Data v. Whiny Idiots (Throttle Response Edition) - Page 3 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Race Prep Miata race-only chat.
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 08-23-2011, 12:39 AM   #41
I'm Miserable!
 
Join Date: Feb 2010
Posts: 584
Total Cats: 0
Default

Quote:
Originally Posted by Techsalvager View Post
so for the turbo car that dyno from 2k to 7k and made say 140wtq at 4k rpms.
Say you are at 4k rpms in 3rd once you open the throttle all the way, you still will end up waitting somewhat before the power flows in couple hundred rpms, maybe thats extragating it, but thats what I think you are saying there. so you really won't be at 140wtq at 4k unless you started way lower in the rpms when you went wot.

Thats my line of thinking about it after doing my first autocross in the turbo miata when I dropped down to low rpms off throttle, sure on the dyno it may of said 130-140wtq in that area, but even than still took a while to get back into the power band. Wasn't like bam open throttle back in powerband, more like a delay and than bam.

That of course is not taking into consideration the rest of the drivetrain and connections to the engine\tranny\rear end and any other outside variables.
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.

In the case of the side by side video I posted above…had I been in that turbo car, it would have done better. I'd have had the turbo engine loaded against the brakes as the V8 car rolled up. Since I acknowledge that there is some lag without having a hissy fit, so then I will work to minimize it as best as I can.

As the horn was honking the turbo car would be either floored or with a good chunk of gas pedal. Then you will have some boost waiting for you. So at the 3rd honk you get your foot off the brake pedal and simultaneously add more throttle (if it was not already floored). That would get rid of most of the initial fall back the car experienced in the video. This would be done a short time before you need it, not 2 minutes earlier!

No matter what you do there is some lag. For instance any of the resonant elements in the intake or exhaust create some lag. Same concept can act up in loudspeakers too. Ported subs can sound a bit different than sealed. Part of this is because the resonant elements cause what is termed Group Delay. At the same time as they can provide a useful boost in output. It's just Physics in the end.

Last edited by sjmarcy; 08-23-2011 at 01:02 AM.
sjmarcy is offline   Reply With Quote
Old 08-23-2011, 12:49 AM   #42
Elite Member
iTrader: (2)
 
Join Date: Jan 2007
Location: Los Angeles, CA
Posts: 8,782
Total Cats: 119
Default

Quote:
Originally Posted by sjmarcy View Post

No matter what you do there is some lag.

Big ******* deal.
Faeflora is offline   Reply With Quote
Old 08-23-2011, 12:56 AM   #43
I'm Miserable!
 
Join Date: Feb 2010
Posts: 584
Total Cats: 0
Default

Quote:
Originally Posted by Faeflora View Post
Big ******* deal.
Some people like to improve their setup. Watch out if you race against them!

When you measure things closely enough, you just see the imperfections. Some of them can be dealt with or worked around.

Finding some lag does not mean you have to throw all your toys out of the crib and flush your cell phone down the toilet.

Attached Thumbnails
Data v. Whiny Idiots (Throttle Response Edition)-tantrum.jpg  
sjmarcy is offline   Reply With Quote
Old 08-23-2011, 02:11 AM   #44
Elite Member
 
Join Date: Jul 2005
Posts: 6,454
Total Cats: 80
Default

Quote:
Originally Posted by sjmarcy View Post
It does follow, after the brief intermission. You can see the same things happen with normally aspirated cars. If you are not using a sluggish logger, just compare the different signals. On my 97…throttle opens…vacuum is generated…air rushes in…you then see the MAF signal start to ramp up…and then the accelerometers indicating that the vehicle has started accelerating after another lag.
And why would a turbo car show a greater lag in torque after MAP rise, than a naturally aspirated car?
JasonC SBB is offline   Reply With Quote
Old 08-23-2011, 02:25 AM   #45
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

I'm really tired of "throttle response" killing good threads.
hustler is offline   Reply With Quote
Old 08-23-2011, 05:09 AM   #46
Elite Member
iTrader: (1)
 
Join Date: Jun 2006
Location: Warrington/Birmingham
Posts: 2,658
Total Cats: 39
Default

I don't think it's killed this thread, it's pretty interesting, though some members need to take their dolls back and suck their thumbs again.
richyvrlimited is offline   Reply With Quote
Old 08-23-2011, 07:55 AM   #47
Supporting Vendor
Thread Starter
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,355
Total Cats: 1,322
Default

What does driveline lash and bumpsteer have to do with anything? Every car has driveline lash. A 300whp turbo car will not have more or less driveline lash than a 300whp naturally aspirated car.

