forgedlt4

First run, i spun the tires on the dyno....


second run, i put some people in back for weight. made UNIMPRESSIVE numbers

NUMBERS: 531 rwhp and 629 rwtq. made PEAK horse power at 4500 rpms. i suspect valve float. doesnt matter.. i only did this as a before and after test. i am putting pistons in this winter, and i am doing some major head work.


the curve looks great until 4600, then it goes to ****... and that bothers me.

what's wrong guys?
spark blowout?
valve float?
sissy heads?

FYI, it's a 383 with home ported lt4 heads, single plane intake, blow thru carb, E85, GT42 T6 turbo, 4.5 inch exhaust.

oange ss

iTrader: (50)

operator error or tire slip, curves should cross at 5250 rpms

Silver408z

iTrader: (1)

^^^this

From what I understand your torque and hp curves should ALWAYS cross at 5250 rpm.

The Alchemist

iTrader: (19)

Guys, check the torque and horsepower scales, they are different, so look at hp at 5252, and torque at 5252 and they are the same.

Cam72aro

iTrader: (28)

Could be a lot of things wrong. Give us the exact run down on the build. Cam, what exhaust, etc. Could be a combination of many things.

black98ws6ta

iTrader: (77)

Boost level? Did the boost drop in the upper rpms? Measure backpressure? Intercooled?

forgedlt4

7lbs. boost was pretty steady throughout the pull.

no back pressure measurement.

no intercooler, it's blow thru

black98ws6ta

iTrader: (77)

Blow thru carb??

forgedlt4

yeah. im running a C&S blow thru carb.

I'll post more engine info when I get off work, and I am on a real computer. typing it out on a cell phone stinks.

Sarg

iTrader: (6)

Well, being non-intercooled, the higher the rpms the less efficient the turbo and the hotter that charge is going to get.

tc3

iTrader: (2)

hp = tq * rpm / 5252

forgedlt4

from everything i have read...blow thru carbs don't require an intercooler at these boost levels, since the fuel can pull the heat out of the airstream.

madmax4499

iTrader: (3)

your fine without an inter-cooler, find another dyno shop if your that worried about the #

forgedlt4

previously this motor made 400/400 rwhp and rwtq with a different cam, and lt4 intake. I changed to a single plane intake, and a smaller cam for boost.

what the rest of the motor is:
home ported lt4 heads, basically cleaned up castings, and gasket matched.
comp 918 springs
gasket matched Vic Jr intake
C&S Blow-thru carb, running E85
383 rotating assembly. fully forged.
11.3:1 compression
cam card:


GT42 turbo, T6 divided housing. Turbo headers, 4.5 in exhaust to about the tail shaft of the transmission, then it divides into dual 3 inch

gimmeluvin

iTrader: (10)

I like how you split the wastegate tubing into each side of the crossover. I did the same thing. I envy your exhaust system!

forgedlt4

gimmeluvin, these are a few pics I had on my photobucket:





I hope that helps.

Chicago TDP

iTrader: (3)

Very nice craftsmanship!

Where do you get your merge collector and tubing at???

forgedlt4

I wish I could claim I built the kit, but I did not. interia fab works in Arnold MO did all the turbo work.

It's all generic off the shelf mandrel bent stainless pieces on the hot side that were cut and fit to this kit.

bad6as

iTrader: (17)

very nice looking kit.
i think its your cam. to small

slow67

iTrader: (2)

Whats your ignition setup?