xsocaltrashx

Looking for a tall 0.73 or even a 0.68 gear. If anyone knows where to find one please let me know. Thank you!!!
I have a 948 ls1 swap with a ROW 0.83 and highway RPMs are terrible. I'm pushing like 3k rpms at 70mph. HELP!!!

V2Rocket

FYI the .73 will only drop you a few hundred rpm.
3k might turn into 2600.

Dan Martinic

That sounds about normal, no?

xsocaltrashx

hmmm, so whats the best solution here to get a lower cruising rpm? I think that's about right. It's been awhile since I've drove the car. I mean whatever I can do to get the rpms as low as possible when on the freeway. Cause right now its a little ridiculous. Addict I think at 70 Im like at 3-3200, Ill have to drive the car and check again.

V2Rocket

what's the problem, just noise?
my Impreza cruises 3200 or so at 70 too.

Dan Martinic

xsocaltrashx

Just seems a little ridiculous and a lot of extra wear and terrible gas mileage to run these engines while cruising at 70 at 3200rpms. Goodluck travelling far distances. Also the car tops out at like 110 or so because the engine redlines at 5300 rpms. I never did upgrade the L33 engine I dropped in the car to achieve higher rpms, something I might end up doing, either that or selling the car.

Paulyy

Like i tell everyone else, You dont buy sports cars to be economical.
Yes the newer stuff is very much now eco as modern engine and electronics.

For it's age the 944 is pretty good. If you want better economy, Start looking at ECUs, sequential injection ect.
Playing with gear ratios is just not necessary imo.

Kurt R

Are you guys missing the part where he says he's swapped in a GM L33 V8?
My truck, running the same basic engine, is barely at 2000rpm at 70.

Paulyy

I missed it.
But also having a better ECU than the factory one (depending how old it is) can also help with said issue.

Dan Martinic

I've never owned a V8.. I figured they turned fewer rpms but wow that's a big difference.

As for fuel economy, word on the streets is that NAs get superstar mileage... like 400+ miles per tank in the city? If so, why would the turbo, driven conservatively for the intention of a decent tank week (no WOT, little boost, etc), be so much worse? Is it the lower compression?

Paulyy

Generally speaking, Turbochrged cars are just as economical and or better than N/A these days.
But yes, turbo lag & Low comp has a play in it.

Dan Martinic

V2Rocket

just to clarify, the type of engine has no bearing on RPM and speed...
a V8 driving a 951 gearbox is running the same RPM as a 951 engine would, at the same MPH and tire size.

but you should be able to tune the ECU or your foot to get good MPG still.

Dan Martinic

Yes, I've been thinking about this: I've driven many small-engine 4 cylinder cars some that would rev quite high all around yet still get fantastic mileage; and even though they rev lower, V8s are known to use more fuel. In fact, USA government figures show an 88 Porsche 944 at 20mpg combined https://www.fueleconomy.gov/feg/bymo...sche_944.shtml while an 88 Corvette is rated 18mpg combined https://www.fueleconomy.gov/feg/noframes/4123.shtml.

Maybe revving higher would lead to *better* mileage for that V8: you'd be pulling less vacuum and running under less load. Simply spinning isn't what is burning the fuel; I think it's the load, no?