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Has anyone raised their rev limiter?

Mike King

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#1
Is it set that low because the stock turbo runs out of breath? When I get my big turbo, I would like it raised but I don't know what is safe. My Lotus was at 7500 and I drove it that way for over 10 years. I drove a Matrix XRS when I worked for Toyota and it feels/sounds so good at 8000.
 


the duke

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#2
Most aftermarket tunes can raise it, it’s an electric limit. Early 2014s had a 6750 redline, which was switched to 6500 within the first few months. The turbo is done after 5 so it was as you said, just shift and use the torque.

I believe COBB tore a motor down and the belief is 7500 is the limit for the valve train and rotating assembly.
 


OP
Mike King

Mike King

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Thread Starter #3
Most aftermarket tunes can raise it, it’s an electric limit. Early 2014s had a 6750 redline, which was switched to 6500 within the first few months. The turbo is done after 5 so it was as you said, just shift and use the torque.

I believe COBB tore a motor down and the belief is 7500 is the limit for the valve train and rotating assembly.
So when I go big then I will have Jason tune me to 7400, sweet.
 


Dialcaliper

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#6
Besides the sound, you’ll see limited benefit from raising the rev-limiter too much beyond 7000 without going to a built motor with serious head-work.

You’ll see valve float (valves losing contact with cams/buckets) at some point, which is all kinds of bad. It sounds like you’ll see around 7500, (as stated above). It’s good to leave a bit of margin there. Usually float happens before your rods decide they want to leave your engine, but that’s a consideration too.

Practically speaking, you’re limited by all the same things an all-motor build requires at higher RPM - cam duration and head port flow being too brief to let enough air in, valve diameter too small, intake and exhaust manifold runner lengths too long, etc.

Even if you get a monster big turbo that will flow enough at higher RPM without running out of breath, it’s generally so much more effective in a turbo motor to just turn up the boost wick to get more power, especially since factory turbo engines are designed to flow at lower RPM ranges with a broader powerband - exactly the opposite of of a peaky high RPM motor, so you’re fighting a lot of OEM design decisions.
 


haste

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#7
I had mine at 6900 with my x37 for over 6 years without issue. Bumped it up to 7000 with the S280.
 


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#8
I've been able to rev it out all the way in all gears (the tune it has removed the rev limiter) but the hybrid turbo runs out of steam just before red line so it doesnt really matter in my opinion.
 


OP
Mike King

Mike King

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Thread Starter #10
Besides the sound, you’ll see limited benefit from raising the rev-limiter too much beyond 7000 without going to a built motor with serious head-work.

You’ll see valve float (valves losing contact with cams/buckets) at some point, which is all kinds of bad. It sounds like you’ll see around 7500, (as stated above). It’s good to leave a bit of margin there. Usually float happens before your rods decide they want to leave your engine, but that’s a consideration too.

Practically speaking, you’re limited by all the same things an all-motor build requires at higher RPM - cam duration and head port flow being too brief to let enough air in, valve diameter too small, intake and exhaust manifold runner lengths too long, etc.

Even if you get a monster big turbo that will flow enough at higher RPM without running out of breath, it’s generally so much more effective in a turbo motor to just turn up the boost wick to get more power, especially since factory turbo engines are designed to flow at lower RPM ranges with a broader powerband - exactly the opposite of of a peaky high RPM motor, so you’re fighting a lot of OEM design decisions.
Strange that the XRS limit is 8,350rpm and I saw them with way over 200,000 miles. Of course that would be comparing Toyota to Ford and we know who engineers things better.
 


TDavis

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#11
Why tf would you want a Matrix, out of all the cars, to rev to 8k rpm?
 


kivnul

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#12
Using a x47r, Stratified limited it to 7000. Tunewerks raised it to 7000 as well, but Randy was not really comfortable with that. On E30; His rational:

"Alright, you are out of fuel injector in the upper RPMs at this point for the colder ambient temp runs. That is due to the higher boost. I would not rev beyond 6300 RPMs. Or I can reduce the boost. That would reduce power, of course. Whatever you prefer. With the hotter ambient runs the injectors can keep up with the boost level so you can rev higher than 6300 RPMs if you want."

Cold in this case was 45f, Hot was 90f. I would send him logs from early morning and afternoon of the same day. It is astonishing how differently the car performs between hot/cold.
 


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#14
Why tf would you want a Matrix, out of all the cars, to rev to 8k rpm?
Not trying to dig too hard... but why would you want a Fiesta/Mazda 2 too have 200ftlb of torque?

Seems like a fun practical hot hatch to me, who cares who makes it...

The Matrix XRS was the "ST" of the Toyota Matrix lineup. The Corolla XRS was a pretty sweet little car in the 2000's all things considered, why not make it a hatchback?
 


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#15
Guys, these are Open Deck engines with cast pistons. Run these engines too hard and you'll be looking at buying a new engine. If you want more power the best option is to start with an engine block constructed to handle higher revs and bigger turbos. I would suggest your first purchase be a Mountune MRX short block, then you can start increasing the revs and boost. BTW, if you get the MRX long block you also get a head that has been CNC ported and a set of cams designed for an extended high rpm power band.
 


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#16
Guys, these are Open Deck engines with cast pistons. Run these engines too hard and you'll be looking at buying a new engine. If you want more power the best option is to start with an engine block constructed to handle higher revs and bigger turbos. I would suggest your first purchase be a Mountune MRX short block, then you can start increasing the revs and boost. BTW, if you get the MRX long block you also get a head that has been CNC ported and a set of cams designed for an extended high rpm power band.
There is a lot of bad information in this post. The MRX short block is, also, open deck. It fixes none of the issues that the OEM engines have. The stock engines are very durable, and are still the most durable, widely available option. I suspect we will see better options in the next year or so as I know multiple companies are working on them. You can more than double the horsepower on the stock engines before reliability becomes a concern. Personally I have made over 400whp/wtq on two different 1.6 engines.
 


dhminer

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#17
There is a lot of bad information in this post. The MRX short block is, also, open deck. It fixes none of the issues that the OEM engines have. The stock engines are very durable, and are still the most durable, widely available option. I suspect we will see better options in the next year or so as I know multiple companies are working on them. You can more than double the horsepower on the stock engines before reliability becomes a concern. Personally I have made over 400whp/wtq on two different 1.6 engines.
Amen. You’ll likely blow the trans long before the engine.
 


M-Sport fan

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#18
Strange that the XRS limit is 8,350rpm and I saw them with way over 200,000 miles. Of course that would be comparing Toyota to Ford and we know who engineers things better.
That (naturally aspirated, BTW) engine was built/specced specifically to rev that high from the factory, whereas most boosted factory engines are not.
 


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#19
Is it set that low because the stock turbo runs out of breath? When I get my big turbo, I would like it raised but I don't know what is safe. My Lotus was at 7500 and I drove it that way for over 10 years. I drove a Matrix XRS when I worked for Toyota and it feels/sounds so good at 8000.
Didn’t the Matrix/Vibe share an engine block with the Elise?
 




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