looking for opinions

[Steve Wood]

A 3.73 will not spool as well as a 3.23 or higher because it will not load the turbo as much.  Too much gear multiplication .

[Scoobum]

We had a delay when the ONDR guys were in town last summer. I was talking to a gent in the staging lanes with a 63 Impala with a BBC and a blower hanging out of the hood. Off hand I asked him what rear gear he was using and he said a 3.08. The engine made so much torque that it would snap the slicks loose with any bigger rear gear.

[Scoobum]

Thanks gents my original thought was a 3.23
I speculated that the tire size and the weight would make it difficult to create load for the turbo.
Did some research on a gear set and with my 4series carrier the lowest I can get is 3.73
This would be great in the 1/8 but probably hurt me in the 1/4
I could always try a spool  this 12 bolt has 9" ends and 30 spline axles.


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Larry...3.73's MAY work...and this sounds like a match made in hell...but have a read. Norbs ran 3.73's with a 200...a 109 stock stroke...with a 2800 Precision LU...a 70 P Trim with a large exhaust housing...bigg er than an .83 Precision...an d would launch it off the trans brake at 20 lbs. Best of 10.3 at 134 with 34 pounds of boost. Car was full weight with air con.

[TexasT]

This is one of the reasons to go to a taller tire. Load that turbo up and let it eat.

[motorhead]

Can you get a custom ground cam for a Buick V6 these days?

[good2win22]

Can you get a custom ground cam for a Buick V6 these days?

Yes

[larrym]

This why I come here great discussion, Ideally I would run a lower gear to try and keep the car in its power band as long as possible 3.23 or even a 3.08 this would also help fuel economy lol.


If i went with a tight converter and the 3.73 would that load the motor more like Norbs did?


I had also thought of a custom cam or installing it slightly retarded to move the power band up the RPM so I could spin it past 6000 rpm with a tight converter I don't think my 60' is going to suffer too much with the 3.73.

[reality]

Seems like a lot of time and effort for little gain to me.
Lets try to put this in perspective
Your current car goes 11.30 now so just putting that entire drive train as is in the Vega theoretically will go 10.30 with no change. The 373 just complicate matters.


Didn't Dave Bamford use 456 gears in his record car.

[larrym]

You are right Ron I am probably over thinking this its a bad habit lol. The issue at hand is the narrowed 12 bolt I have has 456 gears in it I need to get those out, if I want to use the current posi carrier the lowest I can go is 3.73 with out a new carrier or a spool.


All the locals are screaming back half and tub it keep the 4.56 hahaha I'm going to be different just to piss them off small tire V6 single exhaust drive it to the track. 

[Scoobum]

Not sure about Bamford...you'd have to do some digging. Larry, I haven't got the IQ to figure out how that combo of Norbs' meshed together to work. Steve might be able to decipher it. If I were to drop my engine/trans into a Vega with my turbo and convertor I'd try a 3.23 or 3.08 rear gear...dependi ng on if I was running the 1/8th or quarter. Jeremy had a good idea. Call Dusty. Not only is he a wizard with convertors...b ut he's a helluva driver. Just type his name in on YouTube. He cuts some silly fast lites and runs stupid fast 1/8th mile numbers. He does/did hold the world record for the quickest single turbo car in a certain classification .

[reality]

Do it your way. worry about the small stuff later.

[nocooler]

Run some numbers http://www.tciauto.com/tc/racing-calculators/

6000rpm, 3.73, 26" tires with 8% slip is 115mph. 28" tires is 124mph

I think it's going to need something numerically lower.

[motorhead]

Run some numbers http://www.tciauto.com/tc/racing-calculators/

6000rpm, 3.73, 26" tires with 8% slip is 115mph. 28" tires is 124mph

I think it's going to need something numerically lower.

Rate of acceleration and RPM drop between gears is going to play a huge part in this.

As for the cam, get something real made - not a 20 year old shelf grind.  There has to be so much to be gained with improved lobe designs and valve events.

[larrym]

Alright so now that I have wasted everyone's time on gearing I pulled the cover and I'm styling it's a 3 series...
So I can go to a 3.08 if need be.


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[reality]

What gear is in it now? I don't think a 4.56 will fit in a 3 series.