Kamaro

Hi all, I just got my newly built 1971 Firebird Formula dyno tuned tonight, it did relatively good at 468/421 hp/tq (attached the dyno screen capture). The engine was built by me in my small garage using a stock L92 block with TSP 416 stroker kit, and a pair of GM LS3 cnc heads, Brian Tooley custom cam and stock everything else. The transmission is a Performabuilt stage 2 4L60E with EZ-TCU box. The weather was HOT in the dyno place (temp was around 105*F with humidity not less than 80%), so I think the engine did good. What do you guys think after looking at the dynograph? how many hps do you think I can get with better intake or heads?

Here is a youtube clip of the dyno run :

flintwrench69

iTrader: (11)

What's the rest of your mods? Intake? TDs? Compression ratio?

Kamaro

Everything els

Kamaro

Everything else is stock, the CR is 10.7 with a 92 octane gas.

flintwrench69

iTrader: (11)

Well I just got my 416 LS3 running, it made 485 & 457 & IMO that's lower than I thought it would be. That's why I'm curious what the rest of your mods are. Like piston type, exhaust, cam size cuz that stuff can't be stock. This is my setup:https://ls1tech.com/forums/dynamomet...ls3-today.html

1989GTA

What stall converter are you running? Do you have information on the camshaft?

blk00ss

iTrader: (66)

So everything else means, stock manifolds, and exhaust? Mmmk

flintwrench69

iTrader: (11)

Exactly! Without knowing all the details its hard to say. 10.7:1 CR? Must have dished pistons then. If he has flat tops it would be more like 11.7:1 I'd be pissed though especially when some stock stroke ls1s are making that!

1989GTA

Like you guys are saying, without the rest of the story it is hard to make a judgement.

03EBZ06

There are ALOT of unknowns from this post. Please post up better details about your engine.

Kamaro

Sorry guys for not posting the whole engine specs, I had an issue with my browser that I couldn't edit my post. Here are all the info about the engine :

-L92 block
-TSP 4 in. crankshaft and wiseco -5 pistons
-GM LS3 heads that are lightly CNC ported (casting 88958758)
-BT cam 239/250@.050 with 113+3. (I think 6.02/6.20 lift but not sure)
-1 7/8 LT headers with turbo mufflers (trying to keep the noise level down)
-stock LS3 intake
-stock LS3 TB
-stock LS3 injectors/fuel rail.
-stock LS3 accessory drive system.
-stock LS3 rockers with trunion upgrade.
-stock LS7 lifters.
-FTI 3000 RPM torque converter.
-9 in. rear end with 3.50 gears & Detroit Trutrack.
-MAF tuned using stock LS3 sensor.
-The dyno place was hot like hell, more than 105F and waaaay too humid.

Ls-x

iTrader: (3)

can you give as more details about the air intake and exhaust sizes and how the setup look like and if you can get as a photos it will be nice.

thanks

Kamaro

The air intake is a simple 4 in. aluminum tubing bent 90* with a K&N cone open air cleaner, the exhaust is a full 3 in. front to back with LT 1 7/8 headers and Summit Racing turbo mufflers (different than the mufflers in this pic).

redbird555

iTrader: (14)

I personally think this thing even with an auto should be north of 500whp. You're in stock cube cammed ls3 territory with LESS torque. Bad weather or not that is a little low imo, i would take it to the track and see what she traps and go from there

1989GTA

I have to agree. I think you are low to but the dyno could be part of that. Like has been said many times take it to the track and see what she does.

Kamaro

The local truck will open for test and tune in a few weeks, I'll see what it can do in the 1/4. So for this engine in a 3500 lbs car, what shall I expect in terms of ET and trap?

kinglt-1

iTrader: (26)

was the converter locked or unlocked during the pull? Unlocked then those numbers make sense.

BODUKE

Dyno is for tuning, don't get caught in the dyno numbers. Take it to the track. I think with traction low 11s.

Jimbo1367

He's got LS3 heads not TFS or AFRs.

FLYZNTN

I don't see any issues at all with the numbers especially since ambient temps were blazing hot. Put it on the dyno when it's 50 degrees outside and it wouldn't shock me to see the exact same car pick up 50-60 rwhp.