yup that sure is good point that you pointing out, i was too lazy to do dyno.....doh!

I did a UNICHIP from an APS kit, you can still tune it on N/A tho japtrix was kinda mad at me lol.

I really wish I did the utec tho =(

If you ever THINK you MIGHT go F/I... get a utec now.

in my opinion what you're feeling is the loss of low end power common with exhaust mods. i basically have the same set up as you...intake, spacer, headers, and i had hfc with the stock exhaust. i have no power loss at all..just a monster after 3000 rpm...try taking your test pipes off and putting the stock cats on...if that resolves the issue than ditch the test pipes and get some hfc...some backpressure is better for torque.

1) your a/f is probably skewered from all those breathing mods

2) topspeed pro-1 is a 3'' exhaust piping - you'll have VERY noticeable down-low torque loss, with moderate up-top gains as a result.

I'll give it a try! thanks!

i see, i'll give it a try as well, thanks for help!

That's why you reflash after you have done a significant amount of mods.

If you decide to get it flashed with Technosquare, and happen to add a new mod, then you have a choice to get it reflashed which will only cost you $150. That's their reflash discount for past costumers.

In my opinion, its not worth spending up to $1,000 on UTEC.

If you're staying NA, a reflash should do just well.

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I agree, well as some said earlier, pretty much all my exhaust system are a disappointment that need to be fixed or swap, will they still be a problem after the reflash? thanks for you time

^^^ You are correct!
That size is for FI applications, which needs little or no backpressure.
NA needs backpressure to keep the torque. Max dia for NA should be no more than 2.5".
Thats the reason right there his butt dyno feels less power, he has a lot less backpressure=a lot less torque.
Doubt if a tune will bring back the torque. Lack of backpressure is the main issue here, imo.

where did you get the topspeed exhaust from.

I want one but cant find them anywhere

Wanna sell yours??? lol

Not sure if Topspeed really is 3" piping, but if it is, then that definately isnt beneficial on a NA car.

A reflash will always help no matter what; but you might see better gains if you had a 2.5 or 2.25" exhaust.

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Let's just say that I'm going to swap to HKS hi-power, and have done the ECU reflash, do I still need to worry about changing HFC for more back pressure?
thanks bud

HFC always helps.

From what I hear, HFC will make you feel more power and torque in the mid powerband.

If you want more info, im sure you can PM "OCG35" for more help; he has alot of bolt-on's including HFC, and had his ecu reflashed by Technosquare.

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you are probably running lean and pulling timing so the car feels like a slug. More than likely if you add fuel you will feel more trq.

When I got HFC I could not believe how limp the car was (search my thread for Crawford HFC)... I went to TS and Tadashi did some tests, I was running pretty lean - he added fuel... after a couple of test drives & tweaking the a/f ratio the car was right at 13 relatively consistently... I immediately notice more trq!

I have CAI, 1/2" spacer, HFC, catback exhaust... when you add that many breathing mods you need to add fuel. This is why so many people think certain mods don’t work. They slap something on without tune and expect amazing results.

OP, get your ECU reflashed and you will be fine.