Data v. Whiny Idiots (Throttle Response Edition) - Page 4 - Miata Turbo Forum - Boost cars, acquire cats.

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Old 08-23-2011, 04:15 PM   #61
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Some say that he is a natural for almost any kind of moderation due to his godlike ability to modulate a throttle, and that he only lacks moderation when it comes to his displays of awesomeness. All we know is, he is called The Hustler.
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Old 08-23-2011, 05:43 PM   #62
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Are you going to answer the questions from my last post or not?
How should we proceed? If I post much, the natives get err…"restless". I wound up semi-banned for a long time after some past threads. Got attacked and email-blasted, etc. My posts got edited by others to be more provocative. Fake screennames showed up. Yet I remained civil, am not profane, or whatever. It took a long time to get off of double secret probation. Can this forum act above the age of 12 or not?

For instance, I did not start this thread and mostly leave it alone. I start posting a bit and then one aggressive member is worried about being banned and starts a thread about that. You are demanding answers (see above).

I think there are a lot of ways to have fun with Miatas. If we want to have some fun in this thread I would not mind having some ground rules.

For instance, don't punch me in the ear like in Fight Club, lol.
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Old 08-23-2011, 05:57 PM   #63
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Answer my questions, as well as Jason's question from post 44. If you want to gain some legitimate respect around here, you need to stop avoiding questions like that.
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Old 08-23-2011, 06:57 PM   #64
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Just read through this thread and maybe I am missing something.

I agree that turbos are much less laggy once engine rpm increases, that being said, rpm does not equate to load and boost. The example I am thinking of is if I am driving along on the highway at 4000 rpm but am just cruising, the turbo is not building much boost, there may be a slight increase in manifold pressure, but it is just north of -10. I also recognize that shaft speed is minimal in this throttle position. In this state, if I go wot there is a delay while the spent exhaust gases energize the turbine..spool it up...increase shaft speed. I think the video back on page 2 is a good demonstration of this, as it takes quite a while before you hear the whine of the turbo(sorry I don't know the technical term) as it starts moving lots of air. I doubt the driver of the turbo car waits to go wot after the third beep. So the delay in turbo sound is a delay as the turbo comes up to speed.

That video however is a poor example of what sav's data log is showing. Sav's data reflects a car at speed on track. Turbo chargers don't stop spinning when the throttle is closed, they keep spinning...stay energized. So, the instant throttle is picked up, the turbo is able to respond with boost, and response. In the video, if the driver of the turbo car had brake boosted the result would have been different, with instant response instead of what we could see and hear which was "lag".

I know there is much more involved that what my dummy down version is covering, but sav's car at speed on track is almost the same as brake boosting, as shaft speed is already increased, due to the fact that he had been at wot for a period of time, before going into throttle modulation thru the corner. Thus no lag when he gets back on the power. Am I going the right direction??
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Old 08-23-2011, 07:03 PM   #65
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I agree entirely with hingston.
F20c crew represent.
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Old 08-23-2011, 08:06 PM   #66
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Quote:
Originally Posted by hingstonwm View Post
Just read through this thread and maybe I am missing something.

I agree that turbos are much less laggy once engine rpm increases, that being said, rpm does not equate to load and boost. The example I am thinking of is if I am driving along on the highway at 4000 rpm but am just cruising, the turbo is not building much boost, there may be a slight increase in manifold pressure, but it is just north of -10. I also recognize that shaft speed is minimal in this throttle position. In this state, if I go wot there is a delay while the spent exhaust gases energize the turbine..spool it up...increase shaft speed. I think the video back on page 2 is a good demonstration of this, as it takes quite a while before you hear the whine of the turbo(sorry I don't know the technical term) as it starts moving lots of air. I doubt the driver of the turbo car waits to go wot after the third beep. So the delay in turbo sound is a delay as the turbo comes up to speed.

That video however is a poor example of what sav's data log is showing. Sav's data reflects a car at speed on track. Turbo chargers don't stop spinning when the throttle is closed, they keep spinning...stay energized. So, the instant throttle is picked up, the turbo is able to respond with boost, and response. In the video, if the driver of the turbo car had brake boosted the result would have been different, with instant response instead of what we could see and hear which was "lag".

