Hi I have 98 Z28 and recently installed a set of Hooker long tube headers and a 3" jet hot y-pipe. Everywhere ive read there should be a 15-20 hp and torque increase but my car is bogging real bad and is slower than stock. I had a 3" single pipe from the Y to a flowmaster but changed it to a 21/2 to build back pressure and it seemed to help a little. Any one gone through the same thing? any info would be great?

 

personally i dont have LT's yet, but from what I have heard, how soon after u installed the system did u try it out? The car computer might need to recalibrate the systems slightly and "learn" the new setup. Also make sure you check the gaskets on your headers, if those aren't the problem than you might have to wait for another response.

 

check ur wires to make sure they are all on. happened to me and i was pissed... then i realized 2 of my wires weren't on the spark plugs. Now ironically enough, The ses light only blinked 10 times then went permantly off. Obviously that was because of a miss fire but it took over 30 minutes of idling and driving for it to even blink.

 

thousands of people have longtubes. i think you are putting a putting a bandaid over a bigger wound with the different pipe diameter.

something else is wrong.

bad wire, plug, gasket, o2 sensor,

 

Definately something else wrong. I had long tubes on my last two f-bodies and it woke it up, not put it to sleep. I had your problem on my LT1 and it was because a wire was burnt. That shouldnt be your case, but you may need to check and make sure if they are plugged in.

 

thanks for the info. guys What did you mean by "putting a bandaid over a bigger problem with the pipe diameter"? and what did you do with the rear O2 sensors?

 

Let me see if I have this right, you put on long tube headers and an off road y-pipe to eliminate back pressure then changed from a 3" intermediary pipe to a 2.5" to INCREASE backpressure..........okayyyyyyyyy

 

02 sims. U can get them at jegs.

 

The "backpressure" myth.

 

lol

You should hear some of the customers I talk to at ramchargers.. i hate being in sales..

 

Where did you install the O2 sims ... Front or back??

 

not sure if ur askin me.... but back.

 

Whats the "backpressure myth" because Ive heard all kinds of things about backpressure and would like to hear some right answers

 

I'll put it this way. I've seen a 3800 Camaro dyno w/ stock pipes vs a 3" B&B. It gained HP and TQ in the whole power band. Bigger gains in higher RPM, but there were still gains in lower RPM.

Even if you do get more torque out of smaller pipes. How often do you race in RPM under 3k? Just in 1st on initial launch. That leaves the rest of a race and 3 more gears in higher RPM. I'd rather launch a little softer and have more power for the rest of the race. I spin bad enough as it is.



Mandrel bent pipes. Ever notice how they advertise more flow and Hp gains over smaller stock systems but never advertise more hp or torque over a pressure bent system of the same diameter? You think they would if there was a sizeable difference.

 

Sorry ive taken so long Ive been back an forth with school an work. I put the O2 sims in the rear O2 plugs. Your right about the torque loss but the horse power doesnt start pulling untill almost 5000 rpms, then I shift at 5400.Thats why I changed the 3" single pipe after the y-pipe to the flowmaster to a 21/2 single. And it helped a little, its pulls alittle sooner at 4800 RPMs. What do any of you think? 21/2 hi flow y pipe to a 3 inch single mite be better since my car doesnt have any cam or head work done?