Open Tuning/Turbo Theory Discussion

[Redline]

@Realgib3 and I were talking about turbo selection as it relates to engine tq/heat/longevity in another thread. It got mucked up, so I decided to move this here. Self-tuners and protuners, please chime in! Or bring up something else (related) altogether

As Sho said, his engine is still running in another car and Jake's engine is actually running in my 6 still, now with >130k on it, and compression still 180+.

I've personally seen a lot more damage from small/inefficient setups being pushed than from bigger setups running efficiently. Not saying a bigger turbo and 500+whp on stock block is bulletproof by any means, but I'd take a smooth 380-400wtq giving me 500+whp over a BNR S3 making the same TQ with a big TQ spike and netting 100 less whp than the BT. That's just me though.

The solution = protune from peeps like Justin. No torque spike or aggressive ramp-up at all, and tq peak at ~4,300 on my S3. Running strong for nearly 30k miles now, and I compression test religiously.

IMHO, there are 2 primary concerns:
1) too much absolute torque; too much torque too low; or too aggressive of a torque ramp-up = potentially compromised rods.
2) Going north of 400whp. There's a direct relationship between power and heat, therefore in so doing, the ringlands are the main concern. Ring butting will happen much more readily in a hotter combustion chamber.

Meh. My response was coming from the view point of a protuner, who's seen more setups, both good and bad, than most can even imagine.

Also, There's a lot more to the relationship between power and heat.

Yes, including how hard the turbo is being pushed. But when you're running a BNR S3 with E28 + 100% 12.8GPH methanol, the sheer amount of alky keeps everything much cooler/happier (ringlands), and I trust Justin's torque management skills as much as anyone else in the world (since he's literally tuned over 1,000 Mazdaspeeds) you know?

Besides, how one drives the car and gets into boost, and things like whether or not they WOT too low in the powerband, or in 6th at all, can have everything to do with a engine grenading or lasting. Unfortunately, there is no perfect equation to avoid it. Some engines are just stronger, for instance. There are uncontrollable, influential variables.

I had a long post typed up for a response, but I decided against it.
Anyway, ironically Justin just posted a dyno sheet of a very well running/tuned S4 on stock block, which perfectly illustrates my point. Same peak TQ as Cas, roughly same rpm for peak TQ, but it can't hold that TQ at all and makes 100whp less.

Just because he made a tune like that doesn't de-legitimize my concern. If you insist, he'll push past "safety" if higher power is your goal. And there's a big difference between 500whp and 420whp. But most importantly, presuming the tune is "safe" whether or not that's 350, 450, 500whp or whatever, I honestly believe more blocks are lost due to driver habits than anything else. But regarding the power level, my understanding is that peak torque isn't all you have to worry about. If you disagree, fine, and I'd love to hear an extended explanation, but most importantly, see actual examples of safety w/ statistics. Seriously - I love talking about stuff like this, and don't want to derail here more, so maybe we could put this in the tuning section?

If Justin told me not to worry about it, then that'd go further with me (since he has literally tuned over 1,000 Speeds - he has unparalleled experience and data with the platform, IIRC). The only other tuner that may be close is Lex I think, but I could be wrong. No offense, man, but he's my tuner and I trust him regarding my S3. I know you've tuned a good number of guys. Then there's Snaild, Dizzy, RichTune, Purple Drank, Nishan, Stratified and some local/NATOR guys. Though they're all great, they're not all at the same level in terms of sheer practical experience with Speeds/# of cars tuned.

No need for a discussion. What do I know anyway, I only have 4 posts.

Too bad. You may have only 4 posts, but "[Your] response was coming from the viewpoint of a protuner, who's seen more setups, both good and bad, than most can even imagine." That's why I'd love to hear more, seriously - no snarkiness at all. I don't presume to be correct, but am explaining where I'm coming from. Hopefully you'll decide to share your viewpoint as a protuner. Have a website yet, BTW?

@Jason@DizzyTuning , you're really good about sharing your practical tuning wisdom. Would you mind sharing your perspective?

