67camaro02

Currently topping out @ around 125MPH with 28" tall ET Street tire TH400, 4000 stall and 4:11 gears rev limiter set @ 6500 and leaving off the TB. By my math this combo should be closer to 135.

1. Why is the MPH low? vert slipping?
2. Best way to pick up MPH? Lets shoot for trapping closer to 150
3. Wouldn't dropping to a 3 series kill my 60'?
3. How do guys run an 4.56 gear and 30 or smaller tire and still trapping so high? Spinning it way high or tranny?

edit: I'm bouncing off the limiter @ around 127 MPH going through the traps...I need to stay with a 27-28" tall tire (unless I switch to DR's but I don't know if they'll hook leaving off the TB @ 4000???) I also do not want to tub or mini tub

AutoRoc

150? I'd suggest 3.50 gears. 25mph will be achieved with a 325-350 shot.

Raise the limiter a few hundred? You're on the edge. it doesn't look like the converter is slipping too much, i could be wrong.

3.70 gears shouldn't hurt you BAD in the 60. My guess is .05 slower. If it's a bracket car, it might become more consistant and you wouldn't be touching that limiter....ever.

rskrause

What is the calculated rpm at 127mps? The difference between them is the converter slip.

actual rpm-expected rpm/expected rpm = % converter slip

Rich

67camaro02

@ 127 I should be around 6200 (calculated) and with the limiter at 6700 I should be able to hit ~136

In reality @ 127 I'm pinging off the limiter (6700 rpm and for 200-300')

Sorry, I mistated earlier I shift @ 6500 that is not the limiter

67camaro02

and I am debating about dropping to 3:73 which would calculate to 150 MPH but...from real world results that doesn't look like it would be enough. Is ~8% (100-(6200/6700)) considered acceptable slippage (word?)

The Engineer

So, what ETs are you running with those 125/127 MPH trap speeds? also, I assume those are 1/4 mile trap speeds?

WD

JakeRobb

A Vigilante converter with the 5-disc lockup clutch should add a few MPH.

EDIT: looks like they don't make it for the TH400.

67camaro02

10.70@124.3 on a 75 shot bouncing off the limiter by the 1000' mark. Yes 1/4 mile

So it sounds like dropping to a 3:73 gear is the best way in my situation to pick up the MPH? I thought for some reason that a 3 series carrier was wekaer than a 4 series. I also thought that it would be a significant negative impact to my 60'


As for a TC...the one I have I'm very happy with. Unless 8% +/- is excessive slip.

BTW...The converter is for N2O.

rock1501

I am running 410 gears also but with a 26 inch tire and I got through the traps right at 7000@127mph
I have a th400 and an ATI 5200 stall 8 inch race converter

I think you need a 373 gear for the spray as I will also when I spray this spring

T/A lt1

Yeah those numbers sound very close to mine. I run 123mph crossing about 6,400-6500rpms with 4.10's, 28" drag radials and a Th350. I am going to 3.73's next month once I get it running best N/A. Later Clint