MADJAK's NA8 - 200+HP N/A

[speed]

Loving this thread!

[madjak]

That's a pretty simple brake upgrade for the rear! Do you know what the honda hat part number is?

I'll trace the bracket and make a CAD file next time I have it off. The Wilwood Hat part is: 170-6288 - $125 US , but you also need the 11.44" rotors Part no: 160-0201 - $80 US and don't forget to order a bolt kit as well, or source them locally like I did. If you use cap head bolts, then you need to grind a little bit off the caliper for them to clear. Otherwise use the torx wilwood kits as they are a lower profile head.

So around a total of $430 US for this setup on the rear... It's pretty much the biggest rotor you can fit with the stock caliper. Actually you have to be careful where your wheel balance weights are sitting as they were rubbing on the caliper with my Kosei K1 rims. I also had to remove the dust shield with a cold chisel and some tin snips.

Later I'd like to put a Wilwood caliper on the rear but I want to retain the handbrake. I know FM sells a caliper with a handbrake, but it's only just functional and no good for holding the car on a steep slope.

Also - getting 2 pairs of your radiator mounts cut this week - THANKS!

Are you planning a smaller radiator install or for a full width radiator?

I did this mod over a year ago now but I'm pretty sure I had to remove the existing radiator brackets from the chassis rail. From memory I think these are bolted on in two places but also spot welded. I had to cold chisel them spot welds to get them off.

My bracket attaches to a couple of the bolt holes from the oem support, plus the two front sway bar bolts. Then I added a couple of other fixing points with some M6 nutserts.

Here is another picture of the hanger in position.



Also a shot from the front showing the oil cooler and radiator with the front mouth boxed in with 1.2mm ally sheet.

[madjak]

Aluminium Exhaust

I like to experiment. Sometimes it works, sometimes it doesn't. This one worked... sort of. My exhaust consists of some custom made 4-1 SS headers, that goes into a 3" ally exhaust that runs pretty much straight all the way to the back. I purchased some 3" ally tube for $70 and a mandrel u-bend and cut and fitted the exhaust myself. I then sent it off to my welder to join. The entire exhaust is extremely light and very cheap.





Initially I had an aluminum muffler and it was beautiful... but I blew that to bits after my third event. At launch I was reving my engine and it blew or melted a chunk of the perforated tube out of the middle and spat out all the packing. I didn't think that there would be enough energy to do that to a straight through muffler. My engine exhaust pulses are very violent at anything below 4000 rpm due to the massive cam overlap. At idle if you hold your hand at the end of the exhaust the air actually slaps your hand so hard it stings.

Here is a video of the car at idle... you can't really see the slapping air but you can hear it.



So after I blew up my ally muffler, I upgraded to a straight through SS muffler which weighed 50 times more. After a few more events this muffler also failed with all the internal welds cracking and failing. My exhaust just destroys mufflers! I think it's a combination of the temperature weakening the muffler and then the pulses finishing it off by shaking it to bits.

I'm now running a Magnaflow muffler which are made a bit better with higher temp packing... That's lasted 6 events and a dyno run which is a new record for me so far so it's looking good! I'm also adding a secondary round muffler right after the headers to try and quiet it down a bit more. Whilst the car sounds awesome, to say it's a little loud is an understatement. On the dyno its deafening! I think that's the issue with the 3" exhaust... they are just too loud. I don't want to change it though cause it's obviously working so well!



Unfortunately all these heavy SS mufflers are destroying the nice ally exhaust I started with but I think that's more to do with my engine than anything else. For a less aggressive engine I think a full ally 2.5" exhaust with ally muffler would be ideal. Someone try it please!

Everyone comments on how good the car sounds on the track. It has a really nice sing to it due to the ally tube. The extra wall thickness helps to reduce that tininess of SS.

[Apu]

Interesting feedback on ally exhaust. I have a similar setup on my Integra but that has not visited the track yet.

I have been told however (after I had it built) that ally exhausts do tend to blow holes, so your experience doesn't surprise me...well, fingers crossed I guess!

[madjak]

I have mine off at the moment and everything looks great. There is a bit of damage where it rubbed against the diff housing before I changed the rear support. The tube thickness I've used is fairly thick at 2.3mm but it's still super light.

My father in law ran an ally exhaust on a race car for 15 years and had no issues. I think it comes down to supporting it well along the length and good welds. Ally will fatigue quickly especially when hot, so everything has to be strong enough not to flex. Maybe the 3" tube helps with that too.

The other issue with ally is that any rock hits or ground hits will damage it easily. On the MX5 you can sit it up in transmission tunnel and next to the diff so even at 3" it's higher than everything else in the car and fairly protected from stone damage.

Actually one thing I forgot to mention is I had to cut my rear bumper up to fit the exhaust tip in this location. I recon they look good like this anyway and it helps reduce the bumper dragging the air.

[madjak]

E85 Fuel System

This was a very easy upgrade that I decided to do. It was based on NitroDann's post on how easy it is to add E85 to a MX5. For me it was especially easy as I have a Haltech ECU which can talk to the GM based flex fuel sensors and read the ethanol content. The ECU adjusts the tune to blend in more timing and fuel based on the e85 content it reads.

