Turbo housing sizes

[Dred]

Without pulling apart, what's my tubro housing size 6 or 7cm?

I have stock 14b with all stock components. Thinking of a new (and not cracked) exhaust manifold.

Also, I've heard of a few people getting 2g exhaust manifold because they have better flow. Do they port them or just stoc the 2g manifolds are better. Also, what I dont get is how can a 2g manifold go with 1g 14b housing since from what i know they dont really match up in diameter. Or I'm totally lost and need some guidence.

Tried search.

 

[oldman]

14b has the 6cm. What you want to do is get a 2g manifold and port and match both the manifold collector and your 6cm turbine inlet to a 7cm gasket and you're good to go.

 

[Dred]

perfect!
i'm set straight now.

Cept for one thing tho...
Why does the 2g mani have the larger outlet than the 1g yet has a t25 with tiny housing?
Or does it?

 

[oldman]

Cept for one thing tho...
Why does the 2g mani have the larger outlet than the 1g yet has a t25 with tiny housing?
Or does it?

I don't know if the collector is larger on a 2g but I know the runners are larger and it doesn't crack easily like the 1g. Both 1g or 2g are smaller than 7cm so you will have to port anyway. BTW 2g manifold is a directly bolt on for the 14b.

 

[johnk]

The big benefit for the 2g mani is that they don't have cracks in them like our cursed 1g parts. The evo mani is bigger and if your looking for more then Slowboy has a cast mani that is even bigger. It comes out a little more from the engine(tough with hard water and oil lines fitting) then the mitsu parts do and if your sticking to your 14b as your choice of turbo it's overkill.

Here's a 1g/2g comparison http://www.vfaq.com/mods/exhman.html
and Evo/SBR comparison http://www.slowboyracing.com/more.php?id=1891&

 

[pboglio]

I disagree. I would port to a 6cm size, roughly 2.125", just to get rid of the ring step. Try the car out, feel the improved throttle response and top end. Hold off on the 7cm port job till later if you must go that big, but I recommend against it.

 

[Dred]

So, the only real benefit with going to 2g mani is that it's more durable.
What about gettin an after market "tubular" header, anyone know anything of these. Do the outperform the stock ones, lets say pacesetters for example. Do they crak in like 10k miles or any input on "performance" manifolds would be nice.

Thnx for everyone who answered already.

 

[johnk]

Did you just look at the pictures? The comparison was with a ported 1g manifold and the runners were the same size after he did all the work on it. I didn't notice until after I posted the link. The header didn't say that it was so I posted hastily.

 

[Dred]

Yep just looked, tks alot.
They are better flowing then 1g manifolds then.
Still, curious to hear some opinion on performence manifolds.

 

[JiveMasterT]

So, the only real benefit with going to 2g mani is that it's more durable.
What about gettin an after market "tubular" header, anyone know anything of these. Do the outperform the stock ones, lets say pacesetters for example. Do they crak in like 10k miles or any input on "performance" manifolds would be nice.

Thnx for everyone who answered already.

tubular manifolds have been known to crack... which kinda sucks cause ive seen quite a few of them at really good prices lately. i dont want one for my daily driver though...

 

[Dred]

ive seen quite a few of them at really good prices lately

That's my whole point, I can prolly get one for cheaper than a 2g manifold.

Why dont u want one for you daily driver?

 

[DBR01]

That's my whole point, I can prolly get one for cheaper than a 2g manifold.

Why dont u want one for you daily driver?

Don't know if it's emissions you're worried about but I have the pacesetter setup on my 2G and had them ceramic coated black, no cracks or CELs thrown. They've been on for about 7K miles. Hopes this helps ya!

 

[Revolution]

Tubular headers will almost always out perform the cast counterparts because of how they direct the gasses. My SS-AUTOCHROME Mani hasn't cracked yet and spools my turbo much faster then my cast Mani did. Then again I'm pretty sure it hasn't cracked yet because my custom 3 inch o2 housing has a bracket that mounts up to the old o2 housing local on the block which pretty much supports 80 to 90% of the weight. p.s not only is my car my race warrior but also my daily driver.

 

[25psilaser]

Like revolution said you have to support the manifold, at the shop i work at when we install a turbo header we use angle iron, and make 2 supports from the block to the turbo and we have never had one crack.

