Lexus IS Forum banner

1 - 20 of 55 Posts

·
Not Officially Back
Joined
·
12,742 Posts
Discussion Starter #1
Now that we know how much direct control we have over the throttle, as discussed in Part 1 of our IS300 Drive-by-wire throttle analysis... it's time to go to the next step...



PART 2: Video of the IS300 DBW/ETCS-i in Action

I've compiled a video which shows the DBW/ETCS-i operating.

RIGHT CLICK SAVE AS:
2.18 MB - IS300_80mmTB_ThrottleResponse.wmv



For the "flooring it", "instant off", and "blipping" sections of the video, I sat down in the drivers seat to ensure I was really operating the pedal as fast as possible. For the "Ignition off" and "Various Movements" sections, I used my hand to operate the TCPS wheel so you could easily see it move along with the throttle valve.


Please note... these videos were made on my car, which has the upgraded 80mm throttle body. My upgraded TB also comes from a Lexus vehicle... which uses the exact same DBW/TCPS/TCM/TPS system that the IS300 ETCS-i TB does from our first discussion. All the electronics on the 2 TBs are the same... down to the plugs used to connect the sensors and motor... it's just plug and play. I retain all stock functions... cruise control, TRAC, steering assist, etc.

This thread isn't going to discuss whether or not the 80mm TB is faster or slower than the OEM 60mm one... it's simply meant to demostrate DBW and ETCS-i in action.

You might notice the wiring sticking off the top of the TB... this is the harness I made for Part 3: Exactly how fast is DBW?



Anyone still want to blame DBW for poor throttle response? ;)
 

·
Registered
Joined
·
13,905 Posts
Man, I thought this was going to be a vid of you puttin the hurt on someone. Oh well, nice work. That seems pretty quick. Have what little rep I can give.
 

·
Registered
Joined
·
7,564 Posts
there is still some lag in the video that definitely hinders you if you are tracking a car.

also, John dont you have the spring removed from the TPS or somewhere in the TB somewhere that you mentioned earlier in part 1 as well?
 

·
Premium Member
Joined
·
3,844 Posts
What a pretty little butterfly. :lol: Once again good info Das. ;)

AltezzaBob- so what you're sayin' is there would be enough "lag" that it would be noticable on a gas powered engine in a street tune? I track the car and havn't experienced any "lag" in throttle response. Anyway Das' next installment should cover this subject anyway.
 
  • Like
Reactions: dasgalloway

·
Registered
Joined
·
1,396 Posts
Nice job Das, good write up excellent video, +rep for when i can give ya some more. Love this series.
 

·
Not Officially Back
Joined
·
12,742 Posts
Discussion Starter #7
AltezzaBob said:
there is still some lag in the video that definitely hinders you if you are tracking a car.

also, John dont you have the spring removed from the TPS or somewhere in the TB somewhere that you mentioned earlier in part 1 as well?

Something to keep in mind here is that any "lag" you can see is only one part of the equation... once the throttle itself is open, the air has to start flowing into the motor, and the motor has to increase it's rpms.

What tiny amount of lag you see because of DBW is definitely very small compared to those two things.

And no... I don't have anything removed from the TB in this video.
 

·
Not Officially Back
Joined
·
12,742 Posts
Discussion Starter #9
kponti said:
Ahh once again I will blame the flywheel rather than DBW for our slow throttle response!!!
http://my.is/forums/showpost.php?p=3760874&postcount=2

Thanks Das, I owe you another +rep. I know what my mods will be next year (UR flywheel and Centerforce dual friction clutch)

GUYS DONT FORGET THE DAMN REP CLICK, USE IT!!!

I am apt to agree that the "poor throttle response" is caused by something other than the DBW... the DBW just isn't "slow" by any stretch of the imagination.

I was very surprised when I opened up the TB and started pulling the cable... watching how fast it reacted no matter how crazy I got made me think something was wrong and the cable was actually directly connected to the throttle. :suspiciou It is very hard to discern any real differenece... I expected the throttle valve to take a second or so to fully move after I pulled the cable... clearly by the videos that is not the case.

The only place you can really see it is in the 100%-0% instant off section... when you get off the pedal suddenly you can see that the valve takes a split second longer to close fully.


If it's the flywheel... I wonder if an auto would rev any differently than a 5spd.... it's definitely something we can measure...

I'm getting to the point where I need more expensive measuring devices... my best AD converter samples at a hair slower than 10 hertz (10 times per second, or a resolution down to 100ms). The question is... it it's slower than 100ms... is it something you can detect when driving?
 

·
Registered
Joined
·
3,591 Posts
"You must show some love to other members before giving it to dasgalloway again."

Great vid and info, once again. Just curious, what car is that TB off of, and does it/ will it make a difference in an NA application? Thanks.
 

·
Not Officially Back
Joined
·
12,742 Posts
Discussion Starter #11
Split2nd said:
"You must show some love to other members before giving it to dasgalloway again."

Great vid and info, once again. Just curious, what car is that TB off of, and does it/ will it make a difference in an NA application? Thanks.

