LS1 and open headers... no go
 

Learned a valuable lesson today... after making a last minute decision to drive my car to the exhaust shop with open headers. So I have a new 347ci with a BTR stage 4 cam, LS6 heads and a T56. It was running on a start up tune that my tuner tossed on there to get me running. The tune wasn't spot on as it surges and bucks on the low end, lack of gear didn't help either. Anyway, so I take off... car starts running really bad. Missing, popping through the headers and wouldn't idle. I pull over and smell its running pig rich. Pull a spark plug and its black as can be... so they were fouled.

Called my tuner, he said not to drive it. The O2 sensors can't read with open headers because they won't heat up and are exposed to cool air from the back of the header. As a result the computer doesn't know what to do, other than increase fuel. I never thought of that...

So I rented a Uhaul car hauler and hauled it the the exhaust shop. Got the exhaust installed, fired it up and let it run for a few minutes. The idle cleared up and it ran perfectly. What a difference...

Now its at Intune motorsports getting a street and dyno tune.

Live and learn I guess... EFI sure is different than an old carbed SBC...

Re: LS1 and open headers... no go
 

Small price to pay for the lesson learned buddy. But i bet the beast was turning heads while doing it lol. When I first did my ls1 swap and needed a y pipe made..the car did the same thing so I just unplugged the o2 sensors and it ran perfect after that.

Welcome to efi..better gas mileage while making more power lol.Curious to see what power your car makes..btr stage 4 sounds wicked!

Re: LS1 and open headers... no go
 

Yeah I felt like a moron after that incident... definitely learned what not to do. EFI is awesome though. After the exhaust was installed it ran great, plus that throttle response is incredible.


After Scott gets the numbers I'll post them up... I have my TPI airbox connected to the motor so we are going to dyno it, then disconnect it and dyno it again to see if there is any power loss. If so then I'll order a cold air intake setup. But it has LS6 heads plus this BTR cam so it should make high 3's to low 4's. My tuner has a mustang dyno so the numbers are usually lower than a dynojet. It feels strong though... But I'll let you know what she makes.

Re: LS1 and open headers... no go
 

i also ran the tpi snorkel intake with my lq9 for a time, but felt it was holding me back after my initial dyno, so i installed a gto cold air intake, id be curious to see if my suspicions were right or weather the tpi intake is sufficient for a cammed/headed ls based motor.

Re: LS1 and open headers... no go
 

I'll post up the results as soon as I know.. He is supposed to do the street tune on Thursday, since we are having some severe weather in Tennessee. After he gets that dialed in he's going to strap it down to the dyno. I'm curious to see what the results are also. Would be nice if the TPI airbox flowed well enough to leave it hooked up. But if it doesn't I'm going with the GTO cold air intake setup. Was it a direct bolt in for you're car?

Re: LS1 and open headers... no go
 

pretty much the kit i used was a combination of metal tube with rubber couplers, i didnt use a couple pieces due to the difference in the engine compartments, its 4 inch though, so it should be over kill, if nothing else it LOOKS intimidating haha

Re: LS1 and open headers... no go
 

Dyno results are in... not what I expected but was a learning experience. So our TPI airbox sucks. Plain and simple. My car put down 358hp at 6200 RPM then power fell off. My engine is a 347ci LS1 with LS6 heads and a BTR stage 4 cam. We did the first pull with the airbox hooked up, including the MAF which was not being used as I have a speed density tune on the car. Second pull we removed the airbox from the throttle body. Picked up an additional 33hp bringing it to 391 at the rear wheels. Torque increased by 28 ft. lbs. also. Power peaked at 6600 then fell off at 6800. So now I'm going to order a GTO cold air intake and install it.


I wish that TPI airbox wasn't so restrictive as I like how it looks, but 33 hp at the wheels is a substantial amount. So it's gotta go. Thought I'd share what we found out.

Re: LS1 and open headers... no go
 

Forgot to mention this was on a mustang dyno with a speed density tune with HP Tuners...