 

[JiveMasterT]

Like revolution said you have to support the manifold, at the shop i work at when we install a turbo header we use angle iron, and make 2 supports from the block to the turbo and we have never had one crack.

what kinda mileage are we talking about here with them setup like that?

 

[25psilaser]

Most of the cars we do it to are street cars and the one with the most miles on it is about 20,000 miles its a acura. what most people dont understand is the weight of the turbo and the exaust, and the fact that the motor is moving around alot.We have never had a problem just support the turbo and manifold.

 

[JiveMasterT]

Most of the cars we do it to are street cars and the one with the most miles on it is about 20,000 miles its a acura. what most people dont understand is the weight of the turbo and the exaust, and the fact that the motor is moving around alot.We have never had a problem just support the turbo and manifold.

i figured thats what ultimately cracked them, but then against ive seen SS Autochrome tubluar manifolds with braces that have cracked. So if i get a tubular manifold and support it, then it should be fine? thats good news cause as of late they have been out there for pretty cheap with external wgs. thanks.

 

[25psilaser]

Just run a good support from the block to the turbo and you will be fine.

 

[Dred]

Tks guys, really nice info here.

 

[BaddAssGst]

I disagree. I would port to a 6cm size, roughly 2.125", just to get rid of the ring step. Try the car out, feel the improved throttle response and top end. Hold off on the 7cm port job till later if you must go that big, but I recommend against it.

Anyone agree with this? I would think that 7cm would be the ideal size, even if your just using the 14b. I know the 16g and up have the 7cm housing, so I'm wondering why not use it on the 14b?

 

[oldman]

Anyone agree with this? I would think that 7cm would be the ideal size, even if your just using the 14b. I know the 16g and up have the 7cm housing, so I'm wondering why not use it on the 14b?

I too want to know, I have never heard of this. Maybe pboglio knows something we don't, perhaps he would come back and explain.

 

[pboglio]

I've tried all the possible combos on a 14b & 16g, you name it. The ported 6cm housing with a 2.125" dia inlet, and a match ported 2g manifold (runners untouched) is the best spooling, best throttle response, best overall power band combo for the 14b. If you want a laggy ass turbo, go ahead and put a ported 7cm housing on that 14b, I've done it and the lag is intolerable.

As for theory, everytime you step up and down in diameter you get a flow loss. Going from a small runner diameter, to a huge collector, back down to a tiny little 6cm turbine nozzle is not good for reducing flow losses. Why Mitsubishi uses a honking huge ass turbine collector is beyond me. You don't see this on Garrett turbos. If they separated all 4 runners and aimed them straight at the turbine wheel, instead of at each other, the exhaust reversion reduction would make that sucker spool and flow even better.

Yes, the car benefits from opening up the collector, absolutely. But there is a point where you can go too big, that size is a ported 7cm2 in my opinion, at least for a 16g sized turbo.

What do I run on my car? A ported T28, ported to "6cm" or 2.125" dia inlet. I'm certainly not being held back by this small collector size. I've already hit the compressor limit of my turbo and the turbo response and top end are pretty damned impressive. Most of the backpressure at this point is in the nozzle and turbine wheel anyway. My 2 cents.

 

[oldman]

Well, my butt dyno told me quicker spool after I port matched both my 16G and 2G manifold to the 7cm gasket, I was hoping you would have real dyno numbers instead of speculations.

 

[pboglio]

Well, my butt dyno told me quicker spool after I port matched both my 16G and 2G manifold to the 7cm gasket, I was hoping you would have real dyno numbers instead of speculations.

Typical "Tuner" response. You asked for an explanation, you got one. Don't like it, then don't ask for it.

Provide ANY datalogged or dyno data that your so anal about, and I'll provide before and after datalogs on what I have on porting, smartass.

 

[oldman]

Typical "Tuner" response. You asked for an explanation, you got one. Don't like it, then don't ask for it.

I'm sorry but I'll try and predict what your answer is before I asked or just take your answers as facts.

Provide ANY datalogged or dyno data that your so anal about, and I'll provide before and after datalogs on what I have on porting, smartass.

In 12 years of owning my Talon, I had never heard of port matching a 6cm housing to a 7cm gasket being a bad thing. In fact, this is exactly what vendors do when you pay them for a port job. You're the one making a claim against that so the burden of prove is on you, not me. I wasn't being a smartass, I was being serious in a nicer way.