[Fallenangel123]

Hey everyone, hope you are all well.

I am going to be upgrading the turbos on my 35is in the near future. I am looking to put in a pair of upgraded twins. I am from the UK so no E85 unfortunately, the best fuel I can get hold of is 93 octane (99 ron).

I am wanting to make circa 600bhp at the crank, is this possible with 93 octane, or will I need to consider methanol injection?

My car is RHD fyi.


Thanks all for input.

[david in germany]

Originally Posted by Fallenangel123

Hey everyone, hope you are all well.

I am going to be upgrading the turbos on my 35is in the near future. I am looking to put in a pair of upgraded twins. I am from the UK so no E85 unfortunately, the best fuel I can get hold of is 93 octane (99 ron).

I am wanting to make circa 600bhp at the crank, is this possible with 93 octane, or will I need to consider methanol injection?

My car is RHD fyi.


Thanks all for input.

Everything is based on what modifications you also have and on the tune. Without that info there is no way to even estimate power gains/losses.

[Saif2018]

Originally Posted by Fallenangel123

Hey everyone, hope you are all well.

I am going to be upgrading the turbos on my 35is in the near future. I am looking to put in a pair of upgraded twins. I am from the UK so no E85 unfortunately, the best fuel I can get hold of is 93 octane (99 ron).

I am wanting to make circa 600bhp at the crank, is this possible with 93 octane, or will I need to consider methanol injection?

My car is RHD fyi.


Thanks all for input.

600 bhp at the crank is possible,

You will probably need turbos like RB 2 plus with Inlets and outlets.

Probably best if you speak to a N54 tuning specialist.

Or email RB Turbos and ask Rob.

[langsbr]

475 - 500 whp is about the most hybrids do on 93 octane. The latest RB Game Finishers though have made 581whp on 93 octane. I'm not sure I would drive it on that all day, every day though, as 93 octane can be poor at times. Plus, ethanol gives a good cooling ability which greatly helps since we have cast pistons.

So - TLDR -
Peak - 580whp
Realistic - 475whp

[Saif2018]

Originally Posted by langsbr

475 - 500 whp is about the most hybrids do on 93 octane. The latest RB Game Finishers though have made 581whp on 93 octane. I'm not sure I would drive it on that all day, every day though, as 93 octane can be poor at times. Plus, ethanol gives a good cooling ability which greatly helps since we have cast pistons.

So - TLDR -
Peak - 580whp
Realistic - 475whp

How much is that at the crank?

[Smgs1992]

Originally Posted by Saif2018

How much is that at the crank?

Lets say 15% drivetrain loss 545bhp 670bhp

[BSM n54iS]

To answer you would need to add meth + 93 to get up to 600hp OP w/o any ethanol

[Saif2018]

Originally Posted by Smgs1992

Lets say 15% drivetrain loss 545bhp 670bhp

So about 510whp with that drive loss, for 600bhp at the crank?

That should be possible with 93oct only, depending on the turbos right?

I mean i understand the benefits of Ethanol/Methanol but it's not easily accessible and pain in the butt to get hold of in UK

What would you say is a safe Whp/crank hp to run at for daily?

Also the ratings on RB turbos website are they max whp the turbos can safely push with Ethanol or 93oct?

[Riceball777]

The answer is No. your very octane limited from making big power

Generally with low octane fuel like stand pump 91/93 octane the limit of this engine is about 500whp. This is with all the bolts one and with much bigger than stock turbos.

If you want more power then you must run much more higher boost Numbers and more aggressive timing number that normal 91/93 octane Simply cannot support.

But with high octane fuel like e85 or race gas or meth injection the potential in limitless like well over 1000whp.

Anytime a turbo is rated for say 600whp or 700whp, these numbers can only be achieved with high octane fuel. You can never max out the flow capabilities and the potential of a turbo on low octane 91/93 octane fuel.

