unuseful turbo information
 

been researching turbos and found this uk site well worth a read heres just one section.

i didnt realise that fitting a large bore exhaust creates a problem trying to control boost!!!!

refer to section exhaust systems:
We have a particular component here which divides the tuning fraternity down the middle…some people believe a drain pipe exhaust system (3.5-4.5”) is the way to power nirvana, where as there is a camp that believes in a well made average size (2.5-3.0”) with flowing mandrel bends will be of more benefit…we tend to sit in that camp for a couple of reasons.
1.The engine/turbo combination on any vehicle was never designed to run with a 4” ‘drainpipe’ exhaust with one straight through box at the back.

2. These big exhausts often have very detrimental effect on the turbocharger, the turbo oil seal system is designed to run as a pressure differential seal and the lack of back pressure is one of the first reasons a turbocharger leaks oil (smokes at idle and on overrun). How many turbo cars do you see with 4” exhausts smoking at the traffic lights?
3.The other important fact is that the waste gate system (on integral waste gate units) are designed to have back pressure to equalise the gas pressure before & after the turbine…this differential can be so distorted by these exhausts that the waste gate can no longer control the boost which leads to boost spikes, boost creep and the worst effect can be over speed of the turbine rotor which will cause premature failure of the turbo.
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http://www.turbodynamics.co.uk/faq.htm
I have fitted your new hybrid turbo together with a new 3 inch exhaust and I cant stop the boost pressure rising? This is called "boost creep" quite often when fitting a new hybrid turbocharger and /or a new big bore exhaust system it has a detrimental effect on the balance of back pressure between the turbo and exhaust system, this in turn stops the wastegate from functioning as the gas pressure takes the easiest exit and bypasses the valve.

hahah if anything is proof that a bigger exhaust is better for power, it's boost creep.

the simple truth is that if your wastegate is too small, you will not be able to control boost adequately.

get a bigger wastegate.

This is the stupidest thing I have heard all day...you WANT a bigger exhaust, why do 800+ whp Supra guys run 4" or 5" exhaust?! Boost creep is caused by a wastegate not being able to flow the abundance of boost fast enough, solution=bigger wastegate!

instead of boost controllers we should all just run 1" exhausts for that epic 20psi of BOOZT

when you say bigger wastegate are you meaning stronger spring instead of using a 7psi spring use a 15psi spring tocontrol the boost better?

if not say i have a gt2860rs disco potato how do i fit a bigger wastegate and where from?or are you referring to fitting an external wastegate from that site it says if theres no backpressure the exhaust gas takes the easiest route down the exhaust avoiding the wastegate sounds like back pressure is needed no?
also whats the advantage of having an electronic boost controller over having just a wastegate set at 15psi?

They mean by bigger, the size of the opening in the valve. Like 38, 44, or 46 mm. You will pretty much need to go external on your turbo if you want bigger. Though I have seen people replace the flapper on a internal gate turbo with a larger one and port the opening to match.

think about how a turbo is powered, by exhaust.

if you have such a large exhaust and such low back-pressure that encourages flow through the turbine, how is a pea sized little hole that opens up going to flow enough gasses through the wastegate and bypass the turbine, slowing the turbo, lowering the boost?

3" exhaust is the reason I can't get rid of boost creep, but external wastegates setups arent cheap.

port the wastegate.

i already done did that

right i can understand in order to run an external wastegate i need a manifold that has that fitment for one.but how do i convert the standard turbo to run with an external wastegate?

buy a turbine housing that doesnt have a wastegate in it, or else buy about 5 minutes of time from a good metalworker/welder

If you know a good welder, you can have the internal flapper welded shut...

if i weld the flapper shut how do i control the boost?

if i buy a turbine housing without wastegate will it still have the same 5 holes to bolt up to a turbo elbow?

are you trolling?

your previous post was a question about how to run an external wastegate if you already had an internally gated turbo, then when we told you to weld the internal wastegate shut, and you asked how to control boost?....you have some more to learn.

There are a huge number of turbine housings that are designed to match the 5-bolt setup without a wastegate for the sole purpose of being able to swap your IWG housing out in order to run EWG without needing a new downpipe (though you will need to figure out how to get EWG gasses back into your downpipe.

ahhh sorry i follow now so i weld it shut then i can buy a manifold to which i can mount a tial ext w/g is that right?

or i can just run it without the gasses going back into the main exhaust pipe called a screamer i think.

