Mike.g Posted October 11, 2018 Report Share Posted October 11, 2018 (edited) My co-owner and I have a friendly disagreement about running an engine in the higher RPM range. Lets assume for this discussion the engine is in good working order with proper temps and fluid levels. Opinion 1. Run the engine up to the red line (but short a few hundred from floating valves) is fine for an engine. Major wear and failure comes from when you have higher loads, not high rpms. Opinion 2. Only run it up to 80% to red line. So if red line was 7000rpm, shift at 5600rpm. By not maxing out the Revs every shift you extend the life of the engine. We are just looking for opinions and feedback on this subject since it is related racing. Thanks!!! Edited October 11, 2018 by Mike.g Quote Link to comment Share on other sites More sharing options...
enginerd Posted October 11, 2018 Report Share Posted October 11, 2018 (edited) 26 minutes ago, Mike.g said: My co-owner and I have a friendly disagreement about running an engine in the higher RPM range. Lets assume for this discussion the engine is in good working order with proper temps and fluid levels. Opinion 1. Run the engine up to the red line (but short a few hundred from floating valves) is fine for an engine. Major wear and failure comes from when you have higher loads, not high rpms. Opinion 2. Only run it up to 80% to red line. So if red line was 7000rpm, shift at 5600rpm. By not maxing out the Revs every shift you extend the life of the engine. We are just looking for opinions and feedback on this subject since it is related racing. Thanks!!! If it’s a good engine it will run a very long time if you keep it within factory redline and haven’t done anything bad to it (turbo). Run that sucker full throttle right up to redline! If you are prone to mis-shifts, keeping an 80% shift point will nullify most money shifts and save the engine that way. Edited October 11, 2018 by enginerd 3 Quote Link to comment Share on other sites More sharing options...
CBraden Posted October 11, 2018 Report Share Posted October 11, 2018 Based on my small sample size of experience, high rpm (within factory redline) without added power doesn't mean impending doom for an OE engine. Valve springs and lifters have been items which have failed for us in different motors, but now we replace those and don't know what will fail next. Bottom ends have not flown to pieces for us, but we try to run stuff widely regarded as reliable. I am not picking on any makes, but there are some engines that seem less happy with the use case. Interesting links on the topic: bbobynski Joined: Apr 2005 Posts: 79Detroit, Michigan It is a bit off topic but I will share this anecdote if you are worried about breakin on a new production engine. We did a program back in the mid 90's to determine what sort of engine "hot" tests worked best and to investigate a number of other things. The "test" was done thru Jack Roush's engineering group and contracted on their dynos. It involved taking 150 brand new, 300 HP Northstar engines that had never been fired and running a 2.5 hour hot torture test on them with a post test teardown. The engines were stone green at the start of the test. They were each installed on the dyno and the coolant and lube systems hooked up. Coolant was preheated to 255 F by the test cell equipment and oil was preheated to 285 F. This was done with 50/50 DexCool/water and conventional motor oil...not synthetic. The engine was fired and IMMEDIATELY put at full throttle where it ran at 6000 + RPM at full load with the oil temp controlled at 285 to 300 F. It was harder to get the dyno equipment to live than anything else....LOL. There were no engine failures at all. None. All engines were torn down and judged to be in "like new" condition on all parts. No scuffed pistons, no damaged bearings, nothing. In fact, it was difficult to tell that most of the bearings had even been used as they absolutely looked brand new even under magnification. To say that it was eye-opening to a lot of people was an understatement. The Roush dyno techs thought that we were nuts and would stop after the first few engines blew up....LOL. The only caveat here, is that each engine had the oil routed thru the oil heater and oil cooler equipment which necessitated separate filtration so that any debris generated during the first few minutes of operation that might have bypassed the filter otherwise running at 6000 was caught by the external filtration (it was needed to protect the cooler/heater heat exchangers if there was a problem) so the test indicates performance of fits and finishes of a brand new engine and oil capability at those temps and such but doesn't perfectly replecate a car run immediately to full throttle, 6000 RPM and held there for 2.5 hours..as if you could do that somewhere....LOL. I was the development engineer in charge of this test so I saw it happen, saw the engines at teardown and compiled the results. Anyone concerned about stabbing the throttle during break in can rest easy. Trust me. (above from this thread: https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/129895/2 ) https://www.hemmings.com/magazine/hsx/2009/10/Run-for-the-record---Saab-9000-and-900/2130431.html https://www.motorauthority.com/news/1118232_all-srt-products-undergo-24-hours-of-racetrack-endurance-testing https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/1779600/1 We live in a really nice time to be racing used cars... 3 2 Quote Link to comment Share on other sites More sharing options...
