TSP Level 2A-R (Larry's motor) Complete and Dyno tested.

Yeah that reminds me...the shift point. Your peak torque seems to be higher in the band, and since your engine planes off from 5500-6000, the only thing you lose by shifting higher is the time it takes to rev from 5500-6000, but would bring you out ahead in the end because when it does shift, your next gear will be closer to your peak torque.

You can figure out actual numbers with some formulas located at the end of TA's catalog for MPH and RPM with whatever gear ratios you have in the rear and transmission gears plus tire size.

You should check it out and do some calculating so you can get more exact numbers. :TU: You could figure out where your best shift point is with those formulas. You might discover you only need to rev it to 5700 or 5800 instead of 6000. Might shave some time off your ticket.

As far as your MPG, that's outstanding! If you were to back it down to 55 or 60 I'm sure you'd do a little better. Getting 15 or 16 MPG out of that 500+ HP big block is just NUTS!

There's some hopped up 350's that don't even do that well. I guess it's all about the combination and tune, eh?

---------- Post added at 03:01 PM ---------- Previous post was at 02:38 PM ----------

Very good points. I would like to add that with gas mileage that good, he could afford to get a steeper gear and higher stall, which would work hand in hand both at the strip and going down the road.

Higher RPM cruising would help the stall not slip so much, though he'd take a hit on MPG some.



With the gearing and stall Jim recommends, plus with switching carbs and putting slicks on it, opening up your exhaust, it wouldn't surprise me if you got into the low 11's, possibly even high 10's...

My brother's Challenger went from running 13.30's with 2 1/2" exhaust and 50 series street tires, to 12.60's by going with open headers and using slicks. Every little thing adds up.

I bet your Buick feels super strong on the road! You could just leave everything as is and leave well enough alone if you're happy with it. I don't imagine there's too many hot rods out there that can compete with you on the street (though obviously there's always someone who has something faster) for a stock looking muscle car.

 

It sounds like you had a good time at Cecil, you would have to look long and hard to find a quicker street car than what you have there.:TU:
I am wondering if you ran 1st 2nd and 3rd or 1st 2nd and 2nd over through the quarter.

Bob H.

 

You are correct Bob 1,2 then OD. 2nd gear with OD you get 4.31 Larry you might recall me saying this many months agop No need to use 26 inch tall slicks, short slick=less foot print.

TH375/400/475 3-SPEED AUTOMATIC
Axle Ratio ***4.88**** 4.56**** 4.10*** 3.73*** 3.55*** 3.42
Trans Ratio************************** Final Drive Ratio
1st 2.48 *** 12.10****11.31****10.17***9.25*** 8.80*** 8.48
Over 1.93*** 9.44**** 8.82**** 7.93*** 7.22*** 6.85*** 6.60
2nd 1.48**** 7.22**** 6.75**** 6.07*** 5.52*** 5.25*** 5.06
Over 1.15*** 5.63**** 5.27**** 4.73****4.31*** 4.09*** 3.95
3rd 1.00**** 4.88**** 4.56**** 4.10**** 3.73***3.55*** 3.42
Over 0.78*** 3.81**** 3.56**** 3.20**** 2.91***2.77*** 2.67

 

Larry,

Nice passes!!! I hope to race with you guys next year at Cecil.

 

I know what you mean about the lag Larry. I guess it would take a little practice to get it to shift at the right rpm. On mine the down shift is almost immediate, to bad it isn't the other way around.o No:

Bob H.

 

Video #4, listen to the rpm. It sounds like it leaves in the low stall and then right after the launch the high stall turns on? Ditch the switch pitch and install a fixed pitch, it needs stall speed it leaves like my moms wagon :shock:

 

I love the idea of a SP converter for street use. As long as you don't need high stall to be much over 3200, that is.

I wonder how far up Jim could bump a SP converter from 1800/3200 to possibly 2200/3600? But then you'd be messing with vane angle efficiency. Maybe in a smaller converter?

 

Sounds like a lot of work and money for a couple tenths that you will only notice on your once a year track visits... Seems the switch pitch gives a fair bit of enjoyment on the street as well. Not trying to be a wet blanket just a voice of reason...

 

I've been in that car and an 11.67 @ 115.49 MPH reliable street car is no joke. :TU:
That car runs flawless and knocks out pretty good gas mileage as it stands.

If you make it go faster you'll be looking at a roll cage, longer wheel studs and then your in the parts breakage danger zone. How many runs do you think the track will let you make under 11.50 as the car won't be legal.

The car is too nice to mess with any further. You have a fast street car, not a race car, enjoy it as it is now my friend. :3gears:

 

I'm with the others. I wouldn't ditch the VP converter for the sake of some small gains. Open headers and more rpm sure, but I wouldn't get much more carried away.

Devon

 

Ah, the voice of reason. All very true. The car certainly is just fine as is!

Diminishing returns kicking in pretty heavily now with any more upgrades.

 

With the advancements in torque converters now days it kinda makes the VP a dinosaur, I sent Larry a video from inside a car that has close to 600hp with a 3200 stall, th400, Gear vendors, 3.50 gears and that car cruises at 60 mph and 2000 rpm. I was a huge SP fan for many years but I couldn't keep leaving the et on the table when I went to the track.

Even with this combo Larry should of been sent home early, I wonder if its hurt or something.

---------- Post added at 03:24 PM ---------- Previous post was at 02:52 PM ----------

Larry, try it with this new calculator from Wallace Racing. I used it on the gold car and it came up with 10.89 and it ran a 10.80 so it is pretty close.

JW, is this the same one you used?
http://www.wallaceracing.com/hp-correction-quarter.php

 

How can that calculator predict that?



Not only that, the dream wheel calculators don't factor in frontal area... so the same numbers used for a car, are used for a dragster.

They make some assumptions and in my experience, usually over-estimate the HP available in a car optimized for drag racing.

Those same assumptions kill the calculation in a street car, with all it's compromises.


Case in point..

On a great day at the drag strip in 1996 with the GS (4100lbs race weight, 10" tires, 4.33 gear, 5000 stall converter, good setup) it ran 11.19 at 119mph. The air was 500ft, which around here is crazy good.

The calculators say 593 HP from the ET, and 554 from the MPH.

That motor on the dyno made 538 HP.. corrected to sea Level.

It was an iron head (260cfm) 462, 12-1 with a 308 cam, SP-1, Thermoquad 1000

The inaccuracy goes both ways, so I never much worried about them.

________

According to the drag times calculator, corrected to sea Level, your car ran 11.43 at 118MPH.

___________

We get into these discussions and it's human nature to spit out the ET your car ran one day, with great hook and mineshaft air..

You could only compare to someone who ran that day, next to you. Anything else is pointless. Too many variables.

I guess if the staging lanes were full of low 11 second cars that run 120mph, and drove there 200 miles getting 14mpg, I would be worried.

But I kinda doubt that was the case.

A hot GN maybe, but not anything with 8 spark plugs wrapped in 43 year old sheetmetal.

JW