901 VS 915 TRANSMISSION, 450 HP V8 901 OR 915 Options

[RUDEPEST]

I have a 73 914 with a 450 hp v8 and have went through 3 transmission and am in the process of putting a 915 in it with a wevo side sift kit installed but I was told that I need to change the gears to work and was hoping that someone out there could help with the proper gears so I don't have to spend money learning which gears work.

thanks,
Keith

[bd1308]

that is the longest sentence i have ever seen (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif) breathe man......just breathe

[TravisNeff]

You need to flip the Ring and pinion around, aside from that you should be ready to roll. I am sure there are gearsets that are better choices than stock, but you shouldn't have to change it to get it to work.

[Aaron Cox]

are you asking if you need taller gears that would optimize your v8's drivability ?

[skline]

QUOTE (Travis Neff @ Mar 1 2005, 01:12 PM)

You need to flip the Ring and pinion around, aside from that you should be ready to roll. I am sure there are gearsets that are better choices than stock, but you shouldn't have to change it to get it to work.

(IMG:http://www.914world.com/bbs2/html/emoticons/agree.gif) He is right, the gears should work just fine but you will need to get the ring and pinion flipped and that is not a cheap endeavor. I have heard others say you can just run it upside down but logically thinking, what the hell difference would that make? I have always wanted to ask that question when someone says it.

[rick 918-S]

We've got to see this! (IMG:http://www.914world.com/bbs2/html/emoticons/aktion035.gif)


(IMG:http://www.914world.com/bbs2/html/emoticons/thisthreadisworthlesswithoutpics.gif)

[BIGKAT_83]

Running it upside down would be the same as flipping the ring gear and pinion. Its not that big of deal on a 915 to change. Its the 930 that takes all of the machine work.

Bob

[phantom914]

QUOTE (skline @ Mar 1 2005, 01:17 PM)

QUOTE (Travis Neff @ Mar 1 2005, 01:12 PM) You need to flip the Ring and pinion around, aside from that you should be ready to roll.  I am sure there are gearsets that are better choices than stock, but you shouldn't have to change it to get it to work. (IMG:http://www.914world.com/bbs2/html/emoticons/agree.gif) He is right, the gears should work just fine but you will need to get the ring and pinion flipped and that is not a cheap endeavor. I have heard others say you can just run it upside down but logically thinking, what the hell difference would that make? I have always wanted to ask that question when someone says it.

Scott,

Running it upside down would be exactly like flipping the ring and pinion as far as the direction the tranny would turn. I don't know what other issues would come up though such as where the lube would sit, how would you drain it etc..


Andrew

[skline]

So, I am thinking, if you run it upside down, you now have 5 reverse gears and 1 forward gear. What am I missing?

[bondo]

For 450 HP I'd say neither. You probably won't be happy with the 915 gearing, and by the time you change it you coulda had a 930. You may break the 915 too, 450 HP is stretching it. How long have your 901s been lasting?

[BIGKAT_83]

QUOTE (skline @ Mar 1 2005, 04:29 PM)

So, I am thinking, if you run it upside down, you now have 5 reverse gears and 1 forward gear. What am I missing?

Wrong you would have 5 forward and a reverse running a upside down 915 in a mid engine car.

[Aaron Cox]

QUOTE (skline @ Mar 1 2005, 02:29 PM)

So, I am thinking, if you run it upside down, you now have 5 reverse gears and 1 forward gear. What am I missing?

lets say the output shafts are turning clockwise......
flip it up side down and now they run anti clockwise



think long and hard scott (IMG:http://www.914world.com/bbs2/html/emoticons/ohmy.gif)

[RUDEPEST]

thanks for the replies. I have already fliped the ring and pinion. All you do is flip it over with no machining needed.
I haven't used the tranny to know what is wrong or not, but I want to be able to use first gear. The 901 tranny's first gear is like a granny low and I'm not into rock crawling my 914. A friend is a fan of the 901 and dislikes the 915 so he is trying to make me run the 901, but it just can't hold the HP.

Keith

[phantom914]

QUOTE (skline @ Mar 1 2005, 01:29 PM)

So, I am thinking, if you run it upside down, you now have 5 reverse gears and 1 forward gear. What am I missing?

Scott,

That's what would happen if you don't flip the ring and pinion or run it upside-down. You rotated the tranny 180deg when you moved it from rear drive to mid-engine, that's why it would run backwards. To fix, you flip the ring to the other side of the pinion, whether by re-installing, or by flipping the whole tranny.

Listen to Aaron. He's right for once. (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)


Andrew

[skline]

Ok, I get it now. This is a first for Aaron. Good boy!!!

[RUDEPEST]

The 901 trannys haven't broke but I can tell the two main shafts are begining to separate because the tranny starts making more noise. I usally swap them before explosion happens. After taking the tranny's apart you can tell explosion was going to happen shortly.


Keith

[Type 4]

To make a 901 last you need to swap out the intermediate plate for an Aluminum one, replace the two Bearings with brass roller retainers, with new bearings that have steel roller retainers. Where the intermediate plate bolts together remove the short studs and replace with thru bolts.

HERE IS THE MOST IMPORTANT PART

Let the gearbox WARM UP.
Dont apply full power with a cold gearbox.
iIf you do the above a 901 will handle 300hp.

[TravisNeff]

If a 915 has a vent at the top like a 901, your garage is gonna look a little sloppy flipping it over. I heard of running the tranny upside down, and one of the benefits is that most of the weight is now lower. Never did it, never saw it or whatever..

Oh, if you have a 915 with the later R/P 8.xx ratio instead of the 7.15 that will help (I think they changed to the taller ratio R/P in 74)

[Aaron Cox]

QUOTE (skline @ Mar 1 2005, 02:42 PM)

Ok, I get it now. This is a first for Aaron. Good boy!!!

whatever scott! how many times have i proved you wrong in your own garage?????

the gt rear swaybar? the stock rear springrate? the year fo door sill changes???? i know you remember those (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

bite me (IMG:http://www.914world.com/bbs2/html/emoticons/dry.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif)

[Andyrew]

Call Renegade hybrids... They have a solution for the 915 trani for gearing...

off their web site
"CUSTOM 3.1:1 TALL RING & PINION: The stock gear ratios in the 915 are rather low for use with a V-8. Thus, we offer our custom made, tall ring and pinion, which will dramatically increase your top speed in each gear. Installing this ring and pinion in a 915 transaxle will create ideal gear ratios for use with a V-8 engine.
"