I searched this and didn't find a really clear answer. Also this isn't about a Honda, but I'm sure the theory is the same for all IC engines. Anway,

I have a Nissan Frontier, and I was thinking about going turbo to decrease the pain-in-the-buttedness of accellerating and holding freeway speeds while towing my Civic+Trailer (~3000 lbs). Not a lot of boost, I was thinking twin t25's or something running 5-8 psi-ish. My friend put a t25 on his crx and noticed a decently significant increase in milage on the freeway. Since 95% of my driving is freeway, and there's no use having a heavy foot in my truck, should I expect an increase in mpg? If so, I get about 16 mpg right now, do you think I would hit the 20's?

 

more air = more fuel, you might get bettermilage if you just bolt it up, but you'll be running lean most likely

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by toolowsol &raquo;</TD></TR><TR><TD CLASS="quote">more air = more fuel</TD></TR></TABLE>

True, but in low boost (like freeway driving) people see an increase ~5mpg when properly tuned. Keep in mind I won't be revving past around 2500 rpm on a regular basis.

 

wouldn't teh money you put in the turbo setup negate most savings you would get from the increased gas mileage?

 

I noticed neither a gain nor loss in fuel economy during highway driving. While cruising, the turbo really isn't doing anything; the vacuum the engine experiences will be the same as before, so you should not expect a gain in fuel economy.

What your friend probably experienced is a gain in economy from using a leaner mixture than before in his tuning. Contrary to popular belief, most engines are not tuned for ideal fuel economy nor ideal power. They are tuned for longitivity, and to do this they usually run a bit richer than they have to.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 95stangkillah &raquo;</TD></TR><TR><TD CLASS="quote">wouldn't teh money you put in the turbo setup negate most savings you would get from the increased gas mileage?</TD></TR></TABLE>

Ya, all of it and probably more, but I'm doing it for easier towing, the gas milage was just a benefit I was hoping to see from it.

Is no one else seeing a milage increase after with a properly tuned a/f ratio?




Modified by jolt-tsp at 5:48 PM 8/21/2004

 

makes me wonder how factory turbo cars do it then. I mean, what's the gas mileage on a GTI 1.8T? would a small turbo that comes on at `2500 rpm help? or for the same matter how do big rigs maintain better fuel economy through turbo technology? I would look there first for your application. just a thought.