 

[Realgib3]

I was about to start a thread with this writeup I did a while back, but I think this is a good place to keep the turbo sizing discussion, so I'll post it in here. I had to modify this slightly from when it was originally written because the S4 was later produced and became a turbo I would now include in my "smallest BT to go with" category.

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I hear a LOT of the same old "I want a big turbo but I want it to spool and hit full boost like a k04" that I have ALWAYS hated and have seen over and over again for yeeears with this platform.

With that, I decided to overlay some logs from the 4 main types of setups I support running on a speed. Many others will give 500000 other options, but these are the setups that make sense to ME personally.You all know my experience in this area, so take it or leave it, either is fine by me.

1. Stock block, stock turbo, stock fueling - This is the way the car came, is extremely fun to drive, and plenty of real gains can be made with a tune and even more with e85, but no matter what, you'll have roughly the ko4 power curve shown in the first log.

2. Stock block, BIG Turbo, Stock Fueling - This combo allows for moderate k04-like Peak TQ numbers, with MUCH more peak horsepower and MUCH more area under the curve, while still operating with the limits of the stock fuel system. IMO this group of turbos start at a 5858 size (3076 varients, and the now including the S4) and go up from there. Period.

3. Stock Block, BIG Turbo, AUX Fueling - This setup allows you to have slightly higher than k04-like peak TQ numbers with MUCH MUCH MUCH more horsepower, especially up top, due to the added fueling/cooling capabilities. This setup is only limited by the stock bottom end and the size of the balls of the car's owner. IMO still a great option though. Making 450-485whp and 350-385wtq with a ton of power under the curve is easily attainable here. Again, 5858 size and up for this IMO.

4. Built Motor, BIG Turbo, Aux Fueling - This setup is pretty obvious. It allows for everything in #3, without the limits of the stock bottom end. I really don't see going for anything smaller than a 6266 size with a built motor, but for the MS6 guys who can put more TQ to the ground, earlier, I'd consider a 5862 if you're trying to stay JB or the new 6062 if going BB. I still feel you can make plenty of TQ down low with a 62 or 6466.

Now with all that said, on to my entire point here. In the graphs below you will see very clearly why I advocate these 4 options. For EVERYONE scared about losing TQ down low and having a "Slow" spooling BT...

IT's NOT ALL ABOUT THE WHERE YOUR TURBO HITS 20PSI!

The ko4 car below makes peak TQ from ~3600-4300rpm and EVERY one of the big turbo graphs below eclipses the k04's peak TQ number between 4k and 4200rpm and holds that TQ all the way to redline. You do the math.

Bottom line, if you want to drive your car like a K04 car, keep a k04 on it and enjoy the k04 curve. If you want something other than a k04 curve, please stop worrying about turbos being to0 big, make the right choice and get an actually big turbo. Turbos below go from k04-->5858-->6266-->6466

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Now with all that said, my overall advice is this...Both from a tuner's perspective and as someone who's personally run every different one of these setups, run the most EFFICIENT setup you can afford. If you want things cool, efficient, and safe, then you can never have too much fuel, can never have too much octane, and can never have too free-flowing an exhaust system.

 

[Redline]

I was about to start a thread with this writeup I did a while back, but I think this is a good place to keep the turbo sizing discussion, so I'll post it in here. I had to modify this slightly from when it was originally written because the S4 was later produced and became a turbo I would now include in my "smallest BT to go with" category.

------------------------------------------------------------------------------------------
I hear a LOT of the same old "I want a big turbo but I want it to spool and hit full boost like a k04" that I have ALWAYS hated and have seen over and over again for yeeears with this platform.

With that, I decided to overlay some logs from the 4 main types of setups I support running on a speed. Many others will give 500000 other options, but these are the setups that make sense to ME personally.You all know my experience in this area, so take it or leave it, either is fine by me.

1. Stock block, stock turbo, stock fueling - This is the way the car came, is extremely fun to drive, and plenty of real gains can be made with a tune and even more with e85, but no matter what, you'll have roughly the ko4 power curve shown in the first log.

