Open turbo: mistake or good thinking?

[2js]

Just a piece of advice sir, playing with things that you don't know about is NOT wise

Sorry for the double post, I just saw this response.

My question is then how do you ever learn??? I hope that I wont screw up anything too bad that a mechanic can't fix. I mean, I understand MK3's are getting harder and harder to find, and it is disrespectful to take another one out of the pool of car's because of my stupidity. That is why I will try to post my idea's or google them before I try.

Maybe the reason I couldn't find anything on open turbo is because no one else is stupid enough to let slip their mind that exhaust is hot. HAHA. :aigo:

 

[hvyman]

ddp do add hp because the waste gate will cause turbulence in the exhaust flow robbing some hp. if you reroute this down stream is does not effect it as much. this is only on internal waste gates tho.

 

[2js]

ddp do add hp because the waste gate will cause turbulence in the exhaust flow robbing some hp. if you reroute this down stream is does not effect it as much. this is only on internal waste gates tho.

ohh! This actually makes since to my small knowledge of turbocharged car's. Thanks.

30 hp is huge! I still have a hard time believing that just by swapping a DP you can pick up that many horses.

 

[Poodles]

Why not run a 3" dp to the stock catback? You will still pick up power.

BTW, there is no such thing as backpressure. Just ask Figgie to explain it to you, lol

Stock catback is terrible, though I did see gains with the DDP only, the rest of the exhaust made the biggest difference.

Okay, that sounds like a good idea speedgilligan, I am assuming you are referring to running exhaust pipes out the side of the car under the door? I could probably get my local shop to do that for me, and probably pretty cheap if I don't ask for a muffler or anything special. Sorry I don't know terms very well if this isn't what you are talking about.

No such thing as backpressure? I have read quite a few debates on backpressure, it seems like people say exhaust back pressure doesn't even exist on a built 2jz with 2.5 inch piping. I would believe this but I have to ask why the HP boost when the exhaust is gone then? (Pardon my ignorance.)

Nghty89, I have also been looking at the split DP's with the waste going into a separate pipe, and the manufactures claim some 30hp increase over OTHER DP's. This is an automatic back click on the browser for me, no way is it a 30hp increase, or should I believe this?

I have also read some about the exhaust being really restrictive on the engine, but not because of the mk3 cats. Is this because of the turbo elbow or some other fault in the exhaust?

jdub, if I wanted a FWD fart-cannon I would certainly obtain the wonders that is a civic. :icon_razz

Back pressure doesn't exist, it's flow, velocity, and the scavenging effect. Smaller exhaust raises velocity increasing cylinder scavenging which pulls out the exhaust and because of vallve overlap in the cams, will pull in more fresh air. This will make more power down low. None of that matters on the turbo car as the turbo is the largest restriction in the exhaust (or should be) and the air is forced into the cylinders and valve overlap is at a minimum.

The turbo elbow is a serious restriction, as are the cats if they are clogged. The piping and mufflers are as well. It's not a fault as the supra is NOT a sports car, it is a GT car as such it's meant to be quiet and comfortable as well as perform.

 

[gaboonviper85]

Okay, that sounds like a good idea speedgilligan, I am assuming you are referring to running exhaust pipes out the side of the car under the door? I could probably get my local shop to do that for me, and probably pretty cheap if I don't ask for a muffler or anything special. Sorry I don't know terms very well if this isn't what you are talking about.

No such thing as backpressure? I have read quite a few debates on backpressure, it seems like people say exhaust back pressure doesn't even exist on a built 2jz with 2.5 inch piping. I would believe this but I have to ask why the HP boost when the exhaust is gone then? (Pardon my ignorance.)

Nghty89, I have also been looking at the split DP's with the waste going into a separate pipe, and the manufactures claim some 30hp increase over OTHER DP's. This is an automatic back click on the browser for me, no way is it a 30hp increase, or should I believe this?

I have also read some about the exhaust being really restrictive on the engine, but not because of the mk3 cats. Is this because of the turbo elbow or some other fault in the exhaust?

jdub, if I wanted a FWD fart-cannon I would certainly obtain the wonders that is a civic. :icon_razz

the term "BACK pressure" is a lie and not possible! There is "pressure" though....pressure buildup after the turbo is only going to hinder turbo operation this is true....

So....now you know....and now you'll laugh at all the tards who talk about this mythical beast called "back pressure"....might as well call it lock ness.

 

[IJ.]

"EMAP" aka Exhaust Manifold Absolute Pressure....

It exists between the Turbo and the Head and if it's higher than the incoming boost pressure it WILL effect the engines output...

This could be the mythical "back pressure" people live in terror of.

I guess it could also hold true in an NA if you saw more than 14.5psi measured between the head and the muffler.

 

[hvyman]

ohh! This actually makes since to my small knowledge of turbocharged car's. Thanks.

30 hp is huge! I still have a hard time believing that just by swapping a DP you can pick up that many horses.

30hp is huge for a exhaust gain yes but for major gains its very small.

 

[2js]

Thanks for the explanation. I didn't really understand it, but I will take what you say for granted. I guess when I thought of "back"pressure, I more thought along the lines of excess pressure building up in the small space that is the exhaust piping. Not literal pressure going backward into the piping. And the whole velocity thing makes a lot of since, I mean the smaller a pipe the quicker each molecule has to be moving in terms of flying out toward the back of the car.

The more I think about it the more I realize true back pressure is impossible, especially with a turbo, and even if back pressure did exist I believe I would be correct in assuming it wouldn't exist in the actual piping OF the exhaust, because there is really only one thing for the fumes to do after the turbo, and that is fly out of the piping. There is no reason for any backward pressure on the gas itself.


