Disable turbo on demand. - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


DIY Turbo Discussion greddy on a 1.8? homebrew kit?

Reply
 
 
 
LinkBack Thread Tools
Old 09-01-2011, 10:48 PM   #1
Elite Member
Thread Starter
iTrader: (2)
 
triple88a's Avatar
 
Join Date: Apr 2006
Location: Chicago, IL
Posts: 9,131
Total Cats: 598
Default Disable turbo on demand.

So been trying to find a way to manually open the wastegate on demand to help mpgs...freeer exhaust flow...no boost etc. I've looked at boost controllers and correct me if i'm wrong however those need some pressure to open the wastegate. Anybody have any idea for anything that can be used to open the wastegate on demand (other than full boost lol)?
triple88a is offline   Reply With Quote
Old 09-01-2011, 10:52 PM   #2
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,185
Total Cats: 2,582
Default

if your objective here is to help mpg's then a good tune and keeping the right foot in check will do wonders for you. also using a larger turbo with a big hotside
18psi is offline   Reply With Quote
Old 09-01-2011, 10:55 PM   #3
Elite Member
Thread Starter
iTrader: (2)
 
triple88a's Avatar
 
Join Date: Apr 2006
Location: Chicago, IL
Posts: 9,131
Total Cats: 598
Default

Heh i know that however i'm running with the wastegate disconnected at the moment and i'm hitting 27 mpgs when i was hitting 19 with the wastegate connected

...yes I know the right foot...

Its hard to stay in low vacuum like you can with the wg opened up..
triple88a is offline   Reply With Quote
Old 09-01-2011, 10:58 PM   #4
I'm a terrible person
iTrader: (19)
 
FRT_Fun's Avatar
 
Join Date: Apr 2009
Location: Arizona
Posts: 7,293
Total Cats: 180
Default

Wow 19? Sounds like something is wrong. I consistently got 32mpg with my FMII... with a heavy foot.
FRT_Fun is offline   Reply With Quote
Old 09-01-2011, 11:01 PM   #5
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,185
Total Cats: 2,582
Default

I would get 17-19mpg on mine when I constantly romped on it. But thats with 1k's, and e85. With some restraint it would be 25-29 without much hassle.....You can always install a low boost cut to remind yourself to take it easy lol.

the whole wastegate idea is not terrible but just sounds way more effort than its worth....I mean at cheapest you're looking to spend a few hundred on some type of wastegate and then another few hundred to plumb it all in.....to save a few mpg
18psi is offline   Reply With Quote
Old 09-01-2011, 11:02 PM   #6
Elite Member
Thread Starter
iTrader: (2)
 
triple88a's Avatar
 
Join Date: Apr 2006
Location: Chicago, IL
Posts: 9,131
Total Cats: 598
Default

Well my trips are mainly 2 mile trips so a lot of idling and probably shitty start that probably flooded the cylinders every time.
triple88a is offline   Reply With Quote
Old 09-02-2011, 01:49 AM   #7
Slowest Progress Ever
iTrader: (26)
 
thirdgen's Avatar
 
Join Date: Oct 2007
Location: The coal ridden hills of Pennsylvania
Posts: 5,806
Total Cats: 183
Default

I get average 28mpg with my car, that's with occassional 7psi pulls, and I definately see about 3 psi between shifts just driving it to work. If you want to manually actuate your WG flapper, perhaps you could use a manual choke cable attached to the flapper arm? It might work. You could pull it out and somehow lock it in place to keep the flapper open, and then when you push it in to close the flapper, the wastegate actuator would control the pressure.
thirdgen is offline   Reply With Quote
Old 09-02-2011, 02:27 AM   #8
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,317
Total Cats: 1,915
Default

Quote:
Originally Posted by FRT_Fun View Post
Wow 19? Sounds like something is wrong.
^ this.

My '92 averages 29-29 MPG on the highway if I've got the top up and am at least within plausible deniability distance of the speed limit. Compare that to 21-22 MPG in town if I'm hot-******* it.

