luckymckay21

I recently installed a set of BBK Shorty headers along with the O/R BBK X/Pipe to go with my flowmaster mufflers on my 2002 GT. It feels like i have lost a considerable amount of torque and HP from roughly 2100-3600 RPM. Once i get above 4000 RPM my car has definetly benefitted from the Headers/X-pipe. I was hoping you guys could give me some suggestions on how to help gain back the lost HP/Torque in the low end! I was thinking the Predator tuner combined with the K&N FIPK air intake might help me. Any suggestions would be great guys. Thank you

tcuallstar

it sounds like youve tackled your exhaust, but now you need to help her breathe. i would definately go with a CAI, and tb/ plenium combo before you bought the tuner. or the easy way to gain back that umph in your low end is swap in some 3.90s or 4.10 gears thats just my opinion. the headers and exhaust combo is what i plan on next whenever the cash comes

Machwon

when opening up an exhaust you are reducing the backpressure the engine uses to build low end torque. As stated above one of the best ways to regain the low end torque- besides getting a tune - is to put in some lower (higher numerically) gears. IMO at least 4.10 +.

luckymckay21

Well if i go with gears, i was thinking the 3:73 gears since i have a manual and dont want to constantly shift all the time. Would i still see a considerable gain in performance with the 3:73's instead of the 4:10's? And im pretty sure you need a tuner with new gears in order to correct your speedometer correct? And since i need a tuner anyway, will the tuner combined with the 3:73's, more than make up for the lost torque/HP due to the exhaust? thanks guys

Machwon

Yes you will need either a speedcal or a tuner to adjust for the new ratio. I know many people that have manual daily driven cars and 4.10s are perfect for them, and they have only experienced a 2-3mpg loss on the freeway with 4.10-4.30s. I really think that if you want to cutoff some time at the strip (3 tenths), get into the rpm range a lot faster and have a more pleasurable (believe it or not) daily driver then you should look into the 4.10s or at least give them a little consideration, like I said everyone I know is either Very happy with them or wish they went with 4.30s in the long run. If you get a tuner like the predator or Xcal2 remember that the tuner itself is only as good as the person tuning is knowledgeable about the car. I'm not saying that you wouldn't be able to get more power out of it, but if you take it to a dyno/performance shop and have it professionally tuned with a/f and a dyno- than the results will be much better and maximized. Then you can take your handheld and make small preference adjustments afterwards. Anyway hope some of that helps with your decision!

03sonicgt

Get some intake mods now, get a cai and a good tb/plenum.

monkeydude3

headers, the long tube ones always sacrifice some low end for some wicked top end power

George

70 MACH I

Yep I agree, I did my intake mods first, then I used the BBk shorties, Slp Catted X, and flowmasters, My car RIPS 2000 rpm and above, much, much better at the higher RPM's where it used to fall flat. I am going to install gears myself this summer, more than likely, 4.10's. I want to get my engine up into the "happy zone" much quicker. Right now, I can be cruising in OD at 1500 rpms 55 mph, down shift to 4th, and pass a car hitting 90 when I back off. And you can definitely hear it pulling through the intake. The only low end I lost is directly off idle, a little bit of the snap it had with the manifolds, but from there it fell flat as it tried to overcome the exhaust and intake restriction. I can spin my tires so much easier now than before. In the short term, take the snorkel off your air filter housing. That will give you a little more flow.

John

2000GT4.6

Thats your problem right there. Shorties are almost competely worthless other than the difference in sound they make on a N/A 4.6L.

If you lost power though, I would definatly look into getting a dyno done. not a tune nessicarrily, just check the a/f ratio. You could be throwing off the stock computer with the new exhaust. I was missing quite a bit of power after I installed my new exhaust.

BTW, the thing where people claim LTs will give up any significant tq or horsepower down low is BS. I have never seen a before and after dyno acutally showing LTs losing power anywhere in the band, if the tune remains dead on. The whole backpressure thing has been scientifically proven bs.

70 MACH I

BTW, the stuff people say about shorties being worthless, is BULL, the car sounds/pulls 10 times better than it ever did with manifolds, the only loss I've noticed is on starts in first, it's just not as snappy. Unstuff, your intake side as stated previously, you'll be pleased. Install gears, even more grin! I truly love the way my car pulls now, it is awesome. And, I'm street legal and not leaving parts of my exhaust on country backroads!


John