2. Stock block, BIG Turbo, Stock Fueling - This combo allows for moderate k04-like Peak TQ numbers, with MUCH more peak horsepower and MUCH more area under the curve, while still operating with the limits of the stock fuel system. IMO this group of turbos start at a 5858 size (3076 varients, and the now including the S4) and go up from there. Period.

3. Stock Block, BIG Turbo, AUX Fueling - This setup allows you to have slightly higher than k04-like peak TQ numbers with MUCH MUCH MUCH more horsepower, especially up top, due to the added fueling/cooling capabilities. This setup is only limited by the stock bottom end and the size of the balls of the car's owner. IMO still a great option though. Making 450-485whp and 350-385wtq with a ton of power under the curve is easily attainable here. Again, 5858 size and up for this IMO.

4. Built Motor, BIG Turbo, Aux Fueling - This setup is pretty obvious. It allows for everything in #3, without the limits of the stock bottom end. I really don't see going for anything smaller than a 6266 size with a built motor, but for the MS6 guys who can put more TQ to the ground, earlier, I'd consider a 5862 if you're trying to stay JB or the new 6062 if going BB. I still feel you can make plenty of TQ down low with a 62 or 6466.

Now with all that said, on to my entire point here. In the graphs below you will see very clearly why I advocate these 4 options. For EVERYONE scared about losing TQ down low and having a "Slow" spooling BT...

IT's NOT ALL ABOUT THE WHERE YOUR TURBO HITS 20PSI!

The ko4 car below makes peak TQ from ~3600-4300rpm and EVERY one of the big turbo graphs below eclipses the k04's peak TQ number between 4k and 4200rpm and holds that TQ all the way to redline. You do the math.

Bottom line, if you want to drive your car like a K04 car, keep a k04 on it and enjoy the k04 curve. If you want something other than a k04 curve, please stop worrying about turbos being to0 big, make the right choice and get an actually big turbo. Turbos below go from k04-->5858-->6266-->6466

----------------------------------------------------------------------------------------------------

Now with all that said, my overall advice is this...Both from a tuner's perspective and as someone who's personally run every different one of these setups, run the most EFFICIENT setup you can afford. If you want things cool, efficient, and safe, then you can never have too much fuel, can never have too much octane, and can never have too free-flowing an exhaust system.

Thanks, @Realgib3 , for sharing this. Do you happen to have a graph that has an S3, S4, GTX2867r or CS Turbo? Those are a popular segment that I think would be good to include in the comparison. Personally, I like the fact the S3, for instance, still has guts down low and spools almost as quickly as the K04, but obviously it doesn't have the top-end of several in the graph you posted. And the slower spool adds to safety in terms of rods not seeing torque ramp up nearly as fast. To be clear: my tune is quite neutered down low for rods' safety (which is definitely more of an issue with the "mid" turbos), but I get the idea that with bigger turbos it's a non-issue because they can't make too much torque down low/don't spool fast low in the powerband = automatic safety measure in place. And for me on the S3, since it can still develop a potentially dangerous amount of wtq too low in the powerband, I modify my driving style accordingly, never going WOT <3k in most gears, <3.5k in 5th, and not at all in 6th. I think driving style can be as influential as many other factors in avoiding ZZB, just based upon physics. I wish I had real data to back it up, but the principles at play/general consensus is this is the case.

Having said this, when I get built, the EFR7163 is my dream turbo for numerous reasons, including the fact it has the spool of a K04 and the top-end of a GTX3076r. Have any graphs of that turbo?

I completely agree about lots of alky, and have implemented that in my setup. As do I about exhaust piping. I say this all the time when I hear the "exhaust is just a sound mod" myth. There's more to it than that, especially when you do a turbo upgrade. In my BNR S3 tuning thread, I saw literally a +35whp gain going from full 3" DP/Mid Pipe and stock 2.5" axleback to full 3", finishing out the end of the exhaust with custom 3" piping and a straight-through, perforated core Magnaflow. The power change was on the exact same map; empirically speaking, I was very much choking the S3.

