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I spent all summer tuning my setup, running at about 16-17psi max and topping out my 1000cc injectors on e85 at 90%ish duty cycle. This is on warmer days when my ECT was 190-195° and IAT was in the 120's usually.

Now we are having some cooler weather and my ECT is 180-185°, IAT in the 80's and it was running leaner, so I started adjusting my compensation curves. Now I am maxing out my injectors at 98% duty cycle and only 15.4psi of boost, had to turn it way down. Once I got it dialed in, both compensation factors combined are adding roughly 10% more fuel to achieve AFR in the 11's. Does this seem like a normal amount of compensation for these temperature changes, or is it more likely a different problem in the fuel system that is causing it to run out of fuel?

I did not think my 1000cc injectors (actual flow rate ~925cc) would run out at such a low boost level on a t3/t4. I will probably need to turn it down even more once the real cold weather hits.

Anyone else have similar woes trying to dial in temp comps in the midwest with 100 degree seasonal swings? Or does sticking with the stock compensation tables normally work?

Aradin

I have never had any luck with the stock compensation tables with a heavily modified vehicle. You have to think there's a lot of extra stuff that's been added in something like an aftermarket turbocharged setup that Honda engineers never planned for. Naturally some adjustment will be required. Typically I don't mess with the ECT compensation too much unless the car runs fairly warm in the summer. Most I've tuned(including my own) will stay around thermostat temp all year unless it's during long sessions in heavy traffic or similar. I'm on the east coast and I would say we have about an 85-90 degree difference between winter and summer so it's pretty similar to what you're experiencing. Most of the time I have to play with the low/high load IAT corrections to get everything right for all seasons. I have always made the two most common ECT values, say 210 and 180, fairly close as far as correction factors go so that even when the ECU interpolates between them there's only so much range of adjustment. It seems to work out better for me but my car runs around 180F all year so your experience may vary. Also take into account that I'm running water/meth so even on a 100F day my IATs will peak at ~90F or so under boost.

Otherwise, what you're seeing as far as duty cycle and having to drop boost is normal I would say. Cooler air is denser air and in a turbocharged vehicle that makes a big difference. I have to drop 5-6 psi during the winter as well because my car picks up a dangerous amount of power at any given boost level going from 90 degree ambient to 20-30 degree ambient.

Are you running E85 or regular pump gas?

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Aradin

Yeah it should be making near the same amount. I usually go by fuel consumption to keep power steady between seasons. As a rough example, let's say the same setup is at 80% duty cycle @ 11.5AFR and 15psi during the summer, and 80% duty cycle @ 11.5AFR and 11psi during the winter. One could make a relatively safe assumption that the power levels are very close even though boost is dropped during the winter. That may not work as well for you unfortunately. E85 adds another variable since the blends will differ throughout the year.

IATs do make a big difference. There's a reason you see serious supercharged guys icing their blowers before runs. The general "rule" is 1% power per 10 degrees IAT dropped. I feel that might be a bit on the conservative side depending on the efficiency of the setup though. If I stayed at the same boost level all year I would see a very noticeable 40-50hp bump during the winter. It's dangerous for me though because I'm pushing a stock bottom end pretty hard as it is. I had a setup years ago that was fine all summer but snapped a rod in half and bent 2 others in the dead of winter because it picked up so much power.

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