I know there is much more involved that what my dummy down version is covering, but sav's car at speed on track is almost the same as brake boosting, as shaft speed is already increased, due to the fact that he had been at wot for a period of time, before going into throttle modulation thru the corner. Thus no lag when he gets back on the power. Am I going the right direction??
the highlighted is the only part that is correct and has anything to do with sav's post. first part, yes your right, the turbo car had lag because one or more of many possible reasons. and yes, brake boosting would have helped. but fyi someone incorrectly stated that rpm had nothing to do with the response in a turbo setup. had the turbo car in the video in question been at a higher rpm, it would have had alot more exhaust energy available and when the throttle was "cracked open" would have taken off instantly. i know because i have roll raced many times in my galant vr4 with a previous laggy setup. i made sure that i was at 4500rpm atleast in whatever gear before we took off, and i would pull on stroker motor vettes with both of us punching it at the same time. but like you allured to, this has aboslutlely nothing to do with what sav. was posting. i think that's where the problem lies. all the itb fan boys and many in this thread have never been on a racetrack to know what's happeing when coming out of a corner. #1. unless your a newb, the throttle isn't closed at the apex of a turn. by that point your foot is already on the gas and @ 20-30% throttle or more (in most cases, this is a generalization) #2 your rpms are high. hence the need for rev match heel and toe, etc... #3 you can't just crack the throttle open. if your cornering like you should be, some of your available traction is being used to turn as your coming out of the corner, leaving a small but ever increasing amount available to accelerate with. even if it only takes 1sec. before you can go wot, combine #1, 2, and 3 and that's more than enough time to have zero net lag with even a slightly larger than necessary turbo. with a correctly sized turbo there is zero disadvantage in response to a n/a machine on a track.
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Old 08-23-2011, 08:37 PM   #67
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The highlighted part is all I got right??? Sh*t I must be a dumbass. Based on your statement to me shaft speed is constant with rpm. These are turbochargers not super chargers. Turbochargers build shaft speed with load and rpm. Also since turbos move more air the faster they spin there will be less perceived lag at 4k vs 2k.

Not trolling for a fight just trying to confirm a concept that I thought I understood
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Old 08-23-2011, 09:42 PM   #68
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Quote:
Originally Posted by hingstonwm View Post
The highlighted part is all I got right??? Sh*t I must be a dumbass. Based on your statement to me shaft speed is constant with rpm. These are turbochargers not super chargers. Turbochargers build shaft speed with load and rpm. Also since turbos move more air the faster they spin there will be less perceived lag at 4k vs 2k.

Not trolling for a fight just trying to confirm a concept that I thought I understood
no sir, that is not what i said. below you will see my statement and the crucial part you missed.

the highlighted is the only part that is correct and has anything to do with sav's post. the first part was correct, but like the video, had nothing to do with sav's arguement.

as for rpm, wether perceived or actual the outcome is the same. unless the turbo setup is super laggy, high rpm before wot will cut down the spool up time a huge amount. on our shop car (crx w/1.8 swap and turbo) the turbo makes full boost at 4500rpm. if i launch at 4500rpm it will bog down because it won't have the "load" or rpm to spool before traction. if i rev it to 6-6500 rpm, it will only drop to 4.5-5000 rpm and will instantly spool to full boost and start ripping the slicks down the track. it didn't have a 2step rev limiter to put a load and build boost, but didn't need it with enough rpm. my aforementioned galant vr4 with old setup wouldn't build boost fast enough even with a 7k rpm launch. that car/setup needed the 2step rev limiter to build boost before launching or it would simply bog down. even 2-3psi when staging would mean instant boost. so yes your right, rpm and load are integral parts of spool up, but whoever said rpm didn't mater was wrong. also that same galant that wouldn't launch off the line without a limiter, would respond instantly from partial throttle cruising @ 4.5-5k rpm. the problem with all of this again, is that it has NOTHING to do with the OP's post.
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Old 08-23-2011, 09:52 PM   #69
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Got it. Your explanation is much more eloquent than my attempt. Thank you for clearing the water!!
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Old 08-23-2011, 10:03 PM   #70
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Quote:
Originally Posted by sjmarcy View Post
Yes that is it. You won't get 100% of what you were expecting at first. After a short delay at WOT, you will then achieve the turbo car's dyno curve torque.

