[rjd_F30]

Originally Posted by BunkerJ

You will see it for sure when you're in that top end but only with a point of reference, to be honest. Sure, you might be able to "feel" that it's not running out of breath at the top but having a car next to you that the only difference is turbo and AWD, it amplifies that. It would be even better if it had a tune to specifically take advantage of the bigger turbo.

Ahh, I was kind hoping you'd say it made a world of difference, and that it pulls like a freight train up top now. Anything I can get to try and justify another $2k spent on this car lol. But I don't think I could see myself spending that kind of cash on something that'll be so hard to realize the benefits of, even it is a bit faster up top and pulls on stock turbo cars... I guess I'd just want to see more for $2k. (saying 2k because I'd probably go to a shop for a turbo install, don't know that I could handle that one in my garage).

Yah, I'm sure tuning for the larger turbo would help a lot, but it's cool that it still runs so well on an OTS map from a totally separate company.

[BunkerJ]

Originally Posted by rjdnyy224

Ahh, I was kind hoping you'd say it made a world of difference, and that it pulls like a freight train up top now. Anything I can get to try and justify another $2k spent on this car lol. But I don't think I could see myself spending that kind of cash on something that'll be so hard to realize the benefits of, even it is a bit faster up top and pulls on stock turbo cars... I guess I'd just want to see more for $2k. (saying 2k because I'd probably go to a shop for a turbo install, don't know that I could handle that one in my garage).

Yah, I'm sure tuning for the larger turbo would help a lot, but it's cool that it still runs so well on an OTS map from a totally separate company.

Well, the benefits are going to be stifled by the OTS map and that's true with any turbo on any car. I would have to get a custom tune to see the full benefits but yes, I'd say it'd pull like a "freight train" up top if it were properly utilized.

[rjd_F30]

Originally Posted by BunkerJ

Well, the benefits are going to be stifled by the OTS map and that's true with any turbo on any car. I would have to get a custom tune to see the full benefits but yes, I'd say it'd pull like a "freight train" up top if it were properly utilized.

So do you have any plans of getting a custom tune?

[BunkerJ]

Originally Posted by rjdnyy224

So do you have any plans of getting a custom tune?

I have plans but they're on the back-burner for now. This summer and leading into fall have been full of all sorts of fun transitions that have put it on hold. To top it off, the VA screwed the pooch on G.I. Bill housing payments, so I'm still awaiting that lol. Once that's figured out, I'll likely get a minimum of a custom 91 tune but would like to shoot for the E40 one. I may not do either as I approach the sale of the car.

[mineralgrey_f30]

With the correct hardware, i.e chargepipe, boost pipe, and fmic, no cats. You should be all good! Happy boosting!

[rjd_F30]

Originally Posted by BunkerJ

I have plans but they're on the back-burner for now. This summer and leading into fall have been full of all sorts of fun transitions that have put it on hold. To top it off, the VA screwed the pooch on G.I. Bill housing payments, so I'm still awaiting that lol. Once that's figured out, I'll likely get a minimum of a custom 91 tune but would like to shoot for the E40 one. I may not do either as I approach the sale of the car.

Understandable. As much as I'm sure we'd all love to, sometimes the car thing can't be a financial or time-devotion priority.

That said, still crossing my fingers that you do end up with a full custom E40 tune, just so we get to hear about it

[BunkerJ]

Originally Posted by rjdnyy224

Understandable. As much as I'm sure we'd all love to, sometimes the car thing can't be a financial or time-devotion priority.

That said, still crossing my fingers that you do end up with a full custom E40 tune, just so we get to hear about it

Hunter has the custom E40/E50 tune going on right now.

[rjd_F30]

Originally Posted by BunkerJ

Hunter has the custom E40/E50 tune going on right now.

Stock turbo... though I guess not for long!

I think 350whp would be pretty easy with a bigger turbo and an E40/50 tune. IssaF32 we need dynos and 1/4 mile runs!

[M2_MEDUSA]

Originally Posted by BunkerJ

When you're talking about the safety of the engine, we have two concerns: throwing a rod (as a result from a broken rod bolt) and blowing the piston ring. The former is going to happen when either car is operating at a high, consistent power delivery (Track use) and the torque destroys the hot, weakened bolts. We aren't sure how much the stock bolts could take from use just on a strip or street use, but I'd garner to say that it's within 100lbs of the track cars that pushed 350 and threw rods left and right. The other is due to too high of pressure in the cylinder. We've had what, two guys now that have overboosted (JB4) into the 25 range and rings in one or multiple cylinders were destroyed.

