one sick car

Actually it is coming from the rear section. Its resonance is so drastic that it is vibrating all of the plastics in the boot. I have a feeling it is the cans. I think GReddy put those resonators there for a reason.

SAM: Will I have this problem with the custom exhaust????

My thoughts - very doubtful. The way GReddy designed this exhaust is what is causing the issue. Again, those resonators are there for a reason. :) I was foolish to remove them for the extra gain.

If you are talking about the GTM 3" it is mellow compared to the GReddy exhaust.

How much boost are you running? I think at low boost levels internal wastegates work great.

Loved reading this thread over and over I can't find that video that shows the car running in the streets and fly by

7psi mostly. I have a "high-boost" setting of basically 9psi. But, I have yet to even run it at this level.


Here ya go.

YouTube - GTM 370Z NISMO TWIN TURBO PROJECT 518RWHP 420RWTQ @ 9 PSI

Thanks Jeremy!

See its threads like these that get me excited!! I dont even have a Z yet but am foaming at the mouth!! Thats a really good video too... did GTM make the video or did you? This gives me hope.

We did the video, waiting on Storm's version going sideways :D

Sam

by far the best TT install ever, looks amazing on the nismo. Question, are your boost gauge and wideband in a 2 gauge pillar or did you just install them in the stock piller?

They are installed in little cups mounted to the stock pillar. They are actually ingenious little things that Sam came up with. Very little room taken up and no need to move your head when going around sharp left-hand turns. Completely unobtrusive. I love them.

Update on the GReddy Exhaust
 

Update on the GReddy TI-C TT exhaust. After putting the resonators back into the cans, all is right with the world. These are absolutely there for a reason. Drone is acceptable at cruise and cabin noise now consists more of tire and typical road noise. Best of all, I'm no longer vibrating the rear deck apart from 2500-3000 RPMs.

Are these the silencers or something else?

very very sick car hahaha makes me very jealous i dont have 18k to through into this setup.

Yes. Resonators/silencers, whatever you wish to term them, they work! And I didn't have a noticable drop in power after putting them back, either.

i love how a TT 370 looks bone stock just with long tube intakes... even with the hood open, total sleeper

hey stormcrow just wanted to let you know me and sam were talking about you the other day. I was looking in the market for exhaust and I was telling him about the noise you were having with the greddy so thats why I decided to go with the HKS. i like the sound of it and think it looks pretty cool.

So now my build is consisted of
GTM stage 2 Twin Turbo(turn key)
GTM competition oil cooler
2.5 Test pipes
2.5 HKS exhaust

Every thing bought and paid for just waiting for it to get to my door so me and my buddy's can install it. So my HP goal is about the same as yours. I am looking for 500rwhp because I agree with you anything more for the street and random track visits is pure waste. Thanks again for the post and sharing your build since it had a huge influence on mine
Frank

If your goal is 500 I would go 3" down pipe and 3" exhaust

Honestly at first I was thinking this same exact thing, but sam reassured me that I will have no problem hitting 500 rwhp with this setup. Also isn't this a ongoing argument Fusz weather to get 2.5 or 3 for TT. I think some say with 2.5 your lower end is better but 3 gives you better top end then lower end. LOL i don't know feel free to chim in on that and take me to school lol.

As for what I have ordered I am just going to stick with the 2.5, like i said Sam said there will be no issue hitting my goal with this setup
Frank

You are correct with your stats, but I think you will get to 500 easier with 3"

No problem, Frank. Glad you could learn a bit and that I could help. I look forward to your thread with your final build and results! :)


No reason for 3" for 500whp on a DJ on the 3.7l motor. Actually, if you go with internal wastegates (which I did) you can have issue with boost creep/spikes on larger exhaust. I'm not sure if Frank went with external wastegates or not and would not have issue if so...but, he will still be fine with his goals on 2.5" exhaust. Maybe a little more wear on the compressors over time, but not much.

Now if you "massage" the downpipe(s) into 1" there may be issues. :ugh2:

Hmm, 3" was recommended for bigger turbo setups on the STI (2.5l F4). Much smaller engine, granted target boost was 23psi for me then, but I would imagine the 3.7TT flows a lot more than the 2.5T did. Freer is better for FI apps. .02

no 3" really is not a must have for all applications and ecspecially if you are not pushing too much power.