[Saif2018]

Originally Posted by Riceball777

The answer is No. your very octane limited from making big power

Generally with low octane fuel like stand pump 91/93 octane the limit of this engine is about 500whp. This is with all the bolts one and with much bigger than stock turbos.

If you want more power then you must run much more higher boost Numbers and more aggressive timing number that normal 91/93 octane Simply cannot support.

But with high octane fuel like e85 or race gas or meth injection the potential in limitless like well over 1000whp.

Anytime a turbo is rated for say 600whp or 700whp, these numbers can only be achieved with high octane fuel. You can never max out the flow capabilities and the potential of a turbo on low octane 91/93 octane fuel.

500whp is almost 600bhp at the crank, so op target of 600bhp with upgraded turbos at the crank or close to it, is possible.

[stewbets]

Talking about a crank number is just inviting all sorts of unknowns and bad guesses since the drivetrain loss % isn't necessarily linear, nor is it precisely known, nor are most people great at math. 500whp could easily be between 550hp and 667hp at the crank, depending on who's doing the math and what loss % they're using.

In this thread, 475whp was said to be 545hp at the crank, given a 15% drivetrain loss, and this is the kind of wrong math I see most people do. 475 x 1.15 makes sense to most people, but this is not a 15% loss on the crank hp. This is a 15% gain on the whp, and that's not what we want. To find the theoretical crank hp, you must divide the whp by the remaining percentage after loss is subtracted. In other words, crank hp = whp / (100% - loss %). In this case it's 475 / .85, which is 559hp at the crank.

Thanks for letting me get this off my chest.

[Saif2018]

Originally Posted by stewbets

Talking about a crank number is just inviting all sorts of unknowns and bad guesses since the drivetrain loss % isn't necessarily linear, nor is it precisely known, nor are most people great at math. 500whp could easily be between 550hp and 667hp at the crank, depending on who's doing the math and what loss % they're using.

In this thread, 475whp was said to be 545hp at the crank, given a 15% drivetrain loss, and this is the kind of wrong math I see most people do. 475 x 1.15 makes sense to most people, but this is not a 15% loss on the crank hp. This is a 15% gain on the whp, and that's not what we want. To find the theoretical crank hp, you must divide the whp by the remaining percentage after loss is subtracted. In other words, crank hp = whp / (100% - loss %). In this case it's 475 / .85, which is 559hp at the crank.

Thanks for letting me get this off my chest.

Drivetrain loss is higher on Xdrive compared to rear wheel drive?

Do we have actual loss figures for both?

I mean obviously it will vary, just like dynos vary, but do we have some sort of ball park figures for both?

[stewbets]

Sure, the drivetrain loss is higher on xDrive than RWD, but I don't think anyone has actual loss figures for either of them. And at the end of the day, it's a rather vain pursuit since whp is what determines performance anyway.

From what I've gathered, 275whp is a pretty average stock 335i number while 260whp is standard for a stock 335xi. 275whp with 15% loss gives you 324hp at the crank while 260whp with 20% loss gives you 325hp at the crank. And since it's common knowledge that the N54 is underrated, 325hp is likely very close to the actual crank power.

So I'd be inclined to go with 15% loss for a stock 335i and 20% for a stock 335xi, but who knows what happens to those figures as power is increased? I don't think you can expect to see the same 15% and 20% losses with a 600hp engine. The drivetrain will certainly absorb more hp with a 600hp setup, but I would bet it would be at a much lower percentage, perhaps 10% and 15%. Does that make sense?

But to get back to my main point, anytime you're taking whp and attempting to convert it to crank hp, you're guessing and adding in unknown variables in order to arrive at an impractical result (aside from having a higher hp number to brag about). This is why it's best to leave crank hp numbers to the manufacturers (who tend to lie about them anyway).