You have to be sure you differentiate between lb/min and psi here. Pressure is pressure. 22psi in a small turbo and 22psi in a large turbo both exert the same amount force here. Now the difference in flow rate or CFM, is the difference. At 22psi, the smaller turbo could be pushing only a measly 30lb/min of air and fall on its face in the higher RPM band due to a low air velocity and not being able to keep up with requirements of the car. To make up for this, you can spin the turbo faster to increase PSI and hope to push more air into the cylinders, but as you push it out of its efficiency range, the charged air temp rises and you lose density and overall air volume. On a bigger turbo pushing 22psi, you could be pushing 50 lb/min and thus be making more power due to a higher volume of air. The deficiencies of the smaller turbo become advantages of the big turbo, just like how the advantages of the smaller turbo become the disadvantage of the bigger turbo.

So, rjdnyy224 , your last statement is correct that a larger turbo here is delivering more consistent power in the higher RPM range. Does it shift the power curve at all? Depends on the turbo. MHI/Dinan and similar will likely not shift it. They are "bigger" turbos, but not like what you'd think. They're still Twinscroll and spin up just as quick as the stock turbo, it just operates more efficiently in the top end. Swapping in this turbo isn't going to change your boost on the same tune, as I've already logged this and there are no differences there. Hunter and I have also seen this difference on the street. Back when we were rocking the same parts and tune, I had my turbo replaced with MHI. I initially thought it was generating more lag but turned out to just be an adaptation thing. We later (safely and legally) raced each other from I think a 40 roll. He still took off ahead in the beginning, but I'm going to say that it was from AWD + some quick honking ; however, the entire way up was me creeping up on him and by 90-100, I was eclipsing him. Now, his AWD contributed to that factor as well but my creep wasn't that grand before in previous races.

So, I think the only other point I saw in here was regarding the torque curve. In the end, you're only going to want to shift it if you're putting in a turbo that spools quicker and making bigger numbers. BM3 thankfully has a reduction in boost by gear, and that would easily solve it. You could work with your tuner to shift it also but the turbo itself isn't going to shift it until you get to a bigger one (and I mean much bigger).

Also, the MHI turbo is rated for 32psi but good luck, have fun.

I think that's it. Please tell me if I missed something. It's 7:30 and I'm still drinking my first cup of Joe for the day.

Kind of what I said in a way. Sure dinan and MHI aren't that big but it does take a tad to spool up might hit max boost half a second after stock turbo unless u measure the time of max boost from a pull on both turbos but still a half a second is better than nothing

[M2_MEDUSA]

Originally Posted by rjdnyy224

Stock turbo... though I guess not for long!

I think 350whp would be pretty easy with a bigger turbo and an E40/50 tune. IssaF32 we need dynos and 1/4 mile runs!

I hit the strip on a e30 tune I was at a high density altitude and used a calculator to adjust my times based off elevation and humidity. I ran a 13.3 @ 105. With the calculator adjusting it ended up being 13.1 @107 at regular altidude and good conditions

considering this is not what I want and "readjusting" based of conditions is poop. I now am working on finalizing an e50 tune with 16-17 degrees of timing and 22.5psi of boost. With this I am going to trailer my n20 to a 30ft above sea level drag strip for a negative DA in sacremento which is a couple hours away to get the best possible times. with new tune I should see 12.7 stock turbo and mhi or dinan I could most likely see 12.4-12.5.

This is going to be a Send it tune.

Then plans after that is Part out and Sell and go GT-R or play conservative and go B58.

Also, Im 320awhp right now on e30 tune. e50 custom tune should get me to 340whp with rod bolts that's where im stopping. 330-340 seems to be stock turbo limit

[rjd_F30]

Originally Posted by IssaF32

I hit the strip on a e30 tune I was at a high density altitude and used a calculator to adjust my times based off elevation and humidity. I ran a 13.3 @ 105. With the calculator adjusting it ended up being 13.1 @107 at regular altidude and good conditions

considering this is not what I want and "readjusting" based of conditions is poop. I now am working on finalizing an e50 tune with 16-17 degrees of timing and 22.5psi of boost. With this I am going to trailer my n20 to a 30ft above sea level drag strip for a negative DA in sacremento which is a couple hours away to get the best possible times. with new tune I should see 12.7 stock turbo and mhi or dinan I could most likely see 12.4-12.5.

This is going to be a Send it tune.

Then plans after that is Part out and Sell and go GT-R or play conservative and go B58.