Unless it's a GT1241, merely having a turbo inline with the exhaust should have absolutely zero measurable effect on your fuel economy.


Quote:
Originally Posted by triple88a
Its hard to stay in low vacuum like you can with the wg opened up
?!?!?!

Staying in vacuum is easy, just don't press the throttle all the way to the floor.

I'm not being sarcastic here. If you're in boost, then you're accelerating. Rapidly. What you are saying simply does not make sense.
Joe Perez is online now   Reply With Quote
Old 09-02-2011, 02:51 AM   #9
Slowest Progress Ever
iTrader: (26)
 
thirdgen's Avatar
 
Join Date: Oct 2007
Location: The coal ridden hills of Pennsylvania
Posts: 5,806
Total Cats: 183
Default

Quote:
Originally Posted by triple88a View Post
Its hard to stay in low vacuum like you can with the wg opened up..
This is very true. I had to run my stock ecu one time and I wired the WG flapper open. The vacuum gauge went towards zero a lot faster than it did at partial throttle than with the WG not wired open at partial throttle. I'm no scientist, but I think it's because the turbo spooling slightly in vacuum causes there to be less throttle to be aplied to move the car. In other words, the more the throttle body is opened, the closer to zero the vacuum gauge will go. A turbocharger increases the volumetric efficiency of the engine, which is why you will actually get better fuel mileage out of boost with a turbo than with natural aspiration.
thirdgen is offline   Reply With Quote
Old 09-02-2011, 03:15 AM   #10
Elite Member
Thread Starter
iTrader: (2)
 
triple88a's Avatar
 
Join Date: Apr 2006
Location: Chicago, IL
Posts: 9,131
Total Cats: 598
Default

I'm assuming my timing had more room for improvement. Anyhow even stock i have never gotten more than 26 mpg.
triple88a is offline   Reply With Quote
Old 09-02-2011, 03:54 AM   #11
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,363
Total Cats: 1,323
Default

Pre-turbo I got 22mpg around town, 25mpg highway. Post-turbo I got 16mpg around town, 25mpg highway. Best ever was 30 highway, worst ever was 12mpg highway.

Keep your foot out of it and your mileage will go up. Drive like a dick and it will drop. Simple as that.
Savington is offline   Reply With Quote
Old 09-02-2011, 03:57 AM   #12
Elite AbsurdFlow Member
 
Laur3ns's Avatar
 
Join Date: Mar 2008
Location: Enschede, NL
Posts: 2,058
Total Cats: 11
Default

Quote:
Originally Posted by Savington View Post
Pre-turbo I got 22mpg around town, 25mpg highway. Post-turbo I got 16mpg around town, 25mpg highway. Best ever was 30 highway, worst ever was 12mpg highway.

Keep your foot out of it and your mileage will go up. Drive like a dick and it will drop. Simple as that.
Whahaa you talking about fuel consumption in mpg instead of lph. Really?
Laur3ns is offline   Reply With Quote
Old 09-02-2011, 04:37 AM   #13
Elite Member
iTrader: (1)
 
Join Date: Jun 2006
Location: Warrington/Birmingham
Posts: 2,658
Total Cats: 39
Default

Quote:
Originally Posted by triple88a View Post
Well my trips are mainly 2 mile trips so a lot of idling and probably shitty start that probably flooded the cylinders every time.
2 mile trips won't do anything for your MPG, the car won't even get fully warm.

If saving fuel is that much of an issue, why not walk or ride a bicycle instead. 2 miles is not that far at all.

Disconnecting your turbo WG isn't the answer.
richyvrlimited is offline   Reply With Quote
Old 09-02-2011, 04:49 AM   #14
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,363
Total Cats: 1,323
Default

Quote:
Originally Posted by Spookyfish View Post
Whahaa you talking about fuel consumption in mpg instead of lph. Really?
This was all before I stripped it and put the AF 2871R setup in. Now it gets like 5mpg tops
Savington is offline   Reply With Quote
Old 09-02-2011, 10:53 AM   #15
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

I get 24mpg going 85-95 with a few burts of 130mph...while pulling a 300lb trailer. Without the trailer I've seen 34mpg and this was calculated with googlemaps because my speedo no worky.

