[PDU]

Hey Guys,

Just wanted to share some pics of the N20 PI Kit we're developing for a customer who is running an upgraded turbo & forged internals.

[jetbill]

Well it's good to see not everyone has abandoned the N20. Share some more info on the build if you can.

[Stubok]

Yes very interested in this! I want to go this route at some point. Had a quote to have my engine rebuilt with Forged internals... Little off putting.

Would love to know more about the engine build? Perhaps your client would share something on that??

I take it the stock fuel rail and injectors run out of volume when you start pushing towards 400hp on the N20, thus the need for PI?

[FSociety]

rustyminded e46m3lol there u have it lol

Stubok i think stock fuel rail starts running out of fuel on any aggressive ECU Flash, i've experienced was doing 298whp 329wtq

[sonicsonic]

Forged internals on N20? Something new for me Custom made?

[Seraphblade@sg]

I am interested in the forged intervals too. Be it just pistons and conrods.

Any quotations or insight?

[Stubok]

Some of this applies to other threads, but just putting here. It all links up anyway.

@ROBNYC thanks for sharing that man. Interesting that the fuel system has that low of a limitation.

I spoke to Matt at GSR about going with a turbo upgrade. Apparently the stock turbo can achieve enough boost pressure to grenade the stock internals, but supposedly can't provide enough flow to hold the boost level up through the higher rpm range. That resulting drop off in boost pressure means a drop in torque/power.

Apparently depending on what Torque/HP numbers you want you may or may not need upgraded internals.

If you are only interested in the current peak torque (ie where many of us are with a Flash) but want to keep it there through the rev range by holding the boost level longer with a higher flowing turbo, you may be able to keep the stock internals. However if you want more HP then you'll need higher boost as well as increased flow to hold that torque through the rev range. That would certainly require stronger internals.

Problem is, it's not like you can try the stock parts and only change them when they break since that would mean a destroyed engine.

Anyway since I'm interested in this I thought I'd do the basic math (not taking transmission loss etc into account).

Let's say you'd like 350 HP at 5500rpm. since HP = TORQUE x RPM ÷ 5252
then: TORQUE = HP x 5252 ÷ RPM
So TORQUE = 350 x 5252 ÷ 5500 = 338lbft.

That's what we can get already (with around 22psi boost), though that's at around 3000rpm. For reference making 300HP at 5500rpm means we're making 286lbft there.

So for more power all we would need to do is provide more flow to hold the boost up longer (5500rpm or higher) and viola we'll have 350+HP. Easy huh lol.

To get to 400HP at 5500rpm you'd need 382lbft. Not sure what the boost pressure would need to be, but most likely over 23psi for a start, which past experience tells us is in the "grenade" range. At that torque level we would also have a problem with the auto transmission (rated at ~340lbft) and because of the higher boost the fuel would likely need to be of higher octane, so I guess e85 or meth.

So perhaps for those of us with Autotrans its not worth pushing more boost and the added octane requirement... but just be glad with the added HP from the higher flowing turbo.

If it's true that the stage 2 turbo can hold as much flow and boost as needed (what Pure told me a while back), then 338lbft at 6000rpm gives about 380HP. I would love that!

At that range I will still venture to say that forged internals would probably still be necessary.

Something else Matt mentioned is that the stock MAP sensor may not be up to any higher boost (he said that's his experience of the N/S55 engines) and that because of the DME PID loop you may also need a piggyback to intercept the MAP sensor/wastgate to keep surge under control.

At any rate knowing that the stock rail and injectors run out of volume, adding the PI sounds great, but how would additional fuel volume it be controlled??

Presumably you would use a piggyback to manage the boost level over the stock DME boost map and add fuel to keep the AFR right while more flow is provided to hold the higher boost (for its relative rpm).

[Stubok]

Originally Posted by sonicsonic

Forged internals on N20? Something new for me Custom made?

ABR have apparently test fitted after market forged Pistons and rods, but as far as I know have not built an upgraded N20 engine. They've built many N/S55's that have broken records. Will have to check with Alex again.

From the work GSR did under Nick, before Trinity took over (not sure where that project has gone). Their engine (pushed to the limits) gave up because the rod bolts stretched and threw a rod... Boom!

From memory another case involved a cracked piston.

Nick also shared that under certain hard breaking conditions and hard corners oil starvation can happen. Which helps speed up the failures above.

So oil pan baffles and Forged Pistons, Conrods and Rod Bolts are what we need!

[dt20011]

Originally Posted by Stubok

At any rate knowing that the stock rail and injectors run out of volume, adding the PI sounds great, but how would additional fuel volume it be controlled??

Presumably you would use a piggyback to manage the boost level over the stock DME boost map and add fuel to keep the AFR right while more flow is provided to hold the higher boost (for its relative rpm).

A Split Sec AIC4 would control the PI Injectors. The injectors themselves are triggered via boost & rpm signal that is programed via the software that comes with the controller.

Terry is currently working on PI/JB4 integration also.

[Seraphblade@sg]

Originally Posted by Stubok

Some of this applies to other threads, but just putting here. It all links up anyway.

@ROBNYC thanks for sharing that man. Interesting that the fuel system has that low of a limitation.

