How fast will our cars go?

Went for a surf today (chasing hurricane waves) . Met a guy at the Beach with an older modded M-5 . We were appreciating each others rides. He asked me what my ride topped out at . He claimed he could hit 180 on a long staight. I said I'd done a buck 30 at the track but had no real intension of finding out. So theoretically what will a good stage II-III leggy do (more out of curiosity) 160-170 MPH?

i've seen 140 on my speed-o-meter with more rpm's left on the tach..i've always wondered myself

260ish at the crank for a sedan means you can should be able to get into the high 150s and maybe scrape at 160. Wagons should be just behind it. Getting up to 170+ means nearer 400hp or beyond.

Dare I say, faster then you need to go.

I think you might run out of gearing to hit 170+ unless you have an 8000 rpm motor. Someone could do the math. I say 150ish. I don't recomend trying it.

IIRC, the stated top speed on a stock 2005 GT was right around 138-140.

I think you might run out of gearing to hit 170+ unless you have an 8000 rpm motor.

 

^^^ this

 

if gearing isn't your limitation drag will be. The Leggy isn't exactly a model of aerodynamic efficiency. That said I have eeked just past 150 on a mile long straightaway... right before the engine began to overheat:lol:

155 mph is where the car (5MT) would gear out.

Have had it at an indicated 135 (which is probably 120 something) on the track and felt like it had more.

 

I suspect it will pull to redline or near it. Might take a while though.

MY07+ Spec. B's should have a higher top speed with the extra gear.

Don't remember where ...........I read somewhere that the car is speed limited (electronically) at 135.

ive gone 136 and im completly stock not to shabby i'd say and it really didnt take that long to get up there im pleased with stock up next stage 2! maybe 3

if gearing isn't your limitation drag will be. The Leggy isn't exactly a model of aerodynamic efficiency.

 

It's not? Cars.com says an 09 LGT has a drag coefficient of .31 I found these numbers for other cars:

 

 

Mustang GT500: .38

 

Corvette Z06: .34

"Regular" C6: .28

 

4th gen Camaro: .33

 

Dodge Challenger: .35

 

Current Eclipse: .34

2g Eclipse: .30

i've seen 140 on my speed-o-meter with more rpm's left on the tach..i've always wondered myself

 

Yea my stage 2 car had no problem getting to 140 and felt like it would have no problem going past that. I just dont trust the stock tires so I shut it down at 140.

Top speed is usually a moot point, it's the average speed that you are able to keep on the track that's important.

I've had mine over 140 at the track but at those speeds my eyes are glued to the track. There is a bit more pull even there so I'm guessing 155 is the top end.

Depends on tire size and if your a 5EAT, 5MT, or 6MT ...

 

I've had my 5EAT at 155mph and lots left.. Gearing wise there is a calculator somewhere. I do not feel like finding it.. I plotted it out with my old tires and came up with something around 186 @ 6500 rpm and 20X @ 7500rpm. I'm not sure if it was plotted correct or not but the 5EATs having longer legs.

Had the 2.5i up to 138 with about 1000-1500 revs left... 155 sounds about right.

http://i31.photobucket.com/albums/c390/piening2150/ludicrous.jpg

I know my 06 LGT before I did the accessport was governed at 140 don't know what it is capable of with the programmer on it but I heard it defeats the governor

You hit fuel cutoff at just over 165 in 5th gear (just burying the speedo if you dare look down). With the Spec-B 6MT or a modified vehicle, that number could inch north of 170 mph, in my test there was still some room in the motor.

 

You would need to have at least a stage 1 tune as the stock chip is limited at 138 mph. "Maddie" my '08 QSM found this out just after the Tampa/St Pete skyway bridge where there is about 4 miles of 4 lanes perfectly straight (Northbound). Hope that answers the question.

The real question that should be on your mind at those speeds is, "How fast can you slow down?"

You would need a really big turbo or a lot of water injection or another form of cooling because at high rpms on a small-to-medium turbo the heat for such a long period of time will be quite bad.

 

The real question that should be on your mind at those speeds is, "How fast can you slow down?"

 

Drag will slow you down quick enough until you can safely start to push the brakes without overheating them. Wouldn't go too fast without a long run out. Or get squeaky pads.

You would need a really big turbo or a lot of water injection or another form of cooling because at high rpms on a small-to-medium turbo the heat for such a long period of time will be quite bad.

 

 

 

Drag will slow you down quick enough until you can safely start to push the brakes without overheating them. Wouldn't go too fast without a long run out. Or get squeaky pads.

 

So if, for example, if a bone stock LGT were to be driven as fast as possible on a track (a long straight-away) or the Autobahn, you're saying that it wouldn't be able to maintain that speed for a while without overheating? Is that a problem inherent to all turbo cars with small/medium turbos or is it just Legacy/Subaru specific?

 

And about the brakes (again, assuming a bone stock LGT)... shouldn't they be able to stop the car from its top speed without fading to an unacceptable level? These hypothetical scenarios are pretty interesting since the fastest I've gone in my car was 85MPH or so

Gearing will only let the car reach 160ish.

My 05LGT had a CoD of 0.29 afaik, the way it was calculated did not change mid 2006 like the SAE horsepower.

Well guys, we really shouldn't be posting what top speed we have reached on here. I know what mine will do but I'd never post it.

 

Probably the best post in this thread;

The real question that should be on your mind at those speeds is, "How fast can you slow down?"