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Managed to collect the 3D print, check the hole positions against a std mazda exhaust manifold gasket then invest the time in mock fitting it (car remains a runner between mock ups etc.).
Tried the thicker plate with the larger chamfer first to see where it gets us. Gets the turbo away from the head and bonnet well. Comes down a little close to some of the hoses below and pushes the exhaust manifold out out to close the downpipe clearance a little too much.
I've taken dimensions from this mock up and next move is to get a slimmer version 2 print drafted and then mocked up.
Still no absolute red flags on the feasibility front.
Originally Posted by Dr.Sep
props for doing something different in a methodical way... on a running car!
I have to agree!
The initial mock up looked like it would burn the paint off the hood...
The wedge plate install looks like it fixed the turbo placement just fine.
The wedge looks thick enough to allow decent threshold blending between Miata and Mits patterns.
Coming along nicely!
You just adopted another cat...
Thanks for the props everyone. Its a good hobby project.
Originally Posted by Full_Tilt_Boogie
On a serious note. Hows the down pipe clearance looking? Hard to tell from the pics youve posted.
I did a template of the current orifice with Cardboard Aided Design then transposed it onto a sheet of paper to see the options. You could stick a 2.5" exhaust and a 1.75 divorced screamer through the space.
3" downpipe which is what I'm aiming at will require the rear shelf lip knocked down/in. Don't think it will need more so should not require any cutting, welding. Water pipes to heater matrix will still work with some attention.
Thanks for the props everyone. Its a good hobby project.
I did a template of the current orifice with Cardboard Aided Design then transposed it onto a sheet of paper to see the options. You could stick a 2.5" exhaust and a 1.75 divorced screamer through the space.
3" downpipe which is what I'm aiming at will require the rear shelf lip knocked down/in. Don't think it will need more so should not require any cutting, welding. Water pipes to heater matrix will still work with some attention.
The flow area of the two tubes is just a tiny bit larger than the flow area of a 3" tube.
Merging them along side the transmission to a 3" will improve flow (reduce lag) through the turbo.
Only down side to this is the smaller pipe will go through significant temperature variations depending on boost.
You have to come up with some kind of "strain relief" for this pipe.
If you're just dumping to atmosphere it doesn't matter.
Last edited by technicalninja; 03-09-2021 at 07:37 PM.
Reason: Only the ninja knows...
The wastegate pipe will be short as it has to have merged into the 3" DP before the shelf, space for a thermal expansion solution on the wastegate pipe will be tight so may have to wing it and then revisit it if I have issues. If the rest works then it will get the investment of time required.
We think we can grow the 2.5" turbine outlet to 3" within the exhaust flange pretty close to the same expansion rate as the turbine housing which buys us space for the bends out of the flange to then get under the car.
I've got the second 3D print to try. This one is thinner than V1 and creates less chamfer so the turbo will sit slightly higher. This will bring the housings closer to the bonnet but further away from the pipework below the evo manifold which is the goal.
This one has the evo exhaust stud holes added to it and I've checked they align with the manifold holes off the car. The step in the port is only to visualise the difference in port sizes. This will be a smooth blend on the actual adapter.
Looks good so far, still no material red flags. Hope to get a change to mock it up again soon.
Managed to get the slimmer 3D print adapter onto the car for a mock fit. Can see how the oil drain will orientate, lifts the Evo manifold away from waterpipes etc. Not too close to the bonnet or head - packaging is actually quite neat.
Rear shelf will need massaging to get a 3" downpipe in but I don't see the requirement for any cutting.
I think I'm done for mock ups. I'm going to reduce the clearance size of the outer Mazda stud holes to increase the sealing surface area between the evo ports and the mazda stud holes where it is quite tight (these holes are for M12 counter sunk cap head bolts into the Mazda head. I'll turn the cap heads down on the outer bolts so there is still clearance within the holes for movement.
Now its finding material and an engineer. We have a family friend who has offered to supply and machine the initial adapter out of stainless.
