I hung around a nice STi last night, on I 85 south. Had the plate "FORCED4". Very cool car, and cool driver too. I was driving back to NC from CT (900+ mile trip, and I'm finally back)!

Anyway, we just played around. Got on it together 4 times. He did a stint w/me just watching once as well. We got on it on his mark pretty much every time. I had no problem keeping up, but it was somewhat close, one of the closest I've had. I don't know how fast these cars are but I'm about even w/a 6 speed C5.

Anyway, it was very nice. Anybody have accurate specs for these cars (I would appreciate the upper speed range #s like 60-100etc.). It seemed like he also had better response/less lag compared to my car. Appeared to be bone stock.
Ahmet

 

I too have raced one. Very fast. I had to shoot a VERY tight gap to beat him. I've got turbo problems though. They are fast and have way less lag time then us. Seems like everything has less lag then us though...

 

Yes, I am interested as to why the technology behind the new turbos, which have no lag to speak of, can't be applied to our cars. I have a GTCruiser which has no significant lag.

????Why can't we apply this technology as a retro fit????

 

Could the pre turbo cat have anything to do with this on the subi? Getting all that extra power from my fuel dumping chips would be nice...........

 

i dont know the higher specs right off, but 0-60 is sub 5 seconds, tested by the press at about 4.8 give or take depending on your source, top speed 147, 2.5 liter turbo, 300 HP 300 torque, road holding index of about 1.03 or so. they have the rally technology, thats probably why their turbo spools so quickly, marvelous car.

 

My buddy just finished the break in period on his Sti so he let me take her for a rip. I gotta say that intercooler spray button is the coolest thing. It's very quick for sure, especially off the line. There is no perceptible turbo lag and the 4 wheel drive with the awesome rubber that comes from the factory makes it feel absolutely glued to the road. I didn't get much of a chance to really play with the variable center diff, but it is a neat little trick.

It's definetly got more off the line power, but I think the 944 still has it beat in the mid and top end (same quality gasoline). Handling is hard to say as I didn't work the STi too hard, but it hapilly ate up everything I threw at it. It is really high up; I wasn't used to looking down at civics, but still no complaints about the handling. I kept losing the cars behind me from either driving away from them so fast or because that giant wing hides them. Tranny is very nice, but very close ratio that I'm not used to, so there is lots of shifting.


Justin

 

One of my friends' WRX lags very noticably until 3k - perhaps you guys are just used to extreme lag from our cars? I haven't raced him yet, but it oughta be close until I do any mods. He's already upped the boost and put in a piggyback ECU, gained about 40hp. He'll be knocking on Sti power levels soon.

The pre-turbo pre-cat doesn't help their spool at all, I swapped the up-pipe in another friend's WRX (3 of them have WRXs, all hunting my Porsche) and reduced lag noticably, besides picking up some power also.

As for reducing lag, techniques aren't really anything secret. Newer turbos do have less lag due to better manufacturing tolerances and increasing use of ceramic ball bearings, which make a world of difference. Besides that, maximizing the pressure drop across the turbo via optimal flow in headers and up-pipes, and then maximum flow in exhaust, is basic.

We do have the advantage if we go standalone engine management. Production cars today will not have anti-lag due to emissions issues. (There've only been a few production cars with anti-lag from the factory, the one most prominent in my mind is the Evo 4, they released a street version with anti-lag to meet Group N homologation standards - any feature on the race car had to be on a certain number of production cars.) Going standalone allows us to program anti-lag into our cars.

Sam

 

Well, the subi is a horizontally opposed 4 with a really small turbo. As such, it probably has more compression and less boost. I drove one a couple weeks ago. You couldn't really tell when you were on boost or off boost. From that, it looks like the turbo comes on when the cams give out or what not. The actual turbo system design sucks. They have the intercooler right on top of the motor, and the BOV is like welded on to it in an awkard fashion. On the freeway, it didn't feel like the car had much pull around 80+. The boost gauge got up to around .1 MPa which is around 14.5 psi.... and as I said before, I could tell when it was on boost... perhaps since the turbo is sooo tiny (we're talking old school Saab/Volvo turbos here - the size of my fist) its not moving much volume. Either way, I wouldn't buy one for the street - I found the interior to be pretty crappy, and otherwise tacky. The stereo was ok. Its fine for stop and go around town stuff since it has quite a bit of low-end torque and whatnot, but on the freeway it felt pretty dang slow.

 

What a coincidence. I just had a WRX next to me recently in traffic. He was a younger guy and yelled over, "man, those cars are bad ***". Told him I thought the same about his. Asked if his was sti and he said no. He didn't even try to race with me. Guess they know about our cars I am always surprised by the other turbo/sport compact guys that they are very familiar with our cars.

Justin: Did you notice any gains when the intercooler sprayer is engaged??

 

Rcl, we're talking about an STi here... The 2.5 liter 16 valve w/the sodium filled valves, and the ceramic coating (that's from memory) +a descently sized turbo... Not the regular WRX which pulls fine but nothing spectacular and dead above 80ish, I'm with you on that. STi is a different story, however... Keep in mind both have 3 catalytic converters, one before the turbo, so there's some room for getting rid of even more lag.
Ahmet

 

Todd,

The tank was empty so I didn't really get a chance to blast it. But that car is a rocket from a stop. There is no way a 951 can keep up for the first few feet. I'm pretty sure my 951 pulls harder in third gear at full boost, but from a stop the Sti would be so far ahead, it would take quite a bit of distance before the 951 could come storming past. I've driven both the WRX and the STi and I can't feel any lag in either of them. Sam you're probably right in that I'm just used to the all or nothing from our cars. (It makes it feel faster for passengers with us! )

We can only get 92 octane gas here so the Sti timing is getting knocked back a bit too, so I didn't feel the "full" potential.

Justin

 

My mate has the 240bhp 2litre rb5 model, before i had done any upgrades to my car i could not compete with him, we are not talking a massive gap between us but enough to p**s me off!!, i raced him a couple of weeks ago, we came round a corner and he floored it a good bit before me and he pulled about 10-12 car lengths on me but by the time we hit 120 i had caught him and even had to let off a few times to keep a gap back from him, was quite a windy road so not any opportunity to pass him but we both knew that given a straight bit of road his subura was toast!! we raced back with me in front but my 255 wide back tyres were kicking up loads of stones and one chipped his windscreen so he let off, he knew he was beat anyway lol, he has now got his car booked in for a chip upgrade and a new downpipe which will take his car to 300bhp, thats ok i have an sfr stage 2 turbo and guru racing chips mapped for running 18psi on order so hopefully that will be enough to keep him firmly in my rear view mirror

 

No pun intended?
(i wonder if anyone gets this?)

 

I get it, and we actually did quite a bit of laptop tuning on the piggyback to tune out a bit of knock due to AZ's horrible 91-octane gas and heat.

Sam

 

I've driven a couple of heavily modded WRXs and been around a couple of STIs. They are certainly quick. One that I drove has removed all of the CATs except the main one, as well as having a monster exhaust piping to the turbo. There was very little lag, even with the STI turbocharger. Neither the STI or WRX have ball bearing turbos, so that's not the trick. I think it's just about modified compressor fins. Flow characteristics of the turbocharger are similar to the K26/6. It flows ~15psi to about 5K rpm where it runs out of steam. All this except the WRX is only using 2.0L, requiring less from the turbo than the 2.5L STI. Subaru has taken a lot of effort to tune the STI. I like to think of it as Subaru's version of the S2000. I think it would only be fair to compare a modified 951 to a STI bacause it is essentially a factory modified WRX.