Lets talk risk factor

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Jul 2, 2017
255
#1
Was reading up in another thread where a stock turbo n54 blew. Now my question is, all stock blocks.
1. Stock turbos at 23psi 450whp and so, so timing correction at 12* target.
2. Upgraded turbos at 25psi 600whp and LESS timing corrections 9* target.
3. Single turbo, 23psi 700whp, less psi but making more power. 7* timing with minimal corrections.
Say all same mileage, stock block, etc. Maybe difference in fuel hence timing corrections.
Lets say
1. E30
2. E60
3. E85
Which one would be at higher risk ? In a nutshell, I understand theres more to it, but generally speaking. More whp more risk ? Or more timing corrections more risk ? Or higher cylinder pressures more risk ?
 

iminhell1

Specialist
Jun 17, 2018
88
#2
Cylinder pressure is the ultimate demise.
It's just a matter of how fast the rise happens ... rich AFR's slow the combustion process ... and when, which is controlled by ignition timing.

The next thing is hp isn't going to break anything by it's self, at least not without knowing what rpm it's at. It's Torque that you really want to look at.


But just a quick answer, more boost and less timing should be easier on the engine; the rods and rod bearings at least.
 
Jul 2, 2017
255
#3
So out of the 3 scenarios, which would be safest in your opinion. I understand its a tricky question because theres many variables. As I said, generally speaking.
#1 has the least cylinder pressure but has worst timing for whatever reason.
 

iminhell1

Specialist
Jun 17, 2018
88
#4
So out of the 3 scenarios, which would be safest in your opinion. I understand its a tricky question because theres many variables. As I said, generally speaking.
#1 has the least cylinder pressure but has worst timing for whatever reason.

Single is going to be easiest IMO. But it's a loaded question because like I said, rpm matters. The single tend to make the power up top. If you look at the graphs they won't make as much power as twins until that higher rpm. That's the lower timing at work. They rely on the higher rpm to do the work, vs mid rpm grunt of the twins.
 
Jul 2, 2017
255
#5
Understood, just curious to see people respond. Have read on stock turbo blowing motors, upgraded twins blowing, and singles as well. Im curious as to what blows motors more. Higher psi, higher whp, higher torque, or just not fully tuned stockers getting more timing drops even though its less power and still breaking ringlands or cracking pistons etc.
 

[email protected]

Lieutenant
Platinum Vendor
Oct 24, 2016
511
Scottsdale, AZ
#6
Boost isn't boost. Boost is a measure of restriction, change the turbine/flow path and the same boost is more air flow. This is why turbos like our GC's make the same power as stock frame's that are running a pound or two more boost, all else equal.

Additionally 23 psi... where? Midrange? Redline? What redline? 6200 RPM? 7200RPM? Those are huge differences in airflow.

As far as longevity goes... guys, these motors are NOT bulletproof. Not only have we blown up our fair share, we hear about it all the time (many of them turn into built motor customers.... so I hear the stories often). I think you should be at logs that are very clean nearly all of the time (or more often). Don't tune it to the edge of knock on a dynojet then go beat on it on the street and expect it to be pretty. Log, keep your tunes conservative, and stop maxing out hardware like it's going out of style. I understand that you want to get as much as you can for your mods/money, but it can certainly stop being fun when you find metal in your oil filter (at least not cheap). I really like this platform at/around the 600 whp mark with proper mods/fueling/etc. It's fast, mods needed are for the most part reasonable, and it'll hold for quite a while (anecdotally... but lots of evidence).

To answer your question directly, with higher power comes higher risk, as a general rule, which means it becomes even more important not to be a dyno cowboy if you actually drive the snot out of your car (which I think is the right thing to do). A good tuner is worth their weight in gold. I highly suggest people do their own homework there (i.e. log and learn how to read them!).

Chris
 
Jul 2, 2017
255
#8
Boost isn't boost. Boost is a measure of restriction, change the turbine/flow path and the same boost is more air flow. This is why turbos like our GC's make the same power as stock frame's that are running a pound or two more boost, all else equal.

Additionally 23 psi... where? Midrange? Redline? What redline? 6200 RPM? 7200RPM? Those are huge differences in airflow.

