Impellor Member 835 Member For: 14y 7m 14d Gender: Not Telling Posted 22/12/12 12:03 AM Share Posted 22/12/12 12:03 AM Hello fellow enthusiasts.Being one to always looking to improve upon the factory item where possible, both functionally and visually, I found a plenum on ebay which I managed to get for $36 delivered. The idea was that I would have a look to see if I could improve the flow characteristics, and give it a polish as well.What I noticed firstly, was how poorly the entry area was cast, and how it was smaller than the throttle body opening ( While I had the T/B off I sanded it smooth also, as it had on been machined to just behind the butterfly) . So with die grinder in hand, I spent many hours removing the casting and dags around the inlet opening, whilst opening up the intake path. In the region of 15-20 % larger. I then proceeded to remove the many casting lines within the plenum. Next step was to remove 3mm off the long triangular region that flows straight into the runners. I used a gasket as a template and was able to open and smooth all areas. The most difficult part was sanding inside the tumblers. For this I just used long strips of sand paper (folded) and applied a see- saw action to sand. This took hours, but was well worth. Initially I ran a hose (water) through the tumblers just to get an idea of flow. Once sanded when I through the hose back in the water was flowing out much faster and landing approximately 2 feet further than the non-sanded item.Particular attention was paid to creating a better flow path to cylinders 1 and 6, as these seem to be areas that run lean. This was achieved by grinding a better suited angle on the opening. As I felt that the factory angle was better suited for 2 and 4 at best. After the initially problem of disconnecting my solenoid wire, I started the car. Once up to operating temp I noticed that the car was idling at 700rpm not 750. So one can assume there has been an efficency gain.The external part of the polishing was done to "I dare say it" improve the thermal efficency. As my goal is to get the air into the engine as cool as possible. This was done by using a flapper sanding disc (120 grade) on the angle grinder, then a mouse sander (150 grade) then 400 dry sand, then wet sand, 1200 wet sand. The quality of the plenum material is very good, as I was surprised by the results. This is an excellent project for the first timer, as it will give you a good result for minumal work. My thoughts are that the factory item is well designed, and quite a nice piece in standard form. But I also think that with a little work it can be improved upon greatly. How much better, I'm not really sure. But the general consensous is that its good for 550rwhp. So I think from some quick calculations I should be able to see around 650rwhp, based on increased capacity, and greatly reduced internal turbulence.Unfortunately my pics of the internal work failed, you can't see anything, but here are 2 of the item installed. As you can also see, I have done crossover as well. Again it was ported and smoothed internally.Just a heads up, if you do this its a great opportunity to tighten your inlet runners (on head) up whilst the plenum is off. http://s1191.beta.photobucket.com/user/Impellor/library/Engine%20Bay?view=media#/user/Impellor/library/Engine%20Bay?http%3A//s1191.beta.photobucket.com/user/Impellor/library/Engine%20Bay?&_suid=1356130572967021685840450073612Cheers Link to comment Share on other sites More sharing options...
Panda Eyes flame magnet Gold Donating Members 5,674 Member For: 16y 9m 18d Gender: Male Location: adelaide hills- 'race air' central Posted 22/12/12 02:13 AM Share Posted 22/12/12 02:13 AM looks good. Link to comment Share on other sites More sharing options...
Adam Here since the start... Lifetime Members 10,282 Member For: 21y 10m 8d Gender: Male Location: Victoria Posted 22/12/12 02:21 AM Share Posted 22/12/12 02:21 AM Do you have any flow tests to show the problems you're talking about vs your changes or is just all hypothetical?I prefer the black piping and crossover vs the polished/silver stuff. Good work in any case. Link to comment Share on other sites More sharing options...
Impellor Member 835 Member For: 14y 7m 14d Gender: Not Telling Posted 22/12/12 02:44 AM Author Share Posted 22/12/12 02:44 AM Purely theoretical Adam. Based on greater capacity, and an environment conducive to faster smoother flow. Remember when you were a kid roller skating at a rink. Then you went roller skating on the road. Which one did you go faster on (given there both flat). Why?, less friction. Its all about the friction, or lack thereof. These plenum's are sand cast. Rough as guts on the inside with many ridges and dags. But for a factory item there quite good. Cheers Link to comment Share on other sites More sharing options...
sexual harrassment panda I see a red door and I want to paint it black Donating Members 5,919 Member For: 15y 4m 8d Gender: Male Location: Far north queensland Posted 22/12/12 02:56 AM Share Posted 22/12/12 02:56 AM (edited) Going to do the exhaust manifold as well.Mine looked to be a pretty good casting but maybe port match to the head might help. Edited 22/12/12 02:56 AM by sexual harrassment panda Link to comment Share on other sites More sharing options...
NickBA-XR6T Bronze Donating Members 386 Member For: 12y 11m 23d Posted 22/12/12 03:25 AM Share Posted 22/12/12 03:25 AM Looks great! Something different that's for sure. I think I'd maybe prefer the plazmaman replacement kit though. Saves all that effort but yours is very unique. Link to comment Share on other sites More sharing options...
Panda Eyes flame magnet Gold Donating Members 5,674 Member For: 16y 9m 18d Gender: Male Location: adelaide hills- 'race air' central Posted 22/12/12 05:29 AM Share Posted 22/12/12 05:29 AM but air doesnt rollerskate... 2 Link to comment Share on other sites More sharing options...
JETURBO ...JD TUNING ADELAIDE... Gold Donating Members 23,708 Member For: 16y 9m 3d Gender: Male Location: Adelaide Posted 22/12/12 05:50 AM Share Posted 22/12/12 05:50 AM Piks of rollerskating air please 2 Link to comment Share on other sites More sharing options...
Never had any say Panda I <3 Floods Silver Donating Members 11,198 Member For: 13y 7m 5d Gender: Male Location: South West QLD Posted 22/12/12 07:23 AM Share Posted 22/12/12 07:23 AM Good job impellor!How long did it take you? Link to comment Share on other sites More sharing options...
Impellor Member 835 Member For: 14y 7m 14d Gender: Not Telling Posted 22/12/12 07:43 AM Author Share Posted 22/12/12 07:43 AM (edited) 3 days in total. Goes in for tune next month. I am more interested in running at optimum efficiency. Due to basically running a standard exhaust and intake. I'm not sure what it will make on this round of mods. But optimistically, I am thinking that it should make 281Rwkw's on 10 psi (using a basic algorithm). If things are working in my favour it may make 303rwkw's on 12 psi. But this, I believe is a best outcome scenerio. Its likely that the extra 2 psi will just be enough to push intake temps out of the car setup efficiency range. But here's hoping.A quick run down of mods.Ported and polished, crossover and plenum.Monza 10.260 cm3 intercooler, with aluminum/fibreglass wrap. $200Rear Muffler removal $150Walbro 255lph high pressure pump located in 1/3 larger cradle $30060 lb Deka's. $200My own CAI, incidently I believe it is vastly superior to anything on the market, fitted with K&N filter $76 Upgraded silicon pipe connectors, and clamps $25Oil/ Air separator catch can $80NGK BKR6E .8mm gapped plugs. $25 Cheers Edited 22/12/12 07:58 AM by Impellor 1 Link to comment Share on other sites More sharing options...
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