1970 caddy sedan deville(sinister) lq4 s475 turbo cam=)
#562
TECH Fanatic
Thread Starter
No, power wise feels the same, blows the tires off just as it did before,
Only reason I did the 5" to begin with was just cause I could, and I thought it would be "cool"..........yea not cool........
I think I will chop up the rest of the 5" stuff and make myself a "race" exhaust that dumps out behind the front tire under the pass side fender, maybe it will shoot fire!!!!
Only reason I did the 5" to begin with was just cause I could, and I thought it would be "cool"..........yea not cool........
I think I will chop up the rest of the 5" stuff and make myself a "race" exhaust that dumps out behind the front tire under the pass side fender, maybe it will shoot fire!!!!
#564
TECH Senior Member
iTrader: (7)
What is your R&P ratio, and tire height?
Andrew
#565
TECH Fanatic
Thread Starter
I did measure length of drive shaft, it's 69" u joint center to center. Gears are 3.73, and tire height is 28"
#566
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Thread Starter
#567
TECH Senior Member
iTrader: (7)
I definitely wouldn't put this thing on a chassis dyno. Dyno runs are done in direct drive (1:1 on whatever transmission you are using), so at 6500 engine RPM, the driveshaft speed will be, well, 6500RPM at a theoretical vehicle speed of 147 mph.
Keep all that in mind when you're doing highway pulls!
Andrew
Here is a tech bulletin from Mark Williams, but it does not go as high as 69"
https://www.markwilliams.com/servicebull/sb0049.pdf
#568
TECH Fanatic
Thread Starter
With the new information and assuming .250" wall thickness of the driveshaft tube, critical speed is just under 4700rpm. With your gear and 28" tall tires, you will reach that driveshaft critical speed at 105mph.
I definitely wouldn't put this thing on a chassis dyno. Dyno runs are done in direct drive (1:1 on whatever transmission you are using), so at 6500 engine RPM, the driveshaft speed will be, well, 6500RPM at a theoretical vehicle speed of 147 mph.
Keep all that in mind when you're doing highway pulls!
Andrew
Here is a tech bulletin from Mark Williams, but it does not go as high as 69"
https://www.markwilliams.com/servicebull/sb0049.pdf
I definitely wouldn't put this thing on a chassis dyno. Dyno runs are done in direct drive (1:1 on whatever transmission you are using), so at 6500 engine RPM, the driveshaft speed will be, well, 6500RPM at a theoretical vehicle speed of 147 mph.
Keep all that in mind when you're doing highway pulls!
Andrew
Here is a tech bulletin from Mark Williams, but it does not go as high as 69"
https://www.markwilliams.com/servicebull/sb0049.pdf
#570
TECH Fanatic
Thread Starter
Not sure, it was a surprise to me when I went to Mexico and accelerated quite brisk and it basicly felt like I shut it off.....did it 3 times and each time it was at 105......
Now, I'm not saying that the Speedo is calibrated correctly, but it is limited none the less......
Now, I'm not saying that the Speedo is calibrated correctly, but it is limited none the less......
#572
TECH Fanatic
Thread Starter
#573
TECH Resident
I have a damaged driveshaft from a '99 K1500. Let me measure the thickness. I seem to remember it being much thinner than the guestimated 1/4 thickness. Not sure how much difference that would make in the calculations.
#575
TECH Fanatic
Thread Starter
So what's the remedy? 2 peice drive shaft? Steel?
If I had done a two peice, that could have changed what I had to do my floor/trans tunnel .........
Don't want to have to stay under 105 on Mexican roads..........
If I had done a two peice, that could have changed what I had to do my floor/trans tunnel .........
Don't want to have to stay under 105 on Mexican roads..........
#577
TECH Regular
I'd call a driveshaft company like PST and ask them.
As I understand it the larger the diameter the higher the critical speed. The strength and weight of the material also affects the calculation.
As I understand it the larger the diameter the higher the critical speed. The strength and weight of the material also affects the calculation.
#578
TECH Resident
^^^ X2. They'll get you straightened out. The built-in limiter needs disabled also. Your driveshaft situation has me wondering about mine. Mine is steel. Wonder if it would be close to the right length for your car? I'll try to measure it and let you know. Then you could salvage yard one up.
#579
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#580
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Join Date: Feb 2016
Location: Whitinsville, MA
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Looking good, glad to see you're still going!! Question for you though - do you still have the old 500 and trans?? Accessories?? My plans have changed slightly in that I need to get it a running and driving car ASAP so I can start enjoying it. I decided a running driving project will be best for now. Let me know!! I may be interested in getting some stuff from you....