1 5/8" header for a 1600 turbo

[advinnie]

Hi all I'm still getting my parts together for my 1600 turbo build. All I need now is a header.
Now I've seen a CB performance hide a way header that places the turbo down low but the piping size is 1 5/8" or 41mm will this be to large for a 1600 ?
The parts I'm using
Renault 5GT turbo carb, fuel pump, filter, garrent T2 turbo and so on. IM only panning on running 7-8 psi
What do you lot think about this size header?
Link to it below
https://www.coolairvw.co.uk/Item/Shop_b ... _Size.html

[buguy]

I think 1 3/8" would be best but I'm sure 1 5/8" will work fine for that boost level.

[advinnie]

I was unsure if the exhaust gases would slow down to much with such a large manifold.
I don't want the rpm to be to high before she comes on boost cause I was only planning on 4500 rpm max

[buguy]

I don't think it would affect it enough to tell. I always wondered the same thing and just went from a 1 3/8" up pipe to a 2 1/4" and I can't tell any difference. That is 2 1/4" after my collector to the turbo (about 14"). Plus that's a tiny turbo you have... The wind should spool that thing!

[advinnie]

Yes it is a small turbo so hoping a fart would be able to spin it up. I only went small cause of the limited rpm range of the crank. I was at the being going to use a gt15 turbo but think that will be to small and on boost all the time ?

[buguy]

Hard to say. Try 'em both!

[petew]

I have precisely this header on my 1600. I'm sure a slightly smaller diameter pipe might work better, but aside from the wastegate location (which I blanked off anyway and used an internal gate on the turbo), it's not bad. I realized there was no way I could build something better for that amount of cash. I made an adaptor to use the IHI RHF4 VF13 subaru legacy turbo I'm using. It's pretty tiny and good for 14psi max. Which is another point worth making... smaller is better.

turbo 2.jpg

What's it like to drive? As expected, there is some lag, however I have solid boost by 3000rpm and usable torque below that. And I'm only running 6psi (factory wastegate pressure) at the moment.

The only other thing worth mentioning is this, that header hangs low. If you want to run super low in the rear, you wills scrape it on things. I also had mine ceramic coated to avoid rust.

[advinnie]

Thanks for that mate. I take it you used drilled and tapped an external sump for the turbo oil drain?
Any photos of it all fitted?

[petew]

Yes, initially I did drain the turbo into the external sump. You can see the pipe going forward to the sump on the left hand side with the brass fitting (which I was terrified of tearing off on debris).

oval engine.jpg

However, I had ongoing issues with oil leaking through the front seal into the compressor. I thought it just need a scavenge pump which I added.

The problem was the turbo wasn't draining vertically. I also didn't have enough restrictors in the oil feed to the turbo. The factory barrel bolt has a 1.5mm restrictor but I need an extra 1mm restrictor as well. Part of the drainage issue was my own mistake with clocking it slightly off vertical (15deg.), but the header didn't help me a lot. So you'll have to watch out. I ended up with a vented oil drain catch tank feeding into a scavenge pump.

Oil drain 2 and oil tank 1 installed 2.jpg

The scavenge pump lifts the oil from the tank and pumps it into the rockercover on the right hand side of the motor. No more dramas, but it nearly killed me figuring this all out. In summary...

1. Make sure you have enough restrictors. If it's a ball-bearing turbo, you will likely need two.
2. Make sure the turbo drain is VERTICAL. Let me say that again, VERTICAL. So it drains properly.
3. You may well need a tank (vented)/scavenge pump. Look up what the Porsche 930 guys do for tanks. A pump is cheap off ebay...

http://www.ebay.com.au/itm/12v-Heavy-Du ... Sw7U5Y~aTA

Cheap, cheerful, noisy and heavy.

Scavenge pumps are standard fare for low mount turbo systems. All the V8 guys with rear mount or low mount turbos do the same things.

[yellow_snocone]

Pete,

Do you think having the oil feed completely vertical would help with draining over using a scavenge pump? I have the same headers and will need to have an adapter for the flange since ill be using a suby turbo as well. I was thinking of giving the turbo some more height to aid in draining.

[petew]

Pete,

Do you think having the oil feed completely vertical would help with draining over using a scavenge pump? I have the same headers and will need to have an adapter for the flange since ill be using a suby turbo as well. I was thinking of giving the turbo some more height to aid in draining.

Yeah, definitely, probably, maybe, unlikely, no... sorry, just messing with you.

Look there are guys who are using this header and not needing scavenge pumps. And yes having a vertical drain helps a lot. Extra turbo height will be a packaging problem with the turbo hitting the back apron. I had to cut a hole in mine to fit the waste gate in. It will also make tinware harder. As I mentioned first, you need to have your restrictions right in the oil feed. Then you have to get the drain right. Most people say you need a few inches of vertical drop before you route a line to the sump. My experiences tells me that at that point the drain is too low to flow probably back to the sump by gravity. Additionally oil from the sump may be rushing back down the drain line under acceleration.

So I'm not saying don't try, but I am saying be prepared to add a scavenge pump and tank. We all look back to what Porsche did on rear engine boxers. They had factory scavenge pumps. So what does that tell you?

[yellow_snocone]

I will definitely get my oil feed right before working on the drain. Hopefully i can get by without a scavenger pump but if its needed its needed. What size restrictor would you recommend i have a td04 13t turbo?

[Clonebug]

The TD04 turbo does not use a restrictor.....just feed it with a 3/16ths or AN-3 line.... no larger.

Make sure you have a 5/8ths drain on it and you should be good to go...

[yellow_snocone]

The TD04 turbo does not use a restrictor.....just feed it with a 3/16ths or AN-3 line.... no larger.

Make sure you have a 5/8ths drain on it and you should be good to go...

Thanks clone

[petew]

The TD04 turbo does not use a restrictor.....just feed it with a 3/16ths or AN-3 line.... no larger.

Make sure you have a 5/8ths drain on it and you should be good to go...

I've not used a TD04. I would try and see what size hole the barrel bolt that came from the factory has in it. I'd suggest there will be some sort of restrictor there.

In a high mount situation like CB's buggy, you can get away with drainage a bit better. Low mount not so much. So keep an eye on your intake tract for a film of oil. If there is any oil in there, you're supplying too much oil, or not draining it effectively.