You can drive around these things with some effort. So in autocross, practice up your left foot braking for a turbo car. This can help you get to the good stuff faster along with getting the timing better. It takes awhile to become an effective left foot braker. And it is a good thing for any type of engine for some other reasons having to do with handling and driver control.
3 years ago I autox 2 years straight in a fwd N\A sentra, Since my first autox event I've been LFB (it was an auto), and when I autoxed my miata recently I also used lfb, problem was my feet were getting in the way because the pedals are so close.

maybe if the seat held me better, my other thought was to use antilag for when going out of the throttle.
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Old 08-24-2011, 12:15 PM   #71
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Originally Posted by Savington View Post
My point is that in the real world, where you are not snapping, but rather rolling into the throttle, the lag is much, much less significant than many people believe it to be. Would you agree?
On a well setup car yes.

It seems most turbo charged cars miss the mark due to poor design or OEM smog restrictions. This has caused the masses to assume that poor response is the norm for a turbo car.

To date I have only tracked turbo charged cars. My current turbo setup is brilliant! Great power delivery. Very easy to modulate power. One of the past cars not so much. It was very difficult to modulate the power in the corners due to lag. I did hit 150mph down the front straight at thunderhill though.

Trivia note my screen name comes from the love hate relationship of the K24 turbo. Hated the lag but loved the rush of power on the street.
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Old 08-24-2011, 12:18 PM   #72
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hell I can go around corners WOT because the way my boost onset is so linear and smooth; full power out of the corner.
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Old 08-24-2011, 12:36 PM   #73
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Quote:
Originally Posted by Techsalvager View Post
3 years ago I autox 2 years straight in a fwd N\A sentra, Since my first autox event I've been LFB (it was an auto), and when I autoxed my miata recently I also used lfb, problem was my feet were getting in the way because the pedals are so close.

maybe if the seat held me better, my other thought was to use antilag for when going out of the throttle.
I like how you are pondering the ergonomics. Boosted cars can be trickier to drive to their full potential due to how the car responds. Why deny it and become outraged?

It makes sense to see that the driver AND the car can left foot brake effectively. LFB took me nearly a year to learn well enough that I was clearly faster doing instead of RFB. This is per the logger and not just fooling myself. Besides allowing one to manage the engine's output timing a bit better, there are handling benefits which can ensue. Winter karting got me over the hump, along with doing it all the time on the street.
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Old 08-24-2011, 03:04 PM   #74
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Quote:
Originally Posted by sjmarcy View Post
Boosted cars can be trickier to drive to their full potential due to how the car responds. Why deny it and become outraged?
Because you spend all your time on this forum spreading garbage information, and when a thread like this attempts to refute you, you just ignore it and continue your bullshit rhetoric.

Why won't you answer Jason's question from Post 44? Why won't you answer my questions from Post 47? It's clear that you have read both posts, since you continue to respond to the other members. Why are you dodging these questions? They are legitimate questions.

I've already admitted that turbos have lag when you snap them open from 0% TPS and low RPM, but you refuse to admit that turbos have very, very little lag when you slowly roll into the throttle from high RPM, like you might do on a road course. Instead, you continue to spread this garbage rhetoric that turbo cars are "tricky" to drive without giving any situational qualifiers.

You are doing a significant disservice to this community by refusing to answer questions like the ones in post 44 and post 47. This forum thrives on good, unbiased analysis, which is something you seem to be allergic to.

Last edited by Savington; 08-24-2011 at 03:26 PM.
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Old 08-24-2011, 03:19 PM   #75
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Quote:
Originally Posted by sjmarcy View Post
Boosted cars can be trickier to drive to their full potential due to how the car responds.
Properly set up boosted car should not be tricky to drive just like properly tuned suspension should not have dynamic toe out in the rear.

