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what would give better mileage?

1K views 24 replies 17 participants last post by  superdewey58 
#1 ·
Ok, I realize that people here a likely baised to the D engine but I would like some honest answers from people how may have seen examples first hand.

What would give better milage in a 89 Crx?

A: a D15 with Rbh5 turbocharger, starion IC @6psi on a auto trans.

B: a LSvtec (B18 with B16a head) with 5spd
 
#2 ·
D15 with RHB5 and an Hf 5 speed would be great for milage, but shit slow. If you want to go a little quicker you could move to a DX tranny and still get 35ish MPG if your not always in boost.
 
#4 ·
I have a greddy kit with some additions and am getting 33mpg. That is tuned rich with rc440 injectors and hondata. Just boost a d16z6 and you will get decent numbers.
 
#5 ·
I had a guy tell me that he was getting the same if not better mileage with his LSvtec Crx as his Toyota Echo. I find that kind of hard to believe as a Echo is rated at something crazy like 40-50mpg! Anybody know what a setup like that would really get?
 
#6 ·
If you granny the shit out of it, run the longest geared tranny possible, and tune it (probebly unsafely) lean, you could get 50+ MPG out of it. Is it worth spending the money for a CRVTEC just to use it as an econo car? I doubt it, but someone probebly would. If your really looking for the best fuel economy, just get a D15 and a Hf or Vx tranny depending on if your running a cable or hydro chassis.
 
#7 ·
Ok, let's get one big thing straight here.

Modding your car and gas mileage do not go hand in hand. One will suffer at the gain of another.

Depending upon how you build it, and what tranny you put with it, the LSVTEC will probably be faster than a suby turboed D at 5psi.
 
#10 ·
Ok, let's get one big thing straight here.

Modding your car and gas mileage do not go hand in hand. One will suffer at the gain of another.
I understand that, I want a car that is reasonable on gas but not shit-assed slow either. I'm just wondering given the two setups what would give better mileage, not performance. Performance wise I think either setup would be fun to drive. It depends on what you consider good gas mileage to be.. Either way, once I get my Crx on the road it'll blow away my turbocharged Datsun 280z (in mileage NOT performance) The Datsun is fun, but it gets a little expensive to keep feeding it. Time to turn it into a drive only for fun car and use a Honda as a daily driver. For me a modded Honda IS a gas miser!
 
#8 ·
I want to do an LS/VTEC someday.. Sorry that was a little off topic.
 
#16 ·
Yes I have found that overal the mileage in my Datsun has improved since the turbo swap and ecu tuning.. Granted if I drive it like a animal that is definatly NOT the case, but driven nicely it's definatly better. I am thinking that the turbo simply improves the efficiency of the engine, even if you are not into boost the turbo does spool and help the air to flow into the engine.
 
#17 ·
With out load, the turbo is moveing fast enough for the air that the engine is useing to pass.
 
#20 ·
I'd say 25-30 city driving, you've got to remember, this is D series.org, not ls/vtec.org ;)
 
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