You talk about situations, and then you pull one that fits your pre-conceived conclusions perfectly. How convenient. How about looking at my real-life, real-world situation, since that's the one that I started this thread around.

-High lateral loads
-High speed (90+mph)
-Small transient throttle inputs

Yes, turbo cars have lag if you start them from a dead stop, or from 0% TPS, but that's not the point I was trying to make (although it's the point you've made over, and over, and over, and over). My point was that in real-world examples, where you are NOT snapping the throttle open, but rather rolling into the throttle over time (like 2+ seconds of time), the lag that many people believe to be so significant in every case is virtually eliminated.

Take your dyno torque example - yes, if you snap the throttle it will take a moment for the turbo car to reach its full rated torque at a given RPM. However, if you hold the car at that RPM on the dyno, and then sweep the throttle from 0% to 100% over a period of 5 seconds, what happens then? When you slow the rate of change of the throttle, does the correlation between throttle position and manifold pressure become closer? I believe it does.

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?
Savington is offline   Reply With Quote
Old 08-23-2011, 09:12 AM   #48
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

Quote:
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?
The double-digit horsepower crew will disagree with you.
hustler is offline   Reply With Quote
Old 08-23-2011, 11:04 AM   #49
Senior Member
iTrader: (1)
 
Join Date: Jun 2006
Location: Sweden
Posts: 1,391
Total Cats: 58
Default

Quote:
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?
Now you introduce a factor that is very controversial when it comes to racing on track, the driver...
How you manage predictable situations is one thing, "lag" (if horrible too long due to whatever mismatched parameter) can be dealt with by rolling into the throttle earlier.
But "lag" comes up a lot as an excuse for lost momentum while rescuing a poor setup (e.g. rescuing with a complete throttle lift) by some of my close-by turbo drivers.

I'm not saying that the situation would be much different regardless of engine (the same driver could probably fail even with an electrical motor), but it's a convenient excuse that is widely accepted (especially by those who haven't even tried driving a decent turbo setup, and I'm one of them).
NiklasFalk is offline   Reply With Quote
Old 08-23-2011, 11:31 AM   #50
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

Is this going to go on and on for pages about how the fastest Miatas in the nation offer a miserable driving experience because they don't rev as fast as a 458 Italia-LM racecar?
hustler is offline   Reply With Quote
Old 08-23-2011, 11:32 AM   #51
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,171
Total Cats: 2,574
Default

Ive driven an n/a, m45, and 3076 cars back to back. Shocked to find out the "huge, laggy" setup actually had just as much torque down low, response at 4k+, and just absoultely CRUSHED the others in both power and torque everywhere.
18psi is offline   Reply With Quote
Old 08-23-2011, 11:45 AM   #52
I'm Miserable!
 
Join Date: Jun 2009
Location: albany, ga
Posts: 1,869
Total Cats: 3
Default

Quote:
Originally Posted by 18psi View Post
Ive driven an n/a, m45, and 3076 cars back to back. Shocked to find out the "huge, laggy" setup actually had just as much torque down low, response at 4k+, and just absoultely CRUSHED the others in both power and torque everywhere.
back to back where?
straight road?
autox?
road course?
rally course?
etc
Techsalvager is offline   Reply With Quote
Old 08-23-2011, 12:43 PM   #53
Junior Member
iTrader: (2)
 
Join Date: Dec 2009
Posts: 127
Total Cats: 4
Default

Quote:
Originally Posted by Techsalvager View Post
back to back where?
straight road?
autox?
road course?
rally course?
etc
I'm pretty sure he is referring to the time he was at your mom's house.
AnnorexicRoadster is offline   Reply With Quote
Old 08-23-2011, 12:52 PM   #54
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,171
Total Cats: 2,574
Default



But on a serious note: it was just street driving. A little bit of everything: straights, back roads, around town, etc.

