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PollyMobiles Rebuild

Polly, while we are on the subject of emissions.

I noticed that injecting water into the inlet air can reduce emissions significantly. My initial testing cut CO and HC emissions by almost 15%! My setup wasn't even anything special, 200cc injector with a 3.7bar boat-freshwater-pump (40$ ebay).

Maybe you should look into water injection soon? It would help you clean the combustion chamber, along with running higher boost pressures more safely.

Just throwing it out there :)
 

SuperUno

Buy & Sell Member
Reading something else about the VW diesel issues, and Porsche in the past have used a small air compressor which injected air into the exhaust to lower the emissions.... Clever idea ;)
 
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pollyp

pollyp

Club Member
Polly, while we are on the subject of emissions.

I noticed that injecting water into the inlet air can reduce emissions significantly. My initial testing cut CO and HC emissions by almost 15%! My setup wasn't even anything special, 200cc injector with a 3.7bar boat-freshwater-pump (40$ ebay).

Maybe you should look into water injection soon? It would help you clean the combustion chamber, along with running higher boost pressures more safely.

Just throwing it out there :)
aye may have to consider that on my todo list, read of ppl using expresso machine pumps with a fine nozzles for more reliable better mist.
where did you mount urs without fouling the MAF, perhaps in the inlet mani next to all the brake servo/carbon canister vacuum ports? and running constantly?
 
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pollyp

pollyp

Club Member
Reading something else about the VW diesel issues, and Porsche in the past have used a small air compressor which injected air into the exhaust to lower the emissions.... Clever idea ;)
aye heard bout that. wouldn't a blowing exhaust do the same? although would exceed the noise limits :p
 

SuperUno

Buy & Sell Member
I thought that too, but this was injecting air in (at a pressure higher than the exhaust gas i guess), so should do more than a hole which would just leak exhaust gases and be a MOT fail.
 
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pollyp

pollyp

Club Member
I thought that too, but this was injecting air in (at a pressure higher than the exhaust gas i guess), so should do more than a hole which would just leak exhaust gases and be a MOT fail.
basically diluting the mixture like a fruit juice or watering down pub drinks. adding more volume of air to exhaust so even though more gas volume is chucking out the pipe past the reader, the % of CO/HC per volume is measured as less...
Ooooh you've given me an idea Matt, lets just plumb an air compressor into the exhaust, simples lol
 
aye may have to consider that on my todo list, read of ppl using expresso machine pumps with a fine nozzles for more reliable better mist.
where did you mount urs without fouling the MAF, perhaps in the inlet mani next to all the brake servo/carbon canister vacuum ports? and running constantly?
I run MAP, so I don't have to worry about fouling a MAF. But I inject water a 20cm before the throttlebody. There are many suitable places to inject it, like pre-turbo, manifold runners etc., all different ones have their pros/cons. I chose the pre-TB because I'm only running a single injector, and want a simple & reliable setup.

For MOT, I have a tune that trigger the water injection when the RPMs rise above 2000rpm. It then shuts it off when the RPMs fall below 1900rpm. Simplicity itself. For normal road running, I trigger the water to activate at 1200mbar manifold pressure, and stay on until manifold pressure falls below 1000mbar. I really like my ECU's ability to program general outputs :))

basically diluting the mixture like a fruit juice or watering down pub drinks. adding more volume of air to exhaust so even though more gas volume is chucking out the pipe past the reader, the % of CO/HC per volume is measured as less...
Ooooh you've given me an idea Matt, lets just plumb an air compressor into the exhaust, simples lol
This one will not net as much as water injection. IIRC, you can only dilute the exhaust gas up to 5% 02 (might differ in your country). The MOT tester must manually adjust the 02 reference, when an air-injection system is used. This is because the sniffer must still check if lambda is within 0.97-1.03, something that would be greatly affected by an air-injection system. The 300ZX and 200SX all uses air-injection on the early 90's models. My ECU even has a air-injection output, not that i'm planning to take it into use :p Water/Methanol will do just fine for me :)
 
Reading something else about the VW diesel issues, and Porsche in the past have used a small air compressor which injected air into the exhaust to lower the emissions.... Clever idea ;)
That was allowed though. There were other carbureted cars that used the same principle. They needed more o2 before the cat to get them to work more efficiently. Dont need it now with fuel injection and ECU control.
 
I run MAP, so I don't have to worry about fouling a MAF. But I inject water a 20cm before the throttlebody. There are many suitable places to inject it, like pre-turbo, manifold runners etc., all different ones have their pros/cons. I chose the pre-TB because I'm only running a single injector, and want a simple & reliable setup.

