turning down boost to save gas

[Robotnik123]

My 8G Legnum VR-4 is a mega gas guzzler - 3454lbs curb weight, power loss thru the AWD drive train and slushbox 5sp tiptronc all have an effect. Around town I usually get MPG numbers in the low teens. Granted I am rather lead footed, but anyway: I am thinking of installing an HKS or similar electronic boost controller.

I understand such a device lets me turn up or down my turbo boost. So obviously I can turn my boost up temporarily for a race and back down to stock (which I believe is 8PSI for a 6A13TT) for normal running. I want to know though, if I can reduce boost below stock levels? What if I turned my boost down, to say 4PSI if that is possible. Could I do that and would it make my car more fuel efficient for ordinary driving? I mean I don't really need any boost at all for running up and down to work and to the supermarket.

[DOHCstunr]

I want to know though, if I can reduce boost below stock levels? What if I turned my boost down, to say 4PSI if that is possible.

you can't. because the elctronic boost controller simply modifies the boost signal to the wastegate by bleeding off boost.

you turbos still have a base boost setting that is in the spring of the stock wastegate actuators. so there is no way to lower the boost beyond that point.

the onl way you could do it woudl be to bend the wastegate acuator arms to make them slightly longer. this way the wastegate flappers don't seat all the way and it will cause a dramatic decrease in spoolup.

[seth98esT]

Cant you modify or repalce the stock spring? With you running 8psi, I would assume thats running straight off the wastegate and you cant lower it. You can get an MBC or electronic boost controller and raise the boost from 8 to whatever you want, but not lower.

[ChikagoGTZ]

Just keep off the throttle, dont go WOT, and let the turbo spool up slowly, this should save you alot of gas.

[DryBear]

Put a block of wood or a tennis ball behind your accelerator pedal

[sabzi5858]

if you are serious about keeping the boost low (without getting a new actuator, or messing up your wastegate setup) , you have to keep pressure in the line going to the wastegate actuator. this will also kill your spoolup however. but, the good thing is you can set up a solenoid with a switch so that you can turn this on and off. if you are serious about it, let me know and i'll tell you how to do it.

[Tearstone]

If I were you, I would just simply stay out of boost. That's what I used to do in my car when I had to be economically concious about the amount of gas I was guzzling.

[4-G-rim]

I agree...just stay off boost to achieve better gas milage. That was the reason i was able to achieve 30mph last week. 8)

[seth98esT]

Could also just disconnect the waste gate arms on the turbos then you would be running no boost at all haha. Try that for a day and I gaurantee you will be scrambling to hook the arms back the next day.

The boost, it always makes you come back for more.

[Robotnik123]

if you are serious about keeping the boost low (without getting a new actuator, or messing up your wastegate setup) , you have to keep pressure in the line going to the wastegate actuator. this will also kill your spoolup however. but, the good thing is you can set up a solenoid with a switch so that you can turn this on and off. if you are serious about it, let me know and i'll tell you how to do it.

Thanks anyway. I think the wise thing to do is to try and stop riding the go-fast peddle. On another fourm I have been told get a boost pressure gauge. Then I can see exactly when I am in boost or not in boost and drive accordingly.

[quicksilver22]

I agree...just stay off boost to achieve better gas milage. That was the reason i was able to achieve 30mph last week. 8)

bwahahahah, sorry, had to laugh... 30mph... mpg right? lol


ok, i know it was a mistype, but it was f'n hilarious.

i'm done now.

back to topic.

[4-G-rim]

I agree...just stay off boost to achieve better gas milage. That was the reason i was able to achieve 30mph last week. 8)

bwahahahah, sorry, had to laugh... 30mph... mpg right? lol


ok, i know it was a mistype, but it was f'n hilarious.

i'm done now.

back to topic.

I am serious.

145 miles on the trip ODO and I filled up with a little over 4 gallons of 93 oct. My g/f will vouch for me..she did the calculation on her cell phone. 8)
I usually average 25mph normally..but my new job requires a bit more highway driving so that most likely attributed the higher MPG.

[DryBear]

The boost, it always makes you come back for more.

When my Galant was in the body shop getting the rear fender repaired, I was going nuts having to drive a regular rental car

Boost is evil I tell you... EVIL!!! :twisted:

[seth98esT]

Yah out of boost or highway miles I can acheive up to 310miles per tank without the gas light even coming on. My gauge is off so I dont take it below empty, I dont want to be stranded haha.

And Len, just wait till you start your upgrade path. The boost addiction has only just started lol.

[4-G-rim]

Yes BOOST is EVIL! Fortunately...if I have a uncontrolable desire for HIGH boost I get in my GVR4 and enjoy my 20+psi of boost 8)

[Strahan]

I agree...just stay off boost to achieve better gas milage. That was the reason i was able to achieve 30mph last week. 8)

bwahahahah, sorry, had to laugh... 30mph... mpg right? lol


ok, i know it was a mistype, but it was f'n hilarious.

i'm done now.

back to topic.

I am serious.

145 miles on the trip ODO and I filled up with a little over 4 gallons of 93 oct. My g/f will vouch for me..she did the calculation on her cell phone. 8)
I usually average 25mph normally..but my new job requires a bit more highway driving so that most likely attributed the higher MPG.

Hehe.. he wasn't laughing at the 30 mpg you got, you had mistyped and said 30 mph Gave me a good chuckle too, makes me think it's something I may have said back when I drove an 80s Dodge 400, hehe: "Duuuude! I hit 30 MPH TODAY! It was sweet, I was going down a big hill!"

[seth98esT]

Drive a factory boosted car like a 2.0 1g/2g eclipse, disconnect the wastegate arm so you dont run ANY boot at all. Then you will be happy when you finally reach 30mph, just hope there isnt a hill in front that you have to make up lol

[Robotnik123]

Drive a factory boosted car like a 2.0 1g/2g eclipse, disconnect the wastegate arm so you dont run ANY boot at all. Then you will be happy when you finally reach 30mph, just hope there isnt a hill in front that you have to make up lol

Yeah you're probably right with regard to disconnecting boost on those hamster wheel engined 4 cylinder cars. I drive a factory boosted Galant with a 2.5L V6 24v engine however. I've driven non-boosted 2.5L V6 Galants before and they're good for maybe 165bhp, and seem to have plenty of get-up-and-go.

[sabzi5858]

Yeah you're probably right with regard to disconnecting boost on those hamster wheel engined 4 cylinder cars. I drive a factory boosted Galant with a 2.5L V6 24v engine however. I've driven non-boosted 2.5L V6 Galants before and they're good for maybe 165bhp, and seem to have plenty of get-up-and-go.

yes, well, a factory boosted car has lower compression ratio, so will have less power without the turbo(s) than its non-boosted counterpart.

[Robotnik123]

Yeah you're probably right with regard to disconnecting boost on those hamster wheel engined 4 cylinder cars. I drive a factory boosted Galant with a 2.5L V6 24v engine however. I've driven non-boosted 2.5L V6 Galants before and they're good for maybe 165bhp, and seem to have plenty of get-up-and-go.

yes, well, a factory boosted car has lower compression ratio, so will have less power without the turbo(s) than its non-boosted counterpart.

Yeah that's true, but I was looking at that and the 6A13TT has a compression ratio of 8.5 to 1. The naturally aspirated equivalent 6A13 engine, which is rated at 172hp, has a compression ratio of 9.0 to 1. Also the 6A13 has a SOHC head, but the 6A13TT has a DOHC head. So I'm guessing an unboosted 6A13TT would still be rated at around 160 to 170ish HP.