SC an Engine with 85K?

[tenblade2001]

I have an E93 with 85K. I've had no problems with the engine, clutch replaced (the prior owner didn't know how to drive a manual). I was going to get new M4 but dealer fell through (long story). I love my current car, just wanted more low end; that's the only reason I was going to get M4. So, I was thinking about ESS or Harrop SC (also replace rod bearings). Thoughts...waste of money? Are typical problems that start to occur after 100K?

[cjm41]

Originally Posted by tenblade2001

I have an E93 with 85K. I've had no problems with the engine, clutch replaced (the prior owner didn't know how to drive a manual). I was going to get new M4 but dealer fell through (long story). I love my current car, just wanted more low end; that's the only reason I was going to get M4. So, I was thinking about ESS or Harrop SC (also replace rod bearings). Thoughts...waste of money? Are typical problems that start to occur after 100K?

Following.

I was going to supercharge in 2019 but I spent a lot more on maintenance my first year with the car than I expected.

I'm at 90k miles now and would ultimately like to do a Harrop. I'm under the impression, while quite a bit more expensive, the roots style blower is easier on the engine and provides a more consistent power powerband than a centrifugal SC does.

Plus... you get to drive a BMW that sounds like a Dodge Demon.

[dgoldenz]

As someone that just spent a lot of money replacing the engine in an SC car that blew, I’d say don’t do it.

[tenblade2001]

Originally Posted by dgoldenz

As someone that just spent a lot of money replacing the engine in an SC car that blew, I’d say don’t do it.

details please? which SC, how much boost? did you replace rod bearings beforehand?

[chrisg123]

I’ve had my centrifugal active autowerks supercharger on since 32,000 miles. I have 78,000 now. I’ve done 5 track days with it as well. No problems. I also would think a supercharger with more torque like a roots style would be more stress on the engine than a centrifugal. I was thinking of upgrading the pulley and adding meth at 80k miles. I did replace my rod bearings with coated ones before supercharging. Not sure if that made the difference.

[pbonsalb]

There is a thread he made. I think he did replace the rod bearings first. A few of these cars have also suffered main bearing failures, but it is a tiny number compared to rod bearing failures.

A positive displacement blower should not be any easier on the main bearings than a centrifugal. Both drag on the crank to spin the blower to compress air. A PD might even be harder since it is compressing air across a broader rpm range — it could make full boost at 2500 rpm whereas a centrifugal might make a few psi by 4000 and then ramp up to full boost at redline.

I would do it, but I like power and would accept the risk. The risk for me would be an $8k used engine because I could swap it myself. I am sort of tempted to pull my motor and change the main bearings, but it is a big job and I don’t want to commit to it right now. Could be a week of work for a part time DIYer.

The other part of me says don’t bother. Buy a faster car instead. And after 8 years with my E90M3, I wound not mind a faster, newer, more comfortable cruiser with AWD. Used Mercedes E63 AMG wagon? Used Audi RS7? Can’t afford the new M5 or E63AMG.

[dgoldenz]

Originally Posted by tenblade2001

details please? which SC, how much boost? did you replace rod bearings beforehand?

You can read my post history. Gintani stage 2, rod bearings were upgraded, only 10k miles on the kit. Kaboom.

[kerrit]

centrifugal blower isn't going to add much load day to day since it doesn't really start to make much boost until 5k rpms. I've had mine on for 22k miles with not a single issue (57k now)

You could do a compression and leak down test on your motor first to see how healthy it is.

[MightyM3]

Gintani is known for pushing the limits... I would not compare their kit to ESS...

[dgoldenz]

Originally Posted by MightyM3

Gintani is known for pushing the limits... I would not compare their kit to ESS...

Kit has same HP rating as ESS and I’m pretty sure it uses the same blower. OP can do whatever he wants, just don’t be surprised when the engine needs to be replaced.

[Iyzmi]

Originally Posted by cjm41

I'm under the impression, while quite a bit more expensive, the roots style blower is easier on the engine

As other have mentioned, it's actually the exact opposite. The roots blower will put more stress on the engine as it makes full boost much lower in the RPM range. But if you are after more low-end torque, that is what you want.

Originally Posted by dgoldenz

Kit has same HP rating as ESS and I’m pretty sure it uses the same blower. OP can do whatever he wants, just don’t be surprised when the engine needs to be replaced.

I mean - it would still be pretty surprising given how many thousands of centri supercharged E92s have been running around for over 10 years now with no issues, including many that are north of 100k mi at this point. Not saying it never happens, but I wouldn't say your bad luck is the norm by any stretch.

[dgoldenz]

Originally Posted by Iyzmi

As other have mentioned, it's actually the exact opposite. The roots blower will put more stress on the engine as it makes full boost much lower in the RPM range. But if you are after more low-end torque, that is what you want.



I mean - it would still be pretty surprising given how many thousands of centri supercharged E92s have been running around for over 10 years now with no issues, including many that are north of 100k mi at this point. Not saying it never happens, but I wouldn't say your bad luck is the norm by any stretch.

“No issues”

Seems unlikely

[bing240sx]

i have a VT2-595 kit with 210,000km's (131,000miles), been SC since about 70,000kms (44,000 miles) on a 2009. never done the bearings... not having any issues.

you'll need to do spark plugs and your throttle actuators and other basic things.

[Helmsman]

Originally Posted by bing240sx

i have a VT2-595 kit with 210,000km's (131,000miles), been SC since about 70,000kms (44,000 miles) on a 2009. never done the bearings... not having any issues.

you'll need to do spark plugs and your throttle actuators and other basic things.

Wow!

[pbonsalb]

Obviously any added wear from the blower depends on the driving style. Out of boost, the centrifugal is like any other accessory — the alternator, for example— in terms of drag. In boost, the drag of a centrifugal depends on rpm. A 9 psi kit might make 3 psi at 4000 and will make the rated 9 psi only at 8000 rpm. If you Track the car regularly and spend a lot of time between 4000 and 8000 rpm, there will be more drag more often than a street driver who occasionally does a redline run.

[Iyzmi]

Originally Posted by dgoldenz

"No issues"

Seems unlikely

Your perception is jaded by your traumatic personal experience. I can understand that. I'm the guy who had a 1 in 10,000 VANOS solenoid failure that sent metal shavings into my engine a couple weeks after I bought my car (bone stock 39k mi). I'm quite familiar with being unlucky and dealing with an anomaly that virtually nobody else has to deal with.

I stand by what I said. We have seen over a decade worth of evidence that supercharged M3s rarely have SC-related failures. Doesn't mean it never happens, you are proof of that, but it is in fact unlikely.

Originally Posted by pbonsalb

Obviously any added wear from the blower depends on the driving style. Out of boost, the centrifugal is like any other accessory — the alternator, for example— in terms of drag. In boost, the drag of a centrifugal depends on rpm. A 9 psi kit might make 3 psi at 4000 and will make the rated 9 psi only at 8000 rpm. If you Track the car regularly and spend a lot of time between 4000 and 8000 rpm, there will be more drag more often than a street driver who occasionally does a redline run.

This is the beauty of a centrifugal supercharger. The added wear is minimal unless the car sees a lot of track time or you drive like a madman. The Harrop kit offers a trade-off. It provides the extra low-end torque most of us desire, but at a cost.