Fitting a interchiller is costly but we'll worth the coin in my opinion
My LS1 with a Harrop HTV2300 running only 7 psi had cruising IAT of 50°c, at the drags, or after some long hard pull it rose rapidly to over 80°c, and took ages to come back down to 50°c
After fitting a FI interchiller, with a 10mm thermal spacer, my cruising IAT dropped to around 25-30°c, and, after a run down the strip, so sitting in the staging lane for a while not moving, then a good burn out, then trapping at 124mph, my IAT was only at 35-40°c at the big end
The other benifits of a WTA with a interchiller is your not reliant on the ambient air temperature to cool, say, on a 25°c day, my interchilled WTA coolant temp is around -2-0°c, and it comes out into the little reservior at around 12°c (based of my IR thermal gun)
But, on a blower with no interchiller, on a 25°c day, the WTA coolant temp will always be over ambient temperature, how much depends on what heat sink size and reservior you use (unless you have a ice box), then, when you add in all the heat made by the blower, or turbo, and they make alot of heat, your actual IAT after the heatsink will higher still
High IAT robs power due to the ECU pulling timing for safety (high IAT causes detonation), yes you can change the parameters in the tune to move it so the ECU doesn't pull timing, but, you run the risk of engine destroying detonation, safety parameters are there for a reason
What you need to do is log your IAT after the blower to see what IAT your engine is actually seeing, not the ambient temperature
There are other options than an interchiller though, larger WTA coolant reservior helps, ice boxes as stated help, but, once your ice melts your done, or, if your idling around slowly with only a WTA, even with a larger reservior tank, the WTA system will heat soak and raise the IAT again, until you get moving again and the WTA heatsink (radiator) can dissipate the heat from the system from air passing over your coolant stack (think engine radiator, WTA radiator, engine oil cooler if you have one, transmission cooler if you have one, and wether or not to have a under tray and ducting to help the coolant stacks efficiency
People are sometimes amazed, in a bad way, of what their IAT, coolant temp, engine oil temp and transmission temp are actually at when logged, even a NA LS has way higher actual IAT than ambient
Modifying parts and ensuring powertrain reliability is only possible if you know what you actually have in relation to temps and pressure, the only way you actually know what you need, or don't need, is logging
A basic diagnostic tool that plugs into your OBD2 can sometimes help here with things like coolant temps and IAT temps, others things that require logging sometimes need more sensors and things to read said sensors, dependant on what your OBD2 actually reads
I would be interested in what people's IAT,s are post blower, or even NA when measured at the intake manifold (which is easily found out with a OBD2 scanner)