Black Magic Posted October 11, 2018 Report Share Posted October 11, 2018 (edited) High engine speed is going to result in a sorter engine life, but alot depends on what you allow to happen to the engine and how it is made. One some engines you can go a long time. Most race engines will have a total time at high rpm spec for valve springs. Valves seat surfaces and lifters in some engines have a similar issue. On highly stressed motors once the exhaust valve loses enough contact area (needs valve job) the inability to transfer heat can cause failure at high rpm\load. Some engines with powdered metal rods will have problems with lots of sustained time at high rpm. I think alot depends on piston speed, 7k on a 2.5" stroke vs a 4" stroke makes a huge difference in engine lower end part life. Don't get it hot, use proper oil control devices, use good rebuild parts and start with a decent motor and it is possible to go seasons on the same motor at readline (for well designed motors). I would argue many high rpm failures we see are oil control related, more so than anything else. Edited October 11, 2018 by Black Magic 2 Quote Link to comment Share on other sites More sharing options...
turbogrill Posted October 11, 2018 Report Share Posted October 11, 2018 It seems like most chump engines explode due to coolant loss, oil issues, fuel problems, bad assembly, etc.. I think its rare that a factory engine expires purely from pushing it hard. 2 Quote Link to comment Share on other sites More sharing options...
zack_280 Posted October 11, 2018 Report Share Posted October 11, 2018 Our E30 has never had an issue due to high RPMs. We shift at ~6k +/-. It has had many issues due to coolant not staying inside or water pump not pumping and I believe we had two cracked heads (cracks were there prior to racing, not caused by racing). We have never had a broken rocker or other RPM related issue, but I believe that is typically due to over-rev, not sustained 'high' RPMs. There is definitely more stress on the internal components at higher RPMS, but I would say for the M20 (and probable all of the BMW M engines) you can regularly shift near factory redline without a massive decrease in life expectancy. I do not know if that applies to other makes/models, but I would think that as long as you are shifting before factory redline, it would be oil/water issues that would kill most motors before RPM-related failure. 2 Quote Link to comment Share on other sites More sharing options...
mender Posted October 11, 2018 Report Share Posted October 11, 2018 (edited) Lots of engine testing under controlled conditions showed that engines live quite nicely as long as they're kept within range on temp and rpm and fed oil with no air in it. Cosworth Vega engine testing: "Chevrolet require all engines to survive 200 hours at full load. The Cosworth lasted over 500 hours. For a clutch burst test, Cale Wade revved the engine to 9,400 rpm under its own power without damage to clutch or engine. Three cars, in three different configurations, resumed mileage accumulation in September 1974." It's up to the car builder and the drivers to manage/control those conditions. Edited October 11, 2018 by mender 2 Quote Link to comment Share on other sites More sharing options...
ad3adman Posted October 11, 2018 Report Share Posted October 11, 2018 iv'e been running a stock motor with 109,000 +/- on it when dropped it in 4 years ago and i'm banging off the rev limiter all the time with no issues. change the oil after every event. used mobile 1 for a while now i use valvoline 20w-50 for endurance. 1990 miata 1.6 2 1 Quote Link to comment Share on other sites More sharing options...
