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I want 40MPG!

i think you can probably get close.

It costs $ though.

My B21ft, with a mild tune running 14.5AFRs on the way home, did 30mpg on my two hour all-highway drive from college to home. Thats a b21ft. 7.5:1 and a big dumb turbo that I liked to roll-in on, and a k-cam.

It has 373 gears, the 3.35 t5, and megasquirt. Now do I think you can get to 40? No.

But if it had the ever-illusive 3.31 gears or the 2.95 t5 with the lower 5th gear... and a high-comp b230, I think you can get low-mid 30s out of it. I hope to find out shortly what my 10.2ish:1 b230f+t will get me. Im hoping for the 32 mark with the same drivetrain.
 
can somebody tell me which conditions needs to be met in the LH2.4 to achieve cutoff during coasting/downhill?
QUOTE]

you need to be over about 1250rpm with throttle closed (the switch in the TPS will be closed) and coasting in gear. (N = idlespeed = fuelconsumption)
once below 1250 rpm the injectors are fired again.(driving in 1ste gear in a traffic jam is when you can feel the ecu switching)
 
Thank for pointing out the IN GEAR coasting JANSPEED, you solved a long time argument on how to achieve better mileage with a few friends, I have a bunch of free lunches now!
As for the tall tires, a quick research tells me the biggest tire I can accomodate on the Volvo with 15x8 wheels are 235/75X15, so next question is if they must be P or LT? Then, is there a way to recalibrate the electronic speedo to remain accurate?And I also was thinking that maybe the car riding to tall from the ground will have more drag.One of my friends says the 240 its going to look like a Jeep Cherokee with a trunk on those tires.
 
Higher volumetric efficiency.

You could also run the 4 valve head as an Atkinson's 4 stroke cycle by retarding the intake cam a lot, which would increase the efficiency even more.

if you look at the torque curve of a B230F and a B234F you may start to suspect that the VE at lower RPMs is higher with the B230F.

IMO a 16 valve could only make more economy if you went from 2.3L to 1.8L and used the extra cam to still make 115 HP when required.
 
you need to be over about 1250rpm with throttle closed (the switch in the TPS will be closed) and coasting in gear. (N = idlespeed = fuelconsumption)
once below 1250 rpm the injectors are fired again.(driving in 1ste gear in a traffic jam is when you can feel the ecu switching)

On some cars. Volvo phased this out on the later LH 2.4 cars. It won't cut the injectors out unless you're above ~2000 RPM.
 
if you look at the torque curve of a B230F and a B234F you may start to suspect that the VE at lower RPMs is higher with the B230F.

IMO a 16 valve could only make more economy if you went from 2.3L to 1.8L and used the extra cam to still make 115 HP when required.

That cannot be possible. VE of a 16valve head is like high 90s and a stock 8v is high 70 low 80.
Thank for pointing out the IN GEAR coasting JANSPEED, you solved a long time argument on how to achieve better mileage with a few friends, I have a bunch of free lunches now!
As for the tall tires, a quick research tells me the biggest tire I can accomodate on the Volvo with 15x8 wheels are 235/75X15, so next question is if they must be P or LT? Then, is there a way to recalibrate the electronic speedo to remain accurate?And I also was thinking that maybe the car riding to tall from the ground will have more drag.One of my friends says the 240 its going to look like a Jeep Cherokee with a trunk on those tires.

If you're really wanting the milage, I think something like a 175 or lower would be in order. Less contact area, less friction and stuff1
 
at 4500 RPM+ i believe you, but below 3000 RPMs (where a fuel economy discussion can be had) your going to have to show me more data.

the car has 16 valves.

16/8 is 2.

That means it has twice the number of valves as an 8valve.

I searched lightly and couldn't find any sort of flow-bench results or anything. But I just can't imagine any situation, low RPM or high, were the 16 valve would not be in an advantage...except a timing belt snap.
 
the car has 16 valves.

16/8 is 2.

That means it has twice the number of valves as an 8valve.

I searched lightly and couldn't find any sort of flow-bench results or anything. But I just can't imagine any situation, low RPM or high, were the 16 valve would not be in an advantage...except a timing belt snap.
+1.

It's not chance that almost all modern economy cars use a 4 valve head design. The VE of most 4 valve head designs is 90-95%. For a 2 valve the general rule is 75-85%.
 
the B230F makes 136 ft-lb peak at 2750 RPM

the B234F makes 150 ft-lb peak at 4450 RPM

something tells me that at 2700 RPM the B230F is making more torque. which means its making more poke for each unit of air it ingests. which means that at that RPM its more efficient that the B234F.

FYI i own a B230F B234F and a B230FT volvo... its not that i hate the B234F. but from the standpoint of optimizing 2.3 liters of motor for efficiency, i think its not the way to go.

if you could benchrace changing displacement, then ya, lets go 16 valve on a smaller motor to make the same 115 hp.

modern economy cars use 16 valve motors to reduce displacement and get the same overall HP rating AND better efficiency from the reduced displacement/more open throttle plate at cruise/etc.
 
it really comes down to what rpm the VE peaks at. Find it and drive at that RPM. Maybe when i'm done doing WAVE simulations for school I can set up a redblock in it.
 
can somebody tell me which conditions needs to be met in the LH2.4 to achieve cutoff during coasting/downhill?
QUOTE]

you need to be over about 1250rpm with throttle closed (the switch in the TPS will be closed) and coasting in gear. (N = idlespeed = fuelconsumption)
once below 1250 rpm the injectors are fired again.(driving in 1ste gear in a traffic jam is when you can feel the ecu switching)

I think you are over simplifying things. In most situations coasting in neutral with the engine at idle will be more fuel efficient because you will be able to go much further without engine braking. If on the other hand you are trying to slow down or coast to a stop, you are better off in gear for the reason you mentioned. In most cases, neutral is best.
 
Re: Head flow of a 16v vs. an 8v:

<a href="http://picasaweb.google.com/lh/photo/WdCngr1K9YUeJL0nGmcOiQ"><img src="http://lh6.ggpht.com/_7EUAij74Ycw/STM1OSWlrmI/AAAAAAAAPFc/dkUHoOCkHlc/s800/b234v530.PNG" /></a>

Numbers at 28" of vacuum from a couple of Jens Gustavsson's threads on S?varturbo.
 
the B230F makes 136 ft-lb peak at 2750 RPM

the B234F makes 150 ft-lb peak at 4450 RPM


something tells me that at 2700 RPM the B230F is making more torque. which means its making more poke for each unit of air it ingests. which means that at that RPM its more efficient that the B234F.

FYI i own a B230F B234F and a B230FT volvo... its not that i hate the B234F. but from the standpoint of optimizing 2.3 liters of motor for efficiency, i think its not the way to go.

is the 16 valve making LESS than 136 ftlbs at 2750? It might be, but is it?
 
LOL my lightened 740 B234F automatic with no PS no AC and an e-fan averaged like 22.7 mpg with me driving like a bitch the whole tank.

my stock 240 automatic always averages like 25 mpg a tank.
 
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