This is a beautiful example of the reason why you don't believe every theory postulated in a forum. Every bit of it is rubbish.

please explain why it is rubbish

try reading all the previous posts on this thread, they already explain why it's bunkem.

i want you to explain why its rubbish though

1. No matter how 'well made' a 2.5 or 3 inch exhaust is, they will never be able to flow enough air to produce large amounts of power (500+whp).

2. Read up on how pressure differential across the turbine affects boost threshold and power production. (Hint: It has everything to do with both).

3. As for oil burning due to lack of pressure. I can see that being an outside possibility, but frankly if there is so much pressure in the exhaust that it is keeping back the oil AT IDLE, then you have a serious fucking problem.

4. The theory that wastegates rely on exhaust backpressure to control boost is somewhat founded, but incorrectly interpreted. Yes, having higher backpressure will make a smaller wastegate better able to control boost, and once you free up the exhaust you will encounter spikes and creep. But as EVERY SINGLE FUCKING PERSON in this thread has pointed out, the issue is resolved by simply RUNNING AN ADEQUATELY SIZED WASTEGATE. The sad truth of the matter is that cars, no matter how well they were originally engineered, tend to be finalized by accountants. Internal wastegates are a. more economical to package, b. cheaper to produce than full on external setups and c. adequate for stock power levels most of the time.

The holes are just too small to control boost in a performance setting.


It seems to me that the author of that article is essentially stating that a stock piece of equipment should be perfectly adequate to handle increased power output without issue. This is bullshit. If that were the case, all turbocharged cars should come with 2600+lb pressure plates (or twin discs) forged cranks, rods, oil pump gears, and pistons. Heavy as fuck, shotpeened, cryotreated gears and 9" differentials.

But they don't.

running 3" catless system on the mazdaspeed 3 greatly increases your chances of smoking at idle due to oil leaking from seals (i did but found ways to fix/hide it)...but that is because of the shitty turbo. guys who slap on a garrett turbo never have that issue.

Is this the dose pipe guy?

BECAUSE ITS NOT FUCKING TRUE, THATS WHY

There is an extraordinary amount of misinformation on the web about turbocharging and engine performance in general. Misinformation is not allowed on this forum, so if everybody is telling you that the shit you read on jdmsrt4forum.org is wrong, just accept it until you actually understand what youre talking about (its clear at this time that youre still learning)

yep its me the dose guy that was something i found on youtube not something i nor many associates practice!

yep iam learning and still researching hey i helped someone clock their turbo on the next thread down so i must be storing what iam learning.

the more i read into turboing my car the more expensive its getting what with external wastegates :(

at least you understand that to do it correctly you're going to want to invest in good/expensive parts.

So your saying this boost creep I had was cause by my massive 2.5" exhaust and muffler? not the tiny wategate? :giggle:
Attachment 194607

I has a 2.5" DP....

http://www.boostedmiata.com/gallery2...oost_creep.jpg

I have had a 3" exhaust on my turbo car for like 40,000 miles or so and my car dont smoke at alllllll. ask braineack. he can vouch.

edit: also my large wastegate means I never boost spike. I sealed up the lame internal gate and put on a tial external.

There are lots of places to save money

Basically, the big espense is a T3 manifold w/ flange for EWG.
Then get a small chinese T3 on ebay and an ebay (XSpower) EWG, replace the spring in the WG with a Tial spring and now you have a good wastegate on the cheap.
Then just figure out a downpipe and a dump tube for the WG (dump tubes are hella cool)

Lulz @ thread title change...

lol

although once again the turbo Gods have released their ingenious wisdom to counter the force of the former NOS-slapping-sticker queers,

can i just say THREAD FAIL.

I don't feel like going back to the first page to check, but has no one pointed this guy toward the FAQ or suggested he read up on how turbocharging works?

Wirelessly posted

Sure someone did... But you how some people are.

I started two different long explanations that I never got to post because my work laptop keeps crashing. I'm not putting forth the effort again. Google it and read more just like we all did as newbs. I'm tired.