I spoke to Matt at GSR about going with a turbo upgrade. Apparently the stock turbo can achieve enough boost pressure to grenade the stock internals, but supposedly can't provide enough flow to hold the boost level up through the higher rpm range. That resulting drop off in boost pressure means a drop in torque/power.

Apparently depending on what Torque/HP numbers you want you may or may not need upgraded internals.

If you are only interested in the current peak torque (ie where many of us are with a Flash) but want to keep it there through the rev range by holding the boost level longer with a higher flowing turbo, you may be able to keep the stock internals. However if you want more HP then you'll need higher boost as well as increased flow to hold that torque through the rev range. That would certainly require stronger internals.

Problem is, it's not like you can try the stock parts and only change them when they break since that would mean a destroyed engine.

Anyway since I'm interested in this I thought I'd do the basic math (not taking transmission loss etc into account).

Let's say you'd like 350 HP at 5500rpm. since HP = TORQUE x RPM ÷ 5252
then: TORQUE = HP x 5252 ÷ RPM
So TORQUE = 350 x 5252 ÷ 5500 = 338lbft.

That's what we can get already (with around 22psi boost), though that's at around 3000rpm. For reference making 300HP at 5500rpm means we're making 286lbft there.

So for more power all we would need to do is provide more flow to hold the boost up longer (5500rpm or higher) and viola we'll have 350+HP. Easy huh lol.

To get to 400HP at 5500rpm you'd need 382lbft. Not sure what the boost pressure would need to be, but most likely over 23psi for a start, which past experience tells us is in the "grenade" range. At that torque level we would also have a problem with the auto transmission (rated at ~340lbft) and because of the higher boost the fuel would likely need to be of higher octane, so I guess e85 or meth.

So perhaps for those of us with Autotrans its not worth pushing more boost and the added octane requirement... but just be glad with the added HP from the higher flowing turbo.

If it's true that the stage 2 turbo can hold as much flow and boost as needed (what Pure told me a while back), then 338lbft at 6000rpm gives about 380HP. I would love that!

At that range I will still venture to say that forged internals would probably still be necessary.

Something else Matt mentioned is that the stock MAP sensor may not be up to any higher boost (he said that's his experience of the N/S55 engines) and that because of the DME PID loop you may also need a piggyback to intercept the MAP sensor/wastgate to keep surge under control.

At any rate knowing that the stock rail and injectors run out of volume, adding the PI sounds great, but how would additional fuel volume it be controlled??

Presumably you would use a piggyback to manage the boost level over the stock DME boost map and add fuel to keep the AFR right while more flow is provided to hold the higher boost (for its relative rpm).

As I do not stay in the states, would be great if the new pistons and conrods can be purchased and installed =) But i guess that will not be anytime soon, even if that is possible

[Stubok]

@Seraphblade@sg it has to be possible. Yes the engine is complex, but surely a good engine builder/specialist anywhere in the world would be able to do it. You just have to find those guys. The interesting part for me is can it be done for a reasonable price?

Questions I have about replacing the internals:

Does the engine have to be removed from the car? I'm pretty sure that's a yes.

Does the engine have to be completely broken down? Or can it be done by just dropping the bottom end?
In addition to the Pistons & Rods will the stock crank need to be changed too and if so will all the bearings need to be changed?

One thing that also concerns me is adding a piggyback over the top of a flash. I wanted a flash (got GSR) to get away from a piggyback, and now it seems to go further we'd need a piggyback again. It's a shame the original ECU can't be used to control the PI fueling and manage the turbo/wastgate at higher capacity.

Looking at this from a rough price perspective:

$1500 for PI
$500 for JB4
$2000 for Stage 2 Turbo

So $4k before you even look at internals and engine rebuild.

[sonicsonic]

Germany has already 350bhp N20 with upgraded turbo but they went another way -> sports fuel + flash tune only. I think the can make better results using transmission software from m235i and jb4 for more boost and for ignoring torque limits

https://www.facebook.com/SL.Tuningsolutions/posts/982260465155318

[Stubok]

Originally Posted by sonicsonic

Germany has already 350bhp N20 with upgraded turbo but they went another way -> sports fuel + flash tune only. I think the can make better results using transmission software from m235i and jb4 for more boost and for ignoring torque limits

https://www.facebook.com/SL.Tuningso...82260465155318

Wow thanks for sharing! I've been waiting for someone to crack the autotrans limiter!

@robnyc have you seen this!?

We finally have the answer, coding it for a different car!

I always bet on the fact that BMW wouldn't use different transmissions, that ours would be the same 8AT as the 335, but coded differently. I really hope this is true.

Once I get upgraded bottom end, pistons and rods, I plan on going upgraded turbo (hopefully With ball bearings instead of journal bearings - for faster spool, which is needed since a bigger compressor/turbine wheels spin slower, so it balances those out). Then I'll backed flash and add E85, Meth or PI and JB4.

My turbo guy says the turbo would be good for 400HP. I have been saying less than 340lbft because of the autotrans, but if here is a way around it, we could be finally seeing the N20 come alive!!!

Exciting times!

[sonicsonic]

Good luck with your project! If I can help in something just let me know..

[cncmastr]

Sub'd for more info!