Despite my recent pulley swap, I have gotten slower. It seems like from a stop, I've got a lot more power. But, I have this spot where I test, somewhat less than a quarter mile, that ends with a certain sign. When I first got the car, I'd be going 77-78 at it, the fastest I've achieved is 84. Now I'm back to 77-78. My car is obviously affected by heat, it runs much harder when cool. When it heats up, it gets way slower in upper RPM'*. I just got colder plugs and they did help some. Should I go back to a 160 t-stat, or is there another route I could go to combat heatsoak? I assume I am getting KR and the timing is getting way retarded. Check my sig for other things I've done.

BTW, some of that is due to my 17" wheels. I noticed I lost a fair amount of top-end with these heavier wheels.

Don't go with the 160° thermostat. Drill two 1/16" diameter holes in your 180 instead, ADD a tranny cooler, either right in front of the stock cooler, or on the other side. This will drop your temps another 10° or so. You may want to consider a wrap on your intake pipe, and improve your CAI for better shielding from engine bay heat.

Are you hitting about 12 psi of boost at WOT?

Possibly a stupid question, but sometimes we overlook the obvious in an attempt to find an answer...did you swap smaller wheels for bigger ones (and did those raise the overall size of your tires?)? Could your speedometer be off because of it?

I went from 16" to 17" that are a fair amount heavier. I made sure to get tires that are very close to OEM diameter. The intake pipe is wrapped up pretty well. I am probably getting 12-13 lbs boost. BTW it is a 94-95 M62 on a 92. I think I will try to drill the stat. Tranny cooler later.

I drilled it. Do those two little bitty holes actually do much?

Another thing, before someone brought up an obstruction that would prevent certain thermos from opening completely. I didn't seem to have that obstruction.

A few recent changes and its back up to eighty, but not where I'd like it.