386 replies to this topic

[Shiney005]

It's no wonder HSV gave up on the idea!

[Shtstr]

It's no wonder HSV gave up on the idea!

More room in the adventra body shell.

[Shtstr]

To give you all a better idea of how bloody tight it is here is what I did to a set of hsv avalanche 4 into 1 headers to get them to fit. Note these only have a 1.5 inch primary pipes and a 2.5 inch secondary pipe. Look at how much I had to squash these to clear the torana rails.
Then remember that the ones I made are a 48mm pipe just shy of 2 inch primary pipe and a 3.5 inch collector will be used.

Attached Files

•  20210211_190108.jpg   174.15K   9 downloads

[Shtstr]

Note how much I had to squash these on the primary pipes and then the secondary pipe.
They just wouldn't flow enough for the hp I'm after.  20210211_192343.jpg   223.92K   10 downloads

[Shtstr]

For a better idea of the difference between the stainless steel bend and the steam pipe bend radius. Ignore the leg length just take notice of the widths of the 2.
It's clear that the steam pipe has a smaller radius.

Attached Files

•  20210213_074514.jpg   111.72K   9 downloads

[Shtstr]

Well I just pulled it all back out to get final measurements of each pipe length and it's not as close as I would like but will work fine for the hp I'm after.
From longest to shortest is 194mm difference in length.
I was hoping for 50mm or less but there is nothing else I can do about it.
See photo below for all measurements of each primary pipe.
I've written it down in the firing order so you can see from one to the next inline of firing.
There will also be the collector to go on yet but each pipe will lose the same amount of length equally.

Attached Files

•  20210217_164301.jpg   707.51K   12 downloads

[Shtstr]

The interesting thing is they are still closer in length than a set of defilippo pipes I measured from a commodore.
As they sit before I weld them out

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•  20210217_153356.jpg   237.07K   10 downloads
•  20210217_153410.jpg   210.96K   6 downloads

[Rockoz]

Just about every off the shelf set of headers is made more to fit than to length.

I remember looking under the bonnet of one of the Commodores at Bathurst in the early 80s.

There was a hell of a lot more pipe visible going around and about in the race car than the set on my VB Commodore.

They were made for tune on the race car obviously.

My VE SS when I bought it was used for the first headers and twin 3 inch system that was on the market in 2006.

It spent more time at my brothers exhaust shop than it did in my garage for the first couple of months.

The headers on it werent made for length, but what would fit in the area available.

Still made a decent power increase over standard.

 

Cheers

 

Rob

Edited by Rockoz, 18 February 2021 - 12:53 PM.

[neglectedtorana]

Do you measure the length of each pipe with a tape measure which would be difficult with all the bends

Or fill each pipe with water and measure the volume?

Which would give the better result?

[claysummers]

Best measurement would be to compare flow rate for given pressure. Another way to try and balance them is to put more bends in the shorter runs.

early Holden nut

[Shtstr]

Best measurement would be to compare flow rate for given pressure. Another way to try and balance them is to put more bends in the shorter runs.
early Holden nut

That is how they are made. Shortest pipe has more bends.
Only time will tell now.

[Heath]

Impressive stuff. That is a mammoth job.

[Shtstr]

Impressive stuff. That is a mammoth job.

Thanks mate.

[Shtstr]

Do you measure the length of each pipe with a tape measure which would be difficult with all the bends
Or fill each pipe with water and measure the volume?
Which would give the better result?

I know the length of the bends via the radius. Then add the length of the straight pipe sections and you have the overall length of the center line of each pipe.
Long radius 90 degree bends are 91mm and the 45 degree bends are half that. Yes granted there might be a few mm difference but that's at a minimum for each pipe.

[Shtstr]

I have decided to give myself 3 different header options.
1 standard factory cast headers from adventra match ported with a custom made dump pipe. 2.25 inch out to 2.5 inch same size as the exhaust system.

2 my custom made 4 into 1 headers with 3.5 inch collector reduced to the 2.5 inch system.

