overhere

iTrader: (2)

i have a cam only lq9 6.0l blowthru C&S carb. i had a D1SC on the car running 9lbs of boost. i switched to a tc78 .96 ar turbo set up now running 11-12psi. flipped truck manifolds, 2.5" hot side to turbo, 3" cold side threw intercooler (didn't have with d1) and 4" down pipe dumped in front of tire. the car has been 5 mph faster but still e.t. .13 slower. during the swap ive added an intercooler and swapped from 3.73 to 3.27 gears. other than that everything is the same. on the 142mph pass i added 2* of timing over the procharger setup. 14* to 16*. i know i need a transbrake (going in over winter) to drop my 60ft. but i was hoping to run a little faster with the turbo any opinion's?

D1SC 9psi
60ft --- 1.507
330 --- 4.128
1/8 --- 6.312
mph --- 112.99
1000ft --- 8.198
1/4 --- 9.815
mph --- 137.74

tc78 11-12psi best et
60ft --- n/a
330 --- 4.320
1/8 --- 6.468
mph --- 115.10
1000ft --- 8.320
1/4 --- 9.951
mph --- 131.13

tc78 11-12psi best mph
60ft --- 1.732
330 --- 4.413
1/8 --- 6.597
mph --- 113.57
1000ft --- 8.467
1/4 ---10.047
mph --- 142.47

98TA6.0

iTrader: (42)

as you know turbo boost pressure correlates with load and supercharger with RPM. in a car without a T brake or 2 step the SC car will get to the tree first most of the time as they have more "grunt" and turbos need load to get the ball rolling. i would say you will pick up alot more with the T brake and 2 step later on. Also a larger back half on the turbo will help you down the line when you wanna put more in it. the .96 is almost too small for a 5.3 in most cases. also you should take a look at your cam profile. turbos dont favor alot of overlap where as SC cars can get away with a few extra degrees. post a detailed list of your combo so the experts can give you a much better answer. Also is the TC78 setup heavier? just curious

overhere

iTrader: (2)

stock lq9 6.0l
.232/.240 .595/.608 115lsa cam w/ upgraded lifters and springs
vic jr intake
c&s carb93 octane
50/50 water meth
tc78 .96 ar
3.27 gears with 28" tire.
th400
it was 3000lbs with me and the D1sc haven't weighed it since, im guessing really close to the same, removed long tube headers, dual 3" exhaust, with twin bullet mufflers. but added intercooler, and more coldside piping. d1sc only had about 1.5ft.

ive been doing alot of searching and i kinda found the same thing that the .96 ar might be choking it. this is my first turbo so i am learning ALOT. i couldn't get it to build any boost on the line my foot brake would only hold it to 2k rpms.

Nitroused383

iTrader: (10)

The most important thing in drag racing is your 60' time. You've got a 9.6x in it at the same boost level with a 1.5 60'. Get a 2 step / trans brake and build boost off the line. Why didnt you up the boost on the D1SC, they have a lot of potential, about the same or more max power as a TC78 I bet.

skinnies

iTrader: (33)

Also what converter are you running? Just adding a 2 step should get you to leave in boost and 60ft a lot harder.

overhere

iTrader: (2)

ive always wanted to go turbo and i couldn't pass up the deal on the turbo, sold the d1sc and bought the tc78 the same day. also i figured the turbo set would be easier on the stock bottom end not having to spin the procharger and i thought i could make the same if not more power at the same psi but that dosn't seem to be the case.

im running a fti 3600 nitrous converter. i know it probably not ideal but its what i have right now came with my trans.

im just still disappointed in the results. even tho im not building boost right off the line with the turbo but once i get into it i have the 12psi alot sooner in the rpm range that alone i would think would net me a better e.t. over the 9psi at redline with the d1

skinnies

iTrader: (33)

Get a 2 step, it's all in the 60ft, the car has more mph and leaving in boost will help it also. No reason with a 2 step it shouldn't go 9.5's.

overhere

iTrader: (2)

i have a 2 step never new the msd6010 had one built in until i was told at the end of the day on my last outing the problem tho is my foot brakes wont hold the car. you can only set the 2step down to 2000rpms and my brakes will only hold to like 1900rpms the tires slowly spin and ive adjust the brakes and proportioning valve and nothing helped it might hold on a very stick track so im not sure if im going to make another pass this year with out a transbrake.

skinnies

iTrader: (33)

Sounds like you need a better converter then honestly.

overhere

iTrader: (2)

do you think once i get a transbrake the converter is going to hold me back?

is there anything else that might be holding me back? ive read more and more the .96 ar might be to small?

skinnies

iTrader: (33)

Yes the converter will still hold you back, I recommend calling PTC and getting a converter.

overhere

iTrader: (2)

ill look into getting a converter too.

could the cam be holding back alot of power? along with the .96 ar?

The Fugitive

iTrader: (6)

i would say pay the $75-150 to put it on the dyno and see where the turbo falls off at before switching it out, best to confirm the problem. Also check our backpressure I think they say 2:1 is ideal.

overhere

iTrader: (2)

ill look into the dyno, how do you check back pressure? do i have to weld in a bung ?