First day at the drag strip working out the bugs

[vanrah]

Greetings Jim & all; Don't we wish we could be back in that warm weather. A hot day at the drags, the smell of burnt rubber & cooking burgers on the grill! At Byron Ill., my favorite drag strip they're always grilling burgers & the smells entwine. Anyway I had time to read some this morning & was interested in you first outing. When you say a bigger torque converter, you mean a higher stall speed. Generally a bigger (size) converter means lower stall speeds. And again generally a smaller converter means higher stall speeds. I'm a great fan of challenging nearly everyone with a hot rod to a drag race & my usual bet is a beer! I've drank free sometimes & did some buying over the years. But the beer bet has made me many friends, no one is out much money. So if we raced I'd be buying the beer as my best is a 12.47 @ 111 MPH. Oh my converter is a 2100 RPM stall as back roads are my focus - theme. Drag racing & Auto X come after the street - road priority. Enjoy & good luck, you'll make the 11's, Ole' Bob.
Ps: I'm curious what are your cam specs? And what heads are you using?

 

[Jim hopper]

Yes I mean a hire stall speed and smaller converter

 

[Jim hopper]

Dont no cam specks but heads are aluminum lt1 fast burn port matched and polished just asked my Builder for all my spec's he has to find them

 

[motorheadmike]

It dynode at 475 it needs a bigger torqconverter!!

If that was at the crank it would be putting about 380 at the wheels (20% driveline losses). Your trap RPM would be extremely misleading to the trap speed shown on the timeslip - and since we don't know this, we cannot confirm anything to support the 475hp claim. So with a tight converter and lower numerical gearing/tall tires you may be way below peak power through the beams.

When we ran our "stock" LS1 Camaro it was punching 110mph through the back end - which is right in the 350hp range (the high-end for the factory LS1 ratings in Vettes/GTOs - given there were no real changes). The secret? Gearing. That car had 4.10s in it and a 27" tall tire - it was trapping just past peak power at 5700-6000rpm if I remember right. It was doing 1.9 60' times on street tires with the stock 1600-1800rpm stall.

Too many folks shift at "peak power" when they should be shifting past peak power at an engine speed about equal to their RPM drop between gears (which is dependant on trans gear split and the efficiency of the converter) to take advantage of power under the curve (the most area) between MBT and peak power - this gives one acceleration.

 

[lilbowtie]

It dynode at 475 it needs a bigger torqconverter!!

Don't put the cart before the horse - it's the whole combo that has to work together. The carb, intake, runner volume, CID, compression, cam, convertor, and rear end all have to complement each other. When they don't - performance isn't optimal. MPH tells the story on HP and the convertor isn't going to change that.

 

[UNGN]

109 mph is actually a couple mph slow for a 88 mph 1/8th mile (and that 60ft), so it may need a converter for a better 60ft, but it seems to be missing something uptop, too. Looser converter generally bring trap mph down, so the top end problem could get worse with a converter swap.

What rear gear are you running? What rear tires are those? pressure?

What is you best 1/4 mph?

 

[Jim hopper]

109 mph is actually a couple mph slow for a 88 mph 1/8th mile (and that 60ft), so it may need a converter for a better 60ft, but it seems to be missing something uptop, too. Looser converter generally bring trap mph down, so the top end problem could get worse with a converter swap.

What rear gear are you running? What rear tires are those? pressure?

What is you best 1/4 mph?

That was my best time slip and it has 410's whith a spool dont no tire size right now and I'm gowing thru the traps at 6200rpm remember it still a work in progress have tofinesh getting the bugs out of it it rains hear so much that we had a total of 8 race days and I dident go to all of them so can't wait for summer to come back so I can get more runs in I think I ran the car 3 times

 

[UNGN]

That was my best time slip and it has 410's whith a spool dont no tire size right now and I'm gowing thru the traps at 6200rpm remember it still a work in progress have tofinesh getting the bugs out of it it rains hear so much that we had a total of 8 race days and I dident go to all of them so can't wait for summer to come back so I can get more runs in I think I ran the car 3 times

If you are only running 26" tires you should switch to 28" tires, before switching to a looser converter.

Going the through the traps at 6200 RPM already, switching to a looser converter will slow you down, unless the cam you don't know the spec's to is a solid roller.

Because of the fall of of mph from the 1/8th mile to the 1/4. you appear to be over your HP peak through the traps.

 

[Jim hopper]

It's not a roller motor

 

[fleming442]

Who doesn't "no" what tires they have on when they go to the track?