3 make a set of try y 1.3/4 primary to 2 inch secondary to a 2.5 inch collector same size as exhaust system.

Now to find the $$$ to do the try y set as I already have the other ones.

What I was surprised at is that I've found out that my adventra donor car has a ls6 engine from factory.
They make more hp and torque than the std factory ls1 engine due to a refined inlet manifold and exhaust manifolds that flow better than the stock ls1 stuff.
Even though I won't be using the inlet manifold it's nice to know that I have a sort after factory inlet manifold that I can sell later on to get some $$ back. Won't be much but every $ helps.

[Shtstr]

Spoke with a shop that does a lot of custom fab work with cars.
They told me to try and stay away from stainless steel headers as they will end up cracking down the track.
So will just stick with the 4 into one headers and the second back up set of the factory cast headers as they are a step design from 1 7/8 up to 2 inch and then 2 1/4 outlet that steps up to 2 1/2 inch.
The 4 into 1 setup I have trimmed back to 38 inch average length into a 3 1/2 collector.
Both will work fine for what I'm doing.

[Shtstr]

First one done ready to refit and set up the collector area and join to the exhaust system.
Also started making the factory cast setup to fit and bolt in exactly the same so they are a simple swap over if need be.
Once everything is sorted they will all be sent off to get hpc coated.

Attached Files

•  20210313_171034.jpg   143.5K   17 downloads
•  20210313_171103.jpg   112.62K   16 downloads
•  20210313_171045.jpg   106.95K   12 downloads

[Shtstr]

Got the second set of 4 into 1 pipes welded up and cleaned up.
Also started setting up the factory system as a fail safe setup.
Once the factory setup is completed I will swap over the 4 into 1 pipes and set them up as a bolt in swap.
That's why the cat coverters are set back further than normal.
This way I can just unbolt each header system at the flange and swap them over without any problems
Not much left to do with them now and then I can start that dreadful process of paint prep as all rust repairs have been done.
Getting closer by the year haha.

Attached Files

•  20210316_163504.jpg   152.2K   9 downloads
•  20210316_171110.jpg   206.72K   12 downloads

[Shiney005]

It would be great to see a dyno run with each set. The steampipe ones certainly look impressive.

[Shtstr]

It would be great to see a dyno run with each set. The steampipe ones certainly look impressive.

It's something that I'm looking at doing to see what provides the best power and torque curve.
Will be interesting to see the back to back results that's for sure.

[Shtstr]

Well finally got the last set of exhaust flanges delivered yesterday.
Put them in today and got them 50% welded in place.
Now I can pull the engine and box back out to finish welding them up. Then put the whole lot back in and confirm all fitment and clearance is good.
So hopefully by next week the exhaust system will be finished off and then I can finally get started with paint prep in the engine bay before winter hits and it's 2 cold.
Would be nice to get it done before winter hits but if not so be it. It will just take a bit longer as I like to let everything dry properly between processes.

Edited by Shtstr, 31 March 2021 - 07:03 PM.

[Shtstr]

Well have finished the 4 into 1 setup and the factory cast setup manifolds.
Have decided to run with the factory cast setup to start off with and keep the 4 into 1 setup in reserve for now.
Only due to added cost for ceramic coating at this point in time.
I need to keep cost down as much as possible right now. But still keep options open.
So the new engine build will be put on hold too for a while until funds improve a bit.

[Shtstr]

Spent Sunday in the shed working on the front suspension setup. Have modified the adventra front sway bar to fit into the new narrowed suspension setup.
Brought it in 110mm to fit back into the adventra crossmember and clear the struts.
When I pickup some shorter struts this week I will be able to see if it clears everything.

[Shtstr]

Well I borrowed a set of vr commodore 25mm lowered front struts with 2 inch lowered springs on them.
Looks like they are about the right height.
Top of front guard height works out to be around 875mm.
That's with no front panels on and the front tyres are still too tall by about 20mm. So it should sit around 840mm top of guard when the springs settle and the correct tyres are on it.

[rodomo]

PICS!