Engineering the weak link into my project
08-13-2010, 12:02 PM
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Engineering the weak link into my project My first post here guys. Been lurking for a while (insert other newb comments).
The car is a back halfed (ladder bar) 87 Mazda rx7. Car will weigh >2200lbs without driver.
9" ford (currently with spool and 4.56) will have a locker and 4.10s
car will accept 31x13 slicks but will run with 295 DRs. Car always worked well at the track with slicks so the radials should hook in dirt.
Transmission is a powerglide stock case with 6 clutch hub, new pump, deep pan and sportsman transbrake valvebody.
Converter will likely have to be restalled as I think it's going to be tight.
Car will see alot of street time. Must retain driveability!
The powerplant is where I have thought of engineering the weak link. I can get 5.3s all day for $300-800 I have at least 5 in mind that I know will be there if I need them.
If I run a 5.3 with a 76+ turbo I think I could make great prower and still get plenty of miles out of it pushing it pretty hard. I would like to upgrade the cam and valvesprings and push 14-16lbs. If it spits the rods out in 2,000 miles I can just replace the motor and be driving again by the following Monday.
The car has run before. With a 406 sbc with 461 heads on ally 13.5:1 it ran 10.28 @ 128.
Any opinions?
The car is a back halfed (ladder bar) 87 Mazda rx7. Car will weigh >2200lbs without driver.
9" ford (currently with spool and 4.56) will have a locker and 4.10s
car will accept 31x13 slicks but will run with 295 DRs. Car always worked well at the track with slicks so the radials should hook in dirt.
Transmission is a powerglide stock case with 6 clutch hub, new pump, deep pan and sportsman transbrake valvebody.
Converter will likely have to be restalled as I think it's going to be tight.
Car will see alot of street time. Must retain driveability!
The powerplant is where I have thought of engineering the weak link. I can get 5.3s all day for $300-800 I have at least 5 in mind that I know will be there if I need them.
If I run a 5.3 with a 76+ turbo I think I could make great prower and still get plenty of miles out of it pushing it pretty hard. I would like to upgrade the cam and valvesprings and push 14-16lbs. If it spits the rods out in 2,000 miles I can just replace the motor and be driving again by the following Monday.
The car has run before. With a 406 sbc with 461 heads on ally 13.5:1 it ran 10.28 @ 128.
Any opinions?
08-13-2010, 12:11 PM
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ttt Dont think a stock motor will hold very long with 16 psi on it. Should do better with good springs and good push rods. Sounds like you know what you are doing. Also I good thing is the weight of the car being over 1,k plus less than most cars out here on the street. Good luck with her man...
08-13-2010, 12:31 PM
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Look into Skinnies set up, also a 5.3 tc78 rx7. Stock bottom ends will hold 15 fine so long as you stud the heads and use good gaskets. I have 3 cars here that have ls9 gaskets on and 0 water pushed at 15. One is even a 5.3 with the stock bore.
08-13-2010, 01:40 PM
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I appreciate the help guys. So if I have this straight I will need:
good rod bolts, head bolts/studs, springs, and pushrods, turbo cam.
What type of power is attainable from a setup like this? I figure the motor I had before made roughly 520-550hp. The car had 4.70 gear on 29.5x10.5ws. The car had a 1.35 short time, 6.38 @ 106, and 10.38 @ 128. I have also removed about 200+ lbs since then.
Any guesses on et?
I doubt the 5.3 @ 15psi willturn a 1.35 but I think it will haul *** on the top end.
good rod bolts, head bolts/studs, springs, and pushrods, turbo cam.
What type of power is attainable from a setup like this? I figure the motor I had before made roughly 520-550hp. The car had 4.70 gear on 29.5x10.5ws. The car had a 1.35 short time, 6.38 @ 106, and 10.38 @ 128. I have also removed about 200+ lbs since then.
Any guesses on et?
I doubt the 5.3 @ 15psi willturn a 1.35 but I think it will haul *** on the top end.
08-13-2010, 02:04 PM
#7
IMO, you wont need rod bolts unless you spin it high. Also, turbos are easier on rod bolts compared to N/A and Blown motors due to backpressure (99% of the time, rod bolts let go during the exhaust stroke since all the contents of the cylinder are evacuating).
