BMW M2 3.0L I6 and Mazda's 2.5T

[N7turbo]

This car is interesting to me.

It's just as heavy as a Turbo AWD CX-5 at 3,800 lbs. I don't know how they managed that with a 2WD coupe.

But the engine is 3.0L vs our Mazda 2.5L in the 3/6/CX-5/CX-9/CX-30/CX-50. It reportedly runs about the same amount of boost at 17.4 psi.

What I want to figure out is, what accounts for the extra 200 hp and 3.9 second 0-60? Heads, cam, intake, & exhaust can't be all that aggressive from the factory. Or are they?

The biggest difference I can see is more airflow via 2 turbos even if the boost pressure is the same. But 200hp is a big gap, even considering that. The transmission may also help it move a little quicker.

I'd like to see our 2.5T in the 400hp range. I know it's possible.

 

[Lazy2.5]

This car is interesting to me.

It's just as heavy as a Turbo AWD CX-5 at 3,800 lbs. I don't know how they managed that with a 2WD coupe.

But the engine is 3.0L vs our Mazda 2.5L in the 3/6/CX-5/CX-9/CX-30/CX-50. It reportedly runs about the same amount of boost at 17.4 psi.

What I want to figure out is, what accounts for the extra 200 hp and 3.9 second 0-60? Heads, cam, intake, & exhaust can't be all that aggressive from the factory. Or are they?

The biggest difference I can see is more airflow via 2 turbos even if the boost pressure is the same. But 200hp is a big gap, even considering that. The transmission may also help it move a little quicker.

I'd like to see our 2.5T in the 400hp range. I know it's possible.

It is an Inline 6. Not a V6.

 

[njaremka]

https://www.bmwusa.com/vehicles/m-models/m2-coupe/overview.html

Yes, inline 6, twin turbo, 473hp. Its a completely different engine from the 2.5 Mazda turbo engine. For one, Mazda's 2.5 turbo is a 4-cylinder... Also, Mazda doesn't go for big horsepower numbers, like BMW's M cars.

 

[N7turbo]

https://www.bmwusa.com/vehicles/m-models/m2-coupe/overview.html

Yes, inline 6, twin turbo, 473hp. Its a completely different engine from the 2.5 Mazda turbo engine. For one, Mazda's 2.5 turbo is a 4-cylinder... Also, Mazda doesn't go for big horsepower numbers, like BMW's M cars.

Regardless of the number of cylinders, they are smaller and the total displacement difference is only 0.5L. I think that hardly makes for much of the difference.

 

[njaremka]

[snip]...I think that hardly makes for much of the difference.

And yet, it makes a HUGE difference....

 

[N7turbo]

And yet, it makes a HUGE difference....

Huge is not the term I would use at all. Look at Mazda's inline 6: the power increase is in proportion. The BMW is way outside of that. The reason I basically answered myself when formulating my post noting all the similarities. The biggest difference has to be the amount of airflow provided by the turbos at the same psi. It just provides another data point that the Mazda 2.5 is held back by an undersized turbo. Not undersized to Mazda's design goals, but for those wanting more.

I do plan on doing a downpipe before getting a tune but ultimately if I ever want to take things further, it will require a larger turbo. Until then this motor will top out in the 300-350 whp range.

 

[Lazy2.5]

The biggest difference has to be the amount of airflow provided by the turbos at the same psi. It just provides another data point that the Mazda 2.5 is held back by an undersized turbo.

The Mazda is being held back by nothing. 300 whatever ft/lb of torque in a crossover is plenty.

If you care about all out HP and Torque figures in your 3800lb crossover, the way the entire vehicle was carefully tuned from the ground up must be considered. The engine was designed for usable torque in daily driver scenarios, not to make 350WHP.

Undersized (Turbo) according to Mazda's design goals, and for those wanting more.

Those wanting more, such as yourself, account for < 1% of CX-5 owners.

I do plan on doing a downpipe before getting a tune but ultimately if I ever want to take things further, -

You should certainly be looking into a different car.

 

[yrwei52]

This car is interesting to me.

It's just as heavy as a Turbo AWD CX-5 at 3,800 lbs. I don't know how they managed that with a 2WD coupe.

But the engine is 3.0L vs our Mazda 2.5L in the 3/6/CX-5/CX-9/CX-30/CX-50. It reportedly runs about the same amount of boost at 17.4 psi.

What I want to figure out is, what accounts for the extra 200 hp and 3.9 second 0-60? Heads, cam, intake, & exhaust can't be all that aggressive from the factory. Or are they?