Team Infiniti Posted October 11, 2018 Report Share Posted October 11, 2018 (edited) Stock used engine + auto trans = redline every shift with no over revs, 37ish races with 3 engines have displayed one common failure mode, slow degradation of ring seal manifesting as blow-by/reduced max hp, next failure point has been rod bearings but they usually go glitter and can be changed before crank damage. Results will vary depending on inherent weakness of chosen unit. Edited October 11, 2018 by Team Infiniti 1 Quote Link to comment Share on other sites More sharing options...
endura Posted October 12, 2018 Report Share Posted October 12, 2018 6 hours ago, ad3adman said: iv'e been running a stock motor with 109,000 +/- on it when dropped it in 4 years ago and i'm banging off the rev limiter all the time with no issues. change the oil after every event. used mobile 1 for a while now i use valvoline 20w-50 for endurance. 1990 miata 1.6 Same. junkyard 1.6 , 4 years. over 80 hrs. turbo, >200whp . engine lives between 4500-7000. Theoretically, lower revs mean less wear. Practically, in a race car, it's a non-issue as life expectancy will more likely be cut short by ripping off a cooler/rad or a wreck/mis-shift. In other words, nice discussion to kill time but inherently meaningless for an amateur race car. 1 Quote Link to comment Share on other sites More sharing options...
karman1970 Posted October 12, 2018 Report Share Posted October 12, 2018 We trashed a used D16 in less than 2 hours at our first race. Spun a bearing. The block original to the car had a hole in it where a rod exited prior to our purchase. While it's probably safe to say that everyone's experience may vary, I'll never touch a D-series Honda again and we keep our B18 below 6K. 1 Quote Link to comment Share on other sites More sharing options...
mender Posted October 12, 2018 Report Share Posted October 12, 2018 17 minutes ago, karman1970 said: We trashed a used D16 in less than 2 hours at our first race. Spun a bearing. The block original to the car had a hole in it where a rod exited prior to our purchase. While it's probably safe to say that everyone's experience may vary, I'll never touch a D-series Honda again and we keep our B18 below 6K. We've been running our B18B at 7000 rpm so far ... and I won't mention what I did at Portland! 2 Quote Link to comment Share on other sites More sharing options...
ad3adman Posted October 12, 2018 Report Share Posted October 12, 2018 12 hours ago, endura said: Same. junkyard 1.6 , 4 years. over 80 hrs. turbo, >200whp . engine lives between 4500-7000. Theoretically, lower revs mean less wear. Practically, in a race car, it's a non-issue as life expectancy will more likely be cut short by ripping off a cooler/rad or a wreck/mis-shift. In other words, nice discussion to kill time but inherently meaningless for an amateur race car. id like to know more about your turbo setup. i have some points to spend. 1 Quote Link to comment Share on other sites More sharing options...
endura Posted October 13, 2018 Report Share Posted October 13, 2018 9 hours ago, ad3adman said: id like to know more about your turbo setup. i have some points to spend. stock junkyard engine. coolant reroute/proper ducting at bumper mouth. Essentially a FM turbo system/MS2. GT2860RS. 12-14 lbs boost depending on ambient temps. water holds @190/oil @240. Done enough 3 hr enduros, in summer, have no doubt powertrain would survive a full 8 hr event. Fuel economy is another matter, however. It would not be competitive unless fuel cell was added. 1 Quote Link to comment Share on other sites More sharing options...
Mike.g Posted October 14, 2018 Author Report Share Posted October 14, 2018 Thanks for everyone replying. I didn't want to say who's opinion was who above, but I was the one who always wanted to run with the limited RPM. But it looks like most people side on the side of that it will not hurt a car to run up to the red line. I know from my personal experience when I ran our car at Road America. Our redline is 6500. I shifted out at 5000, and had the fastest lap time of the weekend. Plus once that saved me during a missed shift when trying to go to 5th gear I went up into 3rd gear, it reved up to mid 6000rpm before I was able realize I screwed up and went into the proper gear. So I had extra room for error with the lower rpm shifts 2 Quote Link to comment Share on other sites More sharing options...
Team Infiniti Posted October 14, 2018 Report Share Posted October 14, 2018 2 hours ago, Mike.g said: shifted out at 5000, and had the fastest lap time of the weekend This alone speaks for something, question, what do your lap times do when you wind it to red? Quote Link to comment Share on other sites More sharing options...
