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hey guys just wondering if there are any benifits with splitting the wastegate gasses for the first 10-20 cm on downpipes... i think i saw hks ones similar to this!

and on the other end of the scale there are the single 3" pipe catering for both!

like batmbl is selling!

what are the pros and cons of these designs?

after taking the advice on the Next recommended upgrade thread i started a while ago i have since bought a fmic and have done a bit of research and found there are 2 ways to route the inlet air from the core!

---either in through the engine bay and infront of the engine and over the fan..

----or back under neath the core..therefore being able to follow factory pipes from this side!

from what i can see the first option is safer for the piping..however one has just spent all this money to lower inlet air then the pipes are sent right next to the engine..with the heat sink on this pipe thus reheating the air that had just been cooled! what a waste!!!!!can thermal tape fix this?

secondly to run the pipe under the core would be hard considering i gave R34 GTR end tanks and i have seen some cooler kits specificly designed for the end tank to point back the other way! also this return pipe has a greater chance of being damaged!

which option would be the best?

thanks ;)

pete

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The way id look at it is, what your planning to do with future mods. If your planing to change your inlet plenum to a front facing type then it would be easyer to mod pipe work thats run across in the engine bay. the intercooler still works fine when run this way. Prob would be easyer givin your gtr cooler is set up that way.

runing the pipe work back to the standard set up would prob cost less as you can use standard pipe work.

Both ways you still have to cross the hot engine to TB.

heat wrap is another tacktic used to try and keep inlet temps down, it will help to a small degree but some of the cons that people have told me is it can cause corrosion from traped moisture. i have wraped the standard crossover pipe and not had any problems.

I have heard from some people that having a separate wastegate pipe doesn't really have much of an advantage over a complete dump pipe (dump pipe without any separation of exhaust gasses) when dealing with the stock turbo. On the other hand I have had others tell me there would be a few kw in difference between the two pipe designs. I personally believe that with a stock turbo the separate wastegate pipe would give slightly better performance over the single pipe, with the real advantages been unlocked with a larger aftermarket turbo application.

The advantage of the separate wastgate pipe is to avoid/reduce any interference to the flow of exhaust gasses from the turbine when the wastegate is open, which in theory the single pipe will not do as well. Also the separate wastegate pipe should have a venturi effect on the wastegate gasses from the flow of the other exhaust flow, so the flow of the other exhaust gasses should "pull" the wastegate gasses out quickly due to the pressure difference out and keep the exit of both exhaust gasses fast. Please correct me if I am wrong though.

The advantage of the single 3" dump/front pipe would be the price, which would probably be cheaper than the separate wastegate dump alone, but of course choice of brand will influence this.

In the end I guess you have to work out if the slight increase from the separate wastegate pipe is worth the extra money and how extensively you will further modify the car in the future to determine which pipe is worth it.

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