Also, Im 320awhp right now on e30 tune. e50 custom tune should get me to 340whp with rod bolts that's where im stopping. 330-340 seems to be stock turbo limit

Send 'er on kill and see what she does! Looking forward to seeing how you do... Would love to see a stock turbo N20 in the 12's (that isn't killing itself).

[ilivas]

Originally Posted by rjdnyy224

I believe PTF uses the former, setting a boost target at XXXX rpm. Also found this tidbit on MHI's website about making power with a bigger turbo:

https://www.bimmerworld.com/Exhaust/...-F22-228i.html

What I gleaned from this is that they too, would agree that the extra power (assuming same tune) comes from the larger turbo flowing larger volumes of air than the stock turbo, at significantly cooler temperatures (that little turbo spinning as fast as it can generates a lot of heat, which is eliminated by a bigger turbo). They also mentioned 20% gains without increasing boost.

So, issaf32, I very respectfully am gonna stick to my original statement that just the larger turbo won't increase boost. You might pick up a half a psi or something but I'm not counting that lol. The benefit I think is that you flow a lot more air, quantitatively, at the same pressure or boost level, thus making more power.

The ability of a turbo to flow a larger volume of air isn’t going to make an real power difference. It will make a difference but it should be slight simply because it’s more efficient at that boost range. You have to look at boost like this.... boost is simply an air restriction of your motor. If you open up the restrictions in the motor to make it able to breath better, downpour, exhaust, cams, intake manifold, Etc. Then it will make more power at the same boost level.

Your turbo will spin for example 100k rpm to make this boost on a stock motor. However if you open up the restriction by adding a down pipe, then your turbo will have to spin 110k rpm to make the same boost on your motor but your turbo will flowing more air over all because it takes more air to generate 20psi on that motor now.

[rjd_F30]

Originally Posted by ilivas

The ability of a turbo to flow a larger volume of air isn’t going to make an real power difference. It will make a difference but it should be slight simply because it’s more efficient at that boost range. You have to look at boost like this.... boost is simply an air restriction of your motor. If you open up the restrictions in the motor to make it able to breath better, downpour, exhaust, cams, intake manifold, Etc. Then it will make more power at the same boost level.

Your turbo will spin for example 100k rpm to make this boost on a stock motor. However if you open up the restriction by adding a down pipe, then your turbo will have to spin 110k rpm to make the same boost on your motor but your turbo will flowing more air over all because it takes more air to generate 20psi on that motor now.

That's a really good explanation. My original thoughts were that no more pressure is generated from just a turbo, and that a turbo swap alone won't move the power band. Didn't really think about the air volume thing. I thought it was actually the other way around about de-restricting the exhaust, and that it would make the turbo work easier, but now that you explain it like that makes perfect sense.

However, I think your second sentence is what's important. While it won't literally generate more horsepower or torque, it'll be more efficient at feeding air into the cylinders where the stock turbo isn't. From what I can understand, that's the only benefit to a turbo upgrade on these cars (if you maintain stock internals, if you go further you could run more boost and realize more benefits of an upgraded turbo, but you get my point).

[BunkerJ]

Originally Posted by IssaF32

Kind of what I said in a way. Sure dinan and MHI aren't that big but it does take a tad to spool up might hit max boost half a second after stock turbo unless u measure the time of max boost from a pull on both turbos but still a half a second is better than nothing

But that's what I'm saying... The difference in spool up time is likely milliseconds, if that.

[BunkerJ]

Originally Posted by ilivas

The ability of a turbo to flow a larger volume of air isn’t going to make an real power difference. It will make a difference but it should be slight simply because it’s more efficient at that boost range. You have to look at boost like this.... boost is simply an air restriction of your motor. If you open up the restrictions in the motor to make it able to breath better, downpour, exhaust, cams, intake manifold, Etc. Then it will make more power at the same boost level.

Your turbo will spin for example 100k rpm to make this boost on a stock motor. However if you open up the restriction by adding a down pipe, then your turbo will have to spin 110k rpm to make the same boost on your motor but your turbo will flowing more air over all because it takes more air to generate 20psi on that motor now.

Depends on the stock turbo as well. In our case, you see a bigger bump in power in the higher RPM band than you do down low. So the power difference from 0-4.5/5k will remain roughly the same but above that will definitely rise. You could keep the boost up all the way to redline instead of dropping it 3-4psi.

[ilivas]

Originally Posted by rjdnyy224

That's a really good explanation. My original thoughts were that no more pressure is generated from just a turbo, and that a turbo swap alone won't move the power band. Didn't really think about the air volume thing. I thought it was actually the other way around about de-restricting the exhaust, and that it would make the turbo work easier, but now that you explain it like that makes perfect sense.

