I am thinking of swithcing from my hedman LT's back to some hedman shorties with a dual 3" Y pipe to get some ground clearance back. I am wondering just how much HP this will cost me? I think the dual 3" Y-pipe will help, but just wanted to know if anyone has had any experience with this? Also, what size is the collector and Y-pipe on the SLP headers?

 

eyour gonna loose top end hp and trq thoreugh out the power band.. how much? well a dyno would be the only way to tell to be honest... but i bet you loose 15llbft and 10 or 15 peakhp...

 

You gain horsepower up top and lose torque down low with long tubes. You get midrange torque and horsepower with shorties with loss of horsepower up top. Go with shorties. There was a guy at camaroz28.com who actually lost power with long tubes and didnt even make additional power ti'll he had something like 800 rwhp. 1 3/4" shorties will be the best.

 

with short tubes you shoudl lose over the board vs long tubes if the primary tubes are the same

long tubes first off are tuned for low rpm ranged if you think about resonance tuning

also they tend to be a more efficient design by not having all the bends and kinks in the system

either way both are better then stock though

 

Check out dyno runs, long tubes do not beat out shorties all over.

 

i was reading a mustang magazine at work. they did a comparison of exhaust

Unequal length shorties were the lowest, followd by unequal length lts, then equal shorties, then equal long tubes. also did open, h pipe, and x pipe test (results in that order)

 

i have about half a dozen or so engine dyno runs of my hooker 1 3/4 lt's vs the slp 1 3/4 shorties (which happen to be a pretty decent shorty design) ewith both having straight pipe off the headers (can't exactly hook up a y-pipe on an engine dyno)

the difference was incrediable...

through both curves, the lt's produced a solid 10-15more ftlbs and the same in hp, and at peak made more torque beyond the peak than the shorties did.

Sorry, this might be different with other headers, but i honestly thing only the amounts will be different. lt's scavenge better for lower rpm power, and high rpm hp

 

I have checked out some dyno runs

most the time LT work better


take a look at the theory for resonance tuning and scavenging

the lt with longer distance are tuned more so at lower rpm ranges then the short tube headers

also with long tube headers generally it is easier to make them equal legnth

then comes the bends

some short tube headers are just NASTY with bends causing a nice loss of flow


and so forth


a lot of times though long tubes seem to be using larger tubes then short tube headers


and that is about as fair as comparing a 212/222 flat tapet cam with a 256/256 solid roller cam

and then saying the flat tappets give you more low end power

 

my dyno experiance was with the same size primaries...