I muted Top Gear to watch your last video. Top speed of a tuned Bugatti Veyron, 417KM/H. I however was more interested in watching you sandblast your floor. Keep up the work. One less thing to do later.

I can't get that COSMO jingle out of my head. I'm humming it at the breakfast table the next day...

Haha, too true for me too.

Bummer about the floor rust, but I'm actually surprised its not worse, with the age of the car and it's rough condition when he found it. As usual, Mr. Cake shows us how to do it right, rather than do it over later :)

I just wish that there were patch panels available. Watching Chop Cut Rebuild and seeing them able to purchase virtually ever bit of sheet metal for their Charger (which, lets face it, should have been crushed and not restored) has annoyed me a little. Still, the areas I have to patch aren't very complicated and honestly, my repairs don't have to look factory. They just need to be solid, safe and complete. Since any seams will be covered by Dynamat anyway, I'm not going to care if the patches don't look 100% factory. More important to me is that the car is solid.

So... wanna start mass-producing patch panels for the Cosmo? No? The last person who thought of this apparently didn't want to either. :lol:

It would be nice if I could just get patch panels, but obviously it is unrealistic to expect them to be available. I do have the local Mazda dealer looking for any Cosmo sheet metal they can get, though.

Part 7: My 76 Mazda RX-5 Cosmo Restoration - Intake and Exhaust Porting
 

Has it been nearly a month since my last episode? Wow, time does indeed fly. I've been quite busy preparing to build the engine. So in part 7, I cover the intake and exhaust porting. The engine is being built with GSL-SE 6 port plates and the Cosmo rotor housings as the basis for a 6 port turbo setup. This port job is fairly conservative, only opening up the primary ports a little and bringing the exhaust ports close to 2nd gen RX-7 specs. The goal is to maintain fuel economy, low and midrange torque, and idle quality. This episode covers everything involved in porting including: marking out the new ports, grinding the port shape, smoothing the bowls, smoothing port to runner transitions, smoothing the runners, grinding and blending the exhaust ports.

http://www.youtube.com/watch?v=y1Gy5sVMK3o

Have you thought about "peel n seal" as a cheap alternative to dynamat? http://www.canadiancaraudio.com/onli...et-milton.html


BTW, good work on the video!

I know a while ago you talked about keeping the Aux ports functional in some way on this build is still the plan or is a secret still?

Wow, that was neat to watch the porting process. Love the template for the intake ports. I'm really enjoying the videos on the work you've been doing.

Aaron, you are porting the primary intakes, but not the secondaries. Is that because they are already a good size? Do you at least give them a little casting cleanup and polish?

You made the exhaust ports alot bigger than stock. What effect would you expect if you just ported the exhaust side, as you did, but left all intakes original. Could you calibrate in terms of anticipated horsepower impact?

Are you getting any sponsorship for your tools?

You act so relaxed and make it look easy. Nice vid...again.

The thing about those kinds of products is that they are basically tar paper. I've heard from a number of people who used them, only to find on the first hot summer day that the tar melted and pooled on the floor under the carpet. Products like Dynamat may look like tar paper, but they are generally a rubber compound. On automotive forums, someone has an idea like "Let's use tar paper!" and a bunch of people agree and then do it...yet you never hear from those people again on the subject...partly because they are busy cleaning tar out of their car. :)

There are cheaper products than Dynamat and I may try some of those out. However I do have a box of Dynamat in the garage already.

Yes, the aux ports will be fully functional. The lower intake manifold will be GSL-SE using the sleeves and the actuators. The actuators will be connected to a boost source through a solenoid and the solenoid will be activated by the Megasquirt above about 3500 RPM.

For the record, the intake port template is a slightly modified Mazdatrix 6 port template. Shockingly, I found that the stock Cosmo 13B center iron had exactly the same bottom port measurements as the Racing Beat turbo street port template. But there isn't enough room in the GSL-SE center plate (or any non-early 13B center) to go that big.

Correct. The secondary and aux ports are already huge. If I was to change the timings on them, all I would do is create more overlap and thus lower low end and fuel economy. The 6 port setup already has huge port area, as is demonstrated by when crazy people wire the ports open and immediately lose about 25% of their low end. So keeping those ports stock or close to stock is the best bet for most people unless they are building an engine that is expected to make power above 8000 RPM. Me, I'm trying to emphasize low and midrange by using a very small port job and a smallish turbo. I did clean up some of the casting weirdness in the secondary port but the aux port is untouched because it is machined for the rotating sleeve.

The exhaust ports are much bigger than the stock Cosmo ports, but smaller than the stock 2nd gen ports. The second gen engine is made to make power higher in the rev range than an engine for a luxury car. There is only a limited amount of area to move out to side on exhaust ports because past a point, the apex seal starts flexing. By going out to the side, you are just increasing flow and not changing timings. With the appropriate supporting mods you would fee up a bit more power but the real impact comes from timing changes.

