Is the V8 Miata really a modern day Cobra?

Lots of articles have hyped the V8 Miata as the modern day Cobra; but is it really?

To answer the question I found a review Car and Driver Magazine did in 1965 of the 427 Cobra. Check out the specs compaired to my Jenna: 

                            427 Cobra              Jenna
Curb weight          2529 lbs                  2580 lbs with a full tank of gas

Weight dist           48 F / 52 R              52 F / 48 R with driver and full tank of gas

Engine                 427 CID                  347 CID

Final gear ratio        3.54                              3.55

From the article: “The Cobra will break traction to speeds beyond 100 mph and imprudent applications of power will send the tail end sideways"  Jenna broke them loose at 85 in 3rd and I have no doubt she will beyond 100...

                            427 Cobra            Jenna

Horse power         485 @ 6500         488 @ 6700 (425 adjusted to 1965 SAE ratings)

Torque                 480 @ 3500          413 @ 5000 (apx with my cam and tune)

Wheel base          90”                        89.3”

Track width           56”                        56.2”

Height                  49”                        47.2”

“Others defend the Cobra arguing that its raw power, great brakes and advanced suspension create such unabashed excitement the owner won’t give a damn about creature comfort"  Agreed but I do like windows and a top!

                               427 Cobra          Jenna

1/4 mile time            12.2                     11.5 on drag radials (time from swaptastic)

0 to 60                     4.4                      4.0
0 to 100 to 0 time     14.8                     14.4 but I will kill that with better brakes
Top speed               165                      Not with me in the car!
Mileage                   9-12                     18-25 typically. My average is 22.

"The driver of the Cobra has about as much fear of being passed by a faster car as he does heard of stampeding water buffalo"  I know the feeling...:-)

                                427 Cobra             Jenna

Cost 1965 dollars       $8,000                  $2,516

Cost 2013 dollars       $57,425                $18,000
 

Pretty cool huh? If you would like to read the entire 65 Cobra article click the Cobra

 

So is Jenna a Modern day Cobra then?  At her core she is the same combination of American muscle and great suspension in a small foreign car to create dazzling performance.  Her modern features like A/C, decent gas mileage and a folding top might very well be a part of the Cobra if they were still being made today. 

 

Still I cannot bring myself to see Jenna in the same light as the iconic 427 Cobra.  It's like I can love current southern rock but there will never be another Lynyrd Skynyrd. There can only be one legendary Cobra and it's no slam to any car that nothing can ever rival it.   

 

 

So it's up to the V8 Miata to find her own glory and leave her own mark on us.  Indeed after 4500 miles of driving one I find it most disconcerting to look down at a Miata interior and hear what amounts to a raucous, unvarnished Grand Sport Le Mans racer emanating from within!

Road Test #2 - V8 Miata Autocross Racing!

No trip home on a trailer -YAHOO!  But do have a couple if issues I need to fix... 

In a 65 second autocross the temp gauge goes from 195 to 225 and after the 3rd run in 20 minutes it was at 250. The other thing is she developed pretty significant power steering leak on the last run.  I think it was damage from when I dropped the engine that came to light under the stress of the day.

OK this is raw video with no enhancements to the audio or speed of it. Obviously there is no image stabilization either!  My friend Steve is doing the driving so crank up your speakers and enjoy the ride!  Click the pic below 

0 to 60 V8 Tire Shredder meets the Klutz!

First up you should know I am a convertible guy.  I have owned a half dozen convertibles with at least one made in each decade going back the 70s.  Suffice to say I have a great deal of experience with convertible tops.

So I’m rolling along to work yesterday when the sky opened up with a TREMENDOUS BANG!  

3 things happened in the same nanosecond. 1, the top went down with such force the back window exploded, 2, I woke up, and 3, I found out the brakes are very good in the car!