Technical Advisory Committee Ray Franck Posted October 14, 2018 Technical Advisory Committee Report Share Posted October 14, 2018 2 hours ago, Mike.g said: Thanks for everyone replying. I didn't want to say who's opinion was who above, but I was the one who always wanted to run with the limited RPM. But it looks like most people side on the side of that it will not hurt a car to run up to the red line. I know from my personal experience when I ran our car at Road America. Our redline is 6500. I shifted out at 5000, and had the fastest lap time of the weekend. Plus once that saved me during a missed shift when trying to go to 5th gear I went up into 3rd gear, it reved up to mid 6000rpm before I was able realize I screwed up and went into the proper gear. So I had extra room for error with the lower rpm shifts just cause the engine will turn 7200 to the chip doesn't mean its making power up there . I would shift at 5800 ,noticing the tach moving quickly to that point and like waiting for paint to dry from 6 to red line . Have a teammate that bangs the chip constantly guess who is much faster , of course its me . 2 Quote Link to comment Share on other sites More sharing options...
mender Posted October 14, 2018 Report Share Posted October 14, 2018 Dyno sheets tell a story ... 1 Quote Link to comment Share on other sites More sharing options...
craig71188 Posted October 14, 2018 Report Share Posted October 14, 2018 Kept under factory redline. most motors will live just fine. An old timer once told me there are so many RPM's in an engine, revving higher just uses them up faster..... I think the real issues have been touched on: 1) Fuel economy 2) Are more RPM really any faster? As to fuel economy, running at lower RPM will use less fuel. Are more RPM really faster? Depends on the motor. Looking at HP & Torque curves, often the answer is "no". Depending on the transmission/rear end, often shifting well below redline better utilizes the HP/Torque and saves on fuel. Lots of RPM sounds cool, but I will shift a little lower, save a bit of fuel, and go just as fast or faster than my co-drivers most days. Quote Link to comment Share on other sites More sharing options...
Mike.g Posted October 15, 2018 Author Report Share Posted October 15, 2018 9 hours ago, craig71188 said: .... 2) Are more RPM really any faster? " Lots of RPM sounds cool," This trumps everything! You gotta' sound cool on track! Otherwise, what's the point! Quote Link to comment Share on other sites More sharing options...
theblue Posted October 15, 2018 Report Share Posted October 15, 2018 18 hours ago, craig71188 said: . Depending on the transmission/rear end, often shifting well below redline better utilizes the HP/Torque I thought this was debunked by the fact that torque multiplication and landing higher in the next gear makes a car faster. The whole S2000s are fast without a high peak torque number because they rev higher than most other cars deal. Quote Link to comment Share on other sites More sharing options...
wvumtnbkr Posted October 15, 2018 Report Share Posted October 15, 2018 (edited) Tractive force versus engine speed will tell you where to shift for optimum power delivery. That would be where the dyno sheet is REALLY useful. Edited October 15, 2018 by wvumtnbkr 1 Quote Link to comment Share on other sites More sharing options...
chip Posted October 15, 2018 Report Share Posted October 15, 2018 I usually shift a couple hundred under redline as there isn't much to gain in the upper range. The only time I really run it to redline is to avoid a quick shift. But shifting at 80% is just leaving stuff on the table, and since we are racing... Quote Link to comment Share on other sites More sharing options...
craig71188 Posted October 18, 2018 Report Share Posted October 18, 2018 On 10/15/2018 at 12:45 PM, theblue said: I thought this was debunked by the fact that torque multiplication and landing higher in the next gear makes a car faster. The whole S2000s are fast without a high peak torque number because they rev higher than most other cars deal. On 10/15/2018 at 2:01 PM, wvumtnbkr said: Tractive force versus engine speed will tell you where to shift for optimum power delivery. That would be where the dyno sheet is REALLY useful. All depends on the car and data is your friend. Quote Link to comment Share on other sites More sharing options...
theblue Posted October 18, 2018 Report Share Posted October 18, 2018 (edited) I'm trying to think of any how any car would be better off by landing lower in the next gear on an upshift? Edited October 18, 2018 by theblue Quote Link to comment Share on other sites More sharing options...
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