The biggest difference I can see is more airflow via 2 turbos even if the boost pressure is the same. But 200hp is a big gap, even considering that. The transmission may also help it move a little quicker.

I'd like to see our 2.5T in the 400hp range. I know it's possible.

Are you sure the 3.0L turbo from BMW is a V6?

BMW’s in-line 6 is their bread-and-butter and most famous engine series. And in-line 6 is the smoothest and most balanced engine configuration among all automobile engines. I doubt they’d switch an I6 to a V6.

BMW has been very aggressive on power to design its twin-turbo I6 used on the M series. Mazda could have designed a turbo engine from their 2.5L NA with more horsepower than the current output. But a much more balanced 3.0L I6 definitely has big advantage to boost the horsepower more than a 2.5L unbalanced I4.

Actually I’ve been saying many times that Mazda should have used their 2.0L for the turbo like everybody else. It’d be easy to achieve the same power like the 2.5T, but the engine itself should be smoother with smaller displacement even without the additional heavy balance shaft which has to be added to control the vibration on the 2.5L I4. Who knows, using the 2.0L to add the turbo could have avoided the cylinder head crack issue on the 2.5T as it has more room to work on adding the turbo.

 

[Antoine]

Let's keep this discussion open here, even if the majority of CX-5 owners are not interested in more power, there's nothing wrong with discussing it...Just as some owners wish to discuss DIY maintenance, some people want to explore more performance from their vehicle whatever it may be and with regards to Mazdas, they're definitely welcome to here..

 

[sm1ke]

Huge is not the term I would use at all. Look at Mazda's inline 6: the power increase is in proportion. The BMW is way outside of that. The reason I basically answered myself when formulating my post noting all the similarities. The biggest difference has to be the amount of airflow provided by the turbos at the same psi. It just provides another data point that the Mazda 2.5 is held back by an undersized turbo. Not undersized to Mazda's design goals, but for those wanting more.

I do plan on doing a downpipe before getting a tune but ultimately if I ever want to take things further, it will require a larger turbo. Until then this motor will top out in the 300-350 whp range.

Just to tag on here.. Terry from Burger Motorsports has mentioned before that in their testing with the JB4, the 2.5T's holdback is the turbo. We'd need a bigger turbo to make any more meaningful increases in power, past the 270whp and 365tq that the JB4 currently affords. I haven't been following any other tuners and the progress they have been able to make, though.

A note that Corksport has been developing a larger turbo for the 2.5T, specifically for use in the Mazda3. Lots of useful info can be found here.

 

[N7turbo]

Just to tag on here.. Terry from Burger Motorsports has mentioned before that in their testing with the JB4, the 2.5T's holdback is the turbo. We'd need a bigger turbo to make any more meaningful increases in power, past the 270whp and 365tq that the JB4 currently affords. I haven't been following any other tuners and the progress they have been able to make, though.

A note that Corksport has been developing a larger turbo for the 2.5T, specifically for use in the Mazda3. Lots of useful info can be found here.

Oh, I know, and I want one. But it will probably be a few years until this car has one. Until then the plan is TIP + DP + tune.

 

[Muggs1]

You will need too much internal work to get the 2.5T to have anywhere close to 400hp. We are talking about a truck engine with a small turbo by design to help with the down low torque. Not to mention that it is an old design that will require probably a lot of work to make it better.

Maybe if the new CX5 will get the same setup as the larger vehicles, than we might be talking differently.

 

[N7turbo]

Now the 2.5 T is a truck engine. Learn something new everyday

Seriously though, it's a stout engine with reportedly factory forged internals which means it won't take bottom end work to make more power. We already have people in the 330 hp range. Why is it hard to imagine these engines making 400? I think 450 with a turbo upgrade is in the cards.

 

[sm1ke]

You will need too much internal work to get the 2.5T to have anywhere close to 400hp. We are talking about a truck engine with a small turbo by design to help with the down low torque. Not to mention that it is an old design that will require probably a lot of work to make it better.

Maybe if the new CX5 will get the same setup as the larger vehicles, than we might be talking differently.

How can you know this without seeing any 400hp examples of this engine? Or remains of the engines that were trying to get there?

So far, what we know for sure is that the engine's current limitation is the turbo, according to at least one professional tuning company. Change the turbo to push it further, and see what shakes out. When something else starts to fail or break, that's your next limitation. It may not be internals.

