Stainless Steel Exhausts

About a year ago I received much advice and positive help here on the conversion of my 2006 V8 GXI-F to closed circuit cooling, (as apposed to raw water cooling) Much discussion was about whether to include the exhaust manifold/risers in the cooling circuit.

On this subject someone suggested replacing the heavy cast iron manifolds and fitting SS extractor exhausts, then the problem would go away.
Well I did this late last year and the results are very real and obvious!!
They weigh approx 1/4 of the cast iron units. So much so that the top of the stern drive is now about 1.5" above the water line.
Because the internal curved "extractor" design allows for much greater and freer exhaust flow I recon I have gained about 30-35HP (I am not exaggerating) The suppliers do state a gain of 30HP on a 270HP engine.
The acceleration is also much quicker.
Also I estimate that the fuel usage at a moderate speed of 40-50Km has decreased by about 15%
They are of a one-piece design with no separate riser bolt-ons so the problem of corrosion and hydraulic locks goes away.
They are designed as a single one-piece fitting from the engine manifold ports to the flexible transom pipes, so they need to be specifically frabricated for each engine/stern drive configuration.

However there is one caveat: Because they are individually fabricated to fit the engine model and type (of which there are many). The mounting brackets for the ECU, ignition control unit, oil filter and other components that are normally mounted on brackets which bolt to the OEM exhausts, now need to be accurately positioned and welded to the new SS exhausts.
This is where problems can occur.
In my case I had to make additional extensions and adapters from 3mm mild steel plate so as to match the located positions of the components as they were fitted to the cast iron risers on my 2006 GXI engine.

Now this is not a high price to pay IMO for the vast advantage that the SS exhausts offer and for other engines there may be no problems at all.
I cannot understand why the big three do not fit them as standard, unless there are problems that I do not know about.

First.. whose did you use and if I may ask, how much did they cost...how long to deliver?

Second... the manufacturers are very "cost conscious". An example, recently bought a pair of MERC Dry exhaust elbows for my 5.7 SBC. They were almost $280 each (discounted). The elbows come with two 3/4" threaded ports and a blocking plug so you can use the one you need. In manufacture, they did not bother the protect the threads either with a caplug ( about $.25 ea) or tape ( about $0.05) before painting. As a result, I had to spend some time clearing the threads before the plumbing would seat properly. If I had had to pay a mechanic to do this, and he had the proper tools handy ( I didn't) it would have been at least 15 mins of shop time for the pair of elbows.

Lastly...Manufacturers aren't motivated to either reduce their sales of repair parts or reduce the income of their "certified" mechanics.

Hi Bob,
I used the units supplied by Hi-Tek who are based in Queensland Australia. you will find them on the web.
I obtained them for AUS$2,500.00 (inc all gaskets and bolts) which would be about $2,000.00 in your money.
And they come highly polished which looks ***y but does nothing for performance!
He will not say what SS analysis he uses, but my own experience in metals is that it would probably be Duplex SS
Now when you think how much a set of CI manifolds and risers cost, the difference in dollars is not that great.
I believe that he used to make them in OZ but now gets them fabricated in China (where else!!!) and has them delivered direct to the customer, so the delivery is about 2-3 weeks in my case.
This business model does mean that he does not have an opportunity to check them before delivery to customer.
As I indicated they may require some mods to the brackets depending on the engine manufacture date. He can not be expected to track every detail change on every make and model.

What is interesting is that he indicated that he has tried to get the larger marinas "on-board" in offering and fitting them, but they are not interested. When you consider that a fair percentage of work involves the fitting of CI manifolds, risers and the like plus all the work arising from the resultant engine problems maybe it is not surprising.
I should state that I have no connection with the supplier, other than being a very happy user.

Hi nimbus,
I enquired about a set of S/S exhausts for my engine in February. I have not received any reply back from Hi-Tek. At the time their web site stated that the business was for sale. After reading your posts I'll try and give them another go.
Cheers.

Hi Bob,
I have been briefly in contact with Allan of Hitekmarine he will call me back in 2Hrs and I will then post again to you.

Hi Bob,
Allan has just called me. He says that he is offering his company for sale, but is still continuing to manufacture
his SS marine extractor exhaust systems.
hitekmarine.com.au (0419 688 694)
You may have been trying to contact a group in WA with very much the same name.