Too much gear? Not enough converter?

Race Ready Fabrications on March 14th 2011, 10:47 am

So after running my car this weekend with these new heads and cam it's obvious I've got some room to improve. Here's the setup:
D9TE block, two bolt mains, not filled.
4.390 bore
4.140 stroke, cast crank
Venolia 6.700 aluminum rods
Ross 14:1 pistons
Comp solid roller speced by Blake Cartwright
.786 .798
274 282 duration @.050
108 LSA
TFS raised port Mafia heads by Charlie Evans
Intake Exhaust(no pipe)
.100 70 52
.200 150 107
.300 238 150
.400 301 184
.500 344 215
.600 365 250
.700 376 262
.750 381 265
.800 385 267
Intake: new trick flow mafia intake.
1050 holley...for now.

The converter is a BTE 9" that only goes 4700 wide open on the brake. 9" rearend with a 5.00 gear. Seems to me that the converter should be more like 53-5500 and the gear a 4.30. Just need some opinions on where to start. I have fought sluggish 60 foots ever since I built this car and i thought all this new power would cure that. Apparently I've still got some work to do

Would it be silly to go ahead and change the gear and have the converter loosened at the same time? Or do one at a time?

richter69 on March 14th 2011, 11:08 am

what tranny and tire height? 1/8th only or some 1/4?

Race Ready Fabrications on March 14th 2011, 11:13 am

Glide with a 29" tall tire, 1/8th mile only

D. Sea on March 14th 2011, 11:14 am

With the kind of torque you are generating, use much less gear so you can run both 1/8 & 1/4.

i.e. I'm running 31" tires, 4.30 gear, glide and 9" 5500 converter. 1/8 mile passes are no issue while running 116-118mph and 1/4 mile runs = 7000-7100 rpm at 143-145mph.

3200#

richter69 on March 14th 2011, 11:18 am

Converter needs to be 5600-5800, I'd use a 4.57 or so gear.

Restalling a 9"converter to those numbers may make it not very aggressive up top.

Race Ready Fabrications on March 14th 2011, 11:41 am

D. Sea wrote:With the kind of torque you are generating, use much less gear so you can run both 1/8 & 1/4.

i.e. I'm running 31" tires, 4.30 gear, glide and 9" 5500 converter. 1/8 mile passes are no issue while running 116-118mph and 1/4 mile runs = 7000-7100 rpm at 143-145mph.

3200#

You run the same gear for both 1/8 and 1/4 mile?

Race Ready Fabrications on March 14th 2011, 11:44 am

richter69 wrote:Converter needs to be 5600-5800, I'd use a 4.57 or so gear.

Restalling a 9"converter to those numbers may make it not very aggressive up top.

So it wont pull hard in high gear? Please explain.

Is it still a good rule of thumb to shift a 1000rpm over the converters stall?

D. Sea on March 14th 2011, 2:20 pm

Race Ready Fabrications wrote:
D. Sea wrote:With the kind of torque you are generating, use much less gear so you can run both 1/8 & 1/4.

i.e. I'm running 31" tires, 4.30 gear, glide and 9" 5500 converter. 1/8 mile passes are no issue while running 116-118mph and 1/4 mile runs = 7000-7100 rpm at 143-145mph.

3200#

You run the same gear for both 1/8 and 1/4 mile?

Yep.... BBF Torque! Twisted Evil

I shift into High gear about the 330' mark

Curt on March 14th 2011, 5:52 pm

A good rule of thumb is to stall 200 rpm below peak torque and shift 200 rpm above peak HP. Sometimes you will need to loosen the converter up if you have a heavy car or one with a lot of parasitic loss in the power train. Loose wil also be more consistant, to a point.

bbf-falcon on March 14th 2011, 9:07 pm

I agree w/Damon. A 4.30/4.57 would be best for 1/4 and 1/8. I can't believe you picked a 5.00 gear for a BBF. Its not a high winding small block that needs a big gear to keep the rpms high. You will be amazed what a gear change will do. Good Luck brother Smile

richter69 on March 14th 2011, 9:09 pm

we run a 5.00 in our high winding small block deal............... Laughing

Race Ready Fabrications on March 14th 2011, 9:18 pm

bbf-falcon wrote:I agree w/Damon. A 4.30/4.57 would be best for 1/4 and 1/8. I can't believe you picked a 5.00 gear for a BBF. Its not a high winding small block that needs a big gear to keep the rpms high. You will be amazed what a gear change will do. Good Luck brother

The gear choice was more of just what I had laying around. I've got a set of 4.10's I can try, is that gonna be too much change?

bbf-falcon on March 14th 2011, 9:45 pm

It will be better than what you got imo. Use it until you get what you need.

richter69 on March 14th 2011, 10:07 pm

Race Ready Fabrications wrote:
bbf-falcon wrote:I agree w/Damon. A 4.30/4.57 would be best for 1/4 and 1/8. I can't believe you picked a 5.00 gear for a BBF. Its not a high winding small block that needs a big gear to keep the rpms high. You will be amazed what a gear change will do. Good Luck brother

The gear choice was more of just what I had laying around. I've got a set of 4.10's I can try, is that gonna be too much change?

get the converter happy it will be fine.

whatbumper on March 14th 2011, 10:40 pm

richter69 wrote:we run a 5.00 in our high winding small block deal...............

we run a 3.50 in our high winding small block Twisted Evil

Too much gear? Not enough converter?

Too much gear? Not enough converter?

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