Soooo, if I were to try some cheap modifications to the exhaust, would you guys recommend trying to pound out the elbow, and gutting the cats. Or just recommend getting a new DP, and gutting the cats. Should I also buy a new elbow? Or will the elbow be replaced with the new DP?(I am sort of guessing it depends on what downpipe I get...)

 

[Poodles]

Not gonna pound out the elbow as it's cast iron.

There are only 3 reasons not to run cats (really 2):
-You run leaded race gas.
-You're a cheap ass.
-You don't have emission testing where you live (but still, you're cheap).

A properly functioning high flow cat doesn't restrict flow or hurt power, it just cleans up the exhaust so people behind you don't have burning eyes...

 

[Nghty89]

Depending on the DP you buy, it may have an elbow on it. Or the elbow will be seperate. Usually the all in one's tend to be a little less costly than buying both pieces.

For example, here is my DP. Cost $218 shipped. Not bad in my opinion and it is a great piece. 3" from the turbo back, with no restrictive elbow. I will end up with a test pipe and full 3" system from there back until I can get my high flow cat.

This is only one example though. Tons of choices.

 

[2js]

Not gonna pound out the elbow as it's cast iron.

There are only 3 reasons not to run cats (really 2):
-You run leaded race gas.
-You're a cheap ass.
-You don't have emission testing where you live (but still, you're cheap).

A properly functioning high flow cat doesn't restrict flow or hurt power, it just cleans up the exhaust so people behind you don't have burning eyes...

Lmao, I am a cheap ass. I do feel bad about the environment, and I try to lower my carbon footprint as much as possible, so I think I will keep the cats on, I have heard they flow nicely for stockers.

Nghty89, if you have time could you send me a link to that downpipe, I think I will order it tonight. That is a great price. And I can just replace the turbo elbow and DP with this and it will hook right up to the midpipe right?

Also, is that a pre cat on your downpipe I see or what is the bulge? Sorry for the dumb question, I have limited knowledge of exhaust, except that you bolt it and go.

Thanks a lot for the time you guys take to respond to the dumb thread, especially how it started.

 

[Nghty89]

PM Grimsta and let him know which of the items on that front page you want.

http://www.supramania.com/forums/showthread.php?t=61543&highlight=zankoku

It's the $200 megamouth 3" kit. The bulge is a flex section, which I will add is very nicely done as well and actually flexes as necessary. It should remove the first cat, but you will still need the one in the second spot. Call them if you want, Ace can explain anything you need to know about it.

Number is here: http://www.myspace.com/zankokuperformance

 

[S.A. supra]

do it and then take pics of the aftermath PLEASE.

but seriously why? why not just keep the exhaust on till you can actually afford a real one.

Oh man, I busted out laughing and woke up my gf. Maybe i'm just sleepy

Yeah just do every one else does dp or ddp and a test pipe or high flow cat. Then you can run a pipe straight back or a good cat back. Don't kill any brain cells if you don't have too. Those fumes will kill you.

 

[2js]

PM Grimsta and let him know which of the items on that front page you want.

http://www.supramania.com/forums/showthread.php?t=61543&highlight=zankoku

It's the $200 megamouth 3" kit. The bulge is a flex section, which I will add is very nicely done as well and actually flexes as necessary. It should remove the first cat, but you will still need the one in the second spot. Call them if you want, Ace can explain anything you need to know about it.

Number is here: http://www.myspace.com/zankokuperformance

Ohh man, they have a ton of great priced stuff, thanks for the link.

Alright, I will let this thread die now, I have gotten a ton of great information. I really really appreciate no one flaming. Especially because I have said somethings worth flame.

Until the next dumb question. peace

 

[92TealSupra]

Turbos need back pressure too, what would that do if you didn't have a down pipe, plus your harness would fry in about 34 seconds. After that you would roast your under the hood insulator.

 

[gaboonviper85]

Turbos need back pressure too, what would that do if you didn't have a down pipe, plus your harness would fry in about 34 seconds. After that you would roast your under the hood insulator.

Teal....again back pressure doesn't exist and the only pressure a turbo wants is between the head and the turbo...nothing after that...ever!

 

[Flateric]

Unless we start talking about 2 stroke motors, then there is and it actually does need backpressure for best function. On small motors anyways, like 50cc-90cc. I every once in awhile strap a chainsaw motor to a kids scooter for kicks. Got 3 of em now, damn quick little death traps too! LOL

 

[gaboonviper85]

Unless we start talking about 2 stroke motors, then there is and it actually does need backpressure for best function. On small motors anyways, like 50cc-90cc. I every once in awhile strap a chainsaw motor to a kids scooter for kicks. Got 3 of em now, damn quick little death traps too! LOL

That's cause 2 strokes don't have "valves"....2 strokes exhaust system as in reality a musical instrument....sound waves reflect back and at a certain rpm the system syncs and the waves will reflect back unburnt fuel back into the cylinder aswell as push air back in just before the piston seals the port....when this happens you experience the famous 2 stroke powerband

 

[Heavy D]

i had open DP on my 4 banger tercel with a toyota starlet motor in it, thing was a beast and was faster than a RSX, and the turbo spools up at 1500 rpm and was ready at 2200 rpm, and boy did i miss that car, but the DP is very loud, not loud as a supra but still was a bit annoying

 

[Flateric]

For the very brief 80KM or so I got of driving in the late fall I already know without any doubt I will not be keeping the car as an open dump wastegate.

Wayyyyy to loud, sorta sounds like a truck actually and I'm not digging it.

I don't need attention from cops, or anyone else for that matter, not in that way atleast. The honda's can own that loud exhaust market, won't miss being that "cool" for a minute.