Next question.
How do you recon I can make one of these on a budget?
I don't have a massive alloy billet and I don't have a big mill, so that is not practical.
I do have access to a big pile of plywood, and a router. Boost will only be around 15psi.
I was thinking of making a big ply sandwich, with a load of bolts. Do you think it could work?
Or any better ideas?
Matt
No, it 'wooden' work!!
Boom Boom!
About this time of year you should have an empty Quality Street tin.....
quote:
Originally posted by balidey
About this time of year you should have an empty Quality Street tin.....
well, what is it you like about that one? i suggest you like the fact its machined out of a big piece of billet alloy with all the detail. well, you
won't get that from ply wood, so you won't be happy with it i think.
why not get something cut from 3mm alloy, fold it and weld it?
you could also get a sort of insert made for the threaded holes to be welded in the box. get the holes cut on the machine, then tap the threads out
yourself. the hard bit will be the welding done neatly, but for the shape in that photo, its only really 6 short welds. a simple sketch should be
enough to have someone like andyw7de to cut one out for you
What about the square plastic ducting for extractors you can buy from DIY shops? Would that be big enough?
The box is around 14inch by 10in, which at 15psi gives 2100lbs of force. Probably enough to open a quality street box, or maybe ever tupperware!
I suspect it might also deform some 3mm plate, if made in a simple box section. I've made a folded airbox before and it was great in a NA
set-up.
Being shinny and flash is nice, but not really that important to me. What I like about this one is that it is fairly large which helps manage the
pulses. It is servicable (i.e. I can get in and sort the trumpets when they leak). It can handle the pressure. It can be machined to accept
secondary injectors and air temperature sensors. What I don't like is that its £500.
Keep the ideas coming. There must be a standard box out there of about this size that can handle some pressure and can be sealed. Where should I be
looking?
Matt
Get andyw7e to cut you a top an bottom out of alloy, you design, he cuts on the water jet. Then get a sheet of ally, cut a strip the height you want the plenum to be (distance between top and bottom of plenum) and fold that strip to make a rectangle the right size for the bottom to be welded to (competent tig welder will have no problems doing this). The top can be held on with some tabs that you attach (weld) inside the plenum and use some rivnuts and silicone (good seal) to then enable you to bolt the top onto the box and viola, a finished assembly.
i play with nissan turbo motors and fabricated plenums are a plenty from the far east, but they are a bugger for splitting. 3mm wont cut it (for long
anyway). Whichever design you go for make it OTT in terms of thickness and strength. One of the theories ive heard, is that its the pulses that
oscillate the ally and work harden it which is why it fails. Most have ended up with additionl bracing and added rings around the outside (if round,
or D or oval sections.
It may well be that due to the smaller capacity of a bike engine, the pulses will be less vicious, but sods law you will run into trouble eventually.
The best aftermarket are either castings (Greddy, etc) or ally fabrications from Aus and they are well over engineered.
Could you not find a cast ally OEM plenum off a car, and then modify and machine to accept the trumpets?
I see what you are saying. I guess I'd need to get a ring cut to go under the top, as otherwise it will be very difficult to get a decent
seal.
I don't like the TIG bit. Don't know anyone and definitely can't do it myself.
What about getting a top, a series of edges, and a bottom cut. I can then sandwich it all together. The only problem is the wasted material from the
inside of the rings.
That is sort of where I came in with the plywood.
Matt
I have seen on the oldskoolsuzuki forum a guy who built his own turbo gsxr1100 system using solvent welded polypipe for the plenum and pipework. almost certain it was ok at 1bar boost,
quote:
Originally posted by bigrich
I have seen on the oldskoolsuzuki forum a guy who built his own turbo gsxr1100 system using solvent welded polypipe for the plenum and pipework. almost certain it was ok at 1bar boost,
Looks like a sump, could you use hunt for a sump from any car that is suitably square, add the required outlets then make up a plated cover to seal it?
thats horrible *shudder*...
this is the style i would be looking at
Those plenums out of Australia and the Far East, are incredibly expensive too! Anybody have a source a little cheaper? I guess the other option is to
have someone bang you one up. I'm sure you could make him or her a bit of dosh and still be ahead.
The big advantage of the modded plenums is that it lowers the overall height of the engine/sump combination, and fits under a bonnet that's
1" higher. The old, standard one requires a hole in the bonnet, which in reality isn't that important, and does offer a bit of cooling
(although it's the turbo side of the engine that needs it!).
http://www.locostbuilders.co.uk/forum/37/viewthread.php?tid=113365
How about this idea
[Edited on 5/1/11 by jacko]
not sure it can handle the pressure. that's why i left mine alone.
quote:
Originally posted by jacko
http://www.locostbuilders.co.uk/forum/37/viewthread.php?tid=113365
How about this idea
[Edited on 5/1/11 by jacko]
quote:
Originally posted by CNHSS1
i play with nissan turbo motors and fabricated plenums are a plenty from the far east, but they are a bugger for splitting. 3mm wont cut it (for long anyway). Whichever design you go for make it OTT in terms of thickness and strength. One of the theories ive heard, is that its the pulses that oscillate the ally and work harden it which is why it fails. Most have ended up with additionl bracing and added rings around the outside (if round, or D or oval sections.
It may well be that due to the smaller capacity of a bike engine, the pulses will be less vicious, but sods law you will run into trouble eventually. The best aftermarket are either castings (Greddy, etc) or ally fabrications from Aus and they are well over engineered.
