10 Second Club - Need Help !!! Something Doesnt add up

Ok let me know what you guys think about the combo we have and maybe you guys can help me? Let me start with listing the mods of the car

1998 forged 347ci LS1 motor
Texas Speed & Performance (TSP) lid With K&N Air Filter
Machine Ported throttle body
Hooker Ceramic Coated Long Tube Headers & Off-Road Y-Pipe w/cutout
LS6 Stage III Corvette Z06 ported heads
ported LS6 intake
UD pulley
Comp Cam X3-V2 606/608 112LSA, 236/240 camshaft
Comp Cam lifters
LS6 Oil Pump
Rollmaster Dual Roller Timing Chain
Scat Forged Connecting Rods
Mahle Forged Pistons
Hardened Pushrods
Stock balanced crankshaft
Flow-matched 42lb injectors
NX Nitrous system with the big selenoids with 4an lines nozzle system
Nitrous Outlet Dedicated Fuel System with 109 oct in it

Built 4L60E
Vigilante 4000 torque converter
Trans Go shift kit
B&M Aluminum Deep Oil Pan

Stock 10 bolt
3.73 Gears
Stock Suspension
QTP 27.5 X 11.5
Pro stars Drag Set up

We went to the Track and Of the Trailer we forgot to warm up the bottle and ran with a 125 Shot and Ran 11.01 at 121 with a 1.54 sixty then we Bump up the pills to 175 shot and the car only runs 10.81 at 124 with a 1.58 sixty. I figured that the car would have ran alot faster since this time around we shot 175 and we had the bottle pressure at 1000. What do you guys think I think there is something wrong and we should be running much faster I was hoping for 10.50s What do you guys think any suggestions?

Hrm...does seem a little off. Did you make any motor passes THAT day? If your only gaining 7 tenths on a 175 hit (if that 11.5 NA was that same day) I would say something's up.

Did you data log your run by chance?

Afr was at 11.8 on the 10.82 pass and timing was at 20*

went 11.91 on motor

You're blowing thru the converter or the tranny is slipping. With a 4Ljunkie tranny in a car that's making power (I would guess, that you're makign around 420 to 440 n/a to the tires and hitting it with another 175 on top of that puts you well past what one of those POS transmissions will reliably hold) I would almost always look at that first.

What was the RPM's thru the traps at what mph, and what diameter tire are you running?

Calculate your driveline slippage, and I bet you find the answer.

You're blowing thru the converter or the tranny is slipping. With a 4Ljunkie tranny in a car that's making power (I would guess, that you're makign around 420 to 440 n/a to the tires and hitting it with another 175 on top of that puts you well past what one of those POS transmissions will reliably hold) I would almost always look at that first.

What was the RPM's thru the traps at what mph, and what diameter tire are you running?

Calculate your driveline slippage, and I bet you find the answer.


Tire Size is 27.5 X 11.5
RPM was 6600
MPH was 123

how do you calculate the Slippage?

Take the tire diameter, multiply it by 3.14159 (pie) Take 1 inch larger then the tire for growth.

Take that #, divide it by 12 to get the rollout of the tire in feet.

Now, take the mph, and figure otu how many feet per hour that is (123 times 5280) and divide that by 60 to get the feet per minute.

Take the 6600 rpm, divide that by the rear end ratio, then take that # of axle rpm, figure out how many feet per minute the car should be going.

Divide the 2 and you get your slippage.

In your case:


123 mph = 10824 feet per minute

28 inch tire = 7.33 feet.

10824/7.33 = 1476.67 axle rpm @ 123 mph

6600 rpm divided by 3.73 = 1769.43 axle rpm

You are seeing 83% of what you should be seeing, therefore you have a 17% slippage.

You're definitely blowing thru something, either the converter, or the tranny is slipping. You should be seeing around 5 to 10%, even 10% is higher then I'd want to see.

ok so if we change to a better converter could we see better times or are we better off just swapping over to a TH350 but we are still on the stock 10bolt and I know with a break the 10 bolt wont last long what would be the best cost effective way of dealing with this? and if we do change to a th350 or a better converter what numbers could be expected from this set up out of a 200 shot? Goal is High 9s ? is that possible?

I'd start planning on a full drivetrain at this point, Th400, driveshaft, and a rear.

From what you've already done, I'm guessing (and it's only guessing) that the car has a bottom 10 in it (say 10.2) without adding any more power, just by swapping to a TH400/good converter/strong rear that can take it.

Throw more power at it, take out some weight, and you will be headed to single digit territority, as long as your tuneup is good, you probably can do it if the car leaves hard enough and it's not too heavy. Just spraying right off the transbrake is going to make a huge gain, enough so that you're gonna need a full 28 inch slick, etc to get down.

BTW can I Get 10sec Club added to my profile!!!
LOL

Going to swap out to the TH 400 and Upgrade to the 12bolt.

If you still find that you're having issues with the slippage after installing a built Th400, next step has got to be the converter.

If you still find that you're having issues with the slippage after installing a built Th400, next step has got to be the converter.

if he goes to th400 he has to get a new converter

How much does your car weigh? With a 175 shot, your trap should be at around 130.

Also, Vigilante converters are known for being alot looser than advertised. You're probably blowing through the converter like JL stated. Usually, a super loose converter + n20 = crappy ET and mph.

if he goes to th400 he has to get a new converter

Generally, this is the case yes. But, I know a couple people that made a converter for a 4ljunkie work. Had to send it back to the converter company and get the converter output changed... wasn't worth it in the long run, but you can have a converter changed.

Best bet is to have one made, the gear ratio change, etc.etc. generally dictates needing something different.

How much does your car weigh? With a 175 shot, your trap should be at around 130.

Also, Vigilante converters are known for being alot looser than advertised. You're probably blowing through the converter like JL stated. Usually, a super loose converter + n20 = crappy ET and mph.

car weighs 3640

put ur car on a diet ... if u get the 12 bolt try lowering the converter size and spray out the hole... get that bish into the 9 sec

a diet and ported 92/92 would help alot also glad to see your gettin it done on a 10bolt

Wow

My car is full weight cam only on the jug and my times were on par with yours with the same size shot you're running. I have a vig2800 and my slippage on the top end is right around 6%.

Something isnt right. I would think with your mods it would have gone 10's on motor and damn close to 9's on a 175 hit.

What kind of converter slippage are you seeing on motor? Not that it matters but what did the car make on the dyno?

Your set up sounds a lot like a friend of mines(Detroitmuscle) and he has run as quick as 11.30 @ 120 with a stock bottom end LS2 with a cam similar to yours, 5.3 heads, SS4000, LS6 intake, 3.23 10 bolt, @3700lbs ect..