I would stick to what the pros at GTM say you can do and what is safe.

Single piping vs dual maybe?? Dual 2.5 would be 5 inches of total piping.

yeah i think 2.5 is fine for this setup..i believe the greddy kit is externally gated with a dump pipes..

That is not an accurate statement to my knowledge. A 3" single flows more than a dual 2.5" setup. Someone told me once that the single 3 flowed more. Dual 2.5 doesn't equal 5 in this case. The other great thing is that a single 3 weighs less. I loved the JIC Ti I had on my 350z.

definitely 2x2.5 does not equal 5

a 2.5" exhaust has an area of 4.91" to flow the air
a 3" has 7.07, so dual 2.5 > single 3"
and a 5" would have 19.64 square inches, huge!

yeah i would have to agree that two 2.5 setups will flow better than a single 3...the single 3 is less weight but the weight is relatively low to the ground so it really wont affect handling much..also the merging of two pipes into a single collector does create some extra turbulance as opposed to two separate exits..

however i believe the Greddy kit uses disco potatos which are known to push 3 inch piping without any trouble..

Actually, TD06SH-20g's.

Disco potato is a Garrett GT2860RS.

^oh 20g's aren't too bad..id probably ditch those however n run 28r's..haha

Single vs. dual is apples to oranges. Bigger is not always better, even when speaking of FI applications. If it were, why not go 4" or 5"? The reason is that exhaust flows in pulses and if it gets too cool due to a slower rate of flow (bigger exhaust will flow more slowly..especially if oversized for the application) the fluid dynamics change as well as the weight of the air mass. This can cause the exhaust to "back up" in the exhaust sytem and the motor to work harder to expel it.

In truth, with the bends, length, resonators and such in place in different exhausts, it is hard to truly say what diameter exhaust will flow the best. Only flow rate tests can determine this. Who has time for that? :)

EDIT - BTW, the most restrictive portion of the exhaust system is the manifold(s).

troof!

Like you I did go with the internal wastegates. Like I said for the kit wise I stuck to your build for the most part. Simply because you had the same goals as me and the biggest reason to be honest this will be the first FI i did and you have struck me as a person that knows what is going on and how to do the job right. I am extremely excited to put this together and install it on my car. I have a buddy that is going to be helping me that is well qualified with this type of stuff and Sam told me that my kit is going to be shipping with the instructional DVD(thats why my kit hasn't shipped yet). It seems to me this 2.5 or 3 in exhaust is a ongoing battle like i said earlier to fuz and i think it mainly comes down to your goals. I am going to stay with the 2.5 and ride it out and see what happens. I have a strong feeling that it will turn out well and because of Sam's words which i quote "You will not be disappointed".
Frank

Well, to play devils advocate, I am running a 3" catted down pipe, into a 2.5" true dual exhaust. I am tuned at 470RWHP and locked at 6.5 psi.

With the internal gates you will be better off with the 2.5" all the way around combo. I would say, though, to stay within the 450-475whp range. I turned up the boost on mine yesterday for the first time to the high boost of a whopping 8.6psi and 520whp and traction was an issue. Second gear hated me and I quickly reverted back to the lower boost. It was not so much the upper HP causing the issue, but the higher torque numbers down low. Too much for the street IMHO. I think I'm just getting old. *haha*

yea thats where i am going to stay i don't want anymore then 500rwhp. Like i said i am super excited and can't wait to get this all done. I took a week of leave that way i can just sit down and take my time to do this. My Buddy is going to come over and help me out on the weekend to get me started and provide direction if I have any questions and after work he is going to shoot over. As for getting old I don't think thats the problem with not being able to stick lol. I think others between this forum and my350z were having this issue also with all stock. I don't know maybe I made that up lol. The last concern I have is just my warranty. I understand that I pretty much tossed that out the window on the engine and drive train, just if my headlights don't work I don't want the dealership to be like Ohh yea they don't work because of the TT kit you installed so warranty wont cover it lol.
Frank

PS fuz since I seen you reply on this, off topic I am in the market for a altima coupe new(hint hint). I spent my money to play now she want to play also, can't blame her lol

hey storm or anyone else, i have a question do you think I need a electronic boost controller. If so i have to figure out where the heck to put it lol. Thanks
Frank