Any car can be made difficult to handle, drive, tune, idle, start, whatever.
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Old 08-24-2011, 04:42 PM   #76
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Boosted cars are easier to drive because they're not slow pieces of **** so slow that you can phone-***** and eat a McGangbang while on the track and not affect lap times. I remember those days back when I had awesome throttle response and I'd drive around the track on my personal record and think about what I'd cook for dinner or how many of your girlfriends I'd let into my harem that night.
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Old 08-24-2011, 04:53 PM   #77
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throttle response on an NA miata doesnt matter because you need to be WOT 100% of the time that you should be on the throttle.
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Old 08-24-2011, 05:03 PM   #78
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Here are some of my datalogs:

I took em to test out an added 'D' circuit (in "PID") in my AEM's boost control. The right hand plot shows a slow upshift, and a throttle floor-lift-floor test, to try and get a boost overshoot. (left hand plot has no D circuit, thus the boost overshoot)

On the slow upshift at 3900 RPM it takes about 0.5 sec to go from 0 psi to 10 psi. On the throttle floor-lift-floor test, (at 4300 RPM) it instantly goes to around 5 psi (I suppose turbo was still spinning at 5 psi worth of shaft RPM), and takes another 0.2 sec to ramp up to 10 psi.

As some have said, on a track or autox there is no situation where you go from 0 to full throttle in an instant - you modulate the throttle, and in the end, controllability is what is important. A small to medium size turbo has no issues wrt controllability. As for upshifts, you can program a "flat-shift" feature into several ECUs to keep the turbo spooled (you don't lift).

Last edited by JasonC SBB; 08-26-2011 at 01:23 PM.
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Old 08-24-2011, 05:04 PM   #79
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A few days ago I drove the wife's 2.3L Focus with an auto tranny. It has the SVT suspension, and hi perf tires. The Focus is balanced and throttle-steers despite the automatic. This works when you are making fine throttle adjustments through a sweeper. However when you're off the gas and you get on it aggressively, the torque converter produces an annoying lag as it spools up.

In comparison to my miata with the GT2560, the turbo lag is *not* an issue in driving. The torque converter lag is "step... no torque ... wait ... torque!". A turbo doesn't do that. If you suddenly floor it, you get a minimum of naturally aspirated torque, which immediately starts ramping up to full boost. (see my logs above) If you are at some higher RPM, the ramp doesn't take long. If the turbo is still spinning at hi speed because you shift very quickly, the immediate torque you get is more than stock torque because you immediately get some boost.

Additionally, for fine throttle control such as throttle steering through a sweeper, the turbo "lag" is non-existent because the turbo is spinning the whole way through and boost follows your right foot. The analogy with the auto tranny throttle steering holds.

Lastly, NA and supercharged cars do NOT have a 1:1 correspondence between throttle position and manifold pressure or torque. At low RPM you get full torque at something like 1/5th throttle, and at mid RPM's you get full torque at perhaps 1/2 throttle. The reason for this is that a throttle is a power-choking or constant-power device; at low RPM the power is low so the max power for that RPM is achieved at small throttle openings, which means full torque at small throttle openings.

Quote:
Originally Posted by sjmarcy
normally aspirated cars can achieve their full acceleration at some RPM before the throttle is down all the way
This is exactly what I meant above. It is *not* a good thing. It is a liability, because it makes the torque demand from throttle position, inconsistent with RPM. The most ergonomic approach is that the right foot position is interpreted as torque demand, irrespective of RPM. Audi does this with their B6 S4 throttle-by-wire program, for example.

In my car I have TPS controlled boost, which emulates the Audi scheme, after a fashion. So the throttle actually feels more linear than my supecharged M3. It is easier to control engine torque in the miata. Additionally, you never really want torque to go from zero to max in an instant on corner exits - that will upset the tires and lead to a spin. The ramp time of the turbo actually helps in this case. The only time zero to max torque in an instant is desireable, is street drag racing from a roll.

The full-torque-at-small-throttle-openings + very rapid rate of rise of torque, is what makes my M3 more difficult to autox than my turbo miata.

Yes some of you may say "learn more driving skills", but consider that even Ayrton Senna was big on making the car easier to drive.
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Old 08-24-2011, 05:11 PM   #80
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Senna never properly datalogged his MP411pclogorj
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