[hammdo]

So my next experiment is to test the 'efficiency' of the dual pumps -- basically, how well are they working within the intercooler/hx system removing the heat the boost is making (so the timing retard is delayed or avoided). The dual pumps in series increase the flow from about 19% to 25% above the single pump (4.8 GPM to 5.7GPM @ 19%, 6 GPM @ 25% increase).

I needed to do determine how much heat a pound of boost makes and then determine the total heat produced based on the roots style thermal efficiency.

So for every 1 PSI of boost, you average around a 10.42° increase in heat for a 100° day (there is a formula that gives you the 'absolute', but for this, you get an idea). So, now you need to take the 'Thermal Efficiency' of the blower and that will give you the 'expected' temp ° increase so:

Take the estimated temp (10.42°) per lb of boost and divide it by the 'thermal efficiency' (.55, .65, or .75) and you'll get the 'expected' temp increase.

So 100° day:

10.42 / .55 = 18.95° increase per 1 PSI of boost
10.42 / .65 = 16.03° increase per 1 PSI of boost
10.42 / .70 = 14.89° increase per 1 PSI of boost
10.42 / .75 = 13.89° increase per 1 PSI of boost

My car makes 6 PSI so that would be:

113.70° increase over ambient @ 55 % Thermal Efficiency
(100° + 113.70° = 213.70° after 6 PSI of boost)

96.18° increase over ambient @ 65 % Thermal Efficiency
(100° + 96.18° = 196.18° after 6 PSI of boost)

89.34° increase over ambient @ 70 % Thermal Efficiency
(100° + 89.34° = 189.34° after 6 PSI of boost)

83.34° increase over ambient @ 75 % Thermal Efficiency
(100° + 83.34° = 183.34° after 6 PSI of boost)

Now, that is what WOT air temp is 'estimated' (as its not a linear increase, I believe @ 15 PSI, the increase may be 2/3s of the 10.42 * 15) to be depending of how 'efficient' the roots blower is (I think the best its been is 75%, I believe the LSA ZL1 is 70%).

ALL of this is excluding the impact of the engine cooling/heat soaking -- which will impact the recovery and how cool 'out of boost' IAT2 temps can get -- just talking about the heat the 'boost' makes with the IAT1 incoming air.

So, to keep the ECM from pulling timing, we need to make sure the intercooler, pump(s) flow, HX/Reservoir, and intercooler brick have the capacity to cool down those temps.

Knowing the formula and expected results, I can then judge how well my 'intercooler/hx' setup is doing.

My assumption is this will really tell how well the intercooling system is working when I'm under boost -- not really 'after' or how 'fast' I recover since that is impacted by the boost valve opening and cool air from the CAI mixing in (unless you 'drag race', which is impacted by low flow of air from the CAI which is going to slow down the recovery -- I'm just focusing on 'track' here). The lower I can make the 'IAT2' temps after boost, the better I can expect the recovery to be (of course assuming we're still 'moving' and air is coming in the CAI from the 'clean' source).

I did a small test today (not quite a 100°) but the decrease is minimal (70° is 9.857° so, we're really on about .6° per lb of boost different).

I did 3, 5 second WOT runs. Starting IAT2 temps were 104° and at the end of the run they were 116°. So I only gained 12° AFTER the intercooler did its work (engine coolant was 183°, IAT was ambient, oil was 224°).

So, assuming the 70% Thermal Efficiency rate, the temps were 'cooled' by 73.34° with my current intercooler system. Granted this was a limited set of runs (like most straight aways on a track), but gives me and idea of where my setup is.

My timing begins to start pulling @ 122° so doing all I can to keep it under that (plus a multiplier is applied so its maybe 1.65° of timing pulled @ that temp).

So I think this makes more sense to know how well the intercooler system cools the boost charge -- in order to keep from pulling timing.

Anyway, I'll do what I can to 'test' this and see. It's been a while since I had to do this kind of 'math' ;o) and I believe I have it pretty close.

Thanks for reading 'math' talk ;o)

-Don