buddy is trying to tell me that on his 89 TA 350 TPI that longtubes wont make a differance over shorties, and that longtubes will hang too low for his stock ride height. i run longtubes on both my 4thgen LT1 cars and the seat of the pants o meter said 2 thumbs up. does anyone have any or know of any places i can find like a dyno comparison for longtubes to shorties?

 

Car Craft did a nice writeup on this several years ago.

Basically, given the same primary diameter and a quality collector, the long tubes have only 2 advantages:

1. Tuning by adjusting primary tube length.
2. Additional low-mid RPM torque.

Shorties will make the same peak HP (sometimes a little more) and will do so at a higher RPM.

 

I had shorties on my third gen w/ my old motor making 390 at the wheels. Switched to LT's, wow what a difference in power.

Zach

 

Exactly. Typically when guys swich from shorties to LT's and report a substantiated gain of power it's because they increased the primary tube size as well. the length of the tube moves the torque peak down in rpms. It does not give you more or less horsepower. It 'feels' like your gaining power because your torque comes sooner. torque is what you feel.

 

Technically the longer tubes produce a lower frequency scavenging pulse compared to shorties or midlength headers. This should mean that the boost in exhaust efficiency brought on by the scavenging would happen at lower RPM's than with the shorter tubes, WOT dyno charts that I've seen tend to support this.

The longer tubes could potentially provide a solid SOP gain that wouldn't even show up on a WOT dyno pull assuming the gain was mainly at part throttle.

Later, Michael

 

Hooker SuperComps are ok for ride height. The problem lies in buying the Y-pipe for them. You also need to either purchase or make a trans mount that allows the dual 3" pipes tuck up under the car, with my Mufflex Y-pipe, I have 3" of ground clearance with the stock trans mount.

 

You mean like this? Here's mine:




Andris Skulte is making them now and ground clearance for long tubes is no longer an issue! This is for the T56 retrofit application, no less.

 

what about for a 700r4? my car is lowered some but I still want to run long tubes with my new 383..anyway?

 

Well Wishmaster, Why not contact Andris Skulte and ask him for one? I'm sure he'd make one if he saw demand building for it. I got an email yesterday that said he was busy building these crossmembers a dozen at a time. So email him and you never know what he'll shake out. This crossmember is LIGHT but strong. I like it.

 

do they make some sort of y-pipe for long tubes that will follow the same route as the stock pipes...so I can still run long tubes and still have ground clearance? I dont want to run shortie 1 3/4 ..I want long tubes.they sound better.

 

Not going to happen. There is no place to notch the crossmember for the 700r4, the trans is just too wide.