Rb25de (supercharged) Project

[r33_racer]

Ah yep, can't go wrong just port matching. How did you do it just overlay the gasket and draw on it?

Yeh that is pretty well what I did. Used a white out marking nikko.

[r33_racer]

your work looks great, i hope it inspires some people, it would me but i cant be bothered

Cheers.

I hope someone elses tries as well and does it better. It is alot of work and alot of time. Projects always are more involved then what they first seem lol.

[MBS206]

Lol yeh I did, I put it right after a reducer 4" -> 3" 45 cut in the centre. Thats how I was taught to do it as the best setup for maximum vacuum. Hopefully it wont be too much of a restriction.

If it's after/during a restriction, isn't that going to cause a "high pressure" point for it?

Correct me if I'm wrong, but if you have a pipe, with something flowing through it, and you want something to be "drawn" or sucked into it, you would be better off putting an expansion in, because as the pipe expand, the gas flow slows down even though it would rather keep going, and as such puts a low pressure zone in...

Isn't this the same theory the carburettor runs on? Run the airflow in, as it goes through the carb, it expands in size, and this is the point fuel is drawn in at?

[Craved]

Matt - have a read of this http://en.wikipedia.org/wiki/Venturi_effect

[r33_racer]

I was taught the gas velocity has to speed up as it is forced through a reduced section, the increased velocity would generate a low pressure area in the 45 cut tube which would draw airflow through it. The faster the air passing over it the higher vacuum generated.

That link Chris put up explains it better. But it tracks pretty well with what ive done.

[r33_racer]

Well I spent most of this week just working on fabricating a whole new alloy sump to replace the modified factory one I did over the holidays. I wasnt happy with the baffling and capacity it had (only 6.5L) so I started this one and was aiming for 8L-8.5L but its ended up around 9.5L-10L. Im not too fussed about the extra capacity, it can only help.

Its the same depth as factory, just a buttload wider pretty well ev erywhere I could go. Infact its a little too wide towards the back where its close to the crossmember and I think ill have to *adjust* the engine mount points where they flare out towards the middle. I will also need to get a custom swaybar made to go around the front of it. Other then those two little issues its hunky-dory. I got two drain points on the exhaust side wing and two breathers on the inlet side, all dash 10. The drain bung is a dash 12. Also there is three trap doors around the pick up, though they arent fitted yet.

[Craved]

love the sump Michael, always thought it would be good to make an alloy one for the rb25in my car and seems to be fairly straight forward

looks like 10mm plate for the flange? would 6mm work alright you think or not have enough room to have it surfaced after welding?

[r33_racer]

Thanks Chris.

Yeh the flange is 10mm. Lol the very first dry sump pan I attempted I used a 6mm flange and it warped like a mofo. Even the 10mm warps slightly. My advice is a minimum of 10mm, but I reckon 12mm would be pretty good. The steel flange bolted to it is a sump adaptor and even it buckled with the flange. I didnt think it would bow the steel. However the good thing about it is it can bow back to flat just as easy when you bolt it down. My plan is to bolt it to a big straight plate and heat it up to stress relieve it and hopefully it will set flat again!

[Craved]

cheers for that info, 12mm sheet wont be cheap lol

you could look into alloy mig welding on the flange as it generates less heat, looks like ass compared to TIG but it works

[MBS206]

What about welding the flange with it bolted to a spare block? Find one that someone has air conditioned?

Also, will read link later. Haven't done stuff on flow in ages, it's all been forgotten!

[r33_racer]

Problem with that is I needed to weld it all on the inside of the flange. There wasnt enough room around the outside between edge and bolt holes. PITA. So inside is only option, otherwise the block trick would be the way to go.

Mig would look like shit and it will probably blow through somewhere and leave spatter and shit everywhere. Hate it. Tig is so much better. Lol maybe a nice big 50mm thick plate cut out to use as a base for welding so it wont warp.

[Craved]

What about welding the flange with it bolted to a spare block? Find one that someone has air conditioned?

Also, will read link later. Haven't done stuff on flow in ages, it's all been forgotten!

might be a bit tricky welding the sump pan on with your arms through the bores

welds normally need to be done on the inside so you dont foul the bolt heads, other problem i think that would cause is the heat sink the block would create making getting the block and plate up on temp before you start welding essential

[Craved]

Problem with that is I needed to weld it all on the inside of the flange. There wasnt enough room around the outside between edge and bolt holes. PITA. So inside is only option, otherwise the block trick would be the way to go.

Mig would look like shit and it will probably blow through somewhere and leave spatter and shit everywhere. Hate it. Tig is so much better. Lol maybe a nice big 50mm thick plate cut out to use as a base for welding so it wont warp.

damn you beat me cos i was typing slow lol

can you get someone to draw it up in CAD? mates shop CNC plasma cuts 20mm plate you could create a JIG from with some bracing.

