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Engine Specific Info and Questions => IDI Engine => Topic started by: HarryMann on October 05, 2006, 10:05:13 am

Title: Exhaust manifolds
Post by: HarryMann on October 05, 2006, 10:05:13 am

I am currently fitting up an 1.9 AAZ engine with the manifolding off of a 1.6TD (JX vanagon parts).

Having enlarged and re-shaped the ports of the inlet manifold to match the head, I have now been surfacing the exhaust manifold ports (big thick ally plate with 80 or 120 grit paper stuck on with spray-tack).

I've noticed:-

 The exhaust ports in the cylinder head are substantially smaller than the gaskets and the exh. manifold ports. If anything, this seems the wrong way around going from 1.9 into a 1.6 manifold!
 Anyone else noticed this and is it deliberate, to expand the flow suddenly into the manifold perhaps?

Thanks for any observations on this, even though we're turbocharged, getting the gas in nicely and doing whatever it takes to get it out and drive the turbine best is still important, IMHO.

PS. Surfacing both the inlet and exhaust manifolds has been a bit of an eye opener, any leaks or misfits here and you could be throwing hard earned power away. In fact, one of the original exhaust ports (rear, No4) seemes to have been leaking at the gasket, to some extent. Both outer port flanges sit 0.025"~0.050" below the two inner ones, which I magine the gasket can handle .

Title: Exhaust manifolds
Post by: VentoTD on October 07, 2006, 05:27:58 am

Exhaust ports are smaller than gaskets and ex manifold. I ported mine so it got same size as gaskets.

Title: Exhaust manifolds
Post by: HarryMann on October 07, 2006, 07:22:52 am

Thanks Vento. Confirmed that for me.

Did it go any better of worse?

Or too many other modifcations to be able to say?

Title: Exhaust manifolds
Post by: VentoTD on October 09, 2006, 02:39:25 am

Too many other modifcations to be able to say - right. But im sure its good when you tune your engine, good to get rid of hot exhaust gas.

Now its no fun at all my turbo just died...

My manifold and head: http://200sx.kicks-ass.net/album/album.php?username=gasbjorn&cat=5443

Title: Exhaust manifolds
Post by: HarryMann on October 09, 2006, 03:16:45 am

Nice exhaust work!

What is the code on the cyl head? Mine is an 'M' mod number, but I can't find its origin in ETKA.

One point...  I've heard that wrapping the manifold like, whilst obviously maintaining exhaust gas energy can cause very rapid corrosion/oxidation of the steel. In that case, some or all of these oxidation products will be going through the turbine section - is that what has suffered?

Title: Exhaust manifolds
Post by: VentoTD on October 09, 2006, 04:49:17 am

The turbo was in bad shape before i fitted it on this car. And its too big so it surges before i get things spinning... Dont think corrosion is a big issue.

I see some numbers and (*a or an) H, why?

*Dont remeber grammar rules, must have been busy with other more interesting things in school... (my bet is an)

Title: Exhaust manifolds
Post by: HarryMann on October 09, 2006, 08:44:48 am

A long story but due to Cam Cover drillings (different for JX 1.6 head)

My VEGE replacement has these holes drilled for flange mounted studs, so I'm cuious what it came off
Its an 'M' mod number, the JX that used this style of camcover is a K

068 103 351 M

But no problem, not that important.

Believe that frequent compressor surging damages the compressor side bearings.
What are the symptons of surge from a driver's perspective, if any? Noise? Boost gauging falling back? etc.