For MOT, I have a tune that trigger the water injection when the RPMs rise above 2000rpm. It then shuts it off when the RPMs fall below 1900rpm. Simplicity itself. For normal road running, I trigger the water to activate at 1200mbar manifold pressure, and stay on until manifold pressure falls below 1000mbar. I really like my ECU's ability to program general outputs :))



This one will not net as much as water injection. IIRC, you can only dilute the exhaust gas up to 5% 02 (might differ in your country). The MOT tester must manually adjust the 02 reference, when an air-injection system is used. This is because the sniffer must still check if lambda is within 0.97-1.03, something that would be greatly affected by an air-injection system. The 300ZX and 200SX all uses air-injection on the early 90's models. My ECU even has a air-injection output, not that i'm planning to take it into use :p Water/Methanol will do just fine for me :)
You running a megasquirt??
 
Nah mate, Nismotronic, specifically designed for 90's Nissans. There's a link in my signature to my thread (shameless plug)

Back on topic, do you have last years smog result Polly?
 
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pollyp

pollyp

Club Member
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pollyp

pollyp

Club Member
Nah mate, Nismotronic, specifically designed for 90's Nissans. There's a link in my signature to my thread (shameless plug)

Back on topic, do you have last years smog result Polly?
the last time I tried to MOT the turbo setup (with dirty misfiring injectors) was in 2012

IMAG2601.jpg


this time with cleaned injectors that don't misfire as much at 3k, it may be a different so tis worth a try.
 
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pollyp

pollyp

Club Member
time to weld up the rusty crossmember before MOT, bumper off

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knock out as much of the weak rust and blergh look at the holes

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wirebrushed the area

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CAD

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I thought the stick weld was gonna cheesecake the thin steel but I was surprised that it tacked well onto the good thicker steel without burning through.
tack tack tack and it's on. some of the thinner rusty underside obviously burnt abit but meh, the holes covered.

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bit of undercoat to disguise it, job done. not gonna bother doin the rusted rear right corner under the lights cos it ain't structural. reassemble and put it through MOT

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So I just looked it those 2012 readings. I'm sure you know what they mean. It looks like over fueling with an air leak somewhere before the o2 sensor. So there's a few things to check there then. Poor ignition or timing, air leak, or too much fuel. The trouble is, the high hc reading will damage the cat eventually. An air leak before the o2 sensor will exacerbate any problems by causing over fueling as well.
Hope it passes without too much hassle for you Paul.
 
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pollyp

pollyp

Club Member
So I just looked it those 2012 readings. I'm sure you know what they mean. It looks like over fueling with an air leak somewhere before the o2 sensor. So there's a few things to check there then. Poor ignition or timing, air leak, or too much fuel. The trouble is, the high hc reading will damage the cat eventually. An air leak before the o2 sensor will exacerbate any problems by causing over fueling as well.
Hope it passes without too much hassle for you Paul.
2012 was with the stock block, "stock engine turbo map" and dirty injectors.
the current one is the totally rebuilt forged piston engine since 2013 with cleaned injectors and "forged engine turbo map".
so testing this new forged engine with turbo be different than before.
 
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pollyp

pollyp

Club Member
rerouted the catchcan hose neater in front of the rad

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whilst fitting the headlights, thought might as well fix the dodgy RH level adjuster.

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dremel the plastic tabs off to reveal the circuit, looks like the dirty track might've caused the issue

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cleaned the tracks.
to reassemble, rather than hot glueing the board back on, I just cut some plastic pipe to wedge & keep the circuit in place

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reassembled the front, headlight leveller now works fine.
all ready for MOT

DSC01461.JPG
 
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pollyp

pollyp

Club Member
the catchcan had been leaking abit from a small hairline gap out the side so lets make another one.
when I print the whole thing horizontally with support beams holding up the pipe ends, the shrinking overhanging plastic structure always warps & rips the far end upwards off the bed, making the pipes oval and splitting

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so I tried printing vertically to keep the pipes round

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but this causes the thin disc plate section to split apart

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so instead we just print the disc plate flat to keep it flat & solid smooth,
while the pipe section is printed vertically to keep it uniform

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I sand the mating faces smooth flat, bond em together with ABS slurry and smooth seal the whole thing in the acetone tank and it's never looked this good :cool:

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replaced the catchcan top awaiting testing

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pollyp

pollyp

Club Member
she's passed :D:D

took it down to dent motors. met dave & jo, nice friendly blokes, gave me a cuppa tea from machine.
dave checked over the car, seat rail had abit of play, was more concerned bout the seat mounting but tis fine.
rear plate slightly delaminating but reads fine.
he was puzzled why the hazard lights were randomly not turning off, I look down and Ohh it's my alarm going off :p turn alarm off and it works fine.

