top speed of a 2006 STI?

avriette · Post by **avriette** » Tue Oct 10, 2006 4:57 am

I'm a little curious about the top speed of a 2006 STI. Specifically, I have heard varying numbers from "145" to "155", with some people saying they are electronically limited, others saying it is aerodynamically limited. It is clear to me that it can't be much higher than 160 or so mph, as there isn't room in sixth gear for much past that.

Can anyone cite a source or something that indicates how fast the car can go? It would be very helpful if the source could say whether that is an "indicated" or "actual" speed. My STI seems to indicate 1-2% higher speeds than I've seen on the local radar thingies the cops leave lying around (consistently, in several counties, so I'm inclined to believe the radar is accurate, and not my speedometer). I suppose personal experiences would also be useful.

I have recently discussed this with a few people, one of whom says he has seen 155mph+ in his 2006, although he has the SPT cat-back (my guess is this counts for <i>something</i>, although at that speed, it takes a lot to go faster). Many people have replied that the car is electronically limited, but didn't know whether that applied to 2006's, or to STI's, or what.

Thanks.

sirwilliam · Post by **sirwilliam** » Tue Oct 10, 2006 6:52 am

Aerodynamics, gearing and power come into to play here but the true limiting factor is the gearing. From what I heard the STi top speed is between 160-165MPH. You shouldn't be going that fast on the open road. Go to a track or abandoned airport runway if possible.

WANGAN_X · Post by **WANGAN_X** » Tue Oct 10, 2006 8:30 am

i would say they are aero limited to 160ish

gearing is good for around 180 with the 7k rpm limit

anyone know the overdrive/6th gear ratio... I could figure it out 100% with that

sirwilliam · Post by **sirwilliam** » Tue Oct 10, 2006 9:01 am

I thought '04-'06 gearing was all the same on the STi, no? I thought the only change to the '06 was the DCCD(Driver Controlled Center Differential) now has a mechanical limited-slip differential in place of the previous planetary gear/clutch arrangement?

'05 gearing ratios:

3.64, 2.38, 1.76, 1.35, 0.97, 0.76

'05 axle ratio:

3.90

Yes, STi is governed to 145MPH so you would need that removed to achieve the higher speeds.

WANGAN_X · Post by **WANGAN_X** » Tue Oct 10, 2006 9:21 am

ok then top speed gearing limited is 184.26947678847233

if you care to include c/d i can give you the real world top speed

avriette · Post by **avriette** » Tue Oct 10, 2006 9:56 am

sirwilliam wrote: Yes, STi is governed to 145MPH so you would need that removed to achieve the higher speeds.

Hm, where do you see that it is governed to 145? And are you sure the gearing is the same for 2006? Did the tires change at all?

Cereb Daithi · Post by **Cereb Daithi** » Tue Oct 10, 2006 9:58 am

unless I'm mistaken the governer kicks in around 145-150

spazegun2213 · Post by **spazegun2213** » Tue Oct 10, 2006 10:26 am

Cereb Daithi wrote:unless I'm mistaken the governer kicks in around 145-150

I'm not 100%, but I'm fairly certin its 146. And unless he has a UTEC or AP, he will never go faster than that...

Even 146 is not "fast" for these cars. Given a long enough strech, i can see on hitting 160 with no major issues.

Libra Monkee · Post by **Libra Monkee** » Tue Oct 10, 2006 11:05 am

I'm not sure either. I've gotten mine up to approx. 1xxmph before I started punking out and had to slow down.

Post by **Sabre** » Tue Oct 10, 2006 12:14 pm

While this isn't the chart that I wanted, it shows you what you want to see

You're definitely limited while you are stock to a certain speed b/c of HP and the governer... Although I have heard stories <cough> that the governer might not be doing as good a job as it should, haha.

A modded STI can quickly approach the redline in 6th.

sirwilliam · Post by **sirwilliam** » Tue Oct 10, 2006 1:44 pm

sabre wrote:While this isn't the chart that I wanted, it shows you what you want to see

You're definitely limited while you are stock to a certain speed b/c of HP and the governer... Although I have heard stories <cough> that the governer might not be doing as good a job as it should, haha.

A modded STI can quickly approach the redline in 6th.

Thanks Julian. Thank the person you got the graph from as well.