As far as longevity goes... guys, these motors are NOT bulletproof. Not only have we blown up our fair share, we hear about it all the time (many of them turn into built motor customers.... so I hear the stories often). I think you should be at logs that are very clean nearly all of the time (or more often). Don't tune it to the edge of knock on a dynojet then go beat on it on the street and expect it to be pretty. Log, keep your tunes conservative, and stop maxing out hardware like it's going out of style. I understand that you want to get as much as you can for your mods/money, but it can certainly stop being fun when you find metal in your oil filter (at least not cheap). I really like this platform at/around the 600 whp mark with proper mods/fueling/etc. It's fast, mods needed are for the most part reasonable, and it'll hold for quite a while (anecdotally... but lots of evidence).

To answer your question directly, with higher power comes higher risk, as a general rule, which means it becomes even more important not to be a dyno cowboy if you actually drive the snot out of your car (which I think is the right thing to do). A good tuner is worth their weight in gold. I highly suggest people do their own homework there (i.e. log and learn how to read them!).

Chris
Thanks for the reply. Im at about 597whp, on E85, always logging, everything is in check and although I can pull a perfect 3rd gear pull and perfect 1st through 4th on occasions, I do get timing corrections on a daily basis but for the most part, minor, and usually in 1 cylinder. Varies from say #5, next pull #2 etc. Not multiple cylinders correcting or dropping timing to zero. Always comes right back up again as well. So was wondering overall how safe it was compared to others. I used to have perfect timing pretty much always on maxed out stock turbos so am not sure how critical perfect timing is on the N54. Although I have read its normal even bone stock to have corrections, I thought I would ask and any info here may help others down the line.
 
Jul 2, 2017
255
#10
See, these are the things that are contradicting. Singles= more power, less torque down below, etc. So the saying of higher power, greater risk gets contradicted by the people that say / think that a single is safer / less risk factor.
 

Torgus

Lieutenant
Nov 6, 2016
629
Boston
#11
See, these are the things that are contradicting. Singles= more power, less torque down below, etc. So the saying of higher power, greater risk gets contradicted by the people that say / think that a single is safer / less risk factor.
There are lots of factors to consider as well as what your goals all in order to make the decision of what will work best for you and your wallet. I'm not a fan of twins stock or upgraded. Most end up blowing a lot of hot air and the only way to make power with them is pure E85. Pure E85 means you have to have access to it and upgrade the entire fuel system. Also, massive tq down low is fun to hoon around down but low end tq is what bends rods. So by that logic, unless you have your tuner tune it out(so why twins if you are tuning it out?), twins stock or upgraded are more likely to damage your engine than an appropriately sized single turbo based on your whp goal at redline.

Also, no one with twins seems to be able to make the numbers the vendors can. GCs or MMPs making 850whp on a dynojet on 100% E85? GCs making 575whp on pump 93 no meth no E85? I'm not saying the numbers aren't real, it's just no one seems to be able to come close to vendors/manufactures numbers or claims. Both of those turbos for instance have been out for 2+ years. Maybe because the vendors have dumped 20k+ into their engine builds? What I would call 'real world' numbers all seem significantly lower.

Singles seem to be able to hit the numbers you would expect. I assume this is because they are not out of their efficiency range blowing hot ass air. A single will also give the highest whp on pump gas. 80% of the US does not have easy E85 access. So a single will make the most sense for the majority of the people.
 
Jun 27, 2017
41
#12
I agree with Chris. In single turbo land, 23psi on a 58mm vs 23psi on a 104mm turbo are vastly different air flow rates and will happen at different rpms. Unfortunately, nobody really talks CFMs as psi is just so much easier to measure. As far as I've seen/read, stock turbos at any achievable psi won't blow up the engine assuming competent tuning and maintenance. However, for longevity, those stock turbos are going to break down seals/WG quickly when run past their efficiency range like you'd see at 21+psi because of the intense heat.

I'm a novice on upgraded twins/singles -- haven't had any issues with my upgraded twins at both 25 and 30. Seen dynos and builds of others running north of 30psi hitting low 7's on stock blocks without issues and plenty of people in the 600's for years without issue. Personally met 2 guys with north of 800 on stock bottom end and stock pistons that ran that way for a couple years -- but modded heads. They both ended up parting out and getting newer cars, engines still running. While it's anecdotal, one of the big draws for this platform is the robustness of the motor at higher power levels. Overall, I'd say the risk factor on all 3 scenarios you presented for the n54 is low assuming competent tuning and maintenance.