You need to tune it lean, I run 15.6-16.1 in cruise, with a ton of advance. Another win for low compression.
hustler is offline   Reply With Quote
Old 09-02-2011, 11:22 AM   #16
Elite Member
Thread Starter
iTrader: (2)
 
triple88a's Avatar
 
Join Date: Apr 2006
Location: Chicago, IL
Posts: 9,131
Total Cats: 598
Default

Quote:
Originally Posted by richyvrlimited View Post
2 mile trips won't do anything for your MPG, the car won't even get fully warm.
Its 2-3 extra minutes of idling every mourning to get the temp gauge to even move.

But i gotcha guys i guess i'll have to learn how to stay off of it
triple88a is offline   Reply With Quote
Old 09-02-2011, 11:22 AM   #17
Elite Member
iTrader: (1)
 
Join Date: Jun 2006
Location: Warrington/Birmingham
Posts: 2,658
Total Cats: 39
Default

Quote:
Originally Posted by hustler View Post
I get 24mpg going 85-95 with a few burts of 130mph...while pulling a 300lb trailer. Without the trailer I've seen 34mpg and this was calculated with googlemaps because my speedo no worky.

You need to tune it lean, I run 15.6-16.1 in cruise, with a ton of advance. Another win for low compression.

You can tune that lean with shitloads of adavnce even with high compression when at low load i.e. cruising.

16.5:1 and 40+deg advance here on an otherwise stock 2001 engine.

Low comp actually hurts your mpg, but your turbine makes up for the loss in engine VE.

Your setup on a higher compression engine would yield better MPG, but much lower power when at WOT.
richyvrlimited is offline   Reply With Quote
Old 09-02-2011, 11:23 AM   #18
Elite Member
iTrader: (1)
 
Join Date: Jun 2006
Location: Warrington/Birmingham
Posts: 2,658
Total Cats: 39
Default

Quote:
Originally Posted by triple88a View Post
Its 2-3 extra minutes of idling every mourning to get the temp gauge to even move.

But i gotcha guys i guess i'll have to learn how to stay off of it
2-3 minutes of burning fuel and going no-where = shitty mpg.
richyvrlimited is offline   Reply With Quote
Old 09-02-2011, 11:51 AM   #19
meatbag
iTrader: (50)
 
gospeed81's Avatar
 
Join Date: Nov 2008
Location: Houston, TX
Posts: 7,357
Total Cats: 26
Default

Tune it.

I had a small hotside turbo, and a 100mi commute to school, and still consistently got over 30mpg. That's with some "idiot" driving thrown in.

Turbo seemed to boost economy even in vacuum, giving more torque for smaller throttle positions, and with MS you can shoot for low to mid 16:1 AFRs. Win.
gospeed81 is offline   Reply With Quote
Old 09-02-2011, 01:10 PM   #20
Elite Member
iTrader: (3)
 
Join Date: Mar 2008
Location: Granbury, TX
Posts: 6,009
Total Cats: 583
Default

From a thermodynamic standpoint, recovering waste heat with a turbine to increase intake pressure increases efficiency.

I'm with Damon. I get more MPGs than I used to if I drive the same. You just have to tune for it (i.e., lean it out at low throttle settings).
hornetball is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 58 Yesterday 10:04 PM
WTB MP62 (Hotside) (NB2) Rick02R WTB 3 01-03-2016 08:18 PM
Expected intake temps on the track? tazswing Race Prep 20 10-03-2015 12:04 PM
ISO 1.6 turbo cast iron manifold cale saurage DIY Turbo Discussion 16 10-01-2015 12:25 PM


Thread Tools

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 09:08 AM.