Trannys, hot rod engines and diffs oh-my

[sfdon]

Once again I reminded of the be careful of what you ask for conundrum.

Out driving rockminsters car today- 284 cam with m90 engine and 5 speed. Ported/polished with Turner chip.
So much torque that you rip through 1st gear in a heatbeat. Yet in 5th gear at 70mph you are loafing the engine on the freeway and off the cam. Can you imagine swapping a 3.25 diff in? You could do 145-150 mph and they would take your car away. I like a 3.25 in my 745i turbos- but note that max torque is at 2200 rpm not at 3000+ rpm
Just thoughts..

 

[x_atlas0]

With the 5 speed (OD box, I am assuming) it should be able to do 150 with the stock 3.45 diff. These cars aren't really gearing limited, I'd be more freaked out by the front-end lift at high speed.

 

[sfdon]

LOL- 150 in a coupe... can you imagine a gust of wind hitting you on the flank?

 

[61porsche]

I'll get you my pretty... and the little dog too.

Aww shucks ... CS, 130mph, 4speed, Zenith carbs, and cam:

http://forums.bimmerforums.com/forum/showthread.php?p=20332745#post20332745

With his wife in the car. ( She drives a new M6)

 

[shanon]

My brother has footage (somewhere?!) of his speedo wrapping passed the odometer on the big oval at Cal Speedway before he had to dive into the infield road course. The V8s would squirt away then he just ran them back down and passed them with a higher top speed, great stuff.

He was running a 3.5L w/ 275hp at the wheels, 5spd OD with a 3.91 LSD with a CSL air dam (critical) an no wing. Wish he had a GPS in there for an accurate MPH...my guess 140+

good times.

-shanon

 

[sfdon]

Yikes!!

Note to self- install airdam....asap

 

[RJRuiz]

Just installed a front airdam on my '72 CSi with Korman 3.5 Stage II / 5 sp OD / 3.73, front end seriously light at 130.

Have not had it flat our yet- but had plenty left at 130.

Ray

 

[pamp]

Light

For sure at speed, stock, my car got way light and "flying"...front end lift. Haven't had quite the balls to check this out now that I have a spoiler. RCMP have no sense of humor. I wanted to see what the car would do. Reminded me of when I ran a Datsun 240Z at this speed, no steering after 130 mph, scary stuff. My car has LSD and a four speed, ratios are not known by me, I had plenty of tach left when I backed down at 135 indicated.