Rx7 from Hungary

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chc
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Re: Rx7 from Hungary

Post by chc »

Hi George and welcome to the forum. You have a lovely looking version of this much sort after dream machine. May you enjoy and cherish this for many years to come.

Yes this company are excellent - Ross Anderton is the chap to deal with.
I arranged a discount for club members a few years ago and he is willing to honour this.

g-l

[/color][/color]
ian65 wrote:Forget Atkins George, their shipping costs are outrageous..... these are the ones you need and this company is very good...

http://www.ebay.co.uk/itm/Mazda-RX7-79- ... 3a85ffa1e1
Cliff

1983 Series 2 - Stardust Blue Elford Turbo
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Re: Rx7 from Hungary

Post by Rabban »

codge wrote:
Rabban wrote:You are right Codge, if it is not stainless steel, it won't last for too long :( .

George
No, I thought that mild steel would be good at the front end. Runs hot so I would think minimum rusting will occur there.
What I found about mild steel:
-Heat Resistance:
The maximum temperature at which mild steel can be used is 550°C. Above this temperature the formation of iron oxides and rapid scaling makes the use of mild steels uneconomical. For equipment subjected to high loadings at elevated temperatures, it is not economical to use carbon steel in cases above 450°C because of its poor creep strength. (Creep strength is time-dependent, with strain occurring under stress.)

Source: http://answers.yahoo.com/question/index ... 040AA6Fxda

About stainless steel:
Stainless steels are most commonly used for their corrosion resistance. The second most common reason stainless steels are used is for their high temperature properties; stainless steels can be found in applications where high temperature oxidation resistance is necessary, and in other applications where high temperature strength is required. The high chromium content which is so beneficial to the wet corrosion resistance of stainless steels is also highly beneficial to their high temperature strength and resistance to scaling at elevated temperatures, as shown in the graph of Figure 1.

Source: http://www.azom.com/article.aspx?ArticleID=1175

Of course I know that these sources are not perfect, but they make me think that stainless steel is the proper material for a header for my car.

George
codge
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Re: Rx7 from Hungary

Post by codge »

OK George, It does sound better. But I'm sure my old cars:-

1939 Austin
1953 Hillman
1961 Ford Consul
1967 Triumph

All those had mild steel front pipes because that was normal for those early cars. But they were low-powered 'sloggers'.

Having said that, I would probably have bought stainless parts for them if it had been available then
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Re: Rx7 from Hungary

Post by Rabban »

Hi!

I have a new idea :)

What if I leave my thermal reactor untouched, but replace the rest of the exhaust system with stainless steel parts (pipes, mufflers)? What is your opinion? Any experience with such a conversion?

The reason for this idea is that I can't spend a "magyar's ransom" (a lot of money) on my exhaust replacement, and this seems to be something reasonable as it is not my main purpose to increase horsepower.

Thanks,
George
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Re: Rx7 from Hungary

Post by TOOL »

Rabban wrote:Hi!

I have a new idea :)

What if I leave my thermal reactor untouched, but replace the rest of the exhaust system with stainless steel parts (pipes, mufflers)? What is your opinion? Any experience with such a conversion?

The reason for this idea is that I can't spend a "magyar's ransom" (a lot of money) on my exhaust replacement, and this seems to be something reasonable as it is not my main purpose to increase horsepower.

Thanks,
George
Waste of time. The thermal reactor is the first part you change out.
Back in the UK for the summer, maybe longer......
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Re: Rx7 from Hungary

Post by Rabban »

TOOL wrote:
Rabban wrote:Hi!

I have a new idea :)

What if I leave my thermal reactor untouched, but replace the rest of the exhaust system with stainless steel parts (pipes, mufflers)? What is your opinion? Any experience with such a conversion?

The reason for this idea is that I can't spend a "magyar's ransom" (a lot of money) on my exhaust replacement, and this seems to be something reasonable as it is not my main purpose to increase horsepower.

Thanks,
George
Waste of time. The thermal reactor is the first part you change out.
Ok, but why? Rust, unstable operation, technical issues?
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Re: Rx7 from Hungary

Post by TOOL »

It's incredibly heavy and is choking your engine.
Back in the UK for the summer, maybe longer......
codge
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Re: Rx7 from Hungary

Post by codge »

X 2 for that…..

when you pick up a thermal reactor off the car it's a massive weight and totally non aeroflow for the exhaust gases.
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Re: Rx7 from Hungary

Post by KiwiDave »

The purpose of the thermal reactor is to burn hydrocarbons using the exhaust gas. This then reduces the hydrocarbon output to acceptable levels which varied according to individual markets. This was primarily to satisfy US regs.
The sytem also required an air pump to inject air into the exhaust gases and this pump was belt driven.

So you have the thermal reactor which disrupts exhaust flow and an air pump which saps power from the motor.

Unless you have emissions reguations to meet, then you should get rid of the reactor and the air pump. The pacesetter headers look like a good deal. No real point in getting headers built in stainless unless you want them to look shiny and you have deep pockets. Even racing beat only use mild steel for their headers.
1985 Sunrise Red S3 TWR
2006 Mercedes CLK 280 Sport AMG
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Re: Rx7 from Hungary

Post by Rabban »

Hi!

I haven't been writing for a while. So here's what happened in the past half a year:
- I had my fuel tank cleaned and painted from the inside and the outside. My aim was to properly clean an treat the inside of the tank, but during the work, it became clear that the outside needs some care too. As I had a very limited time frame for the work, I could do the inside, but on the outside, I couldn't have a "permanent" solution, but it will be ok for 2-3 years I guess. So, after detaching the tank, I first evaluated the damage. Some areas (mainly the sides) were quite rusty, but I think it was not a big problem. However, I found some tinkering unfortunately. The place where the fuel level sensor is attached (I dont know the proper word) was removed before, but when they put it back together, they drilled the holes to make them bigger (or I dont know), and they drilled also into the tank. Ad to get it sealed, they used some siloplast
The way I found it
The way I found it
2014-03-15 09.43.51.jpg (1.45 MiB) Viewed 3708 times
. I also found a broken bit in the tank... Then, I roughly cleaned the outside with brush and sandpaper to remove the most of it . Afterwards I thoroughly cleaned, surface treated and painted the inside using POR-15 fuel tank repair kit. When it was finished, I applied some chemical rust removal on the outside, and then painted it to black. I bought some fuel resistant sealing material and applied it around the flange of the fuel level sensor (had no better idea). I attached some pictures to get a hint about the before&after situation. This work might seem tinkering too, but I'm just a beginner :)

- As I mentioned in earlier posts, my exhaust system had some problems too. My main dilemma was if I would stick with my thermal reactor system, or if I would replace it with something better. You all suggested me the second way, but I was not sure, so first I decided to get the back end of the system replaced some pipes, rear muffler). As it turned out, the old system was 95 % rust. When I saw it (before that, the heat shields covered all, so I couldnt have a look at it), I couldnt imagine how it could stay in one piece... With the replacement, the mechanic had done some welding to the holes on the front end system, but after a very few kilometers, I smelled the exhaust gas again indicating further holes. At the end, I decided to take your advice replacing the thermal reactor with a catalytic converter system. And here comes my new dilemma :) I found three possible manifold solutions:
- http://www.ebay.com/itm/1980-80-Mazda-R ... 9d&vxp=mtr This is authentic and cheap, but used :)
- http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 1565900987 This is the most tempting one, but the shipping cost from Australia to Hungary are frightening.
- http://www.ebay.com/itm/PACESETTER-1979 ... a0&vxp=mtr - good old Pacesetter

What do you think?

George
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