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)?

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

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... :D

Its hard to stay in low vacuum like you can with the wg opened up..

Wow 19? Sounds like something is wrong. I consistently got 32mpg with my FMII... with a heavy foot.

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

Well my trips are mainly 2 mile trips so a lot of idling and probably shitty start that probably flooded the cylinders every time.

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.

^ 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-dogging it.

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


?!?!?!

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.

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.

I'm assuming my timing had more room for improvement. Anyhow even stock i have never gotten more than 26 mpg.

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?

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.

This was all before I stripped it and put the AF 2871R setup in. Now it gets like 5mpg tops :laugh:

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.

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 :vash:

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.

2-3 minutes of burning fuel and going no-where = shitty mpg.

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.

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).