as my original one was not clear/complete....I meant only the ones with mods....and yes, I'm bias and enjoying owning this car and the mods so far. Maybe is the placebo effect!

Warwick Morris

Thanks for the info Gt4 Driver. Could you please post the link....I couldn't find it.

GT4_Driver

Unfortunately, there is no link. The a-Workx was tested in the SportAuto magazine and it takes a while before they publish their tests on the internet.

ML///

@Cobbtuning you guys provide turnings support to the Cayman GT4s? How often are you allowed to tune the ECU? I thought this was limited? Also can confirm that you provide support to every GT4 on the field for Conti Series?

cox1974

As promised....
Dyno launch comparison only with sport headers and with headers, ipd plenum, 82mm tb and fabspeed custom tune....

cox1974

more power and torque everywhere ... from the bottom to the top end... the car runs more aggressive and pulls hard to the redline...
Most noticeable gains :
@4130 rpm + 11 kw + 25,5 nm
@5400 rpm +14,3 kw + 25,6 nm
@6600 rpm +11,7 kw + 16,9 nn

cox1974

My tuner says that the real deal is the fabspeed pro tune... the ipd+tb combo helps a bit but the gains seem to be from the Cobb-Fabspeed tune....
This is a comparison between my old " only sport headers" run and one run that we made today with all the hardware installed but with Cobb stock/base map (0 map)...and not with the custom map

jmartpr

+1 on the COBB improvements, specially if doing a custom map. My cars had the CG headers and exhaust for a long time and then did the COBB....the improvement with the custom map was evident on the dyno and driving the car.

ML///

fixed

Peter_GT4

Each to his own, I personally do not believe that it´s just placebo or confirmation bias.

I made two close friends drive the car before and after without giving too much information, just like
take a spin and tell me what it feels like. Both were stunned and told me it felt like a different animal.

Maybe dyno numbers and seconds are not the whole story when it comes down to "feel", there´s a lot in the way power is delivered over the rpm range. I guess the wide gap between the two curves along the midrange is what makes it actually feel so good on the road.

That a-worxx GT4 is btw. a different story. As I read in another article, they just modified the stock headers by welding HJS 200 cell cats in them. Makes no sense to me, having seen stock vs. CG sport headers on my garage floor. There´s also no plenum or tb, just the bmc filters.

jmartpr

DeMan posted on another thread that they tested the factory headers with cat-delete (for the GT4 CS) and the gains were zero.....Don't have the details of the test but looks like welding a set of high-flow cats to a OEM header may not be enough to yield any gains.