I have increased the front end air intake and would now like to improve the back end exhaust on my Z. My question is, should I drop the money into a dual exhaust such as the Injen SES or Borla TD first with test pipes or high flow cats later? Or, should I go with the test pipes or high flow cats first with the exhaust later? Thank you for your input.

 

Performance - test pipes
Sound - exhaust

 

test pipes

 

What is your proof for saying test pipes for performance? Seems like it is hard to tell since most of the posts with test pipes also have an aftermarket exhaust. The exhausts by themselves have shown very good gains, especially the Stillen and the Injen. The test pipes definately seem to be a better "bang for buck" product, but I have money to buy an exhaust if that is really a better performance gain. Does anyone have both test pipes and dual exhaust and tried installing each without the other to see where the real gains are to be had?

 

i have the 2.5' test pipes while everything else is stock...tho i didn't dyno it, i assure there are def gains with test pipes...i mean, how can you not gain hp by switching cats with straight pipes....

cheers

 

I'm not noticing much with the test pipe... although my *** dyno isn't as senstitive as some
It is stinky, and it is loud and raspy especially in the 3k-3.5k RPM range

 

I will go to the 100 dollar window that test pipes are good for twice the power of your avg Z catback exhaust. I am talking about reality and not advertised specs. Those are never right. Just look at some manuf's losing power with catbacks and others posting little or no gains. The cats are a serious bottleneck on the exhaust. If you don't feel a gain with test pipes you are certainly not going to feel a gain with a catback. I used to have a LS1 Z28. I had test pipes in that too. I understand the capability that they have. They are fast. With test pipes I outran an LS1 from a 60 roll a while back (I would never post this as a kill - it isn't believable) in my Z. It was a stick car, too. The top end is extremely opened up with test pipes. Extremely. I don't even like to launch from a stand still anymore. This car is shaping up to be a high MPH car and I think that is what my focus will be in my future mods... Anyways...

 

Hraesvelg, are you also using an aftermarket exhaust with the test pipes or stock? Your comments I have heard a number of times about the test pipes, which makes me consider the exhaust before the test pipes. But then there is part of me that is thinking that the cats have been considered by some reputable people here on this site to be the "bottleneck" in the exhaust. It looks as though either mod will give good increases. Maybe the best route is to go headers + test pipes or high flow cats and add a true dual exhaust at another time or possibly never. This would cost maybe a little more than a nice dual exhaust but yield a bigger performance boost.

 

how bad is the smell with test pipes??

 

All I have is the stock exhaust, and Injen CAI, and a grounding kit. The sound is a lot louder, which makes me worry because I want the Injen exhaust because it has the best HP and Torque gains per pound out of all the exhausts. The smell is like a gasoline smell, but it's starting to grow on me along with the sound, the sound is seeming to mellow some...
"I love the smell of" gasoline "in the morning, it smells like victory"

PS. I love the bling bling wheels, where did you get chroms Nissan wheels??

 

It was somthing the dealer did to the car.. I got it used... I am just worried about how bad it will smell.?

 

There is a smell but it is really a non issue. I only smell it when I start it up in the garage. If you are driving no one will ever notice.

 

So lets say that I am sold on the test pipes before the dual exhaust. Which test pipes should I purchase? I have seen a lot on Zred's pipes, but then there is isdunique's pipes too. Zred's pipes seem to be easier to obtain, but are 2.5" in diameter and a little more money. Isdunique's pipes are 2.25" and a little cheaper, but for a long time there, no one was able to get his pipes and I have not seen reviews on them yet making me wonder if they are still hard to get. Is the diameter issue really a big deal? I plan on keeping my car NA and will more than likely drop in some headers at some point as well as a dual exhaust. Are there CEL issues with either pipes?

 

Don't be concerned with the availability of lsdunique's pipes. I just ordered a set and he had them set aside for me so he could ship them out after receiving my payment. He has also been very responsive to PM's and emails. He has changed up his parts a bit since one of his earlier posts. He now has the following available:

2.25" polished stainless - $250
2.25" stainless - $220
2.25" mild steel with either blue or silver ceramic based coating - $185 + shipping.

His shipping prices are reasonable as well... mine was $13. All of his flanges are now laser-cut 3/8" thick. His early mild steel version only had 1/4" flanges. Also, they are 1-piece now instead of two pieces butt-welded together.

I would recommend the smaller pipes if you are staying normally aspirated. They allow enough airflow for good top-end power, but maintain exhaust velocity for good low-end torque.

 

there are a ton of lsdunique reviews. do a search. i have some. let me make it easy for you. they are worth every penny.

 

I think I have his pipes, I got them used from another member. Nice fit, good quality and these were the cheaper mild steel ones. I can only imagine what the higher up versions are like. I recommend them 100%, PM me with any questions

 

so do these replace the cat? If so would i be able to pass emissions?

 

Yes and No. All four cats are removed by installing these straight pipes. Pipes are available with a single cat in each side (Crawford, Nismo, ...), but the hp gains are half or less than that of straight pipes. You'll have to keep your stock cats so you can swap them back for emissions testing.

 

I guess I am lucky here in Iowa as we do not have emission testing for autos. I can drop in some test pipes and never look back.