Could you not find a cast ally OEM plenum off a car, and then modify and machine to accept the trumpets?
Mine runs 7psi, box it's folded 2mm ali and I had to pin it to stop flexing which broke the welds.....
It surprising how little pressure distorts things....
ok, 5mm ali then, but my suggestion still stands, cut and weld
Very interesting comments on thickness and strength.
If its work hardening that is the problem then maybe plywood is the wonder material of the future 
I have seen some of those end entry designs. The problem I have with them is that I don't have the cfd to model where the flow goes. With the
end entry ones there are some tricks needed to avoid the end cylinders getting too much or too little air. If I go with a slightly wider version of
the design in the original post then even distribution of air is pretty much guaranteed.
Not sure what to do, but lots of great food for thought.
Matt
Nissan pulsar GTiR plenum, then have a back plate cut to suit. Its what I did on mine (have a look in the thread) and it works nicely and was neat.
Paid £20 for the plenum and about £40 for the ali plates and spacers. I still have the dxfs for the backplate somewhere.
David
Yes, David, but you are an engineering genius. Wee mortals like us can't keep up!
I thought the Pulsar used the SR20DET engine though, and therefore would need lots of fettling. Are you saying that the backplate is all that needs
changing to fit the CA18det? I haven't looked carefully enough at the SR20 plenum.
I think you may have solved the issue though; one I've pondered for about 3 years!! Pulsar parts are everywhere, even if CA18DET parts are not.
Thanks very much for that info!
[Edited on 6/1/11 by RK]
The main bit of the plenum is just bolted on, so you can change the backplate to whatever you like if you can get the parts laser cut. The Pulsar is a
modded version of the SR20 engine yes.
This is the bit you need:
Then I had these bits cut:
To this:
The plenum shown in the OP is a pretty poor design IMO, I'd be looking at something like the pulsar plenum if it will fit.
I don't know if he's done any forced induction plenum's but TrevD on here is very good with aluminium and TIG and has made a few
airboxes for NA.
He's very local to me (also in Northampton) and so not too far from you either.
He's also fairly recently set up his own business (mostly does very sexy car bodies for equally expensive cars - DROOL!):
http://www.circuitmotorbodies.co.uk/
flak monkey
liking that, very ingenious! 
the Pulsar is indeed an SR20DET, but its a fair bit different than the RWD SR20DET as its based on the FWD SR20. The Pulsar SR uses individual
throttle bodies per cylinder as it was homologated for rallying, whereas the RWD Sr20 uses a single TB on the end of the plenum.
Bellhousing patterns are different too, just to make life difficult!
quote:
Originally posted by alistairolsen
The plenum shown in the OP is a pretty poor design IMO, I'd be looking at something like the pulsar plenum if it will fit.
quote:
Originally posted by hobbsy
I don't know if he's done any forced induction plenum's but TrevD on here is very good with aluminium and TIG and has made a few airboxes for NA.
He's very local to me (also in Northampton) and so not too far from you either.
He's also fairly recently set up his own business (mostly does very sexy car bodies for equally expensive cars - DROOL!):
http://www.circuitmotorbodies.co.uk/
quote:
Originally posted by flak monkey
The main bit of the plenum is just bolted on, so you can change the backplate to whatever you like if you can get the parts laser cut. The Pulsar is a modded version of the SR20 engine yes.
This is the bit you need:
Then I had these bits cut:
To this:
My bore spacing is 86 102 86 (from memory, turns out 86 92 86, although that isn't the bore spacing but the TBI spacing)
Duratec is about 102 102 102 so not so different.
sr20det is 107 107 107 so a bit longer, fair comment NSDev
I have acres of space too, existing air box (NA) is 10 litres or so.
The problem will be finding a GTiR plenum is suspect as googling around shows this mod to be quite popular (unlike the original car). Great idea
though, and very impressive work (as ever) David.
Matt
[Edited on 6/1/11 by matt_gsxr]
[Edited on 6/1/11 by matt_gsxr]
guy breaking a pulsar here
http://www.pistonheads.com/sales/1809593.htm
and another
http://www.pistonheads.com/sales/2366736.htm
and another
http://www.pistonheads.com/sales/1618525.htm
complete inlet mani here
http://www.pistonheads.com/sales/2331183.htm
I guess I was looking on the wrong site.
Matt
quote:
Originally posted by matt_gsxr
I guess I was looking on the wrong site.
Matt
That plenum looks like a suitable alternative to the (rather expensive) Pipercross PX600 airbox.
Mind if I ask how much the new backplate machining would cost?
Andyw7de cut the backplate and spacer for me - if anyone else goes that route then give me a shout and I'll send the dxf's across which
would just need the centre's changing on the big holes. I honestly can't recall how much all the bits were, but it was around £60-70.
You could increase the plenum volume to whatever you like depending on what thickness spacer(s) you use.
Thanks for the info David - I feel a cunning plan coming on
You have U2U
Interestingly I bet the spacer will cost the same to make up as the back plate as they use the same amount of material and also a similar amount of
cutting.
No reason not to cut with a bandsaw though and do a bit of file work, although its nice getting pre-made bits in the post isn't it.
Matt
Just ordered one
WWW.GTI-R-US.CO.UK
£25 + £10 postage
Matt