Hey, I'm in the middle of my build and I have planed on running open dumps. I have been listening to sound clips and I have to say they are loud. The plan is to be around 17-18 psi on wastgate. My queation is. Is it worth the power? Also since I'm going to be at 17-18 psi, Driving around town depending if I stomp on it or not they should stay closed correct? It seems that guys that complain bout them opening while cruising around are at 8 psi wastgate cause thats what the kit comes with and they are running stock bottom end I'm assuming. Lol I kinda still want to hear the turbos spool up. Looking for some opinions.... Thanks guys

 

I say run a WG spring lower than what boost you want to run (so lke a 12-14psi WG spring) and run a good electronic boost controller at 17-18psi. I say this because if you are running off the springs at 18psi, you are stuck dealing with the spring rates controlling boost (so boost MAY not come up as fast as you want), wheras with the BC you will be holding the springs closed as long as possible and the BC will open them at the last moment they can to hit 18psi quicker.

My HP curve came up much sooner when running off the BC vs running of the springs.

EDIT - Pic added.....red line is on the springs, Blue Line is the BC on (don't worry about peaks, different boost, just look at the added lag from being on WG springs alone)



tom

 

turbos will keep spooling until they hit the gate pressure. the jump between 8psi and 18psi is matter of seconds, so the amount of boost you run doesnt matter. If you floor it for any given amount of time, your gates will open.

They are loud. no video can capture how loud it is. drive around with your exhaust off for a real life example. granted its only when you get on it, so it depends on your driving habits.

Most cars dont even show a difference in spool with recirc'd dumps, so unless you like it loud, recirc is the way to go.

What kit?

 

And correct...open dumps are loud plain and simple.

Tom

 

I have open dumps right now and they are really loud, I want recirc, but I went to an exhaust shop today and it would have cost a lot! So I can live with the sound.

 

Could always put a muffler on each wg dump tube.

Tom

 

the sound is so addicting though. was one of my favorite parts i had on the car.

 

i love my dumps....dont get y people dont like it loud...thats like buying a 3inch exhaust and complaining it doesnt sound like stock.....

 

Thanks guys, I like what you said about the boost controler tho I'm going to talk to the tuner. Now just say I wanted to do away with open dumps. I have aam 3 inch down pipes w/ open dumps. How would I go about recirculate? Sorry if it's a dumb question, this is my first turbo build and I'm trying to learn...

 

Need to plumb the pipes coming off the wastegates (that currently just open to atmosphere) into the exhaust somewhere after the turbos (smoother flow into exhaust the better of course)

Tom

 

I'd plumb them into the aam downpipes to keep the wg tube distance as short as possible. Since I have 2.5" downpipes off the turbo, I put them a little further down into my 3" exhaust to prevent a restriction. But as noted mak sure it's a smooth shot to prevent boost creep and other issues.

Ross

 

Ok I got a little confused. I'm going to be runnin 14 psi wastegate springs and a boost control. Sorry if the questions like I said sound stupid just trying to learn all this and get some good advice. I'm for now going to stick with the open dumps. If down the line I want to change them I will. I just had the down pipes ceramic coated and not really up for grinding it off and welding up a flange and fabing a new pipe into the downpipe. Just gonna cost me more money at this point. I'm way over my budget as it is.. o well guess I'll be pissing alot of people off this summer...lol Also does the recirc rob alot of power?

 

Found this and been reading about it. What do you guys think about this if I were to think open dumps were to much. https://my350z.com/forum/forced-indu...-inside-2.html

 

Same here. Open dumps FTW

 

^ +1....

 

i just dont understand the arguement, your building a highly modified car, everything is loud. clutch chatter, noisy pumps, loud exhausts...open dump is an amazing sound. but dont act like a 5 year old who dropped there sweets because its too loud. you want a quite 500hp car, go buy an e55 amg

 

IMO loud isn't the problem with open dumps on a vq35 car, its the raspyness and tone. The boosted g35 I last heard had open dumps and it was loud, but so raspy and hoarse... Compared to a gtr it sounds like sh*t.
Do recirc wastegates sound less raspy and more towards that trumpeting vr38 sound (in person)?

 

might have to do with how the exhaust configuration is laid out. the gtr's merges into 1 large pipe. also, i havent seen any externally gated gtr's (havent really looked for it either i suppose), but gtrs sound much better than any vq ive heard ever

 

I love my open dumps, perfectly quiet around town but when those wastegates open up it sounds menacing.

 

id trade my car for a nice e55 amg anyday.