K8 Top Speed

Custom_V6_Limited_SE · April 9th, 2007, 6:11 pm

I feel like my car isn't going as fast as it should even though it only has a K8. What is the Fastest anyone has gotten their K8 with little or no mods (CAI MSD HEI...)? Mine topped out at 124mph (200km/h). Doesn't really matter since I'm replacing it this summer but just curious.

Nd4SpdSe · Post by **Nd4SpdSe** » April 9th, 2007, 6:15 pm

Search around, there are many top speed threads floating around. The max my k8 went was 190km/h

OutlaW · Post by **OutlaW** » April 9th, 2007, 6:43 pm

Your K8 mx3 must be with some kind of problem.
Ive reached 146 mph without airstream's and that was not even the 5th gear cutoff.
It can do more, i dont do it because my hood is not air tight and it bounces a bit when i reach 115 mph ... but that day i was crazy

hgallegos915 · Post by **hgallegos915** » April 9th, 2007, 8:59 pm

I think the most i did with my k8 was like 120 , that was a tired k8.

Its all in the transmission gear ratios my man. Carefull tho.. the bearings (number 6) tend to get dry at that high rpms. Thats how duncan killed the de.

mitmaks · Post by **mitmaks** » April 9th, 2007, 9:15 pm

OutlaW wrote:Your K8 mx3 must be with some kind of problem.
Ive reached 146 mph without airstream's and that was not even the 5th gear cutoff.
It can do more, i dont do it because my hood is not air tight and it bounces a bit when i reach 115 mph ... but that day i was crazy

sorry, but Ill have to call bs on that one, unless you got ze

Custom_V6_Limited_SE · April 9th, 2007, 10:04 pm

OutlaW wrote:Your K8 mx3 must be with some kind of problem.
Ive reached 146 mph without airstream's and that was not even the 5th gear cutoff.
It can do more, i dont do it because my hood is not air tight and it bounces a bit when i reach 115 mph ... but that day i was crazy

Umm, ya, 147mph on a stock K8 is bs. If you are crazy for doing 115mph once, I must be insane. I break 100mph five days a week every week and probably break 115 at least once a week. God knows what will happen next semester when I have my new setup

Steeb · Post by **Steeb** » April 10th, 2007, 1:26 pm

i did 145mph for 200+ miles with my k8 years ago driving from so cal to vegas, i was in a bit of a rush to get to vegas. its not bs.

Custom_V6_Limited_SE · April 10th, 2007, 1:50 pm

Steeb wrote:i did 145mph for 200+ miles with my k8 years ago driving from so cal to vegas, i was in a bit of a rush to get to vegas. its not bs.

Wow. I was under the impression that our trannies would only allow like 135-140 at the top of 5th. That is very surprising to me that a stock gs can do 145mph. I thought I was a little slow but dang. I guess it's partly because I have 170K+ miles on my engine. What rpm were you at when you got to 145mph? Maybe the 626 tranny will do 160mph??? There weren't different variations that caused this 20mph difference between some cars were there? Just WOW.

MX3ak · Post by **MX3ak** » April 10th, 2007, 8:41 pm

I remember seen square runners in Outlaw's Intake, so I guess it makes it a K8-ZE...

hgallegos915 · Post by **hgallegos915** » April 10th, 2007, 8:50 pm

wow for 2 hrs and the bearings did not bust? wow must be hell of an engine.. my ze wont go over 130. fear of dropping a valve becomes great at that speed.. or a spun bearing.

mitmaks · Post by **mitmaks** » April 10th, 2007, 9:16 pm

Steeb wrote:i did 145mph for 200+ miles with my k8 years ago driving from so cal to vegas, i was in a bit of a rush to get to vegas. its not bs.

I know its hard to believe. Unless you had every bolt on it and you were going down hill. Mazda rated mx3's top speed and it was around 135 or something like that, nowhere near 140's

mmmx3 · Post by **mmmx3** » April 11th, 2007, 12:59 am

When I tried 100mph, my rpm was at 5000,....now it's still the same. I have a 5 speed. I tried 130mph before when I had my new tires...on the flat...my friend was with me. I didn't floor it totally yet...I think I could still go a little more (don't know how much) That time my K8 had less than 90K, now is 120K....it's still running the same or better.

Custom_V6_Limited_SE · April 11th, 2007, 9:29 am

Alright, I just checked some speeds vs rpm in 5th and found that at 4k I go around 77~78mph; at 5k 97~98mph. This means that 6k will be 117~118mph and 7k would be 137~138mph. If you had the power and took it to the rev limiter, it would probably do 145mph, but, there isn't enough power...

MazdaNoob123 · Post by **MazdaNoob123** » April 11th, 2007, 1:54 pm

remember tire size is a factor guys.
I drove from seattle to bellingham one day, and i reached 145 right at 7000.
To bad a week later the #6 rod went. Maybe it was the time i did 65-70 in second gear. 7800 rpm ftw

Post by **Mooneggs** » April 11th, 2007, 3:23 pm

I find it hard to believe a stock k8 with a stock mx-3 tranny will do 145 mph. MAKE A VIDEO AND PROVE IT - Get out on the interstate and hit 145mph... get off at the next exit... pull over... pop your hood and show us the K8... all in one clip - I would be very interested to see that.

The fastest I have ever dared to push my k8 is 125mph and it has 182k original miles... and I felt like I was going to blow it up.

The fastest I have ever been in my klze mx-3 (I have no rev limiter)was 154 mph (or close since our speedo stops at 150). I have a 626 tranny and the 5th gear ratio gives it a little more room to go than the mx-3's. But I was almost at 6500 rpm at that point. I had beat the evoviii I was racing so there was no point in going faster.

I have been to 152 mph one other time when I was racing an M3. Once again the other guy gave up so there was no need to push it

I would say that I could probably get to 160 but then I would not push it past that... I would be afraid to test it now since my ze has about 100k on it... but I was going about 140 the other day....