JGT

I have done a lot of research on this board for myvarious mods and, until recently, was always under the impression that a retune is required once you added longtube headers, even if you keep your cats. Most people say this is required.

However, some, including Brenspeed, have told me that you do not. So what is the deal? I would think Brenspeed would know what they are talking about.

But I recently dyno'd only 265 HP on a dynojet, with CAI/93 octane tune/UDPs/longtubes + catted H-pipe. I bought the tune from Brenspeed with the tune for the CAI a while back andrecently added longtubes. It seems this is a pretty good argument for needing a tune. With the same tune I have always had, the longtubes don't appear to have added any power.

I think I am going to get a custom dyno tune, so it will soon be a moot point, but do the other mail order tuners say you don't need a retune for longtubes as well?

owero01

I heard its not required also but when I do go that route, I going to retune. Can't hurt. I just dynoed at 301 RWHP on Dynojet at Mustang Week.

AmericanMuscle4.6GT

a dyno tune is needed with the addition of longtubes or else your car will run poorly. plus, you won't get the benefit.

thats how it is with almost all mods for our cars.

Stkjock

not necessay....but the custom dyno tune will be worth it IMO

MustangEsq

+1...only need it to turn off the rear O2 sensors....so I'm told...

sharkbait20

only 265 with all those mods? whats up with that. i thought the cai and tune would get up to 280ish...?

JGT

Yeah, 265 is much lower than I expected (although my car isan automatic). I posted about this elsewhere. Car was running lean at 13.6, too. I am hoping fixing the lean condition is good for 5 HP, and then a good dyno tune in better weather (was 95 and humid when I got 265, car might have been heatsoaked) will be good for another 15-20 HP and get me up into the 290 HP range, which would be more reasonable for an auto with these mods.

WhiteStallion06

I ran my longtubes without a tune for a good two weeks. Some say itll throw a code but mine didnt. The only problem with codes your going to face is if you go with an offroad mid pipe. But id get a tune you mines well if you want the most you can get out of the money you spent on longtubes

sharkbait20

let me know how it goes. i have an auto as well and almost got extreemly pissed off at the addition of horse that those mods did. im looking to do a CAI and tune and axle back maybe. im looking for at least 20 horsies to add to whatever its throwing down...

Texas660

I just got home from picking my car up at the shop. Had Kooks long tubes, high flow cats and x-pipe installed. They put it on the dyno before the install and I was making 288 hp / 276 ftlbs torque. After the install and retun I made 301 hp and 296 ftlbs torque. JGT if I were you I would definantly get a custom dyno tune, 265 hp doesnt sound right with your mods.