So today was the first time I've had the S2k out on a really hot day. It was so slow that it felt like I was driving through mud. The revs took forever to build to VTEC and even then, it was sub par. Obviously when I turned on the A/C it made it even worse.

I did some quick Google seaches and appears this is normal? Well that sucks because it's a summer car! Obviously all cars experience some performance loss on hot days, but I've never had a car with such a dramatic difference. From what I read, driving in traffic (which I was) only makes things worse.

Do any of you have this issue too?

 

It is quite common, the car will bog as intake temps increase. My car started running more consistently after I installed a snorkel on the oem air box, without it the intake sucks hot underhood air.

Your car will loose 1% in power for every 10 degrees increase in air temps (approx.). It gets even better with a vented hood. Two mods I really like when driving in hot temp conditions.

 

Yeah every year it's the same thing.

I take the car out when the temps are still cool and the car runs amazing, on a day like today it felt super sluggish. As Joey said, I might invest in a snorkel.

 

^ yup I would take it out in early morning and the car feels great, keep driving it around noon and it turns into a dog. My car runs more consistently throughout the day now, you will still have heat effects as the air outside of the car heats up throughout the day but it won't be anything like underhood heat.

 

But won't that just suck hot air off the road? In my daily driver (Lexus IS 350), I hardly notice when it's hot out, even when I have the A/C on. Why is the S so much more sensitive to the hot temps? The are both naturally aspirated engines, so why so different?

 

Outside ambient air will still be cooler than air from inside the engine bay.

 

Spagolli94 yes you are still sucking hot air ambient air outside of the vehicle, but the S2000 snorkel location sucks much hotter under-hood air. I think the insulation on the bottom side of the oem hood makes it even worse. The Honda ecu can be conservative with ignition timing as intake temps increase. Other vehicles can be less fussy with air temps, particularly with variable valve timing that many engines have these days. Plus losing 20 ft lbs of torque on a 2 L motor will feel much worse than losing 20 ft lbs torque on a larger (more torquey) motor.

 

Makes sense. My IS has 277 lbs of torque. Before that, I had a 335i and RS4, both of which had a ton of torque. So I guess those cars were able to lose a bit of torque and still dig from lower RPMs with no discernible difference.

When you guys are saying "snorkel" I'm assuming you're taking about a CAI? I used to have a CAI on my old GSR and RSX. Both where pretty loud, especially at the VTEC crossover. Any recommendations for a CAI that's not too terribly loud?

 

On the ride home tonight, temps had cooled a bit and I felt like I had my car back!!! In really think it wasn't just the hot day, rather the combination of 30 minutes of stop and go traffic combined with the heat that made it run so poorly.

 

yup. run the highest octane available in the hot weather-we have 94 in Ontario, Canada. the computer will retard the timing to prevent detonation and as a result, feel more sluggish.

darcy