Bottom line for 3": for ~400whp, 3" seems about perfect. I'm surprised more folks in the 500+whp segment don't go up to 3.5". A little research on piping size shows they're likely leaving a ton on the table, esp. when we start talking about 600, 700, etc., you know?

 

[Realgib3]

Thanks, @Realgib3 , for sharing this. Do you happen to have a graph that has an S3, S4, GTX2867r or CS Turbo? Those are a popular segment that I think would be good to include in the comparison. Personally, I like the fact the S3, for instance, has almost as low of a boost threshold and spools almost as quickly as the K04 because I can have more torque down low too, but obviously it doesn't have the top-end of several in the graphs below. And to be clear: my tune is quite neutered down low for rods' safety (which is definitely more of an issue with the "mid" turbos), but I get the idea that with bigger turbos it's a non issue because they can't make too much torque down low = automatic safety measure in place.

Having said this, when I get built, the EFR7163 is my dream turbo for numerous reasons, including the fact it has the spool of a K04 and the top-end of a GTX3076r. Have any graphs of that turbo?

I completely agree about lots of alky, and have implemented that in my setup. As do I about exhaust piping. I say this all the time when I hear the "exhaust is just a sound mod" myth. There's more to it than that, especially when you do a turbo upgrade. In my BNR S3 tuning thread, I saw literally a +35whp gain going from full 3" DP/Mid Pipe and stock 2.5" axleback to full 3", finishing out the end of the exhaust with custom 3" piping and a straight-through, perforated core Magnaflow. The power change was on the exact same map; empirically speaking, I was very much choking the S3.

Bottom line for 3": for ~400whp, 3" seems about perfect. I'm surprised more folks in the 500+whp segment don't go up to 3.5". A little research on piping size shows they're likely leaving a ton on the table, esp. when we start talking about 600, 700, etc., you know?

Let me dig up some more "bolt-on" turbo logs and overlay those as well. When I originally wrote this, the S4 didn't even exist yet and I was personally hating the S3 on the few cars I was working on with them, so I didn't even include it. The 2867 is a great turbo i that range, though I still wouldn't go quite that small personally.

Couldn't agree more on the exhaust piece. I get a lot of people who give the "Well this guy with the same turbo is making X amount more power than me and we have almost the same setup" .... except they're on a smaller intake, stock/unported intake mani, small exhaust, etc... How well and how safe a car end up being relies very very heavily on the entire combination of parts and one wrong piece can kill a system as a whole.

 

[Redline]

Let me dig up some more "bolt-on" turbo logs and overlay those as well. When I originally wrote this, the S4 didn't even exist yet and I was personally hating the S3 on the few cars I was working on with them, so I didn't even include it. The 2867 is a great turbo i that range, though I still wouldn't go quite that small personally.

Couldn't agree more on the exhaust piece. I get a lot of people who give the "Well this guy with the same turbo is making X amount more power than me and we have almost the same setup" .... except they're on a smaller intake, stock/unported intake mani, small exhaust, etc... How well and how safe a car end up being relies very very heavily on the entire combination of parts and one wrong piece can kill a system as a whole.

That'd be awesome!

So, just to make sure I'm tracking, it sounds to me like you agree with the ~380wtq "safety limit" recommendation (and the corollary of pushing max wtq to ~4,200-4,300 rpms), but you disagree with the 380-400whp limit? That's another one of those axioms you hear all the time (just like the 3" exhaust-doesn't-help myth). I saw someone post "max 400whp+ = borrowed time" again just yesterday.

You talking about having tons of alky makes sense to me, though, in that if you're running 500whp but with a ton of alky, it still can be safe. That's logical to me, so long as the wtq limits (peak placement and ramp-up speed, as well as driving style) is still honored. My understanding of the max safe whp is that it's all contingent on cylinder heat management, which tons of alky will address. I think Kmac (sp? the Gearhead on the other forum) was running over 500whp on stock block too, right? I'm not sure about Cld12pk2go; he may have been another.