Typically for a N/A car, you only need 40% ethanol as anything after that, advancing timing further won't produce more power. Forced Induction cars are more limited in timing to start with especially under high boost so adding e85 with 85% ethanol will give much more power. You can see in the dyno plot below the additional 7% power across the board. (Solid line is e85, dashed line is 98)



So the benefits to E85 are:

More power (approx 7% on N/A, more on F/I)
Engine runs cooler
Safer to run as detonation risks are lowered

Negatives:

Harder to source (United sell it in WA, or you can buy it by the drum)
More fuel required - 30-40% extra flow (so larger injectors and larger fuel pump)
Additional complexity in tune
Additional costs for fuel lines

I already had larger injectors and a larger fuel pump so the only costs for me was in the Flex sensor ($75), hoses and fittings ($250) and the tune time ($50). I used teflon fuel lines which I understand isn't required but is preferred. You could do this with good rubber fuel lines and replace them every few years. One issue with e85 is it disolves all the crap in your tank and sucks it through the fuel system. You'll need to change filters often when you first use it. Once the tank is flushed you should be right. For easy access, I've installed an inline filter in the engine bay that has replaceable filters. Once I've run the car a bit and the tank is clean, I'll remove the stock filter at the back of the car.

For even a basic car, $400 for an additional 7% power is a pretty good return. For me that equated to 15 extra HP at the top revs. You need to be set up with an ECU, possibly a fuel pump and larger injectors but if you are this is a great way of adding that little bit extra power. If you do it via a flex sensor and an ECU that blends, it means you can run 98 octane with no issues most of the time and then fill up with e85 when you need that extra power.


Flex sensor, Fuel filter (10 micron), FPR, teflon lines.

[mr bender]

how go does it start with the Toyota COP + e85?
and what sort of plug gap do you run?

[madjak]

It starts as badly as it started before e85. Idle is better but that might be tune related. I am running 1000cc injectors which are big for an N/A engine but if anything its better than the 280cc oem injectors previously.

I'm thinking of trying a higher torque starter to see if cranking is quicker which will help it fire. The engine currently drains the battery quickly so my battery might not be the best.

[beavis]

have this in my race car, never had an issue
http://www.batteriesdirect.com.au/shop/ ... etx12.html

[forcedfive]

4.3kg. Is it really that light?

[beavis]

eh, its pretty small.

[madjak]

Does it have enough cranking amps to turn over a high compression motor? I thought the ext14 or 16 might be a better fit for my engine.

[Magpie]

I'm looking at converting one of my battery packs at home into something like this. That way I can drop down to a smaller battery and use this for starting duties. Just need to decide where the best place is for the plug in point, it needs to be somewhere easy to get to but so obvious that you can't drive off with it still attached.

This setup is probably a bit small for a MX5

[Nevyn72]

Just need to decide where the best place is for the plug in point, it needs to be somewhere easy to get to but so obvious that you can't drive off with it still attached.

Under the bonnet! You're not going to drive off with the bonnet up.....

[madjak]

3D Printed Rear Wing

This is a re-post of stuff I've already posted on here, but I want to bring it all into one thread.

I do 3D Modelling for a living and have a 3D printer at work so I figured I may as well use it to make something cool. I've always been fascinated with Aero design for race cars.

I was researching wing profiles and found a really interesting NACA profile linked from a NASA website that had very high efficiency in my target speed range (100-180kph). This wing profile is designed to run in a narrow angle of attack range so setting the wing up may require some tweaking. I sketched up prototype and I made a 3D model of the wing. The design is pretty straight forward, with two central aluminium ribs, one larger and one for support that run through all the individual 3D sections and also pick up the mounting tabs. These are then all clamped up with inset plates at each end that have threaded holes to mount the end plates.


The endplate design is borrowed from the Singular Motorsports endplates for the COT wings. It's a little different but a lot of work was done to optimise them to keep efficient flow over the entire wing surface.

After around a week an a half of printing time, with 3 different models (Main section x 6, Main section with support tab cuttout x2, Main section with end clamp plate recess x2) all the 3D prints were complete. Each one took around 10 hours to print and weight in around 150grams. All up the plastic parts weight around 1.6kg with a total material cost of around $50.

Next I sent the various aluminium parts to get CNC cut. I have lots of little adjustment holes in the main supports so I can change the wing in increments of 1 degree from 0 degrees right though to around 20 degrees.



The wing just bolts together but I will glue each plastic part to the next and also add a gurney flap to the back trailing edge to bind it all up solid. All up on the scales, including bolts, supports and plastic, the wing weights in at just over 4.2kgs.

Mounting the wing on the car was easy... 4 nutserts in the rail rails on the boot and the wing just bolts on. I have a couple of concerns with the main mount plates in that I think they should have been solid. I can sit on the wing with my two daughters either side (140kg) quite comfortably and I think it could take almost twice that weight spread over the whole wing. The issue is that I think a dynamic load might cause the main mount plates to fail sideways so maybe I need some diagonal wire supports to stop any shear loading around corners. The only issue with that is that I can't then open my boot.




I haven't tested the wing yet because the events I run won't let me run rear aero unless I move into an outright class. I'm trying to win my class this year but next year I'll probably move to outright so I can try some more aggressive lightening and aero. I might ask if I can run it in practice at the next event as I'm very curious how well it will perform.