However, I think your second sentence is what's important. While it won't literally generate more horsepower or torque, it'll be more efficient at feeding air into the cylinders where the stock turbo isn't. From what I can understand, that's the only benefit to a turbo upgrade on these cars (if you maintain stock internals, if you go further you could run more boost and realize more benefits of an upgraded turbo, but you get my point).

I really saw how this became evident on my corvette when I added headers and full exhaust to my car. Keep in mind on a supercharger there is no boost controller, you simply swap pulleys to increase the speed of the blower. I added headers to the car and my peak boost actually decreased but I gained power because the motor was less of a restriction and was able to pump more air.

You can gain top end like bunker pointed out that if your turbo just isn’t able to maintain boost to redline because it’s too small or it’s working way too hard to maintain boost in those upper rpms and it starts blowing hot air.

On a turbo setup relieving the exhaust of restriction does also help the turbo not work as hard which should aid spool up as well. It helps both ways.

[ilivas]

Originally Posted by BunkerJ

But that's what I'm saying... The difference in spool up time is likely milliseconds, if that.

If it’s minuscule, you’ll probably not even notice. When ever I ran a larger turbo, I simply used lower gears to keep it in boost range. Or if I did a highway run against someone, I would just brake boost which keeps the turbo spoiled anyways.

[BunkerJ]

Originally Posted by ilivas

If it’s minuscule, you’ll probably not even notice. When ever I ran a larger turbo, I simply used lower gears to keep it in boost range. Or if I did a highway run against someone, I would just brake boost which keeps the turbo spoiled anyways.

Yeah, this thing is just big enough to keep the turbo efficient throughout the entire band vs. just early on. She's still a twin scroll and small in the turbo world. Just take the current turbo and make it like... Maybe 5-7mm bigger? I can't remember the exact measurements of the stock one.

[ilivas]

I’d like to point out that it’s not necessarily that torque kills the motor. Cylinder pressure, heat, and detonation kills motors. From what I’ve seen on dyno sheets of this car, torque is what the car makes more of. So in that essence, torque is killing it. The reason torque is killing it is because the heads, cam, turbo, intake manifold, or whatever simply cannot carry that torque into the higher rpms. There is a restriction in the motor somewhere. Ideally, you want to carry that torque to redline since as rpms increase up will increase if the torque curve stays flat. So on the n26, the most stress on the motor is where the torque peaks because it simply dies off in the upper rpms.

Notice my torque curve on my Vette. This is an old dyno sheet.

HP=(torque x rpms)/5252

[ilivas]

Originally Posted by BunkerJ

Yeah, this thing is just big enough to keep the turbo efficient throughout the entire band vs. just early on. She's still a twin scroll and small in the turbo world. Just take the current turbo and make it like... Maybe 5-7mm bigger? I can't remember the exact measurements of the stock one.

Definitely. Twin scrolls are super expensive and the way to go. It gives you a much broader power band because of the quick spool.

[BunkerJ]

Originally Posted by ilivas

I’d like to point out that it’s not necessarily that torque kills the motor. Cylinder pressure, heat, and detonation kills motors. From what I’ve seen on dyno sheets of this car, torque is what the car makes more of. So in that essence, torque is killing it. The reason torque is killing it is because the heads, cam, turbo, intake manifold, or whatever simply cannot carry that torque into the higher rpms. There is a restriction in the motor somewhere. Ideally, you want to carry that torque to redline since as rpms increase up will increase if the torque curve stays flat. So on the n26, the most stress on the motor is where the torque peaks because it simply dies off in the upper rpms.

Notice my torque curve on my Vette. This is an old dyno sheet.

HP=(torque x rpms)/5252

Car dies off the track from over boosting or on the track due to hot rod bolts breaking from that instant torque.

[ilivas]

Originally Posted by BunkerJ

Car dies off the track from over boosting or on the track due to hot rod bolts breaking from that instant torque.

The overboosting likely causes a lean condition and detonation. I wonder if it’s a tuning issue. Has that happened a lot? It’s hard for me to wrap my head around instant torque breaking a rod bolt. I can see a lot of factors breaking rod bolts, but it’s hard for me to see a torque curve doing it. NA motors have even more instant torque.

It’s not a huge platform, so really not many people have pushed them to their limits. You’ve been around here longer than I have so you would know better, but from what I’ve seen, only a couple people have pushed them so their may not be a ton of info on the motor. In the other platforms that I’ve dealt with, there are more bad tuners than good ones. I’m not yet sold on a lot of things till I can see a lot more tuners with a solid general consensus.