By the way, if you’re moving to 3.31 from 3.73/3.91/4.11 (whatever’s in there) - you’d be moving to a higher or longer rear gear, not lower. “Lower” rear gear = bigger numerical number.

If the issue is that you want the revs at highway speeds to be lower, then the longer 3.31 gear will help. If the issue is that you want more “get up and go” at higher speeds, the longer 3.31 is going to make things worse.
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82 242-6.2L; '17 Mazda3; '16 Crosstrek

Turbo Group A 242 Flathood, yes?

Though not since last millennia have I been a passenger or a driver of a Turbo 240. Off the North America showroom floor models that were 4-10+ years old and were quite stock as far as I know. For a 240, fast off the line minus the Turbo lag and fast on the highway in top gear with power to spare.

So far as I know, the few Turbo 240s I'd been in were stock, in at least good to perfect tune, not abused. Both Auto and M46 manual transmission.

So, an issue with tune perhaps, if no top end power from 3k to 4500k RPMs at what speed and in what gear? Any mods, beyond your 242 and the mythos of what mods (equipment, tune) may be on a Group A 242 Flathood or not?

The Turbo 240s continued to pull. The sinking-into-the-seat back feeling at the chest center from 60 MPH upward in fourth gear and with overdrive on.

None had the variable timed overhead cam and all had the large catalytic convertor and the few I was familiar with passed CA and MO state emissions handily. None were new, either.

Mind you, an all stock well-cared-for and loved 1979 with K-Jetronic 242 or 245 is fast enough for me. As are the 1989+ factory stock and good or better tune 1989+ 240s.

The southern North America nation has rotten road surfaces. No need to go faster. Yet a need to maintain good tune, suspension, brakes, steering, and tires. Better out west, though. Yet the posted speed limits are fast enough for me.

Watch that off the line stuff from stop signs, lights, and roadway on ramps.

An acquaintance in his 1979 VW Sirocco, with K-Jetronic, after we up tuned it drew the ire of a California CHP in the San Francisco North Bay. He was very pleased, using my tools, of which he may still have a few, of renewed acceleration. Timing belt, water pump, cleaned up the electrics (poor grounds, and loose power connections), new air filter and more. Be nice to adjust the CO as it had been turned rich at the air fuel control unit.

I was advocating emissions tests he needed to pass soon and improved fuel economy. The catalytic convertor was fine. I was protesting his heavy foot action as he was hot dogging the poor VW Sirocco after hour days of tuning efforts. The ignition timing was off, also as it somehow advanced. He also complained of flat top end power. The thing was K-Jetronic after all.

Sorry to digress again.

I really want a 242 again. My fave 240. So, I'm envious. Meanwhile, the 1992 240 GL moonroof gastet replacement leaks with the cheapo Volvo OEM 240 moonroof rear and front gasket offering. The 1991 240 has the factory installed and all is aces. Leaks on the passenger seat. I'll poke the drain holes again at any rate.

Digressions, digressions.

Sure Happy it's Thursday!

Jacked up on the Earl Grey Tea, Boyeeeeeeee, with hunny and milk.
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Especially in older cars, things have often been changed. I’d start out by confirming what gear you have. Jack up rear, mark driveshaft and tire. Make one tire rotation and count DS rotations. 3 3/4 = 3.73, a little more/less than 4 is 4.11/3.91. Lots of online calculators that with rear gear and tranny top gear ratio and rear tire size will calculate rpm for you - or just work through the units. Do the MATH - determine what you need to hit your target. Mine - 3.55 gear, .625 5th, 235/45/17 tire = 2060 rpm @ 70mph.
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82 242-6.2L; '17 Mazda3; '16 Crosstrek

The rear in your previously auto car would be a 3.73. An M46 car of your year would have had a 3.31. Earlier 240's used a 3.91 (what my 1980 M46 245 has). A 3.31 rear leaves the 240 gutless so if that will bother you but you still want lower highway rpm I'd look for a 3.54 - found as the regular rear in 260 models. Otherwise you'll either need a later 240 M46 rear -- or a 1975 164 for a 3.31 - Dave

"3k RPM at 70."

In third gear maybe??



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Art Benstein near Baltimore

If at first you don't succeed, skydiving is not for you.