Help With Battery for 81. Looking to save weight
06-22-2011, 01:23 PM
#1
Racer
Thread Starter
Help With Battery for 81. Looking to save weight
Looking at getting more speed/HP out of my 81 street car so I've begun to do things to improve performance. I know supercharging is the king but at 5 to 6K I could buy another 928 for that. I would like to get the car to be close to an 85 model with the 239 HP so I need to find 20HP or so.
Anyway 1st things first 928int exhaust, no cat (don't need emmissions), rodger's x pipe has been my first step.
Next will be K&N as well as probably some headers. I've also read on the forms about putting in a lager TB but looks like there is not an aftermarket "plug and play" readily available (if there is let me know
)
So going to try to save some weight too. Since I got rid of the cat, I can delete the air pump as well as the belt to the smog pump on the car so that should be good for a few ponies. Rear sun visors are gone, and spare is replaced with a can of "fix a flat". Since it's a street car I don't want to go too far, just the simple things that will still allow me to compete in concorse type events with the car.
The next item has to be that monster of a battery. I have a porsche battery in the back. I've read the posts about the batterys already and searched but didn't really answer the question. The optima batteries are great but it involves mod to the wires and possibly the battery box that I don't want to get involved with.
What choices are available (manufacturer and part number) that would be a direct plug in and not require any mods to the wires and battery box?
Also any other performance or weight savings suggestions would be great.
Anyway 1st things first 928int exhaust, no cat (don't need emmissions), rodger's x pipe has been my first step.
Next will be K&N as well as probably some headers. I've also read on the forms about putting in a lager TB but looks like there is not an aftermarket "plug and play" readily available (if there is let me know
)So going to try to save some weight too. Since I got rid of the cat, I can delete the air pump as well as the belt to the smog pump on the car so that should be good for a few ponies. Rear sun visors are gone, and spare is replaced with a can of "fix a flat". Since it's a street car I don't want to go too far, just the simple things that will still allow me to compete in concorse type events with the car.
The next item has to be that monster of a battery. I have a porsche battery in the back. I've read the posts about the batterys already and searched but didn't really answer the question. The optima batteries are great but it involves mod to the wires and possibly the battery box that I don't want to get involved with.
What choices are available (manufacturer and part number) that would be a direct plug in and not require any mods to the wires and battery box?
Also any other performance or weight savings suggestions would be great.
06-22-2011, 01:40 PM
#2
Burning Brakes
Most fellows around here will tell you to nix the K&N. If you want, I have one off my 87 that I don't use because of this advise. fairly expensive new. pm me. Good luck with teh HP. I have one too, so looking forward to your details.
06-22-2011, 02:21 PM
#5
Rennlist Member
The platinum wires in a MAF-equipped car have a burnoff cycle after each shutdown.
Why foul them further with oil from an oiled air cleaner?
Probably doesn't matter on non MAF cars. To performance either. Removing one today from a 944, it and its new oil replacement kit going to trash can.
Why foul them further with oil from an oiled air cleaner?
Probably doesn't matter on non MAF cars. To performance either. Removing one today from a 944, it and its new oil replacement kit going to trash can.
06-22-2011, 02:32 PM
#6
Drifting
The air pump feeds the cat. With that gone it serves no purpose. Headers will help your car a lot and they aren't that expensive. Used ones come up for sale from time to time.
I wouldn't fool with a bigger throttle. I'm making 270whp through the stock one.
I wouldn't fool with a bigger throttle. I'm making 270whp through the stock one.
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06-22-2011, 03:20 PM
#9
Burning Brakes
06-22-2011, 04:04 PM
#10
Racer
Thread Starter
Interstate MTP91 is the common replacement at 41 lbs 
There has to be a better option then this!
BTW am I correct in roughly every 100 lbs you loose = .1 second in the 1/4 mile; or 10 lbs = 1 HP
There has to be a better option then this! BTW am I correct in roughly every 100 lbs you loose = .1 second in the 1/4 mile; or 10 lbs = 1 HP
06-22-2011, 04:27 PM
#12
Three Wheelin'
Odyssey 680MJ works great in my racecar. I only have to spin 4 cylinders (to start the car), but it's 10.2 compression. You might be good with 8.5 and 8 cylinders. Just keep the battery on a tender, unless it's driven daily.
I can't comment on running accessories, since I have none.
I can't comment on running accessories, since I have none.
06-22-2011, 04:59 PM
#14
Nordschleife Master
You are going to have a hard time making much HP with the 4.5L at 8.5CR... They are just not powerful engines. BTW, I have seen '85's make over 280rwhp... and over 300rwTq... They only had like little stuff done to them as well... Things like RRFP and bigger (Ford?) injectors... Again, I could be wrong about the mods, but they were mild at best. Car had an exhaust, but I think kept the factory "headers".
NOS is probably the cheapest option but MUST be set up correctly to keep from burning up even the 4.5L motor.
NOS is probably the cheapest option but MUST be set up correctly to keep from burning up even the 4.5L motor.