started the car and he began to move it indoors. the racing flywheel & clutch may need getting used to cos he stalled it afew times :D
when on the lift, they slide this jacking beam under to lift the front/rear but even at my reasonable height it kept getting caught near the lower brace / front swaybar and bashed my rear camera abit, thankfully not broke. the turbo oil return fitting still leaking again so was advisory.
my left seatbelt wasn't retracting fully, the return spring had prob all weakened up for some reason. advisory so need to look into it.
noting the bubbly rusty rear left chassis corner but missed the obvious gaping hole on the rear right :p
talked bout fitting cooling vents above the bonnet rather than lift the rear but twas concerned bout soaking the bay with water when washing, suppose I could fit a shield under the opening to divert water past the engine/turbo/electrics.

and now! the emissions :rolleyes:
obviously the exhausts cooled down now so he said hold 2.5k (machine timer only allowed 15sec) and CO was 0.5 - 0.68 - 1.1% irratic all over whilst being closed loop and HC 200-220.
cats not hot enough and the few minutes of idling has sucked oil past the rings and smoking, so asked me to go for a blast
to clear the smoke and heat up the cat.

return back after a blast, recheck at 2.5k and it's still 0.6 - 0.8% CO 200ppm HC, warm idling was 0.5% and 200ppm. I think the cats still not hot enough or it's abit fouled with all the burning oil.
thought twas gonna fail, but cos tis a 1994 it only needed to pass smoke test on tickover which has cleared.

job done, don't have to rip out the turbo etc :cool:
thanks for the recommendation andy;)
 
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pollyp

pollyp

Club Member
nice one paul :) was the high hc down to the oil burning then ?
probably.
there's little improvement in readings before/after the blast
and prev with the non-burning stock engine it's bout the same readings so I guess the secondary cat is pretty useless down there.
 
...so I guess the secondary cat is pretty useless down there.
Congratulations on the pass!

Regarding the cat, I think you are underestimating them. Most vehicles run single cat, and pretty far away from the engine too. I think your high emissions could come from injectors or piston rings?

Here's a link to my most recent smog, SR20VE, single cat far away, very small and balanced injectors http://i.imgur.com/vbemBpk.jpg Should produce much more emissions than a CG-engine, yes? :)
 
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pollyp

pollyp

Club Member
Congratulations on the pass!

Regarding the cat, I think you are underestimating them. Most vehicles run single cat, and pretty far away from the engine too. I think your high emissions could come from injectors or piston rings?

Here's a link to my most recent smog, SR20VE, single cat far away, very small and balanced injectors http://i.imgur.com/vbemBpk.jpg Should produce much more emissions than a CG-engine, yes? :)
I think it's the big 370cc injectors that's the main culprit.
turboing with stock engine that didn't burn oil and big injectors also showed the same readings.
when I revert back to standard injectors & setup it passes no probs.
 
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pollyp

pollyp

Club Member
Isn't there smaller cc injectors you could use?
in the beginning I had red 256cc injectors but Ed fusion recommended the bigger 370 for the hp & application I was aiming for.
new injectors require more remapping & time/money
 
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pollyp

pollyp

Club Member
printed some parts of the last printer design

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but I didn't like how all the sliding rods/linear bearings will create alot of loose rocking/binding play of the moving head.

so I redesigned the whole top end to use the leadscrew rods directly to elimate any chance of clearance/binding issues.

printer assembly 21a.jpg


the longer dual Y-axis motors are mounted to the frame and it moves the dual X-axis assembly rail.
the hot end is mounted on the X-axis assembly rail

printer assembly 21b.jpg


the extended lower part of the Y-axis drive block is used to touch the Y-axis end stopper switch on the frame

printer assembly 21c.jpg


the X-axis end stopper switch is mounted on the hot end mount to touch against the Y-axis drive block

printer assembly 21d.jpg


here's the luvely X/Y drive block

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here's the hot end mount which allows the X-axis leadscrews to move the hot end. a small M3 screw in the middle secures the hot end to the block.

printer assembly 21f.jpg


£90 of extra XYZ motors arrived

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cut & drilled all the frame beams

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printing the new drive blocks & hot end block

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oops whilst popping the part off the glass bed, it stick too well & ripped a piece out :/
went to local glass shop and got pair of glass plate cut for £3 cheap as chips :cool:

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removed the supports & redrilled the holes

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leadscrew nuts fits here

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test fit the X-axis assembly

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after few days work, here's all the required parts assembled

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this is the happy bit where I get to assemble something that I spent many days designing & fabricating.
building up the frame

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assembling the X-axis assembly

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fitted the XYZ motors, extruder feeder, filament holder & bed, looks mega :)
still awaiting more leadscrew nuts from china for the Z-axis.
afew support holes for the leadscrew rods r abit tight so will have to enlarge them very slightly.

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