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They are flat. I thought about doing a bit of a convex but I do not believe it's necessary and may actually change the shape of the journal just a little.
If you are going to go much over 8k RPM they would be a good idea. Same if you were doing a big power boosted build.

Yeah recirc is definitely best. If you are only running a few PSI venting to atmos doesn't seem to mess things up bad but it's not ideal.
Or you can do like the MR2OC SW20 guys and run without BOV.
I wouldn't use the GZE ABV. First it's super big and clunky but it's also designed for a different purpose and may not work right for a turbo. If you are on a budget try to find a first gen DSM metal BOV.

Guessing most of you have seen this stuff on the big boards but I thought I'd throw it up here in case anyone hadn't.
My rear tie rods are finally out. I can't help noticing this is under the Marlincrawler website. If any of you are wheelers or offroaders you may recognize the inner joints on these rear tie rods. If not you will be glad to hear that they are used on crawlers and desert racing trucks. They are way overkill but one of the only metric joints I could find that would work. Yes I am very particular about trying to keep all metric components on metric cars.
I have also tested my tie rods to about 30% more force than the strongest stock tie rod I tested. The tie rod didn't yield. There was no permanent deformation.




http://matrixgarage.com/products/matrix-garage-rear-tie-rods



I am also getting my own crank ladders made.
http://www.matrixgarage.com/products/matrix-garage-crank-ladders

It looks like that would be a TC05-12A.
It looks like a small turbo. I would guess quite small. That would be great for spool but I have no idea what kind of power potential it has.
I would be hesitant to run this turbo for the same reasons as the SC12. It does not look like they are very common. It looks like they have several different flange options. The problem is if you buy a mani and downpipe for this turbo and then blow it up and can't find another one or if you wanted to upgrade you wouldn't have any bolt on options.
Used turbos are so cheap I would buy one that is common and readily available. Or spend the extra on a new turbo that should last forever and would still be replaceable in the future.
A nissan T25 would be a great OEM option. Just make sure to get one with 5 bolts on the turbine outlet. Do that and it will be compatible with Aftermarket Garrett T25s as well as a lot of OEMs. I think those turbos should be easy enough to find in the future.
I used to love DSM turbos and still run them but their smaller turbos like T25 13T 14b etc are getting more rare and will continue to since they haven't been on any car for a couple decades.
Another decent option for you may be a WRX TD04-13T. There aren't as many options for upgrading but it should make plenty of power for your goals, will spool hella fast and they should be plentiful and cheap for some time to come.

It's possible. mk1noob did it and detailed it pretty well in his 4agez threads on the mr2oc.
He also went pretty quickly from SC12 to M90 to twincharged because neither SC setup got him very far. Like me he lives over 5000 feet which devastates pressure ratios and a SCs capability.


There are a couple big things I don't like about the idea.
First is that the SC12s are getting older, rarer and more expensive. They also can't be rebuilt fully. If the internal bearings go it's no more than a fancy paper weight.
Any other SC will take a lot more time and money to install than a turbo and still have much less capability.
If you did do this and decided you wanted more than 200 hp down the road you would need to completely redo your entire system.
If you did a twinscrew you might get over 250 but it would add another $2k or more to the build.

People always like to complain about spool but I like to remind people that the SC12 or M62 are only good for about 180 WHP with a lot of supporting mods. An SC14 or M90 might break 200 with a lot of supporting mods.
The OEM turbos that are considered to be too small and spool insanely quick like the DSM T25, Nissan T25s, 13b, 13T etc can all make well over 200 WHP. With a good tune people have made over 250.
A turbo that maxed around 180 WHP would spool so damn fast that over 3000 RPM you would have a hard time telling it apart from an SC12.

The Eaton M series are a tiny bit more efficient but not all that much. Not enough to be worth switching to in my book.

It has always pissed me off that Whipple claims 85% efficiency but any map you find for their product shows not much better than the 60s.
I feel like the twinscrew manufacturers twist numbers a lot more to make them look more competitive with turbos when they are not. They are slightly better than roots but I have yet to see one that is significantly better.
After extensive discussion with Sprintex I did learn that they act as a big heat sink which means that while they are absorbing the heat they are making they can have outlet temps lower than their rated efficiency would expect but once they are heat soaked they will crank out very hot air and can quickly get dangerously hot. This means that for high pressure ratios they can work okay on drag cars or dyno queens where they have time to cool down after a short pull but are not nearly as well suited to extended use unless the pressure is kept much lower.

http://i11.photobucket.com/albums/a155/elbigjer/whipplew100axmap.jpg

Whatever the case if you are keeping the pressure ratio low like you are then it's not a bad choice. You will have more outlet heat than a turbo would but at 10 PSI it's not hard to get rid of most of it. water/meth injection will also definitely help.

