Quote:
Originally Posted by Mach V Dan
I have not seen this happen, on my car nor any of our customers.
First off, it's not horsepower that will overwhelm the clutch, it's torque. From experience the stock clutch can give out before 200 lb-ft at the rear wheels.
Although this is an oft-repeated piece of conventional wisdom, just because the supercharger itself is hot does not mean the air going into the engine -- which is traveling at something like 150 mph -- is getting any hotter than usual. The biggest chunk of heat is from the compression of the air itself, regardless of whether the supercharger is hot or cold. And although this heat is not insignificant, we can adjust tuning appropriately to account for it. Also, it's spelled "per se".
The intercooler system actually can get heat soaked, since the water circuit can take a while to cool back down. But the non-intercooled supercharger doesn't really have any heat soak issue that I have observed. We've done multiple back-to-back passes on the dyno, and not seen any power degradation. If anything, airflow on the dyno is worse than on-road.
--Dan
Mach V
FastWRX.com |
As far as the clutch concern, I have yet to see anyone at 200-250tq lose their clutch. Maybe that's just me, but I haven't heard anyone having issues until 300+whp. I know a guy who had his clutch go on a 5th gear pull on the dyno which peaked at 303whp. The run before was 297whp and it held strong. No idea his torque though.
I've also used to DD my FRS with 215tq on my stock clutch and had no issues, given every setup is a little different, but if the clutch was only rated for 200tq I would assume I would have heard it.. Given 95% of users who had the issue state it's like 300whp.
The heatsoak issue is defiently there, in the intercooled version for sure. I was just making assumptions based on what I know about the system, in regards to the non-intercooled. AIT is going to be the same, regardless, if you're driving. OP mentioned stop and go traffic is where he is at most of the time. And I can tell you myself, on a hot day in July, after driving for a bit, and you go to make that 5th gear pull which is normally quick and painless, you'll have to go to 4th to get the same power from the power loss. You're just putting excess stress on the blower that's hot. My last setup got hot after 4 runs in the dyno with @
moto-mike and the system started adding some tip-in knock on the top end.