- most chiptuners feed engines with artificially cool air – you will never get IAT 20°C in real life (perhaps in winter at -20°C), especially if you are spirited driver or even worst…track day guy.
- inconsistent results
- I assume that chiptuners are not that stupid and at least warm up engine oil to 80°C for optimal operating condition…still, warmed up engine is still miles away from overheating
- various losses that lead to inconsistency and imaginary results
- rolling road session lasts up to 30 seconds and it doesn’t reflect real full load fun for spirited drivers
- if you cannot drive flat out, chiptuning is not for you in first place
- I want to see some real life simulation of full load dyno session lasting at least 10 minutes
- no heat soaking effect
Chassis dynamometer fundamentals
Perfect chassis dyno
Imagine Hilda HR I compared to “same” car with same ECU calibration – Hilda would be clear winner because she has got rally suspension and minimal losses in transmission. It is said there is about 5% transmission losses but normal car users usually have worn dampers or believe wide tires are better.
As you can see in above by video, it is very easy to fool dyno electronic and provide “more” power to customers. I am not surprised normals want it all, I see it by myself.
I recall a hot discussion on Briskoda forum (before they banned me for brutal honesty of course ROFL) where I shared knowledge about AFR. I brought it upon myself though – Briskoda is sponsored by commercial chiptuners, occupied by tExperts and last thing they need to know is how everything really works.
From all those poor misinformed fools there was only one guy that confirmed my field tests – excessive fueling reduces torque in long term. It is sad day for human kind if one from hundreds humanoids have brain.
Above by mentioned guy pushed his car to the limit more than usual 30 seconds dyno session and confirmed effects of torque limiting due heat soaking and overheating.
Perfect chassis dyno would read IAT, knows wheel diameter and pressure thus compensating for various wheel diameters. If you can read IAT, you can control “real” ambient temperature because no factory/upgraded IC has got 100+ % efficiency. IAT is always at least +10°C above ambient temperature and +30 to 40°C at full load.
If you increase 1HP on dyno, it is logical you need aerodynamics on 61HP racing car, no?
You have been warned
IAT/air density is main reason for engine power loss – for example an engine produces 140HP @ 40°C IAT (40ºC is usual IAT for 140HP TDi engine at full load for short periods of time such as acceleration) but you have got 150HP @ 20°C IAT (possible over winter at sub zero temps)
Of course it goes both ways…if you increase heat, as is usual byproduct of poor ECU calibration, you suddenly hit IAT 50-60°C and you have lost over 6% of torque/power.
Chassis dyno has no real value because even same car on same day has different results every time you do some dyno run. Sole purpose is marketing because duners love to brag about theoretical power gains for 30 seconds.
One wonders if “30 second” power is just coincidence with their usual bed performance. Beautiful things don’t seek attention.