RPM performance and mpg questions for a 240 8v b23/b230

[VolvoLatAm]

What are the optimal shift point rpms for the 8v volvo 240 b23/b230 w/ m46 for performance AND for mpg (without lugging)--what's the minimum rpm in gear without causing damage for optimal fuel economy?

 

[VolvoLatAm]

Bueller?

 

[apachechef]

Sedan or wagon?

 

[VolvoLatAm]

Sedan or wagon?

sedan

 

[sbabbs]

M cam? 2.5 or 3k I'd shoot for, but I rap mine up, need to swap to this A cam i got. THey say for best mileage swap to a T cam. I went from 28 to 25 swapping from T cam to A cam in my turbo car. Just don't lug it. I gotta go at least 60 for 5th with the 3.31 rear in my 88 wagon. I think I need a new center support bearing. I could lug more with more advanced race timing but then I gotta run premium. Now back to normal ignition timing and regular. LH 2.4 flat flywheel.

 

[VolvoLatAm]

M cam? 2.5 or 3k I'd shoot for, but I rap mine up, need to swap to this A cam i got. THey say for best mileage swap to a T cam. I went from 28 to 25 swapping from T cam to A cam in my turbo car. Just don't lug it. I gotta go at least 60 for 5th with the 3.31 rear in my 88 wagon. I think I need a new center support bearing. I could lug more with more advanced race timing but then I gotta run premium. Now back to normal ignition timing and regular. LH 2.4 flat flywheel.

A cam

 

[sbabbs]

Welp if you want better miles per kilometer swap to a T cam..

 

[leecatd8209]

The best MPG I ever got out of my b230/m47 sedan was 30.2mpg on 87oct with an M cam that never saw over 3k

 

[dl242gt]

You can put LH2.4 in your car and have a shift light from Volvo. It usually comes on around 2.5k rpms. I gotta say even with an M cam that shift point had the engine lugging everywhere.

I like to use 3k rpms for minimal shift point and for cruising you can go as low as 2-2.5k rpms. That is how I drove with a B cam in my old B21F 79. Now I rev it up with the V15 in the 93 but it works so well you could use the same shift points.

 

[culberro]

The best MPG I ever got out of my b230/m47 sedan was 30.2mpg on 87oct with an M cam that never saw over 3k

But 28mpg is easily attainable with a b-cam and 10:1cr with a m47, and that includes romping on it.
Bump the CR up a fair bit, and even with a smaller cam you'll have some pretty big efficiency improvements.

 

[dl242gt]

That's what I want to do next on my old 93. A compression bump should give me a good power boost as well. I still want to keep the stock heavy flywheel and right now no matter how hard I run it the mileage is always around 20mpg with the enem bumpstick. Highway I get around 26-27mpg.

 

[culberro]

I’ve always been able to get 28-30 if I kept the speeds reasonable on the freeway. A M-cam and stock compression b230 gets worse mileage above 65/70 in my experience.

Stock CR is well below the published numbers, and getting the CR up helps so much with efficiency. Bonus with the m-cam, it’ll keep you from reving it out all the time!

 

[Jack]

I’ve always been able to get 28-30 if I kept the speeds reasonable on the freeway. A M-cam and stock compression b230 gets worse mileage above 65/70 in my experience.

Stock CR is well below the published numbers, and getting the CR up helps so much with efficiency. Bonus with the m-cam, it’ll keep you from reving it out all the time!

I had the same experience with my 85
If I kept it at 55 I would get like 5-9mpg more vs going 65+

 

[shoestring]

You can put LH2.4 in your car and have a shift light from Volvo. It usually comes on around 2.5k rpms. I gotta say even with an M cam that shift point had the engine lugging everywhere.

The stock shift light brings you in at 1500 in the next gear.

The engine will tell you what it wants as far as shift points. Don't rely on "shift at X" all the time. You can, however rely on load (torque) demand. More load=more rpm.

In the warm months I get at least 28mpg highway at 75mph or so in my '91 245 M47, 9.8:1 (stock head shaved 1mm) and a V cam. As high as 30.7. Cold months it's as poor as 24.5. It's New England, so it's hilly, not mountainous. Compression ratio increase will do a lot.