Racing tranny gearing

[stubble88]

I’ve got this racing trans
I am completely lost when it’s comes to the gearing and just trans stuff in general.
Rebuilding my 3.2 motor and going to 3.4
Race car going back to street/canyon driving.
I believe it has all the billet stuff inside with lsd.
Receipts says it has a guards transmission with 2.000(17:34)
Pretty sure it’s a tall 1st gear like 60 mph stuff.
I’m looking for recommendations on what to do.
Get another trans? Or just swap some gears out. I have no idea what’s involved.
I have the build receipts from ASSE Motorsport.

[stubble88]

IMG_55181729867942.jpg[/img]

[Matt Monson]

What does it say about all the other ratios?

2.00 is normally a 2nd gear ratio. It's not crazy short, but depends on the rest of what's in there.

[stubble88]

Originally Posted by Matt Monson

What does it say about all the other ratios?

2.00 is normally a 2nd gear ratio. It's not crazy short, but depends on the rest of what's in there.

Here are the other trans recipes over a couple years

[Classic 911]

Hi,

Here’s my 2 cent’s

I would open the trans you got and get a complete overview over whats what and then go from there.
You might get lucky with the trans you have or you might find that it has les than favorable ratios and other costly bits and pieces that needs attention.
It is real important to decide on how YOU are going to use the car, not any one else, and most importantly match it to the engines powerband.

I am currently building a full street/ canyon carving box and to date, before it’s completed, has a price tag of $17.000.

The pics shows what I found to be best for my engine and use.





Sent from my iPhone using Tapatalk

[PeteKz]

You have an 8:31 ring and pinion. That's good for a street car. As Matt said it depends on what's in there now, but you may be able to just change 5th to a low ratio (higher gear) to get lower cruising RPM on the highway. You will have to look up the part numbers on those receipts to see what gear ratios are. Or you will have to do something like putting it gear and rotating the engine and counting the number of wheel rotations to engine rotations in each gear to compute ratios (and account for the 8:31 R/P ratio).

[Matt Monson]

OK,

I'm going to take a stab in the dark here. This is what I think you've got in there.

2.00
1.684
1.318
1.117
0.962

Regards,

Matt Monson
Guard Transmission LLC.

[stubble88]

Originally Posted by Matt Monson

OK,

I'm going to take a stab in the dark here. This is what I think you've got in there.

2.00
1.684
1.318
1.117
0.962

Regards,

Matt Monson
Guard Transmission LLC.

So it’s almost like I don’t have a 1st gear. Right? Should I just run it like this? Or am I going to be missing out on a lot of fun with my new 3.4?

[Matt Monson]

Originally Posted by stubble88

So it’s almost like I don’t have a 1st gear. Right? Should I just run it like this? Or am I going to be missing out on a lot of fun with my new 3.4?

That's a race box with what we call an active first. It would be fantastic somewhere like Daytona or Cal Speedway. The challenge of it is 1st off the line is a bit tedious. You could put a stock first and second in there and it would be pretty good for all around hot rodding.

5th is short for highway cruising, so you might want to change that to stock too.

[stubble88]

Ok. I’m rebuilding my motor. So would you say Ide be capable of swapping gears on a trans? I have no idea what’s involved in that yet.

[TimT]

The track you are running at dictates what gear pack you need.....

Lime Rock is very different from Road America or Daytona...
and a 5th that lets you cruiseat lower RPM..

[stubble88]

Originally Posted by TimT

The track you are running at dictates what gear pack you need.....

Lime Rock is very different from Road America or Daytona...
and a 5th that lets you cruiseat lower RPM..

The track is street and canyon driving.

[Matt Monson]

Find Pete Zimmerman’s 915 wiki and start reading. You’ll have to decide for yourself if you are able to do it, but many members here have done them over the years.

[stownsen914]

Tall first gears are great for racing where you want 5 usable track gears. I've had a tall first in two different racecars and am putting one in my 911 racecar. I love a tall first ... once the car is moving. A bit of a pain to get rolling. No way I'd use that in a street car.

[stownsen914]

Originally Posted by stubble88

Ok. I’m rebuilding my motor. So would you say Ide be capable of swapping gears on a trans? I have no idea what’s involved in that yet.

If you can do a motor, you can do a trans.

[PeteKz]

Originally Posted by stubble88

Ok. I’m rebuilding my motor. So would you say Ide be capable of swapping gears on a trans? I have no idea what’s involved in that yet.

Yes. It's just a box of gears. If you can rebuild an engine, a tranny is a piece of cake. You will need some special tools, such as circlip expanders. Since you do not need to change the R&P, you don't need to worry about setting up that combination. The other gears slide on and off the shafts. Some pressing may be necessary.

[Bill Verburg]

I hope that Matt is off on his wag, if he's right that is one truly screwy trans

[Matt Monson]

Sorry. that was dyslexic typing. 1.381, not 1.318.

And it's 24:28, not 23;27. 1.167.

[Bill Verburg]

better but still very odd



here's an SCRS for comparison, this would look even better w/ the SCRS 's much higher rev limit

[Matt Monson]

You’ve still got 4th wrong.

And not really odd when you’re really racing versus bench racing. They used a slightly taller 5th than “optimum” so that it was tall enough for the couple times a year the POC raced at Cal Speedway/Fontana. And they used 1st on track through the slowest corners, something you can’t do with SC-RS ratios. Frequently road racing ratios are substantially different than your optimized drag racing acceleration ratios. They actually involve analysis of real top speed and corner speeds. Aase used to build dominant AC cars for POC and frequently used something close to what I’ve posted.