Post by **Sabre** » Tue Oct 10, 2006 2:37 pm

There's actually a graphical representation of the above graph somewhere, but I couldn't find that one

Oh well, this one does the job

avriette · Post by **avriette** » Tue Oct 10, 2006 6:48 pm

sabre wrote: You're definitely limited while you are stock to a certain speed b/c of HP and the governer... Although I have heard stories <cough> that the governer might not be doing as good a job as it should, haha.

A modded STI can quickly approach the redline in 6th.

I heard the same story, Julian. Actually, the guy I heard that from said that he had seen 5,500rpm in 6th, and that was right around 6,000 rpm. So that seems reasonable 5,500rpm =~ 154mph (indicating his speedometer was in fact correct at that speed). The way he said it, it seemed that the car would have continued pulling at that speed, up to redline. Although this seems a lot further from 5,500rpm than he thought.

Kind of vexing, that if you wanted to get to 200mph in an STI, you'd need to reduce the final drive ratio. Do you have that available as an excel spreadsheet? It would be handy to have that macro. 7,500rpm doesn't seem like it is such a great idea at that speed, so maybe a 3.5 or so final drive would do the trick. Of course, with the gearing lower, you'd have to have lots more power to get it there. I'm continually surprised at how well engineered the car seems to be. It's almost like Subaru decided to pick a ratio that gave the car a relatively high top speed (one it could attain), rather than giving it an outlandishly high gearing (such as in the C5) with a top speed it could never attain.

Or get a 7-speed manual.

Seems the dog box folks have picked up on this and have made the gears a little taller (as well as going to 9k, hm, like Perrin is doing in that silly 3.0 turbo wrx). BTW, Julian, this is your fault for posting the video of the 200mph Evo. Who's up for renting out an airport?

WANGAN_X · Post by **WANGAN_X** » Wed Oct 11, 2006 1:33 am

200 mph is outlandishly hard to reach, my goal for the swapped 2 but it is insanely hard to reach due to the c/d of the brick, i mean STi.

my mr2 has a c/d of .32 right now and when i am done i hope to bring that down to .2x i am not 100% on this but i am sure the STi has a relatively close to evo c/d at .35 which would mean much more power has to be put down to achieve that speed.

i thought the Sti had 235/45's oops, there goes my calcs

avriette · Post by **avriette** » Wed Oct 11, 2006 11:52 am

WANGAN_X wrote:200 mph is outlandishly hard to reach, my goal for the swapped 2 but it is insanely hard to reach due to the c/d of the brick, i mean STi.

my mr2 has a c/d of .32 right now and when i am done i hope to bring that down to .2x i am not 100% on this but i am sure the STi has a relatively close to evo c/d at .35 which would mean much more power has to be put down to achieve that speed.

i thought the Sti had 235/45's oops, there goes my calcs

The guy in the video Julian posted with the top speed runs at an airport had an Evo with "600 or so hp" that did 202mph. I wasn't suggesting that a stock STI could make 200mph, I was lamenting the fact that, even if it did have the power to get there, it was hamstrung by gearing. Anyone who takes the car up to the top of 6th, I think, will agree that the car has room to go a little faster, but that last gear is a bitch.

Post by **Sabre** » Wed Oct 11, 2006 2:48 pm

avriette wrote:Do you have that available as an excel spreadsheet? It would be handy to have that macro....

BTW, Julian, this is your fault for posting the video of the 200mph Evo. Who's up for renting out an airport?

Nope, not available as a spreadsheet unfortunately

I'll see what I can dig up though.

lol, my fault?

WANGAN_X · Post by **WANGAN_X** » Thu Oct 12, 2006 2:46 am

i have a spreadsheet program, just gotta find it...

FYI the Norris Designs Evo made well over 600hp, that maybe what they quoted for the video, but it was in excess of 750, i say was because now they are running an Evo 8 with more hp and less weight.

I wasn't saying it couldn't be done, I was stating it takes alot more hp for a Sti/Evo than a supra or FD, due to coefficient of drag

to break into those speeds you have alot of things to take into consideration...

sirwilliam · Post by **sirwilliam** » Thu Oct 12, 2006 7:09 am

WANGAN_X wrote:i have a spreadsheet program, just gotta find it...

FYI the Norris Designs Evo made well over 600hp, that maybe what they quoted for the video, but it was in excess of 750, i say was because now they are running an Evo 8 with more hp and less weight.

I wasn't saying it couldn't be done, I was stating it takes alot more hp for a Sti/Evo than a supra or FD, due to coefficient of drag

to break into those speeds you have alot of things to take into consideration...

http://www.norrisdesigns.com/