[r33_racer]

tooo sloooowww! lol

Yeh I could just make one at work in the Mill, but if I was doing alot of them It would be worth while. But for one offs, probs not.

You should have a go too chris and make one!

[r33_racer]

So ive been busy over the last few weeks still chipping away at it all. I did all the oil control mods to the block and its all down at the machine shop atm getting some work done. Hopefully get that all back in a week or so. In the mean time Ive modified the engine mount bracket to double as an extra bracket for the supercharger so its now supported at the front and back and it rests on the original shelf thats apart of the OG bracket. Should be alot more rigid now.

I ended up buying some 4" stainless tube to remake the rest of the exhaust. I decided I didnt want to go to all this trouble and then have to redo the exhaust later on anyway. There isnt that much to do from the dump pipe back. So in my effort to 'cheat' again I cut open one of the borla mufflers to modify it to become a 4" one, however the internal perforated tubes only make up the area of a 3" tube, so that stopped me there. But because the dollar is good atm, 2 new 4" borla mufflers delivered from summit only cost about $450! So ive got two new ones coming which solves that little issue. Next issue was not having a 4" flange to go from dump pipe to rest of the system. So I bought a 4" v band clamp from the local truck shop and machined up the two rings to suit. It took something like 7-8hrs total to make them. Started with a 120mm billet and turned it into whats in the picture. What a job!

Also got a new 4" thick intercooler to replace my pwr 3" one. $430 delivered from Performance Wise here on the forums. Fits up pretty well the same and the piping lines back up which is what I hoping for to avoid more fab work.

Ive also drilled out all the bungs in the head and block and tapped them all for grubscrews. Amazing how much gunk there is behind all those factory bungs! Im glad I drilled them out to clean it all properly.

Time to find more stuff to do! Woot!

[Craved]

loven it michael!!

while i love making stuff, after 2 hours machining those vband flanges i woulda given up and bought some from otomoto for $60 lol

did you drill the bungs out of the head? or tig some steel rod onto them then slide hammer? or were the heads bungs also alloy?

[r33_racer]

Cheers Chris.

Mate if you went to the effort of doing 2 hrs worth you might just push yourself to finish it off lol. Other wise thats two hours wasted. I had a look at the otomoto ones, they are the same generic shit that everyone else makes. The sealing faces are just flat and you are relying on the clamp to align eachside and hold them together, that style leaks easily. Ive used some like those from GCG when I made the headers last year and they were the same shit. After that exp, I just figured its easier to make them myself, though a shit load more time consuming, its cheaper and I can make them properly.

Mine have the male lip on one ring and the female receiver on the other. So that aligns them and because they are a nice fit when heated up that will seal internally from expansion. Takes more load off the clamp so now its only holding the rings together. I also machined an internal step on the other end so my 4" tube slips inside the ends of the rings nicely, so all the ID's line up

Michael = 1 Otomoto = 0 lol.

All the bungs in the head were alloy, I just drilled them with a slightly undersize drill and they would collapse around the drill bit and pull out. Except the vct brass plug in the inlet side oil hole. I got lucky when the drill bit grabbed it and it spun out. I think I used some M6, M8, M10 and M12 grubscrews and some M14's but they were the small frost plugs near the vct solenoid hole. Oh and the Solenoid hole thread is a M18 x 1.5mm pitch in case anyone wants to know. Also the big steel grubscrews in the sides of the head are 1/2" bspt from memory, may need to double check that one.

[Craved]

yeah that makes sense to me, didnt realise those types would leak. i did notice your male lip on the flange too, nice touch

i know a guy with a cnc lathe so if you want to share the specs of the rings i'll get him to price em up for me and anyone else who would be keen.

had my machine shop do the black plugs, but for the price i think i'll do the head ones myself if i get some spare time!

[r33_racer]

I can put up the drawings I did. However, I would have to fix them up as things changed on the fly as I was machining them. But thats no drama.

Originally I was going to get some made in the CNC, but it was flat out with work stuff so it went this way. I reckon they could be made quite cheap if you started with the right material. As in some thick walled pipe close to the diameter needed so you dont have to bore out 98mm worth of steel. Perhaps some 116mm OD pipe with a 10mm wall would make them quick to machine. Quick clean up on the inside to 98.4mm and the same on the outside to about 114.3 or thereabouts and just the lip and receiver which is 1.6mm x 1.6mm and the 1.6mm x 3mm up the arse for the tube to slip into and the 45 angled face for the clamp to push up against. The longest bit for me was boring out all the useless material in the guts!

If you have some basic hand tools, drills, bits and taps its a piece of piss to do. Your own time is free!

[Craved]

whats the depth or thickness of each flange? can just get the basics cnc plasma cut in 10mm sheet when thats running at my mates work to get the ball rolling