I agree that 3k is overkill in an NA car.

Sending your oil off for a lab test costs about $20, or the same price of 5 quarts of M1. I am gonna follow the manual and stick to the 3k, I may sent off my next oil at the end of its life and see what they say. My car is dyno tuned but I believe that blower cars still put alot of fuel in the oil and need more changes.

Now before everone goes out and and leaves oil in the pan for 10-15K, make sure you click on that previous link that was posted and see that your filters quit working before the oil does and it really helps that you keep the car topped off.

I was wondering where you got this roots last longer than centrifigal? My vortech was installed in feb of 95. Happy 10th Birthday number 03574. It was upgraded to an s-trim in 2000. It has over 80,000 miles on it. And the tips aren't worn like a roots would have been. Oh yeah its 70% efficent, a roots is 55% efficent. I have an air to water intercooler thats about 80% efficent. You really cant fit a roots on a 4th gen, you really can fit a roots intercooler on a 4th gen. I'll keep my centrifigal.

 

I have not done a lot of reading on blowers but yours is the highest centrifugal milage I have heard of. Take a look at factory equipped blower cars roots is the choice now the reasoning is open to debate but warranty concerns has to be one of them. The aftermarket like centrifugal because they are easier to package and fit under a stock hood. Not saying one is better or worse just two different ways to arrive at the same goal each with pluses and minuses.
Back on the oil, I am not going to recommend everyone test every drain of oil but it can be useful, if the $20 for testing shows you that you can safely begin running your oil to 5K then in the longrun it can save some money provided you just sample occasionally. I went with Oil Guard and bought 3 tests for around $30 I think, I am not as into all this as some of those guys are and just wanted to get an idea of how my motor liked my oil choice, and figured I didn't need the real expensive testing for that.

 

I think the OEM's like roots because they actually take up less space in a factory setup and they usually run off the same silly 6 rib belt. They also usually make more power below 4k rpm, which makes the warranty guys happy. I think I'll give this oil guard company a call. thats a good price.

Centrifgals can get a bad rep because the cars that they are on usually dont get driven much, all LT1's will need a rebuild with one and they just tend to put more stress on everything and more stuff breaks or goes bad, ie clutches. I think nitrious is just as bad.

 

Just for what it is worth, Mercedes recommends oil changes at 13,000 miles
period. They don't have any "extreme duty" service interval. This is also the oil filter at 13,000 miles.

 

bingo..........less engine bay space + no intercooler routing + easier integration = less cost/headache for them = more profit

that far outweighs their concern for longtime reliability, as there warranty only has to last so far.