If you were building a 2nd gen 6 port engine, the exhaust port can be moved up a little if port opening time is not changed much which won't really cause much low end lost but will help in the top end. On a 6 port NA engine for street use I generally recommend porting the primary ports using the template in the video, then just opening the secondary and aux ports a little earlier (1-2MM), and moving the exhaust down 2MM and up 2MM. That's an awesome engine to drive and should make about 15-20 more HP with supporting mods. More power is of course available, but you will always reduce low end in order to chase it. Hence, turbo... :D

I wish I had someone paying for my tools. :) This really isn't my first port job. Once you've done it a few times, it becomes rather easy. Creating the new port shape is easy as one just needs to follow the template. It is the rest of the stuff, like the transition from the port to the runners, that takes practice.

Why not cut the aux bridge in as well since your aux ports will not open until they see boost and are above 3500 rpm?

Any thoughts of using the atkins aux sleeves?

Gives you a neat option of activating them via remote air pump for some brap if you wish as well :icon_tup:

im guessing with that intake/exhaust combo and a small turbo that thing's gonna be a little torque monster
looks good
I should have another rotary powered car on the road this summer too
what size turbo did you have in mind?

Hell, a camden would've made great torque with that set up. A small turbo, good choice...should work well

It won't do much. Truthfully, in all the experience with aux bridges I have, I can only recommend that most people stay away from them. They just don't work out all that well. Mine works fine, but that is because I designed an intake manifold around it. The rotating sleeve approach for an aux bridge just doesn't work as there just isn't enough flow through the port. All it succeeds in doing is lowering mileage and messing up the idle. Keep in mind that even with the sleeve closed, there is a still a huge cavity cut into the iron through with exhaust gasses can bypass into the intake event, so overlap still exists in significant quantities.

I'm an idiot, so I forgot to order them from Atkins when I got the rebuild kit. But I'll certainly be making another order just for the sleeves.

GT3076 w/internal wastegate. I'm flip flopping between the undivided .82 turbine and the divided 1.06. The undividded will make it far easier to build a manifold, the divided will allow similar spool with a less restrictive housing...decisions, decisions.

Hm, I don't think I want to open that can of worms in this thread. :)

^ build both manifolds and buy both hotsides keep the setup you like best???

I mean its not like you enjoy fab work or anything :lol:

The compressor wheel would be a good fit as the thing flows closer to a 60-1 wheel , the exhaust wheel is too small. Now if you could get a BB turbo with the GT3076 compressor wheel and the GT35 exhaust wheel, that would be maybe worth the price and consideration for the 13B.

keep your exhaust housing smaller. 1.06 is kind of overkill don't ya think?
my S5 hotside works well

I'm thinking no. :) If I go with the divided housing, I must also go with an external wastegate which means all the associated plumbing. Space is at a premium especially with how far the turbo needs to stick out from the engine to accommodate the aux port actuators so there just isn't much room to package it all. The undivided housing is available with an internal wastegate which greatly simplifies the manifold and plumbing. With a cat in the 2.5" exhaust I doubt that I will have boost control issues with the internal wastegate so that's the direction I'd like to go.


The 3076R that I'm going to use is a 60MM 84 trim turbine wheel, and the housing is a 0.82 (or 1.06) T3 housing, not the T25 housing typically found on the GT30R. It is going to be near perfect for my application emphasizing low end and midrange. I don't care if it becomes an exhaust plug at 6500 RPM as this is not a car for carving corners, it is a luxury car with different powerband requirements. Comparing the turbine maps between the 3076R and the 3582R show only a 8 LB/Min difference at the same pressure ratio in similar housings and only a 2% efficiency loss from the 35R to the 30R. So the 3076R is the perfect ~300HP turbo for this application. The only annoyance is that the compressor is distinctly designed for higher pressure ratios. There is of course the GTX version of the 30R available now at not much of a premium, but the improved wheels really only extend the turbo into pressure ratios I don't intend to run.

Remember, these are T3 turbine sides I am referring to.

http://retrorides.proboards.com/inde...y&thread=70135

Aaron you should check that page out, its a DIY for panel making, its cool some of the techniques he uses to get different bends. he does amazing work

Awesome, thank you for the link. There is no question that will be very, very helpful fairly soon. Panel beating is one of those things that I am not so sure about, hence starting with something non-critical like the floor. Thankfully, there aren't a huge amount of visible body repairs that need to be done.

Part 8: My 76 Mazda RX-5 Cosmo Restoration - Engine Hole Tapping and Painting
 

And with that...

It's a Festivus miracle that I now present Episode 8 of my Cosmo restoration. Now that the engine is fully ported, episode 8 deals with the final prep of those engine parts before engine assembly. In this episode the rear iron and water pump housing are tapped for sensors and fittings, and then all the engine parts are glass bead blasted and then painted with POR-15's engine enamel. Also included: adapting S4 water pump housing to older 13B, tapping rear iron for turbo coolant feed, masking the parts for blasting and painting, final soap and water wash, watching paint dry.

http://www.youtube.com/watch?v=v-0Yl_Jlx1w

Hurry up, build the engine!! :goodrebuild:

I don't know what is more silly...
You, watching paint dry...
Or me, watching you watching paint dry...

Seeing you playing with that wire harness reminds me of my cat and string...

But I must say, you are multi-talented; as a car guy, videographer, webmaster and IT guy.