I know most will jump in now and say "oh but you didn't do auto-x so it doesn't count".
18psi is offline   Reply With Quote
Old 08-23-2011, 01:26 PM   #55
I'm Miserable!
 
Join Date: Feb 2010
Posts: 584
Total Cats: 0
Default

.
Attached Thumbnails
Data v. Whiny Idiots (Throttle Response Edition)-lagz.jpg  
sjmarcy is offline   Reply With Quote
Old 08-23-2011, 01:43 PM   #56
Supporting Vendor
Thread Starter
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,355
Total Cats: 1,322
Default

Quote:
Originally Posted by sjmarcy View Post
.
Are you going to answer the questions from my last post or not?
Savington is offline   Reply With Quote
Old 08-23-2011, 01:44 PM   #57
Supporting Vendor
Thread Starter
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,355
Total Cats: 1,322
Default

Quote:
Originally Posted by hustler View Post
Is this going to go on and on for pages about how the fastest Miatas in the nation offer a miserable driving experience because they don't rev as fast as a 458 Italia-LM racecar?
Pretty much.
Savington is offline   Reply With Quote
Old 08-23-2011, 01:46 PM   #58
Elite Member
iTrader: (15)
 
Join Date: Dec 2007
Location: San Antonio, Texas
Posts: 4,889
Total Cats: 28
Default

Quote:
Originally Posted by Savington View Post
My point was that in real-world examples, where you are NOT snapping the throttle open, but rather rolling into the throttle over time (like 2+ seconds of time), the lag that many people believe to be so significant in every case is virtually eliminated.

Take your dyno torque example - yes, if you snap the throttle it will take a moment for the turbo car to reach its full rated torque at a given RPM. However, if you hold the car at that RPM on the dyno, and then sweep the throttle from 0% to 100% over a period of 5 seconds, what happens then? When you slow the rate of change of the throttle, does the correlation between throttle position and manifold pressure become closer? I believe it does.

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?
I for one agree completely.
ZX-Tex is offline   Reply With Quote
Old 08-23-2011, 03:13 PM   #59
Senior Member
iTrader: (1)
 
Join Date: May 2008
Location: south texas
Posts: 1,419
Total Cats: 9
Default

Quote:
Originally Posted by 18psi View Post


But on a serious note: it was just street driving. A little bit of everything: straights, back roads, around town, etc.

I know most will jump in now and say "oh but you didn't do auto-x so it doesn't count".
[email protected] auto-x! lol

stop feeding this guy sav. there's nothing you can say or do to prove this to him or any fukboy irtb lover your point.

they will also never experience the power or speed you have, so who cares what they think.

i'm pretty sure this site is called "Miata Turbo" if you don't like it gtfo.
spoolin2bars is offline   Reply With Quote
Old 08-23-2011, 03:39 PM   #60
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

Quote:
Originally Posted by EErockMiata View Post
my favorite analogy in a long while. thanks for the post, always cool when people share data and post it up for discussion.
Maybe one day you too can be a moderator.
hustler is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
elesjuan's mediocre 95 Miata adventure (google fiber edition) elesjuan Build Threads 8 02-16-2016 09:36 PM
The "other" spool question stefanst DIY Turbo Discussion 44 09-28-2015 08:16 PM
VE analyze and Autotune seems funny (noob) TorqueZombie MEGAsquirt 64 09-18-2015 06:03 PM
Interpreting Deatchwerks Dead Times from Battery Wizard compuw22c MEGAsquirt 0 09-14-2015 07:08 PM
Track Video & Bluetooth MS3 Questions ofspunk7 General Miata Chat 3 08-31-2015 03:14 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 07:07 PM.