Exceeding redline and hitting rev limiter on stock engine?

Quote from Mike in Victoria BC

On a stock engine and ECU, I understand redline is 6200 rpm but can someone tell me when the rev limiter cuts in?

What are the risks vs benefits of running the engine up to the rev limiter on hard acceleration? Or is going beyond the redline something you should only do in error? (Does the ECU record it and is it something Polaris might use to void the warranty on your engine?)

My engine is well broken-in now (10,000 miles) so I'm done with babying it. I drive a twisty road in 3rd gear with revs sustained in the 4000-6000 range, which I assume is not doing it any harm. But I do worry about hitting or exceeding redline.

Thanks for any feedback.

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You are not driving hard enough if you are not hitting the rev limit every once in a while.

You can pretty much run the engine at the rev limiter all day long. it is designed to keep the engine well within its limits. Some on here use the limiter as the place to shift to the next gear.

As long as it can get air into the radiator you will be fine. Where it would hurt is on a hot day sitting still doing burnouts. And even that would be hard to hurt the engine due to its onboard electric fan.

I have had my built engine on 6850 bouncing off the limiter.

I don't hit the rev limiter often. It does see well into the red often. Polaris tends to do things their way. Slingshot come with the 2.4L Ecotech, redlines at 6,200, and stated 173 HP that recommends 91 octane gas. My wife's Equinox comes with a 2.4L Ecotech, has no marked redline, shifts when pushed at 7,000 with automatic, stated 182 HP, and runs on 87 octane recommended.

Polaris makes the gauges, or likely contracts the gauges for them. They set the redline where they want it.

The following I've not been able to prove without a doubt. I do interact for my work with some of the people from GM. I was told that the engine we have is their stage II (I believe was what it was referred to as), slightly hotter than the Equinox gets. I was told the stage II a higher compression, requiring the higher octane. It is my thought, that Polaris went with the old standard for fun, 1 HP for 10 pounds of weight. 1730 pounds, 173 HP. I truly believe they de-tuned it intentionally to arrive at those numbers. My Slingshot, like all I've driven that were stock, responded more like it was a carb fed machine. Oh, it would run, but seemed flat under 3k or so. Even then, the response wasn't like our Equinox. Since I put on the CAI, and the header, and have Bob's tune.... there is no comparison to before. Throttle response is brisk, even a little scary unless straighten up before you hit it in 1st or 2nd. Even the tight turns 3rd will drift out now and then. Which makes it just right.....

Also, back to the redline, I have over 24,000 on mine. I have a friend that runs his even harder, his rev limiter is hit often, with around 25,000 on his. Neither of us have had any issues with the engine. Only factory recalls on both Slingshots, nothing else.

The Equinox 2.4 and our Slingshot 2.4 a very different motors internally. Don't let the same displacement fool you in thinking they are close to identical.

The Slingshot motor was most likely chosen based on price. They probably scored a very good deal on these older non direct inject engines and the power was adequate for the machine.

There is a "two stage" rev limiter on the stock ECM. You should shift when you start to feel a loss of power as timing is being cut. If you keep going, you'll actually hear and feel it bounce away. I believe the stock rev limiter is set at 6750.

Thanks for clarifying that @TravAZ. I did not even give a thought to the direct injection. What was told to me would make sense disregarding the direct injection. Still, while I don't mind putting 91 octane in it and always just put in the 93 (hard to find 91 consistent around here, I will if I find it) why would they want the higher octane if it weren't for the compression and pre-ignition knock?

Because it runs a lot better on the 93 non Eth. The Equinox even runs a lot better and gets better gas mileage with the 93 non Eth.

Quote from FunCycle

Because it runs a lot better on the 93 non Eth. The Equinox even runs a lot better and gets better gas mileage with the 93 non Eth.

Not to get into a gas debate but I track my MPG religiously and take notes for temp,tire pressure,type of gas,brand, type of driving and even location and I have yet to find a notable MPG difference on ethanol vs ethanol free on 91 oct gas, maybe is something that those with higher horsepower can benefit from but for my stock engine the only thing that makes a difference is quality gas rather than if it is ethanol free or not.