I've been told by performance-oriented mechanics and owners of fast street cars, if you're venturing north of 700 on the n54, build the motor. Every n54 north of 800whp I've seen on the internet were built.
 
Aug 11, 2017
1,612
Virginia
#13
I think maintenance is a huge issue - tuning and maintenance ... everything seems to fall well behind after that. After doing my walnut blast on a 30k motor, I am not surprised at why so many people have #5 of issues. It costs money to reliably go fast. There is still risk, but one can lower it, and in some cases, even mitigate.

While I appreciate OP's question, it reminds me of an old road racing thing: "instead of buying more go fast parts, buy a few more drivers schools and learn how to be quicker." Unfortunately maintenance and tuning are the top factors, IMHO.

Filippo
 
Jul 2, 2017
255
#14
Ok, just to clear up any confusion. This post was mainly made because my buddy didnt want to create an acct. A little info. My car is 08 E93, hybrids, E85, jb4, custom tune loaded through MHD, xHP stage3, LSD, R888r, R8 coils, blah, blah, blah. Under 80k miles
His car, 07 E93 OVER 100k miles on mhd/jb4 ots bef running E85. Stock turbos are DONE. He is looking to upgrade and get MORE power than me and is on the fence on PS2 HI FLOW or going single as he follows Jake on youtube, lol. This is why these questions have been asked, to get real opinions and thoughts on power vs. safety. I am on PS2 DD and have no complaints. He still wants more power than me (wants to beat me), lol ! I suggested the dd version but since he sees all these videos of high h.p. N54s he wants that, but keeping safety in mind. All bullshit a side he is EASILY influenced by a simple youtube video. Anyways, thanks for the replies and still hope to get some more as this may help others like him trying to compare.
 
Jul 2, 2017
255
#15
Oh, also he saw a video of Payam from BMS with a 300k 750whp or something like that so he feels he can do the same and still have longevity. This is where this topic really stemmed from. 1 video, lol
 
Jul 2, 2017
255
#16
I agree with Chris. In single turbo land, 23psi on a 58mm vs 23psi on a 104mm turbo are vastly different air flow rates and will happen at different rpms. Unfortunately, nobody really talks CFMs as psi is just so much easier to measure. As far as I've seen/read, stock turbos at any achievable psi won't blow up the engine assuming competent tuning and maintenance. However, for longevity, those stock turbos are going to break down seals/WG quickly when run past their efficiency range like you'd see at 21+psi because of the intense heat.

I'm a novice on upgraded twins/singles -- haven't had any issues with my upgraded twins at both 25 and 30. Seen dynos and builds of others running north of 30psi hitting low 7's on stock blocks without issues and plenty of people in the 600's for years without issue. Personally met 2 guys with north of 800 on stock bottom end and stock pistons that ran that way for a couple years -- but modded heads. They both ended up parting out and getting newer cars, engines still running. While it's anecdotal, one of the big draws for this platform is the robustness of the motor at higher power levels. Overall, I'd say the risk factor on all 3 scenarios you presented for the n54 is low assuming competent tuning and maintenance.

I've been told by performance-oriented mechanics and owners of fast street cars, if you're venturing north of 700 on the n54, build the motor. Every n54 north of 800whp I've seen on the internet were built.
Thanks for the response. I have heard over 600 problems begin so I built mine not to exceed that margin.
 

langsbr

Lieutenant
Apr 5, 2017
705
#17
I would think an analysis of the different failures need to be examined. I know there's 2 camps of "the new 2JZ" and "they really aren't that strong" but I think the truth lies somewhere in between. We've seen a number of 700+ whp stock motor cars that are definitely being beat on and not just 1 pull dyno glory runs. I think there are more tuning related failures than people are willing to give credit/admit to. We hear how the DME is so smart it protects the engine at all costs - but that's clearly not the case with engines blowing. We hear that PI is spray and pray, but then in the next breath that it's really not that risky and that a misfire injector cut/PI super lean is a myth.

How are the motors failing? If it's bending a rod, that's early torque as we've all seen. If it's cracking a ringland or melting a hole in a piston it's likely a tuning related/heat issue. Spun bearing? Oiling issue or just due to wear from too much knock/excessive timing.

