Making extractors or making them fit?

[stephen low]

Guys

Am chasing advice on the best move forward with getting extractors into my car.

Followed up on Wayne Proctor's set of RMC extractors that he has for sale and had them shipped down but they don't fit. I thought the RMC and G Force would be sufficiently alike for these to match but no luck.

They are close to fitting but I now realise that any changes needed are likely to generate the need to reweld most of the bits being modified.

I don't have access to a mig and haven't used one otherwise I might have considered attempting the mods. myself and my budget will be stretched if I have to get a fully prepared system.

Anyone got some useful suggestions, as this whole jigsaw puzzle is driving me nuts!!

Cheers

Steve

[Aussie Mike]

There are alternatives to headers. There are a few styles of block hugger and shortie headers out there that may be easier to fit.

You could even run factory manifolds till the funds are available to build a set of custom headers. I'm sure you'll be able to pick up some factory manifolds for your XR8 motor for next to nothing.

I built a pair of these manifolds for my under body system. They started as a pair of factory corvette pressed steel exhaust manifolds that I picked up cheap on ebay. I cut them down and made and new collector and put in an O2 sensor bung. The bend runs in close to the block and bolts directly to the Cat converter. The whole thing is modular and easy to unbolt. Easy to build, compact and cheap.




Cheers

[Churchy]

Mike,

And more importantly than cheap and modular. They are transportable across state borders. For a couple of beers I am sure ...

Cheers

[stephen low]

Thanks Mike but I did get the tri-wire exhaust system that is run standard on this motor and there is no way in heaven that these would have come close to fitting. I would presume there is something similar for the windsors but beyond the aftermarket huggers I haven't seen a similr beast.

If I have to do a cut and shut I may as well use my standard pipes which came with the O2 sensors in place and cats!!

It was just that the RMC and G Force kits looked the same that I took this punt, and clearly they are very close given some of the clearances I have but not just enough.

Given your experiences building these bits, is it terribly difficult for a beginner, or just time consuming? If the latter I am all ears as I have the time if not access to the equipment at the moment!

Let me know.

Cheers

[LoBelly]

Hi Stephen

I ordered some shorty headers that looked good on paper but ended up working on one side and pointing straight at a chassis rail on the other (needed 2 lefts - or something) anyway - gave up on that and swapped back the shorties for a header kit.

Making headers (imho) is one of those jobs where its only moderately difficult if you're not too fussy and where a good looking job requires a degree of art.

It is time consuming but probably within your abilities if you have a mig or other method to make the joins.

But since you dont have a welder and you do have the factory manifolds why not use them. Your 220kW (295hp) engine would have run fine in the car with them - and you were going to get sidepipes later anyway - right?

Chopping down the straight bits to suit the cobra will be no fuss and look nice and legit for Mr Engineer & Mr Rego.

Better to progress that now and get a good result than to get hung up on a set of bespoke header that probably will offer only minor advantages for your engine.

I you really get stuck zapping your tubes let me know

ta
LoBelly

[Plums]

I used to think the RMC and G-Force kits were pretty close, (I was under the impression that G-Force was actually a copy of RMC) but I couldn't be more wrong, they are vastly different beasts...

Having recently made my extractors, the hardest part is the rear cylinders (on my LS1 anyway). The rear-most pipes have to bend down sharply to avoid the footwells.

I have virtually no welding experience and I did them, I just took my time and trial fitted things a few times before tacking them together.... They mightn't look pretty but they'll do the job I hope!

[Gav]

Slowy,
There is no such thing as a bad welder, only a bad grinder!
MIG welders are great, and easy to use. They are like drawing with a texta!
Now, to bring those welds up nice and smooth, use a flap disc in your grinder. They are a disc with overlapping sheets of emery and come in different grades. 80 - 100 grit brings those pipes up beutifully. They are available at most hardware joints, such as bunnings.
You will amaze yourself with what you can do if you just have a go, the rest of us are only a call away.


Gav

[Churchy]

Steve,

I totally agree with Gav. I have just taken delivery of a DIY header kit from Darren at Di Fillipo, and while it was a leap of faith. Now that I have the kit it looks like if I take my time (the old measure twice thing) then my flap disk skills should negate my lack of welding skills.

Churchy

[stephen low]

Thanks guys, I know all about the flap grinding discs, have several on hand for mods. but don't have access to a mig - yet!!!.

I suspect I could hire one but on the timeframe I would like to work to, ie no rush, this would work out as extremely expensive, assuming they can be hired.

So if I am going to chop into a made product, am I better to use the free option that will need far more work to make it fit, or an item I will have to pay for but that is far closer to the fitting mark?

The second option is the RMC extractors and these are a marginally larger tube diameter than the standard extractors. How does the larger size affect engine performance/operation?

Cheers

Steve

[Gav]

If you are serious, I'd have a good look in the trading post and you'll pic up one for nic's.
I use a WIA 150 and are very happy with it.
And besides you just need to tell the missus about all those little jobs about the place that a mig is good for.....
like Cobra building! You will be amazed with the use you will get from it I assure you.

Gav