Speed Limiter removal on NA Eunos

Gladiator · Postby **Gladiator** » Tue May 07, 2013 4:41 pm

I've been wondering how to undo the Jap speed limiting, and I found this http://www.mx5oc.co.uk/forum/forums/t/34933.aspx
I'm hoping to do it before the QR track day, so I'll let everyone know how it goes after that. They are supposedly limited to 180Kph but I hit the limiter on the straight at Lakeside at about 165Kph.

I'd be keen to hear anyone else's experiences on this topic.

Gladiator · Postby **Gladiator** » Tue May 07, 2013 4:50 pm

I also found this http://www.youtube.com/watch?v=XGrb0w2cjak

project.r.racing · Postby **project.r.racing** » Tue May 07, 2013 7:16 pm

IT's the same for Familias of the same era. So I'd say it's probably spot on that info.

Magpie · Postby **Magpie** » Tue May 07, 2013 7:22 pm

You will probably find that the wall you hit was the amount of HP/frontal area required to push the car past the 160. I hit 160 at lakeside however the angle of the rear wing combined with the gurney flap probably caused top speed to suffer but it was more not enough HP and enough straight to get beyond 160 (NA6).

Need to confirm these values, but
Drag coefficient 0.36
Frontal area 1.64m2
Speed 180k

You need 62.7 HP just to overcome drag.

Gladiator · Postby **Gladiator** » Tue May 07, 2013 9:07 pm

Magpie, while I was pretty much flat out, I did actually hit the speed limiter. It scared the sh@t out of me. I thought I'd broken something at first. It made horrible noise, & I don't know but I wouldn't think that's too good for the car. Anyway, I dont need any exta limitations.

Magpie · Postby **Magpie** » Tue May 07, 2013 9:35 pm

I stand corrected then as I did not hit a speed limiter and mine is an import as well. Let us know how you go as I may have to ask after my engine is installed.

koop21 · Postby **koop21** » Tue May 07, 2013 10:49 pm

My thoughts on watch that video you linked appears it only affects people with stock ecu, so Magpie i dont think you have anything to worry about.

Magpie · Postby **Magpie** » Wed May 08, 2013 7:03 pm

Well I just used a program called GIMP to calculate the frontal area of my NA (the wing is now at 5 deg) and it worked out to 2.10 m2. I'm still to work out the Drag Coefficient (Cd) but using 0.36, I would need 75.7 HP to overcome drag alone. So to do 180 in my NA I would need approx 85 HP to get 180 down the main straight of Lakeside. 220 would require 151 HP (approx).