Got the adapter plate back from my dad's friend - cost me a very good bottle of single malt.
I've now to take of the plot coordinates for the Mitsubishi manifold side and pass the plate to a local engineer to machine and tap the Evo exhaust manifold stud holes. I'll then do some port matching with a die grinder to finish it off.
I also had a shot of a friend's vapour blaster. What an ace bit of kit that is:
As a novice and knowing that I hand measured the design and clearances etc. with a free plastic ruler - it is very nice to see it coming together and verifying that my hole positions and ports all align and that have the expected expansion clearances etc. It helps to have clever friends.
The accuracy of engineering to then replicate your requirements in steel still amazes me to be honest. Thinking back to machinery developed during the industrial revolution and in war time utterly blows my mind as to how clever and skillful people can be.
Once the next round of machining is done, Evo stud positions will be verified again and then the two faces will be machined as flat as possible as the last step to promote exhaust sealing.
This thread has fallen behind my actual progress but I struggle to get the time to update. I'm going to keep updating in chronological order or it will get confusing.
Exhaust flange as bought:
I then did a little work to promote wastegate flow from the turbo side.
Exhaust flange wasnt a perfect fit for the turbo so I machined the turbo slightly to match smoothly. Also machined a lip in the turbo without getting into the turbine nozzle area.
Our experience of Evos has shown that the standard turbos can suffer boost creep so I opened up the wastegate holes.
Evo plate now machined for evo hardware - did some port matching
Fruits of my labour (and others!):
I've aquaired a spare engine which may get forged in the future. Its a good mocking up stand for the time being:
I'm looking to put a rear half cage in at some point. Has anyone ever fabricated additional bars which would bolt to the rear cage and then come up to the windscreen like the roof bars in a full cage. These could have the factory hood clamps fitted to then stiffen up the windscreen as if you had a hardtop on. Might be quite nice for a dual road/track car where you can then track it with the roof down but have slightly addtional stiffness and less skuttle shake. Would need to come off when it rains if you don't want to be wet to then put the hood back up. Probably a quick pin arrangement that might work at the connection to the cage. The factory hood clamps would then tension it so it is quick release.
Cant wait to see datalogs and a dyno from this setup.
Years ago I saw a thread on one of the Honda forums where a guy when through the trouble of making a custom manifold to run one of these divided Mitsubishi Evo turbos. It had really good response, even on a 1.6L and IIRC it was still capable of upwards of 300hp.
Cant wait to see datalogs and a dyno from this setup.
Years ago I saw a thread on one of the Honda forums where a guy when through the trouble of making a custom manifold to run one of these divided Mitsubishi Evo turbos. It had really good response, even on a 1.6L and IIRC it was still capable of upwards of 300hp.
Yeah hoping for full boost around 3000 to 3500 rpm - this turbo is rated to c.370bhp flywheel on an Evo so plenty capable on my standard engine where it will be running baby boost.
Main exhaust expands to 3" within the DP flange. Full exhaust is 3". Wategate pipe doesnt have a bellows etc. on it so time will tell on this but it is quite short length so hopefully expansion differences won't be high enough to kill it. If it becomes a problem then it may get divorced in future but I want to keep it as quiet as possible for trackdays etc.
Pipes merge before the rear shelf so the firewall shelf lip only needed bent downwards with a suitable blunt instrument to get the single 3" pipe through with enough clearance. No cutting which was nice.
Picked up a standard Mitsubishi Evo 7 intercooler very cheap. Friends have used this core to very good effect on other vehicles in the past so it should be more than up to the task on my low power application and matches the turbo and throttle body sizes.
No AC in my car so the cooler slotted in in front of the radiator. I made two supports that come up from the AC rad support holes. I then bent the top cooler mount over and simply bolted it through the front panel. All rubber grommets are on the 3 mounting points, nylok nuts etc. Could do with cleaning up the fins and a quick mist of matt black paint at some point but the car is no looker - function over form and all that.
03-09-2021, 10:50 AM
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