For example the MPG from the Ethanol free gas from Kwit Trip and BP is the same as costco gas which has 10% ethanol, however there is a notable difference if i use SuperAmerica(the one near my house) or some random mom and pops shops.

I should also mention that i also track my driving times with the Maverick App which creates a map of my route taken and shows times for all "sections" so I can compare apples to apples so can't use driving habits to justify the differences in MPG from one type to another.

Quote from FunCycle

Because it runs a lot better on the 93 non Eth. The Equinox even runs a lot better and gets better gas mileage with the 93 non Eth.

It might. I've not tried it. Back in 1998, I had a 1996 GMC 4x4. It was an odd one, but I loved it. Single cab, short bed, with AC, cruise, cloth seat and plastic floor cover, no carpet. It had a 305 with a 5 speed hand shaker. I ran 89 or 91 in it all the time, from the time I bought it with 17k on it. Around 30k, I started having issues. I took it to the Chevy dealer, and after 20 minutes the mechanic came out to talk to me with the manager. They asked what fuel I was running. I told them, 89 or 91 from Shell, Marathon.... good gas. They told me to go back to 87. They said it was designed to run on 87, and the higher octane wasn't what it was set up for, therefore had partially plugged up my CAT (the one in front of the muffler, not the 4 legged type). They took it out, used something to clean it (I suspect heat and lots of it) and put it back in. Since under warr, they somehow got it written off. I went to 87, it ran like crap for a couple tankfuls. Then, it started running fine.

I never worried about the SS or the Harley. Both say 91 minimum. Most stations around me are 87, 89, and 93. I just use 93. After being almost burned on the truck that time though, I've not tried but what is recommended. As for non Eth, I noticed a huge difference on my old carb Harley by running 91 non Eth over 93 Eth.

I would always opt for 91 or 93, because its a cheap difference from 87 in my mind.

That being said, I highly doubt that running 87 in a stock Slingshot would hurt anything.

I would venture to guess that the only difference in the SS LE5, compared to the old LE5 motor is the ECM tune. Maybe they run more timing and therefore bumped the recommended fuel octane rating....?

I bet we have a few people that run 87 all of the time on here.

Quote from TravAZ

I would always opt for 91 or 93, because its a cheap difference from 87 in my mind.

That being said, I highly doubt that running 87 in a stock Slingshot would hurt anything.

I would venture to guess that the only difference in the SS LE5, compared to the old LE5 motor is the ECM tune. Maybe they run more timing and therefore bumped the recommended fuel octane rating....?

I bet we have a few people that run 87 all of the time on here.

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I'm cheap and yes I run 87 constantly and it runs like a champ EVERYTIME except when I run the battery dead after a SHORT time of listening to the radio while drying it off. Then it won't run at all.

Sent from my iPad using Polaris Slingshot Forum mobile app

@TravAZ , when Bob did my tune, I watched him. One of the things he mentioned was advancing the timing. Polaris may have it advanced some, but not to what it's capable of running. The friend that let me drive his SS before I bought mine works for GM as mechanic, and he's one of the best in a large area. As soon as he drove mine after the tune, he said it was advanced over his. It "burbles" more at idle (also 1000k idle now, Bob said it was the sweet spot with his tune) and you can hear it break up a little on shifts. Not backfire, just going from acceleration to cutting throttle.

It might be that this engine does have higher compression than most that aren't direct injected. If the compression is the same as the direct injected engine, I could see needing higher octane if not direct injected. I'm glad you mentioned that about the direct injection. I consider myself to be of decent intelligence and mechanically (semi?) skilled. When it went past carbs, I had no way to adjust or work on many of the controls and fuel systems. Just fuel pumps, filters, check fuel line pressure, the basics. I do understand how most of it works (MAP and MAF sensors, Fuel injectors, Direct injectors, Throttle body types), I will admit I got lost when iNewton started talking recently on the "Today's mod" thread.

I also agree with the higher octane being better for the engine on the SS. Just like running good Syn oil, and changing it more frequently than the manufacture's recommending.

As far as Rev limiter and shifting points, I always bounce it off the rev limiter in first and second if for no other reason than to hear the sweet exhaust sound it makes while up there in there in there 4000-rev limiter zone.