 

[Muggs1]

Now the 2.5 T is a truck engine. Learn something new everyday

Seriously though, it's a stout engine with reportedly factory forged internals which means it won't take bottom end work to make more power. We already have people in the 330 whp range, which is somewhere around 380 bhp. Why is it hard to imagine these engines making 400? I think 450 with a turbo upgrade is in the cards.

Yup, its a truck engine that makes torque down low and it dies down at higher revs. It was done in purpose but nonetheless is a non inspiring engine. Mazda slapped a small turbo on their na 2.5 and called it a day. They didn't got it right either, since a lot of them had the known issues at higher mileage.

How can you know this without seeing any 400hp examples of this engine? Or remains of the engines that were trying to get there?

So far, what we know for sure is that the engine's current limitation is the turbo, according to at least one professional tuning company. Change the turbo to push it further, and see what shakes out. When s

I am well aware that the first limitation is the turbo size, however imo is just going to have a trickle down effect on the engine internals, cooling....then you get into transmission issues than into suspension issues.

My point is this "comparison" is quite useless, I understand OP is being a fan of the Mazda turbo engine (based on other threads too), but we are talking about totally different type of engines, company, years of engine development. Even a comparison between the B58 and not S58 would have been out of place. Its like comparing apple with peaches. I would compare Mazda's 2.5T with Hyundai/Kia/Genesis 2.5 T engine, that produces a little bit over 300hp. Mazda's turbo engine has been introduced in 2016/2017 and since then we saw only a mere 6hp/10 torque increase. If it was easier or cheaper or both they would have done it already.

 

[N7turbo]

Yup, its a truck engine that makes torque down low and it dies down at higher revs. It was done in purpose but nonetheless is a non inspiring engine. Mazda slapped a small turbo on their na 2.5 and called it a day.

It's whatever floats your boat--but let's get the facts straight. We've learned that the 2.5T is not a 2.5G with a turbo slapped on. It's using a different crank, rods, and pistons. It likely has a different cylinder head and different camshaft profiles. It has a 10.5:1 CR, not 13:1. It's possible that the block has differences in cooling passages or other modifications. And the turbo transmission, which is larger in just about every way, does not bolt up to the NA motor. The stall speed of the torque converter is higher as well.

Intake (including TIP), downpipe, and a good tune puts you over 300 hp. One person I've talked to is at 330 hp. The next restriction is the turbo itself.

Understanding the level of effort Mazda put into this engine and transmission combo gives one confidence that we have not found its limits yet.

 

[sm1ke]

I am well aware that the first limitation is the turbo size, however imo is just going to have a trickle down effect on the engine internals, cooling....then you get into transmission issues than into suspension issues.

Yes, of course, that's to be expected. My question comes from your declarative statement that "you will need too much internal work to have anywhere close to 400hp". How can you know how much work will be needed to get to 400hp? As far as I'm aware, nobody's run a bigger turbo on this engine yet, and we don't know how much of an increase in HP a bigger turbo would provide.

My point is this "comparison" is quite useless, I understand OP is being a fan of the Mazda turbo engine (based on other threads too), but we are talking about totally different type of engines, company, years of engine development. Even a comparison between the B58 and not S58 would have been out of place. Its like comparing apple with peaches. I would compare Mazda's 2.5T with Hyundai/Kia/Genesis 2.5 T engine, that produces a little bit over 300hp. Mazda's turbo engine has been introduced in 2016/2017 and since then we saw only a mere 6hp/10 torque increase. If it was easier or cheaper or both they would have done it already.

I can see your point here, and I agree with it to some extent. BMW is many years ahead in engine development, they have more resources, different priorities, etc.

 

[N7turbo]

It's easy to imagine a 50-100 hp gain from an upgraded turbo. I bet when moving similar airflow with a larger turbo, the numbers will reach close to that of the BMW, with still a slight skew towards the lower RPMs without changing head & cam design.

 

[youri]

I will play devils advocate here. The engine can already produce 320 ft lbs of torque. It is already strong enough to take it. The problem is it dips fast. If we manage to maintain that torque all the way to the 6000 rpm redline, then it would produce 372 hp.

That redline is pretty low. If it could revs to 7000 rpm, then that would be 427hp.

Realistically torque is very rarely a straight curve, and there is a lot of value in low and mid end torque, even for racing engines.

You might need to change a ton of stuff to get there, because that engine is not designed for it. It is designed for strong low end torque. It might be possible, but may not be worth it at all.

 

[N7turbo]

It will never be a high-revving engine. But I believe the reason for the dip is the lack of airflow.