Engine Dyno vs Chassis Dyno, IC water bath

I'll be tuning a turbo race engine on an engine dyno capable of SS operation. Colant temp is well controlled because of a large cooling water resevoir and the intercooler is in a tub of water that is temperature controlled. Three questions:

1) any changes to procedures you would use on a chassis dyno other than a little less concern about "heat soaking"

2) what temp would make sense for IC water bath.

3) is the water bath for the IC "overkill" ?

Hi Peter, sounds like you've thought this out pretty thoroughly.

In my time tuning I've only used a water bath twice from memory and both times were on an engine dyno (much simpler to arrange). Realistically what you need to consider is what you're trying to achieve - namely to replicate real world conditions. In this sense if you had data on what the actual air temps were under normal race conditions then you'd be best to get as close to this as possible. I would say in most instances the water bath is slight overkill but not a bad idea if you can do it without too much hassle.

On a chassis dyno the real issue with heat comes about as a result of continuous steady state operation so you can manage this by monitoring temps and backing off to allow everything to cool down as and when necessary. I also don't advocate complete steady state tuning on highly stressed turbo/SC engines under positive boost either so the heat gain should be easy enough to manage. I tend to tune in vacuum and slightly into positive boost under SS conditions. You can estimate the shape of the ,map into the boosted areas and then proceed to ramp runs at wastegate/min boost. This may then require a little hand blending. It gets the right result without unnecessarily stressing the engine. It's also very difficult on the road/track to drive the engine at part boost and steady state rpm for prolonged periods so the accuracy of the tune is much less critical in these regions.

With specific respect to question 2, a good quality intercooler will usually get the inlet air temp down to within about 10 deg C of ambient so I'd tweak the bath temp to try and get there if you don't have more specific data.

I trust the above is of some help.

Smart move, especially if you have logs from using the vehicle, or similar vehicles, to refer to for IAT and engine coolant and oil temps.

You can run your testing with exactly the same conditions, repeatedly, in a short period of time as you can bleed off heated charge cooling water and replace it with cold water from the tap. Even better if you can get a similar pressure drop across it, and simulate the rest of the intake and exhaust system.

Thanks Andre, Much appreciated.