I went with shorties and thier is a low end gain however I'll be changing those for LT's eventually wether or not I stay N/A. Ive never heard of anyone loosing anything going with LT's although you might gain more low end with shorties and I wont be able to confirm this untill I change.

 

Well, I put some rather large 1 3/4" Kooks LT's and their new 3" catted H midpipe on and I sure did not loose any low end power. With tall drag radials (M&H 275/50/17's) I was still able to cut some 1.7x 60' times last night. And this is on my lower compression, 9.3:1, 302 stroker that was built for a blower in the near future. I'm probably only putting out around 295rwhp and 320 rwtq right now on it.

I really think it depends on how good the tune is after you install the long tubes that will determine your power.

 

Thanks again guys this is all real useful info but I think im still gonna go with the LT's

 

I gaine torque/HP all across the board with my Kooks 1.75" LT headers and their hi-flo catted X-pipe. Gained 45 RWTQ at peak also.
The low-end power increased dramatically with this exhaust

 

yeah kooks is what I'm saving pennies for at this point. Thats what I shoulda done in the first place.

 

i agree i felt a good gain when i put my ARH LTs on

 

What kind of times did you run?

 

While you may have lost power on the low end, it has nothing to do with back pressure. Back pressure is always a bad thing. Always. By changing the size/shape/components of the exhaust, you are changing the way and velocity your exhaust flows. Shorty headers feel more powerful in the low end, because they're smaller and increase exhaust velocity on the low end.

Bigger, longer tubes (as found in long tube headers) will increase power in ALL ranges provided the engine's intake system can keep up with the flow. Engines that lose power when going to long tubes simply don't have the intake setup to flow that much, and as a result, are most efficient with the stock system because it is smaller. However it is rare for an engine to benefit from shorties and not benefit MORE from LT's. It has nothing to do with back pressure. Back pressure is a byproduct of having a system that is too small.

Think of water flowing through a pipe. The faster you can flow the water, the more power you'll make from the prop it's spinning. If your intake of water is too big for the output, there will be bottlenecking, creating back pressure. You counter this by a bigger, more efficient system to exhaust the water. However, adding a bigger exhaust system to flow the water could inhibit the output power by slowing velocity IF the intake simply cannot take advantage of it.

Again, nothing to do with back pressure other than back pressure being a byproduct.

Seat of the pants dynos are subjective, as your brain is taking in other things such as sound. The change in engine sound can do wonders to the feel of speed the car creates.

 

I ended up running back to back 12.95's. My engine has the VCT lockouts in it so I have lost some top end horsepower. I ended up doing that for safety reasons and I'll be able to safely run a thicker oil in the summer. I'll post my slips below.

I'm sure if I still had my VCT functional I'd probably have been 12.7 or so.

 

You're definitely making more than 295whp with those times then lol!