Vehicle with a Lexus V8... 98-00.

Not prepared to answer the second question, since I haven't tested it, NA.
 

·
Registered
Joined
·
7,564 Posts
dasgalloway said:
I am apt to agree that the "poor throttle response" is caused by something other than the DBW... the DBW just isn't "slow" by any stretch of the imagination.

I was very surprised when I opened up the TB and started pulling the cable... watching how fast it reacted no matter how crazy I got made me think something was wrong and the cable was actually directly connected to the throttle. :suspiciou It is very hard to discern any real differenece... I expected the throttle valve to take a second or so to fully move after I pulled the cable... clearly by the videos that is not the case.

The only place you can really see it is in the 100%-0% instant off section... when you get off the pedal suddenly you can see that the valve takes a split second longer to close fully.


If it's the flywheel... I wonder if an auto would rev any differently than a 5spd.... it's definitely something we can measure...

I'm getting to the point where I need more expensive measuring devices... my best AD converter samples at a hair slower than 10 hertz (10 times per second, or a resolution down to 100ms). The question is... it it's slower than 100ms... is it something you can detect when driving?
with my 5-speed, it did rev quicker. with my auto there is a considerable amount of lag. if its not the DBW, then there must be something else? ignition?

as in terms of lag, im comparing response time to a Toyota GT-S 2ZZ-GE, Honda/Acura's K20A and F20/22, 98 Toyota 1MZ-FE V-6 and even the 98 Toyota (4spd auto tranny) 1MZ revs and responds quicker anyday of the week. Initial response of the 2JZ in the IS off idle is definitely slow and downshift response. could the rotating mass assembly be that much heavier that it takes half a second to respond?

curious what your part 3 is.
 

·
Not Officially Back
Joined
·
12,742 Posts
Discussion Starter #15
AltezzaBob said:
with my 5-speed, it did rev quicker. with my auto there is a considerable amount of lag. if its not the DBW, then there must be something else? ignition?

as in terms of lag, im comparing response time to a Toyota GT-S 2ZZ-GE, Honda/Acura's K20A and F20/22, 98 Toyota 1MZ-FE V-6 and even the 98 Toyota (4spd auto tranny) 1MZ revs and responds quicker anyday of the week. Initial response of the 2JZ in the IS off idle is definitely slow and downshift response. could the rotating mass assembly be that much heavier that it takes half a second to respond?

curious what your part 3 is.
well... both the 5spd and the eshift IS300s use identical ETCS-i systems... so if you've noticed a difference in rev speeds the ETCS-i is probably not at fault.

Comparing rev performance between different motors carries far too many variables to determine anything sustantial about DBW. Rotational mass, tuning, other drivetrain components, etc etc all play key factors (arguably, much more than DBW does) in how quicky a motor can "respond".

The only true test would be to use both the partial-DBW system and a full direct-cable system on the exact same motor, setup, etc. I'm going to get close to that for part 3 by making some variables cancel themselves out... ie, assume that any response performance between pedal and TCPS wheel will be identical for both the Direct cable and DBW systems (both have the pedal dampener spring system, stretch of the cable would be the same, etc)... and assume that once you get the force to the TCPS wheel, a direct cable system will repond instantly (0 reaction time)...

Even though I don't have a direct cable system setup and thus won't be measuring it... we can assume the theoretical direct cable system will be our "control" with a reaction time of 0 after pedal force reaches TCPS wheel. Then I'm going to look at the reaction time for the DBW system... and assume that any latency it has will not be present in the direct cable system, comparing the TCPS and TPS signals to see what lag there is between their movements.
 

·
Registered
Joined
·
1,396 Posts
DAS what about intake runner length, and among other things how long the whole intake is? Seems to me to be a big culprit I'd be curious to see a IS motor converted to ITB just to see the diff in response.
 

·
Not Officially Back
Joined
·
12,742 Posts
Discussion Starter #17
IceCold4x4 said:
DAS what about intake runner length, and among other things how long the whole intake is? Seems to me to be a big culprit I'd be curious to see a IS motor converted to ITB just to see the diff in response.
Yes, I agree there are many factors which will inpact the "responsiveness" of the motor... and I'd wager that, given the speed DBW reacts with, these other factors carry far more weight in the quest for throttle response than a DBW system does.

IETCS-i? Haha... someone make me one.. please? :bigSmile:
 

·
Registered
Joined
·
1,396 Posts
HMMM someone may have it hell i'm sure the motec would have the ability to controll that, LMAO
 

·
Not Officially Back
Joined
·
12,742 Posts
Discussion Starter #19
IceCold4x4 said:
HMMM someone may have it hell i'm sure the motec would have the ability to controll that, LMAO

So does the stock ECU... all you need is a TCM/electroclutch system that has the same behavior as the OEM model but is strong enough to actuate 6 TB valves... plus the TCPS and TPS. Hook the assembly up as described in my first article, and let the ECU do the math just as it always has. Vavavoom!

ITB with cruise control. Hrmmmmmmmm
 
1 - 20 of 55 Posts
Top