Hey Guys,

I just picked up an HKS titanium full racing exhaust (4" from muffler to downpipe). Now my question is should I wait to install this or go ahead and put it on now?

OPTION 1: Basically, here's the situation I'm in. I can either wait and have the exhaust installed when I take it to the shop to install a single turbo and that way I'll be tuned and have a ported wastegate supporting it.

OPTION 2: Otherwise, I could install it now with the following relevant mods:

-Greddy 2-row front mount intercooler
-Pettit Ultimate ECU
-HKS intake
-Efini Y-pipe
-M2 Downpipe
-Supra TT fuel pump
-Koyo Radiator
-Aluminum AST

With OPTION 2 as my car sits now I have some boost issues. I'm almost positive it isn't a vacuum hose issue (still running sequential stock twins) and I'm leaning towards it being a fuel issue, either filter or injectors both of which are being replaced. Now after replacing the injectors and fuel filter if the car still is not boosting right, do you see any problems in me running this exhaust. I figure if the car is not boosting properly to begin with I can't/shouldn't have boost creep issues, correct? If this is the case I'd like to go ahead and put the exhaust on.

In any case, for OPTION 1 I will be having all necessary fuel modifications + Apexi Power FC + HKS Ignition + Boost Controller + the Single turbo kit w/all accessories as well.

Thanks in advance for any advice being offered.

Riz

 

Oh forgot to mention this exhaust will be replacing a catback + hi-flow cat that I'm running. Thanks.

 

I would recommend in just waiting, if you are going to be doing all that other work. The 4" full exhaust will creep like a **** on a stock wastegate if you don't have any leaks in the system.

 

I agree with rynberg. A 4 inch piping exhaust is overkill on anything less than ~500 rwhp. I plan to make 450 in the near future and am content with my 3 inch exhaust.

Also, with a single turbo setup you will have an external wastegate. Porting refers to enlarging the stock internal wastegate orifice. Big difference .

 

Personally I would sell it and get the HKS Super drager launch race exhaust... its a 5 inch exhaust.









J/K







But really, I would wait. Nice exhaust though. GOOD LUCK!

 

Wait it out

 

My mistake. That's actually what I meant. I'll be running an external wastegate in the near future.

Anyways, I guess if my boost leak still exists after changing the injectors and fuel filter I might decide to put the exhaust on otherwise I'll just wait, which will definitely be a challange. Thanks for the help.

 

Farhan, don't worry about the wastegate. I'm sure Sean is more than capable and will know exactly what to do, provided he does the install from start to finish. Just stick w/ his recommendations. He's been doing this for years.

Re: the exhaust, the smart thing to do is NEVER mod the car until it's running 100% fine. Why? Cuz if you *still* have a prob after a mod - or even worse, you develop a new prob, it makes it MUCH harder to try and track down the origin of the prob. If you can't figure out the boost leak, have Sean look at it. I'm sure he can have it done in a few hours if you make an appointment ahead of time. Oh and boost prob is *very* diff from a boost *leak.* A leak, you can isolate the region it's from simply by spraying carb/brake cleaner w/ the engine running until the engine stumbles. As for a boost problem, that's a total diff story...

 

Thanks Ramy for all the info, but I'd like to explain my logic for installing the exhaust. IF I still have, which I believe to be a boost leak since the turbos are still spooling but just not past 5 PSI, I want to go ahead and install the exhaust. From my understanding, the MAIN problem with installing a midpipe is boost creep, and I would imagine that if my turbos are not letting me boost past 5 PSI even after I try to fix what I believe the problem to be then the whole issue of boost creep shouldn't even be taken into consideration. If I can't boost higher than 5 PSI, why worry about creeping past 12 PSI or higher.

I understand that in the end it's probably both smarter and safer to NOT install this part until after I get the external wastegate, but I figured it's better to collect all the details and honestly it's kinda hard to be patient when this exhaust is just sitting in my garage floor. I really can't wait to hear how the car will sound .

 

To rephrase, you wanna install it cuz ya can't wait And I don't blame ya haha.

I say get the boost issue fixed, enjoy the car for the rest of the summer, then once it starts to get cold out, leave it w/ Sean for the big overhaul

~Ramy

PS: While you can't make more than 5psi now, make sure you're not flooring it, trying to boost at all. Cuz you'd literally be pushing your turbos up against a brick wall; they'll continue to spin faster and faster, trying to reach the targeted boost, and can eventually *literally* break apart into pieces. I don't think you wanna know where those pieces can go... So yea, lay off the boost until she's fixed.