Newb FI question
 

Quick question for all my much more experienced fellow members:

I'm looking to make my first mod to my '11z, being a Fast Intentions non-res exhaust. I'm planning to go forced induction with a year (maybe a little longer, depending on funds), and was wondering if this exhaust will be compatible with a twin turbo system, or if i'll need to change the exhaust when i make the forced induction switch. I'd rather not have to buy a second exhaust if I don't have to, and would like to get one that is compatible whether my car is NA or FI. Could someone advise me on this? Is there any other bolt ons that I need to make sure I get a certain type for forced induction compatibility (i.e. intakes, etc.) Thanks in advance for the help, and my apologies ahead of time if this is an ignorant question that I should already know the answer to.

Thanks
Ross

Depends if you're going turbo or supercharged.

If you're going turbo, have Tony at FI make you a 3" exhaust, while you're N/A you'll "make less power" than if you had a 2.5" diameter exhaust.
It depends if you believe a N/A needs back pressure or not.
Generally, the more you open the pipes whether it's intake or exhaust you lose a bit of low end torque and HP and gain it back on the top end.

If you go turbo don't buy cats, because I believe most turbo kits are text pipe or straight pipe set ups, I could be wrong, don't quote me.
But for supercharger you CAN use HFCs, you just have to realize you're putting more stress on them, they will get MUCH hotter and will probably break at one point causing a world of other problems...

Stillen does do Supercharger installs with their 2.5" piped standard exhaust, but I'd feel more comfortable with a 3" if I were you

Don't buy an intake, Motordyne intake manifold, underdrive OR lightweight pulley, and don't buy headers, they'll all have to be taken off and not reused in any way (you COULD use the Motordyne, but if you're going FI, the $500 you spend isn't worth the minimal HP it MIGHT give once you're hooked up. Same with headers if you go supercharged, the money and hassle isn't worth the HP you MIGHT gain)

Actually, if he goes SC he will want to stick with a 2.5" exhaust, a 3" is worthless unless you are moving to a turbo environment.
For turbo you can use your exhaust you have, but if you want to move above 480whp you will need to move to a 3" exhaust. Headers are good with a SC, both short or long tube and are a solid investment but not if you are going for a turbo setup. On the front side I would stick with stock for now as with most kits you get everything you need. Intake, piping, etc.

Save your money and just buy the 3" exhaust when you do the rest of the FI build. If you need noise, buy a used cat back off the forum to tide you over. If you just need something to tinker with until you go FI, sort out the suspension. It sucks to buy parts that turn out to be not what you needed.

This is not true at all.

The dual 2.5" F.I exhaust will be just fine with a properly flowing turbo system. I have customers making over 650+whp with dual 2.5" exhaust systems (350z single turbo), and there is still room for more. The test mule for the twin scroll kit made 550whp with no sighn of slowing down.

Dyno graphs and videos are here:

http://www.the370z.com/forced-induct...o-results.html

There is a big misconception here (forced indction section) about exhaust sizing and the ability of a free flowing 2.5" dual exhaust system to make power.

I am confidend that a 6766 T4 1.32 a/r twin scroll turbo kit will make close to 700whp (or deep in to the 600's) with a proper build and a dual 2.5" exhaust system.

I was not saying it is impossible to use a 2.5" exhaust and make more power, I was saying you probably need to. There are multiple cars on this forum who made 470-490whp with a 2.5" exhaust and upgrading helped free up HP & TQ. Besides that it is not all about HP/TQ when adding this much power to the car. You must consider heat exchange, flow rates of the turbines v exhaust gases, and more. Can it be done with 2.5" sure, but it clearly has been shown on the Z34 platform with a good 2.5" v 3.0" exhaust that the 3.0" is clearly a better choice. Now if you build a full system from front to back around 2.5" and make great power, congrats.

Also, I don't think there is a misconception on this forum. I think it comes from the education of many known people here who have done larger builds on other platforms and VQ motors that show & say a 3.0" exhaust will be more beneficial all around.

Bldg636, I am excited about your modding progress. Enjoy every moment!!! On another note, not trying to thread jack but since it was mentioned:

DEpointIV, I thought it was totally in my mind that I lost initial/low end torque when I installed my intakes and cbe. Now I see that it is not, why the loss in low end torque? And is there anyway to balance it out or get it back without turbos/sc and leaving the mods. I'm just curious, I miss it. Is it possible to have the best of both worlds without FI? I definitely see the difference once I climb higher into the RPM band but I miss the low end torque for around town driving. Thanks for any info you provide!

Not really... You can go from a Stillen G3 intake to shorter intakes for a peppier response, but your gains will be a lot less overall because you now have a WAI/HAI (warm air intake/hot air intake)
If you want to feel lower end, or responsiveness, under drive crank pulley... I have the Stillen because I WANTED the 20%... And it's great! And technically you should gain a gain across the WHOLE RPM range.