Just out of curiosity, how many ~500 stock-block setups would you say you've tuned? Any data on when they were setup/tuned like that/how long you'd expect them to last?

P.S. What issues with the S3 were you "hating"? Boost control problems? v1 or v2?

 

[Sho]

Not that Mark needs any more validation. But here's a comparison of his tuning on my PTE 5858 on a high mileage stock block on stock fueling vs 5862 on a built motor with meth as Aux fuel. You can see the 5858 keeps well within the tq limits of the stock block on low boost, with a pretty fat power curve without really putting all too much stress on the motor.

The only difference in the setups is forged rods and pistons, and a meth kit. No other changes (same exhaust, manifolds, stock head, stock head bolts, stock manifold that was port and polished with vtcs removed, same FMIC, etc)

Stock block tune at the time of the log in the graph below was at 22psi up top, with 12* timing at 7k

 

[Redline]

Not that Mark needs any more validation. But here's a comparison of his tuning on my PTE 5858 on a high mileage stock block on stock fueling vs 5862 on a built motor with meth as Aux fuel. You can see the 5858 keeps well within the tq limits of the stock block on low boost, with a pretty fat power curve without really putting all too much stress on the motor.

The only difference in the setups is forged rods and pistons, and a meth kit. No other changes (same exhaust, manifolds, stock head, stock head bolts, stock manifold that was port and polished with vtcs removed, same FMIC, etc)

Stock block tune at the time of the log in the graph below was at 22psi up top, with 12* timing at 7k

I wonder what it feels like to drive that? The top-end is obviously amazing (nearly 400whp), but I put down more max torque on my 93 S3 tune, let alone my S3 + E28 + 12.8gph 100% methanol tune. I'm pretty sure that 5858 torque curve is flatter, though. Here's my E28 and 93 tune results:

 

[Sho]

I wonder what it feels like to drive that? The top-end is obviously amazing (nearly 400whp), but I put down more max torque on my 93 S3 tune, let alone my S3 + E28 + 12.8gph 100% methanol tune. I'm pretty sure that 5858 torque curve is flatter, though. Here's my E28 and 93 tune results:
View attachment 4174

Never had an issue with traction, really. I autocrossed the car a few times, took it to the tail of the dragon, etc. Was quite fun to drive.

Heres a 3-5 pull with a passenger filming the speedo during a pretty humid day

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[Sho]

Will at PD posted this today. 35r on 34 psi. Probably one of the most usable power curves you'll see for street use. BIG turbos ftw.

 

[HawkeyeGeoff]

Will at PD posted this today. 35r on 34 psi. Probably one of the most usable power curves you'll see for street use. BIG turbos ftw.

I disagree. As a previous 35R running hooligan, it is, in fact, the WORST turbo for street use.

Look at where that log starts....at 2300 or something stupid. The effective time to spool that turbo and get you the usable 300wtq or so is enormous compared to other, smaller turbos. You can do just about 550 on a GTX3076 all day. Much better transient response for street use (really what it's all about....turbo spooling).

 

[Sho]

Who's seriously going WOT at 2300 Rpm on the street? My 5862 does the same thing if I wot down low...

It wont take that long to ramp up if you go wot say at, 3500rpm.

Look at that graph, 300+tq from ~4k to 7.5k. It's not useless. Everything just shifts to the right

 

[broda]

That belongs to Alex from this forum. The ZZB Diairies in the Build forum. He has single runners and a GT3582. Yeah, it's going to take a bit to get going.

 

[Sho]

That belongs to Alex from this forum. The ZZB Diairies in the Build forum. He has single runners and a GT3582. Yeah, it's going to take a bit to get going.

Yep, nothing that changing driving habits (being in the proper gear/rpm) can't help!

 

[HawkeyeGeoff]

Who's seriously going WOT at 2300 Rpm on the street? My 5862 does the same thing if I wot down low...

It wont take that long to ramp up if you go wot say at, 3500rpm.

