Recently added a Borla T.D. exhaust system..Several previous posters have suggested that a dual exhaust would lose some power for a supercharged car. Reason offered was reduction in backpressure. Well I can state definitivly and unequivically that it adds power..No dyno #'s but lots of smiles when I stomp on it..

 

yeah the backpressure thing is sorta a myth. Many people are running dual exhausts

I'm not sure I'd go with an exhaust that's really huge though like a dual 3 inch exhaust until the car is making absolutely huge power. But even still, all it's really doing is shifting the powerband to put out more power up high and maybe slightly less and extreme low rpms

 

Either way, I'd be willing to give up a few ponies for better sound if I was part of the 300+whp club.

Regardless, I love the Borla sound.

 

your car will have more power and do it with less boost with a dual exhaust

 

^^ Probably the best. When I did test pipes I lost nearly 1PSI of boost but the dyno stayed about the same.

 

I just switched exhausts and I felt a loss of low end power. Now this is just the butt dyno talking, but it does feel like there was a loss. I'm pretty sure it is made up on the top end though. I went from the Nismo to the Greddy EVO TT.

 

I couldnt tell much difference at all when I first did it...down low that is .

 

THE TECH, what rpms specifically did you feel like it lost power? like 2500 and under? 3000 and under?

what pulley are you running?

 

I'd have to check the RPMs when I drive it again. I'd guess it was ~3000 or less. Right now I have the 3.33 pulley on. I have the 3.12 pulley sitting here, but am debating on putting it on cause I haven't gotten a good consensus on my searching as to whether the 3.12 is perfectly safe on stock fuel. What do you and Booger think?

 

I didnt have any problems at all with the 3.12 and the stock fuel system . If you dont try to push the timing to the brink of detonation and run a good A/F . If you go to a better EMS like a Utec , where you can control timing better , push the motor closer to the edge . I would upgrade the fuel system .

 

How much of an upgrade do you think is really necessary? Injectors enough? Walbro? Full fuel system? From what I understand, the gains with the 3.12 only amount to another PSI or so, so I'd think some larger injectors might do the trick?

 

Im not sure what alls involved . But you would think a pump and larger injectors would be plenty good enough . Sending the ECU in to have them flash for the injectors only worked real well for me

 

Hmm...my contention is that the weak point is only the injectors. Since the Vortech kit comes with the inline pump to provide more fuel under boost, replacing the stock intank pump with the Walbro isn't going to gain much IMO. It would seem at this point, the weak spot is the injectors being maxed.

 

The aux. fuel pump and the FMU supplies more fuel preasure to the stock injectors . When you go to bigger injectors the fuel preasure doesnt need to be any where near what it did with smaller injectors . So you remove the Aux. pump and FMU and add the intank walbro pump for more fuel flow . A regulator may have to be added to raise fuel preasure at a rate of 1 to 1

 

I know there are guys that went to bigger inj. and a walbro , with out going to a return fuel system . But Im not sure exactly how they get it to work right .

 

Hmm...interesting.

 

Just to add, but I have heard you can go bigger injectors and get rid of the inline pump and FMU and the fuel flow would be more stable. I have seen dyno graphs of 400whp with stock fuel system+440 Injectors, so the stock system should be good to around that power.

Anyways, to get back on topic, I am contemplating getting a true dual for my Vortech. I am a little worried about losing low end torque, because these engines already lack good low end power. How much whp/tq gain could I expect if I updrade to a TD exhaust? Btw, I have resonated TP's+3" Y-Pipe+Exhaust...I am also hitting 8.5 psi on 3.33 pulley.

 

I thought the VQ was known for it's low and mid range torque.

I don't have Vortech but with my Borla TD I definitely notice a shift in my powerband.

 

Well, to me it lacks a low end (under 3k), but has good mid to high end. I'm rarely at 5k+, so losing a significant low end bothers me. I just want to know how much whp I can expect to gain overall with a TD compared to a non-TD exhaust.

 

Exhaust doesnt really matter much for SC unless u are making big hp or u are turbo. The borla will not decrease your low end by any means and it has been dyno proven to give u +8hp over stock exhaust on a stock g35/350z. The borla isnt very attractive (more like stock) compared to the HKS but it sounds like a v8 in low rpms and best part no drooning sound while driving on the freeway (3K rpm above). How many aftermarket exhaust out there gives u +hp and no buzzing noise while u drive on the freeway?