On close examination I decided I must not have had the pin in the hole on the driver’s side latch.  Really Mazda you designed a system that would allow the latch to latch without the alignment pin being in the hole properly?  After numerous tries I found it is quite easy to do just that, but still I felt pretty stupid (and Klutzy) for missing it.

As tempting as it was to box up all the glass and mail it with a hate letter to the Mazda top latch engineer, I decided it would be better to install the Aero latches that had been sitting on my bench for a month so we don’t have a repeat performance from the hood.

The pin under the hood Can't miss getting the pin into the hole on these guys! That will hold her!

In other news over the weekend I put a cow catcher on her.  (front chin spoiler :-)

I’m not sure I like it.  Maybe with side skirts and a wing…

After cleaning up the glass last night we put her in a car show rust, dents and all!

Wait, is that a NASCAR shirt with shorts, black socks and loafers? 

 
Oh no problem he has a camo hat!  Yeah we know what cool is in small town Minnesota! :-)

I still have a few bugs to work out but with the autocross race coming up I thought I better give her a little gas and see if anything breaks. 

So I made several attempts to record a 0 to 60 time. I could get the clutch out and ease the pedal to the floor just fine but no matter what I did when she hit the power band around 3500 rpm the back end gets loose. Backing off or short shifting to 2nd helps but it’s still impossible to maintain traction at full power.

So the best I could manage was around 4 1/2 seconds but I know with some sticky drag tires she would easily be in the 3s.  For a video of some of my later efforts: CLICK ME  (the early ones were all tire smoke...)

The LORD will open the heavens, the storehouse of His bounty! Deut 28:12. Yeah he did that this week!  I hope to have track video for ya in the next post...

Weighing in on the exhaust!

I stopped by the grain elevator on the way home from work and put Jenna on the scale.  Of course I did it on a whim so was not prepared and had my tool box, fire extinguisher, jumper cables, toe strap several bags of parts, a gallon of water and who knows what else in the car.  She weighed in at 2620 lbs with a half tank of gas. 

That’s about 50 lbs more than I had hoped for but considering all the steel and welding wire I added and the packed trunk I’m not surprised.  Race weight with all the stuff out and a full tank of gas I think will be around 2580.  That's 40 lbs heavier than a 427 Cobra but hey I get a radio, air conditioning, power steering, side windows and oh yeah, a top for that 40 lbs!

 But more important she is nearly 1200 lbs less that her predecessor so I am delighted!

Now on the exhaust thing I am still struggling to get where I want to be.  The flyin Miata set up has an OK sound if you like late 90s Corvette. It would be fine for a date car but hardly strikes fear into the driver next you at the stop light.  

I messed around with various configurations and found with enough venting to get the desired volume it sounds like an old Chevy pickup that needs a muffler, and with enough baffling to get the right sound it’s too quiet.  I know she will never sound like a 60s big block but I can still try!

So for now this is what I did.  I cut a hole in the muffler the size of a 2 bolt 2 1/2" flange.  

Then I cut the flange in half so I could get it in the hole and welded it back together inside the muffler with nuts on the back to bolt to.  Yeah that was interesting!

 

Next up I took an auger style header baffle and cut one loop off of it.

I welded the loop and the mate to the flange inside the muffler onto an old piece of Camaro exhaust I had laying around. 

On the other end I put a 3 bolt flange to cap it off for road trips.

And installed like so.

I tucked it up tight to try and make it not show.

That's my babe riding shot gun on the road test :-)

The result is frankly amazing.  It is still too quiet but the sound there is there is really good sound.  It’s big and deep, very much like a 60s muscle car.  It has just enough sound to be noticed and just cam lope to know there is something very not stock under the hood.  I’m hoping to post a track video in about 2 weeks so you can hear it but I know no video can do it justice!

The Lord thundered from heaven and the most high made his voice heard.  2 Sam 22:14.  Yep there is a verse for that!

9/10/13 update I took the screw out of the exhaust becuase it still was not loud enough.  Over the winter I am going to rework it so look for posts in 2014 on it.