I've never been a fan of "horespower' goals. It's such a poor metric. What is your friend's real goal? Does he want a 130mph trap car? Does he want something that will win roll races on the highway in "Mexico" or does he want a fast car with bling to boot? I think one of the main reasons that these cars are so much faster (I won't say quicker cause they can't ET for nothing) than others with more horsepower is the large amount of midrange torque - more torque means more horsepower, which means more average horsepower. These cars (with stock twins, and hybrids at least) have more average horsepower than their competition at the same peak rating.

I know a single conversion is the fad of the century, but I prefer twins. Not for horsepower reasons, but for what I call 'deviation from stock'. The further you deviate from stock, the less reliable, generally a vehicle is. Some may disagree with it, or see it differently, but I've always found the closer you can keep a car to stock, the more reliable it will be.
 
Jul 2, 2017
255
#18
I would think an analysis of the different failures need to be examined. I know there's 2 camps of "the new 2JZ" and "they really aren't that strong" but I think the truth lies somewhere in between. We've seen a number of 700+ whp stock motor cars that are definitely being beat on and not just 1 pull dyno glory runs. I think there are more tuning related failures than people are willing to give credit/admit to. We hear how the DME is so smart it protects the engine at all costs - but that's clearly not the case with engines blowing. We hear that PI is spray and pray, but then in the next breath that it's really not that risky and that a misfire injector cut/PI super lean is a myth.

How are the motors failing? If it's bending a rod, that's early torque as we've all seen. If it's cracking a ringland or melting a hole in a piston it's likely a tuning related/heat issue. Spun bearing? Oiling issue or just due to wear from too much knock/excessive timing.

I've never been a fan of "horespower' goals. It's such a poor metric. What is your friend's real goal? Does he want a 130mph trap car? Does he want something that will win roll races on the highway in "Mexico" or does he want a fast car with bling to boot? I think one of the main reasons that these cars are so much faster (I won't say quicker cause they can't ET for nothing) than others with more horsepower is the large amount of midrange torque - more torque means more horsepower, which means more average horsepower. These cars (with stock twins, and hybrids at least) have more average horsepower than their competition at the same peak rating.

I know a single conversion is the fad of the century, but I prefer twins. Not for horsepower reasons, but for what I call 'deviation from stock'. The further you deviate from stock, the less reliable, generally a vehicle is. Some may disagree with it, or see it differently, but I've always found the closer you can keep a car to stock, the more reliable it will be.
Well he wanted a 10 second car, LMMFAO !!! He already realized its not the best platform. He wants to beat me :smh: so I would imagine traps of close to 130. I have trapped 126. I already told him that more power does not mean "quicker". He is still learning and his "teacher" is youtube vids. When I started the topic I said I was reading up on a stock motor blowing. He was showing it to me on his phone as I was swappn the plugs on his car. This is how the whole thing started. Wanting to be faster than me but longevity as well. I just didnt want to type a book of a question for him, but here we are now and I could have done so from the start :smh:
I am also PI and have had zero issues (thankfully), even when misfired.
Oh, and yeah, he wants to be king of Mexico runs. I say this laughing as 650whp is fast, but nowhere near FAST !!
 
Aug 11, 2017
1,612
Virginia
#19
Lots of good comments in the above post. A couple quick thoughts.
If it's cracking a ringland or melting a hole in a piston it's likely a tuning related/heat issue.
I'm sure I'm super late to this party but it's hard to imagine that misfires which often play along with this issue, are not factored by seriously gummed up intake runners. Blink three times and your intake is fouled up. Who is blasting every 20-30k? Maybe the PI motors have clean intake runners?
... but I prefer twins. Not for horsepower reasons, but for what I call 'deviation from stock'. The further you deviate from stock, the less reliable, generally a vehicle is.
I'm inclined to think this way as well, though this is not my area of expertise.

Filippo
 

Torgus

Lieutenant
Nov 6, 2016
629
Boston
#20
langsbr:

Twins have roughly 2x the failure points vs. a single and still rely on a bad wastegate design.

Twins are 10x as expensive and time consuming to service vs. a top mount turbo.

Twins are limited in output vs. the potential of a single if you take out vendor unicorn dynos(SlowE93's buddy likes Jake he specifically lists why he ditched the twins and went #singlelife it was for reliability)

Twins of similar output cost less vs. a single top mount of similar output. However with the new speedtech bottom mount I think it tips in the single's favor for power output & price.

Prove me wrong ;)
 
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