I'm not sure what your budget or goals are. Most people aren't interested in going into the motor but in a case like yours where making power at limited boost is concerned one of the biggest things you can do is increase the compression.
I have not studied the effects of compression on emissions but I would think as long as you kept it low enough to maintain stock cams and ignition timing you should be able to pass. Bigger cams would help making more power per PSI and allow you to run even more compression but I don't know how much cam you could run before being noticed or failing the sniffer.
I am used to tuning on 91 at 6k feet so I usually figure it's not much harder than tuning near sea level most places that get 93 octane but I'm guessing you only have 91 and at sea level that still limits things a bit.
Still though even on 91 I bet you could run around 10/1 at 10 PSI.
That's all hypothetical but I'd be confident enough to try it on a motor of mine with stock 16v cams. I'd just want good detonation monitoring.
If you are doing water/meth injection then you could set it up pretty near the limits of detonation without it. Just good enough to pass emissions and not blow up if it ran dry or failed.
Now I'm interested to know more about the effect of emissions on compression.
All the good articles I found in a quick search was on diesel though.

Nice build and nice fab work.
I have had a few people come to me trying to make a smaller SC pulley like the speedchaser ones. I usually talk them out of it because that along with an oversized pulley pushes the SC so far outside it's ideal range that I consider it to be not worth the cost. I can see how in your situation not being able to run a big crank pulley means any gains you can get from the SC pulley could be very valuable.
Your design gave me a thought.
I have started working with a Chinese manufacturer who appears to do very solid work. I am continuing to send them more challenging and more precise projects to see if they are as good as they claim.
Since if I remember right there is actually a good bit of room between the pulley and the drive plate it may be possible to make a pulley from the ground up that was a little smaller and therefore allowed the diameter to be a couple mm smaller as well.
Getting one made may still be several hundred but a run of four or so could bring that down to maybe a couple hundred ea.
At least this allows you to run the stock stator and drive plate making the cost look a lot better. Plus making a smaller stator would require some electrical engineering to do right. I think even then it would likely be weaker. Plus you would have to run a smaller drive plate reduces clamping force which makes it much more likely to slip.
Still a bit pricey but I thought I'd mention it. Not sure how far you would want to try to take the idea.
I am not fond of SC14 conversions because just like the SC12 they are only rated to a 1.8:1 PR and even at that are in the 50s to low 60s adiabatic efficiency. The SC14 does improve the efficiency a tiny bit on the horizontal/flow axis but by so little it would be hard to justify.

Nice.
Yeah you aren't going to tear the rollers off any dynos with the stock pistons and ECU but it can make a huge difference in situations just like you say. DIfference between needing to drop to third vs being able to stay in fourth or even fifth and cruise right up.
Also the difference between sitting behind someone for miles because you don't have what it takes to get past in a tight spot or being able to whip out, punch it and fly by.
Hope to see a good build thread if you do it.

I do not believe that to be true but I will admit I have not personally confirmed it. There is also conflicting info out there which doesn't make it easier. For example billzilla does say the smaller cams are SP only however I have seen enough evidence to be pretty confident that around 87-88 they all had the smaller cams.
http://www.hachiroku.net/forums/archive/index.php?t-3709.html

84/85/86 all had the 3-rib blocks with large cams
87 was a weird year... some 3-rib (mainly early production) and some 7 rib blocks.... i personally bought an 87 with an original 7 rib (not in the car anymore though...)
88/89 had the 7 rib with the smaller cams, but obviously still bigport head

http://www.mr2oc.com/showthread.php?t=549665

The smaller cams were only found in three rib motors. By the time the GZE came out all cams were the same smaller cams, NA, GZE and the SP.

Hey guys, I just found this board.
Looks like you have some interesting discussions so I decided to join up.

Compound boosting with a supercharger can work but in order to make it work well you need to put an intercooler between the first compressor and second compressor. Otherwise your outlet temps will be much higher than they would be with just a turbo because the supercharger is less efficient.
If you do intercool between compressors you could actually have lower intake temps than you would with one turbo and one intercooler.

Teflon melts at such a high temp that I have never believed the theories that it does in the SC.
I believe what happens is the rotors being exposed to more heat and having less thermal mass expand more than the housing causing them to hit the housing and or each other.

I believe mk1noob is still compound boosting his M90 AW11. I don't hear from him much these days but last I did he was running about 20 PSI and getting ready to switch to E85 and go big.