Although I have to say I don't use my slingshot as much as many of you do due to having to travel frequently, but when i do its for a nice long run of twisties during the weekend when weather permits.

Also remember that if you run it hard switch oils more frequently than the recommended intervals.

Quote from TravAZ

I would always opt for 91 or 93, because its a cheap difference from 87 in my mind.

That being said, I highly doubt that running 87 in a stock Slingshot would hurt anything.

I would venture to guess that the only difference in the SS LE5, compared to the old LE5 motor is the ECM tune. Maybe they run more timing and therefore bumped the recommended fuel octane rating....?

I bet we have a few people that run 87 all of the time on here.

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Quote from Neosolidus

As far as Rev limiter and shifting points, I always bounce it off the rev limiter in first and second if for no other reason than to hear the sweet exhaust sound it makes while up there in there in there 4000-rev limiter zone.

Although I have to say I don't use my slingshot as much as many of you do due to having to travel frequently, but when i do its for a nice long run of twisties during the weekend when weather permits.

Also remember that if you run it hard switch oils more frequently than the recommended intervals.

But you also have to remember there are those that as long as it cranks up and runs everything is good and you cannot tell them any different. They also believe everything that the goverment says.

My 1989 Firebird Fomula 350 got 50 more miles per tank more on 93 than it did on the 87. Around town, same day - same station every week, most the time it was even the same gas pump. Not many people believed that either, but it was the truth. Back then I checked everything also. My current 98 Trans Am runs and sounds like a diesal on 93 with eth.

I have bounced over the Rev limiter numerous times and it detunes real quick and you know it. Let off the gas shift and go.

Sent from my SAMSUNG-SM-T537A using Polaris Slingshot Forum mobile app

Quote from Neosolidus

I should also mention that i also track my driving times with the Maverick App which creates a map of my route taken and shows times for all "sections" so I can compare apples to apples so can't use driving habits to justify the differences in MPG from one type to another.

What else does the maverick app do?
Will it log G force and acceleration and speed?

Quote from Casey_SS

What else does the maverick app do?Will it log G force and acceleration and speed?

Maverick is not a racing app but rather a mapping app, it has a lot of options for tracking routes and the info logged depends on the device used.

It creates a traceable map which I use to compare my runs(jogging and slingshot) which helps me figure out how I am doing, although it has a lot of functions built-in it is not a lap timer.

Quote from Goats_Hogs

@TravAZ , when Bob did my tune, I watched him. One of the things he mentioned was advancing the timing. Polaris may have it advanced some, but not to what it's capable of running. The friend that let me drive his SS before I bought mine works for GM as mechanic, and he's one of the best in a large area. As soon as he drove mine after the tune, he said it was advanced over his. It "burbles" more at idle (also 1000k idle now, Bob said it was the sweet spot with his tune) and you can hear it break up a little on shifts. Not backfire, just going from acceleration to cutting throttle.

It might be that this engine does have higher compression than most that aren't direct injected. If the compression is the same as the direct injected engine, I could see needing higher octane if not direct injected. I'm glad you mentioned that about the direct injection. I consider myself to be of decent intelligence and mechanically (semi?) skilled. When it went past carbs, I had no way to adjust or work on many of the controls and fuel systems. Just fuel pumps, filters, check fuel line pressure, the basics. I do understand how most of it works (MAP and MAF sensors, Fuel injectors, Direct injectors, Throttle body types), I will admit I got lost when iNewton started talking recently on the "Today's mod" thread.

I also agree with the higher octane being better for the engine on the SS. Just like running good Syn oil, and changing it more frequently than the manufacture's recommending.

Our Slingshot LE5 has a compression of 10.4. The newer LEA and LUK found in the newer GM vehicles have a compression of 11.2.

So that theory is out of the window....

@TravAZ 10.4 is still high compression. Granted, not as high as 11.2, but high enough to likely warrant using the higher octane. Harley is only 9.5, and they recommend 91 or higher.

Thanks for following that up. Honestly, I got sidetracked yesterday. I meant to follow up and check on the compression.