Look at that graph, 300+tq from ~4k to 7.5k. It's not useless. Everything just shifts to the right

I'm not saying that you go WOT at that low of RPM, I'm saying if you did it at like 3k, you'd see a shift even farther right than what is showed there in terms of when torque comes on.

And I think we have a different opinion of what is really usable and transient response time. I'm just saying I lived that life with a GT3582r, had 600whp, and it was awful.

Furthermore, if a GT3582R is a perfect turbo for the street....what is a bad turbo for the street then?

 

[Sho]

@HawkeyeGeoff
Gimme some time to save a little money to hop on the dyno and do a comparison for you. I'll do a pull from 2.5k and one from 3.5k. The curves are the same. The one from 2.5k will be gutless down low and then should be identical to the other once above 3.5k.

BTW I didn't say the 35r was perfect for the street. I said the curves on that particular car and tune were.

 

[HawkeyeGeoff]

Look I'm just saying the transient response is garbage, it's completely worthless in a track situation (especially AutoX), and that was my experience with taking logs especially with that large of a turbo that it does matter where you start it; things were different.

Just look at @Redline 's car vs the 35R car. The difference in transient response is mind blowing for around town trafficking. I wanted to shoot myself driving in 45mph zones.

 

[Realgib3]

Look I'm just saying the transient response is garbage, it's completely worthless in a track situation (especially AutoX), and that was my experience with taking logs especially with that large of a turbo that it does matter where you start it; things were different.

I gotta step in a little.

A 35r is not a "Large" turbo. However, a 35r, especially an old school cast wheel 35r is not a "Good" turbo in today's standards.

And Sho is right in the fact that his turbo from 2k would take close to 2k rpm to reach 20psi target, but from 3500, would take less than 500rpm to reach 20psi from zero.

With all that said, yeah if you're running autoX, you want something a lot smaller/better than an old 35r.

 

[Sho]

Look I'm just saying the transient response is garbage, it's completely worthless in a track situation (especially AutoX), and that was my experience with taking logs especially with that large of a turbo that it does matter where you start it; things were different.

Look I'm just saying the transient response is garbage, it's completely worthless in a track situation (especially AutoX), and that was my experience with taking logs especially with that large of a turbo that it does matter where you start it; things were different.

Well, yeah. I don't think anyone in their right mind is building a car with a 35r with Autox in mind, though lol . That's ridiculous

Hence why I MENTIONED in the original post you quoted me in, for STREET USE that curve was very usable. Not road course, not Autox, STREET!

BTW, I did have to completely relearn how to drive my car to make it usable on the 5862, which really isn't all that big. 3rd gear til 40mph, 4th gear til 50, 5th from 50-65, and 6th above 65 for regular cruising to keep it responsive. Otherwise, yes, if you drive it like you would a car with a smaller turbo, you will have a bad time.

 

[HawkeyeGeoff]

Well, yeah. I don't think anyone in their right mind is building a car with a 35r with Autox in mind, though lol . That's ridiculous

Hence why I MENTIONED in the original post you quoted me in, for STREET USE that curve was very usable. Not road course, not Autox, STREET!

BTW, I did have to completely relearn how to drive my car to make it usable on the 5862, which really isn't all that big. 3rd gear til 40mph, 4th gear til 50, 5th from 50-65, and 6th above 65 for regular cruising to keep it responsive. Otherwise, yes, if you drive it like you would a car with a smaller turbo, you will have a bad time.

I just do not agree that's very reasonable on the street, not that it isn't usable. I'm not a fan of having to roll around at 4k to get any response out of my car. All of those values you stated is about what I use as well, I guarantee on a 35R you raise those values to make it actually get up and go. There is more to a turbo than the dyno graph.

I've attached a VDyno of my 35R setup for reference; it just was not fun on the street at all. I hate waiting.

 

[Redline]

Found this on YT today:

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I must say I was a little surprised because FWIH, Forced Performance generally has a great rep. We have a local with an HTA3076 and that sucker is fast and spools quite quickly. I guess the moral of the story is be wary of the FP SS hotsides.