What RPM range do you drive???

[thom4782]

DD, generally 3000 - 3500

[clickman]

I'm fairly conscious of the poor loading of the IMSB at low rpm's, so I tend to try to keep to at least 3k. Up to 6k regularly. Love that sound!!!

[Meat Head]

Originally Posted by clickman

I'm fairly conscious of the poor loading of the IMSB at low rpm's, so I tend to try to keep to at least 3k. Up to 6k regularly. Love that sound!!!

I understand what you are saying but I worry that if you drive in such a high rpm range you may be saving the IMSB but putting stress on other just as critical engine parts. I would love to know the answer to this quandary!

[KRAM36]

Originally Posted by Meat Head

I understand what you are saying but I worry that if you drive in such a high rpm range you may be saving the IMSB but putting stress on other just as critical engine parts. I would love to know the answer to this quandary!

I'd like to know this too.

[Perfectlap]

Originally Posted by Meat Head

I understand what you are saying but I worry that if you drive in such a high rpm range you may be saving the IMSB but putting stress on other just as critical engine parts. I would love to know the answer to this quandary!

you really aren't stressing the engine unless you are driving the car 10/10's consistently, like on long track stints for instance.
And its not just the IMSB you are hurting by driving below 3K RPM. Actually for 2.5's like yours, D-chunk failures are suspected to be caused by drivers who treat the engines too gingerly or post low mileage. ditto for the 3.4 Carreras. I get the impression generally that if the engine is going to fail, it's NOT because you're driving it in the 3-5K range consistently. More like design flawes that surface with improper attention to cooling --original water pumps in for too long, radiators, bad hoses,etc... and using crap oils for intervals that were too long.

I recall a post by flat six where they indicated that on their test engines they intentionally try to break the engines by subjecting them to all manner of extremes and even then inducing failure is no easy task. Makes me wonder if this included running the engines up and down below the 3K RPM for long periods.

[evan9eleven]

Originally Posted by Meat Head

I understand what you are saying but I worry that if you drive in such a high rpm range you may be saving the IMSB but putting stress on other just as critical engine parts. I would love to know the answer to this quandary!

Me too, but I bought the car to drive it. I'm no expert but I think its fair to say that we all live with the reality that this engine has weaknesses. Drive it as it pleases you.

Per forum advice I try to keep it above 3000 rpm as much as possible. Regular trips to at least 5k are unavoidable as I have a right-foot-left-ear controlled dopamine trigger system in my brain.

[sb01box]

it's my daily drive, 7 miles one way to work.
let the engine idle till the cold start 1000 rpm drops to 700.
1 mile to fwy, below 3K, mostly coasting downhill.
freeway for 5 miles, 3000 or more, keep mostly in 4th (5spd, 2.7)
have hit the rev limiter from time to time. mostly up pass 6000 when getting on the freeway. ( little bit more aware of engine rev but not really.)
once off the freeway, I do somewhat of an active driving.. mostly 3-5K range.
have 135K miles. I do change oil every 5K miles

[stephen wilson]

I drive to work often, highway @75 MPH=3000 RPM. On the back roads it varies from 3-4000 while warming up, to 5 or 6. I take it to 7000 a few times pretty much every drive. I refuse to drive a car based on fear, or trying to forestall engine failure. I bought it for fun, and that's the way I drive it!

BTW, if you never go above 5000, you're missing the best part!

[Johnny Danger]

Never under 8,500 rpm.

[thstone]

Originally Posted by Meat Head

I understand what you are saying but I worry that if you drive in such a high rpm range you may be saving the IMSB but putting stress on other just as critical engine parts. I would love to know the answer to this quandary!

Redline is no worry.

After 60+ track days, where every shift is made at or near redline, my engine must have nearly 10,000 runs up to redline: upshift 4 times a lap x 10 laps a session x 4 sessions a day x 60 days = ~9,600 shifts at redline. I try not to bounce the RPM's off the rev limiter but occasionally do so. 126,000 miles and the engine runs perfect.

My advice: Drive it like you stole it.

[AKnowles]

Originally Posted by clickman

I'm fairly conscious of the poor loading of the IMSB at low rpm's, so I tend to try to keep to at least 3k. Up to 6k regularly. Love that sound!!!

+1

Anytime I can get away with it. In town I often leave it in third just so I can zip around traffic.