You CAN also get the Motordyne intake plenum, now it will rob you of a few, 2-5hp above like 5500-6000RPM, but you'll gain a lot midrange, +10hp/torque


By the way, if you didn't disconnect the battery when you installed your intakes it's very possible your ECU isn't adjusting for the mod as well as it SHOULD... If your car is used to a set of perimeters it takes much longer for it to adjust than if you reset the ECU. (The only "quick" changes your ECU makes is to pull timing when you're overheating, and pulling timing if you're getting engine knock from crap gas, still takes a while to go back to advancing the timing for your high quality gas)
If you're going to try a reset your ECU, please make sure to disconnect the Negative!


I'm glad I could be of some help or insight, and man oh man I feel like a car geek for the essay I typed on my phone, LOL! Just trying to help out the community!!!:tup:

Your "essay" is very much appreciated! I have had the intakes on for about 3 weeks now...I feel the increase in horsepower but just at the top. My technician said the instructions didn't mention anything about resetting the ECU after the install so he didn't do anything of the sort. I'll take it to him tomorrow and see if I can tell a difference. Thanks a bunch the very helpful info!

I realized that I didn't fully answer your question... Why the loss is low end hp/torque, to be honest, I'm not 100% sure, I can speculate that a freer flowing exhaust gives you a bit of a loss because you're losing back pressure... At the same time, back pressure on a N/A is bull, there is no NEED for it, I bet it's more that the engine works better under stress... (Reason why people put like high pressure coolant caps). On the intakes, it's not 100% the temperature of the air, it's the FLOW that helps... And I'm sorry to anyone that has the HPS or similar intake tubes, they don't do anything, since the accordion is AFTER the MAF, it doesn't help...
Getting back to it, I think the reason you may have more of a power loss or lack of initial power is because the air has to physically move further, so short rams are better for that, but the temperature under the hood is ridiculous! So IMO It's better to have drop ins than short ram. (The stock intake boxes' ducting is actually quite good at getting cooler fresh air...) When you install the Takedas or Stillen G3's you run your piping THROUGH the stock intake box inlets.

Lol, cool, glad I could help!

You need to get a boyfriend, and/or I am FULLY confident in your ability to disconnect your battery yourself, lol.
You can even borrow tools from most auto parts stores

If you need help, shoot me a text, I'll show you what you need to do, it literally takes... 3 minutes? Actually, Ray Charles could do it in less than 3 minutes, so I am confident in your skills! Lol

(310)eight nine three-4207

Ok...Yes I need a boyfriend I'm working on that LOL. :bowrofl: But I have NO tools...my tech is on my way to work and handles everything on my Z so its all good. In my honda/acura days I use to change my own oil, brakes, wipers, filters etc, but NEVER touched the battery. Batteries scare me for some weird reason, I have this paranoya of it exploding in my face or something. I'm almost as scared of batteries as I am of dogs and I have NEVER had a bad experience with either. Weird I know:)

The intakes have been on for a few weeks now and it probably won't make any difference but I will give it a shot. Again thanks for the help!!!

Backpressure is used on 2 stroke engines to help keep both the fresh air from exiting the cylinder and to create a scavaging effect to help boost the amount of fresh air in the cylinder.


4 stroke backpressure talk...

Exhaust backpressure the myth - ThumperTalk

buy this one!!!!
http://www.gainesvilletruckcenter.co...OG_BATTERY.jpg

aaaaaahhhh!!!!!:tup:

LOL repped!

;-)

sorry OP, back on topic

It is true you dont need a 3 inch to make 550whp on these cars, it has been proven with plenty of turbo cars out there. But now that there is a 3 inch exhaust available it just makes more sense to jump straight to it.

Thanks everyone for all the information.... Looks like, although not absolutely needed, it might make sense to go ahead and purchase the 3" exhaust now if I have my mind set on big power gains later down the road.... Anyone have any suggestions on good 3" exhaust systems? I looked at the greddy T IC exhaust system, but wasn't all too thrilled with the sound. Anything else out there worth looking at? Also, based on my research, I looks like I'll be opting for a GTM twin turbo kit, so any exhaust I get would need to be compatible with that. Thanks again for all of the help.... It's very much appreciated!

Get the Fast Intentions 3 inch exhaust it's the same one I have on my car. I use to have the Greddy TIC and now have the F.I exhaust, the link to my thread has dyno video's of both, on page 4 it's the F.I exhaust.

http://www.the370z.com/forced-induct...otor-tt-4.html


http://www.the370z.com/intake-exhaus...aust-here.html

That would be a great option! I love the look and quality of the fast intentions systems. Would this be compatible with my current NA stock setup? Also, would I need to get any tuning done after install since the 3" system is a lot more open with less backpressure?