[Saif2018]

Originally Posted by stewbets

Sure, the drivetrain loss is higher on xDrive than RWD, but I don't think anyone has actual loss figures for either of them. And at the end of the day, it's a rather vain pursuit since whp is what determines performance anyway.

From what I've gathered, 275whp is a pretty average stock 335i number while 260whp is standard for a stock 335xi. 275whp with 15% loss gives you 324hp at the crank while 260whp with 20% loss gives you 325hp at the crank. And since it's common knowledge that the N54 is underrated, 325hp is likely very close to the actual crank power.

So I'd be inclined to go with 15% loss for a stock 335i and 20% for a stock 335xi, but who knows what happens to those figures as power is increased? I don't think you can expect to see the same 15% and 20% losses with a 600hp engine. The drivetrain will certainly absorb more hp with a 600hp setup, but I would bet it would be at a much lower percentage, perhaps 10% and 15%. Does that make sense?

But to get back to my main point, anytime you're taking whp and attempting to convert it to crank hp, you're guessing and adding in unknown variables in order to arrive at an impractical result (aside from having a higher hp number to brag about). This is why it's best to leave crank hp numbers to the manufacturers (who tend to lie about them anyway).

We use Crank HP figures in UK, I'm assuming thats why OP mentioned it.

So assuming the OP is targeting 500whp that should be achievable on 93 Oct pump gas (Stage 2 Turbos) right?

[Riceball777]

500whp is very hard to do on normal 91/93octane. Its possible and on the upper limits of this engine assuming you have 93/94 octane and not 91octrane and you have a big single turbo with all the bolt ons with a good tune. Its definitely much much harder with upgraded twin turbos.

Here is my 335i n54 dyno. I made 504whp and 504tq. This is with all the bolts on and with pure stage 2 turbos running 21psi of boost with 50%e85 fuel and 50%91octane. Because I don’t have port injection my high pressure fuel pump is maxed out. With only 91 octane I would guess I would be somewhere in the low to mid 400whp range. If i had port injection i can easily just run full e85 and max out the turbo and be in the 600whp range.

[feuer]

600bhp on 93oct with only upgraded twin turbos is impossible. Will need inlets, outlets, port injection or methanol.

[Riceball777]

Originally Posted by feuer

600bhp on 93oct with only upgraded twin turbos is impossible. Will need inlets, outlets, port injection or methanol.

With meth injection a lot more than 600whp is possible. Meth injection is similar to running high octane fuel.

We’re talking about making power on low octane 91/93 octane pump fuel with no meth injection or race gas or e85.

[Saif2018]

Originally Posted by Riceball777

500whp is very hard to do on normal 91/93octane. Its possible and on the upper limits of this engine assuming you have 93/94 octane and not 91octrane and you have a big single turbo with all the bolt ons with a good tune. Its definitely much much harder with upgraded twin turbos.

Here is my 335i n54 dyno. I made 504whp and 504tq. This is with all the bolts on and with pure stage 2 turbos running 21psi of boost with 50%e85 fuel and 50%91octane. Because I don’t have port injection my high pressure fuel pump is maxed out. With only 91 octane I would guess I would be somewhere in the low to mid 400whp range. If i had port injection i can easily just run full e85 and max out the turbo and be in the 600whp range.

If 500whp FBO, including Inlets with Stage 2 turbos with 93oct fuel only, is pushing the limits of the engine, isn't it pointless without E85?

I mean if all your going to get is about 450whp reasonably, better to stick to stock TD03 and use E85, could easily get 400-450whp.

Asking because I will be in the same boat as OP in future, I don't have easy access to E85, 93oct is easily available

I'm not targeting a specific WHP, but would be a realistic WHP figure for FBO, ( Port injection with Inlets using 93oct only, stage 2 turbos?

[langsbr]

Originally Posted by feuer

600bhp on 93oct with only upgraded twin turbos is impossible. Will need inlets, outlets, port injection or methanol.

With upgraded turbos, I'd say inlets and outlets are table stakes now.