Plenum planning

I worked hard to make a nice airbox on the gsxr engine. Now I am turboing the engine I need an airbox that can handle the elevated pressure. The pressure might be as high at 15psi, which results in big forces over the area of an airbox. For example if the airbox were 14inch x 6inch then the net force of 1200lbs on the wall of the airbox. This means that something strong is needed!

Enter the Nissan Pulsar GTiR Plenum lid. The Nissan Pulsar is a turbocharged monster of a little car. Fortunately it has a plenum that is modular. So you can bolt a plate to it, and in the plate you can put mount the throttle bodies.

They say a picture is worth a thousand words, lets hope so.

The black stuff is tufnol. I used 1/4inch tufnol, because I wanted something that is fairly thick to resist the force from the air pressure, also tufnol is relatively low density (1.4kg/litre), has good temperature resistance (120deg C) but mostly I used tufnol because I had some hanging around and it can be machined using a router.

So I made 3 back plates and then turned 2 of them into spacers. In the process I covered the whole shed with fine black dust!

The next step is to mount the throttle bodies to the back plate. I think I can use the existing gsxr600 rubber mounts, which would be excellent, but I need to make some holes in my new backplate which is a bit scary.

Exhausting progress

I started on the downpipe and measured up for some tubes. The word is that turbos need as little back pressure as possible, so the reason for the big downpipes.

The outlet from the turbo is 70mm (2.75in) downpipe, so it made sense to match that. So I measured up and worked out what I needed. The plan was to reuse the existing silencer (which is big and heavy but nice and quiet) which is 2inch input. So I bought a couple of 45degree 70mm bends. Once these arrived I realised that in my calculations I hadn't accounted for the length of the bend and there wasn't sufficient space before the silencer. So, order new silencer from Jetex which is a bit shorter, and slightly larger bore (2.5inch, you can't get them in 2.75in), and a 45deg bend in 2.5in for the tailpipe.

To get the 70mm down to the silencer I cut 2 8inch long wedges from the bend and then closed that up with a couple of exhaust clamps and then welded it together. I am not much good at welding, but by putting an aluminium tube under the weld means that burning through isn't a problem and the backing reduces the need for purging the weld from behind (something I don't have the luxury of).

After loads of cutting, welding, measuring, grinding etc I ended up with this.

I need to clean up the weld in the middle of the downpipe and weld the downpipe to the flange.


Finally I bolted it all up, welded up a support bracket with a captive nut, and modified the tailpipe to allow it to exit from the side of the body (its great being able to weld, even if I am rubbish at it).

Turbo looks a bit big in there

Hmm, bolted things together today.

The manifold doesn't clash with any chassis tubes.

The turbo looks pretty horizontal (not important but it looks proper), and points backwards.

Problems at the moment are that the compressor outlet points up into the bonnet so will need a sharp bend, and the turbo inlet is a bit close to the bonnet (about 3inch) so will need an elbow on the inlet.

,

I'm thinking that the hot turbo close to the underside of the bonnet will need some thought not sure what to do though.

Managed to take some measurements so I know what oil hose I need, and measured up for the turbo exhaust outlet.

Need to think about clocking the turbo (that is turning around the two housings relative to one another).

manifolds aren't as easy as they look!

Update:

When people ask for advice, why don't they take it???? well in my case I had gone to far already, and I don't know anyone who can tig local to me.

The good news is that when the 12mm turbo flange distorts you can "machine" is back to flat using the flat face of a grinding wheel mounted in an angle grinder (remove the guard, wear gloves)

The bad news is I am a rubbish welder. Don't try to learn to weld on a manifold.

It has been an interesting challenge though.


Do's and don't of making a turbo manifold.

Do:
Draw up flanges in CadStd and get them made by andyw7de
Ask andy to supply a few offcuts of the same stuff to sort settings
Butt weld the pipes
Get a B&D power file and loads of belts
Get a new angle grinder because your last one broke
Think about how you are going to do all the welds
Tack it and then get someone to Tig it!


Don't
Try to learn welding on a manifold
Start welding (beyond little tacks) before finishing off all the pipes, as its difficult to get access later on.
Overlap pipes, well it seems to work, but looks rubbish
Think that welding is easy
Weld it when it isn't clamped up, as it will distort



I've still got a few holes (in the merge), but hopefully I can bodge that together. Then I can watch it all crack when I put it on the car!


Its all about the journey!

First attempt at Turbo manifold

So, made some progress today on the manifold for the turbo.

It is basically the stock gsxr1100wp manifold stubs (including the bit that joins the head and the first bend). These are interference fit into 38mm tube (also in stainless). I cut these different bends from 135deg bends (3 of them), and then these all come together at a merge collector.

The picture shows it tacked up, and was to confirm that it clears the chassis rail (very important).

The nice thing about this design is that I only have 5 joints between pipes, and then the complex merge.

This is my first MIG welding project, so I expect to be doing a lot of grinding!

2010 summary

Aimed to build a garage and sort out wood burning fire in living room.

Built a spanking engine out of old sidecar racing outfit parts. Kept engine in shed.

Took car on track-day to Abingdon. No grip, rubbish suspension, great fun, destroyed water pump but got home.

Became a school governor

Swapped old SVA engine for new engine. Fitted front ARB, stiffer springs, popped on ACB10's.

For the test drive, went to Llandow for track day (350miles in weekend). Met some great fold, awesome day, some oil surge, engine using oil (boo).

Bought accusump, changed gsxr600 throttle bodies to gsxr1000 throttle bodies and built a new airbox with secondary injectors.

Our sons learned to swim

Upgraded MS1 to MS2.

Modified MS software and built new hardware to allow stock gsxr trigger wheel.

Won 5 years funding for a project at work

Installed rear ARB

Started on the turbo conversion.

Aiming to sort out garage and wood burning fire in living room.

post from new phone

So, I eventually got an android phone. Damn typing os a paon. Matt