Please share who has done it and let them know to add to this thread: http://www.the370z.com/forced-induct...ed-builds.html
Really trying to get a solid book of builds together from everything, so far I only have 1 build that made almost 550whp on a 2.5" exhaust and I really do not have much info from the guy other than he cranked the boost up above 10PSI to do it.

The car made 550whp even, and please note that the actual boost pressure at max HP is about 9psi (10psi at 6,000rpm and falling). The reason the boost is up in the early rpms was due to having a manual boost controller. Because it is a manual boost controller, there was no way to controll boost in the upper rpm's (like haveing an EBC and the option to increase the duty cycle). So it was turned up so that we can be as close to 10psi as possible at max power. As a result the boost was up to 12psi at 4500rpm.

http://i18.photobucket.com/albums/b1...scan0001-1.jpg



The reason I say the 2.5" dual will make a lot of power is because of that graph. There is no sighn of it tapering off. It is just a nice linear line, with no dips, and no falling off at the top.

This is a Boosted Performance single, twin scroll turbo with a Precision 6266 billet T4 1.0 a/r. 3" down pipe to a Y-pipe going to the F.I dual 2.5" exhaust system with 14" resonators.

Here is a GTM TT Stage 1 with the 2.5 Fast Intentions it was my friend's car the engine has sence blown up. The care did make 550Whp without a problem, as far as other gas cars there there are countless GTM threads with cars with 2.5 inch exhaust making power.

[IMG]http://imageshack.us/a/img202/392/nismo481212psi1.jpg

Not trying to derail the thread, but for informational purposes - what caused the motor to fail?

Mr. Squeeze..... Can I use the fast intentions 3" exhaust on my current NA setup? Or is this only for cars with the turbos? I will eventually be going to FI but would like to change the exhaust prior and would rather not have to do it twice

I personally wouldn't run the 3" exhaust on a non-turbo car. It's just too big for use with a NA car. I would expect a very noticable loss in torque with a 3" exhaust on a NA car. Buy a used cat-back for a couple hundred bucks from another member here for now, and put the 3" system on when you get the rest of the kit together. Then turn around and sell the used cat-back. I doubt you'll lose more than $200 if you shop around.

gotcha . . . thanks!

How would you lose torque by lowering the back pressure on the exhaust side? If anything your gains between a 2.5" and 3" would be minimal since the 2.5" has been proven to be sufficient all the way up to 500 rwhp. Its all about flow, and only flow, make it flow better and you have less back pressure. Less back pressure less work the engine has to use to move the exhaust out of its cylinders and thus make more useful power.

:icon17: Oh crap. The eternal backpressure debate.

The car was drivin very hard for 13000 miles raced all the time. A rod shot through the side of the block.


You can use it you will lose a little low end tq, but if your going turbo down the line ,and dont mind that then get it.

Did you stop at 7k RPMs? Because after there is a drop off.

This would be a result of pulling timing, falling boost and flow limitation of the 1.0 a/r turbine housing...nothing to do with post turbo turbo exhaust.

:drama:

Sound's like the 6266 is comarable to the GTM stage 2 that's real nice.

Yup, maybe even a bit more power because you can go up to a 1.32 a/r housing with the 6266. These egnines breathe so well, and rev very high....turbine housing size is key.

That's even more impressive, I learned the hard way housing size on my build not looking forward to swapping mine.

I think I remember posting in your build thread something along those lines, and somebody saying that upgrading to a dual 3" will make a world of difference. I can't remember now but I think you only made another 30whp? For comparison sakes, I just had a customer in at R/T with a 6266 T4 .81 a/r (open inlet) 350z make 610whp at 18psi. Vince said there was another 30whp left in the kit with that housing. So the .96 a/r would get over 650whp for sure. All pump gas numbers of course.

I did a lot of EBP (exhaust back pressure) monitoring when developing these kits for the 350z, so I also speak from experience...:tup:. This is the main reason I only use the T4 turbine housing in all the VQ turbo kits.

I wish the 67mm turbos had a 70mm turbine wheel :) really kick it up a notch.

Just to clarify to everyone who thinks loss of back pressure means loss of low end tq. Your wrong. Because you have an enormous tube for an exhaust, it reduces the velocity of the exhaust leaving the motor. The domino effect is it reduces the scavenging effect or more simplistically, a vacuum effect of the exhaust assisting in pulling the gasses out of your cylinder. At low rpm, it's crucial in developing low end tq. The higher rpm you move up the power band, the less effect it will have because now the exhaust velocity is up to an acceptable point to continue scavenging. Exhaust size is critical to the amount of air your trying to move. A 3" dual exhaust will really only benefit you of your pushing 650-700hp at the crank or higher. 2.5" exhausts are perfectly sized for our motors until you start pushing some serious power.

This is entirely correct. To be fair though, this is usually what people are talking about when they claim "a naturally aspirated engine needs backpressure". Kinda like the confusion between tubo lag and boost threshold. Most people have the right idea and the wrong terminology.