Subaru Impreza WRX

duff8 · July 2003

So you can't get low gear torque with a turbo? All turbos? Not just Subaru's? Or is it just AWD turbos? Are you saying a 911 turbo wouldn't burn rubber?

ateixeira · July 2003

For that I'd blame AWD. It's much harder, more than twice as hard. Why?

Well, by default you are sending torque to 4 wheels. Even with a slippery surface, at least 3 wheels will get power because of the rear LSD. So you have more wheels delivering power to the pavement, and since you're dividing total available power by 3 or 4, each wheels is less likely to spin.

An example helps. For simplicity, say you have a net output of 200 ft-lbs of torque. With a 45/55 split, the front axle gets 90 ft-lbs and the rear gets 110 ft-lbs. But that's per axle, each tire only gets half that amount.

The front does not have an LSD, so you could send 90 ft-lbs to one front wheel, that would be the one that would skid first, i.e. burn rubber. You'll spin the inside front tire, since it's unloaded, accelerating out of a turn, for instance.

Each rear wheel would get 55 ft-lbs. The result is forward movement, not wheelspin.

Now imagine a similarly torquey Dodge Neon SRT-4. Again, for simplicity, let's assume 200 ft-lbs net torque. All of that goes to the front axle. But that front axle is not managed, so power will take the path of least resistance. In other words, you might end up with 200 ft-lbs being delivered to one spinning wheel. Sure you can burn rubber, but it won't move out as quickly because it just isn't able to put the power down effectively.

You can do a brake stand, rev up the engine, hold the car with the brakes, then release, but that's the quickest way to ruin your auto tranny.

But wheelspin represents a loss of control/power, really.

Sorry to be so long winded.

-juice

duff8 · July 2003

Thank you. That really helped explain my situation. I appreciate it

robmarch · July 2003

this is why it's so hard to launch even the manual WRX. There isn't enough power (or torque, depending on how you look at it), to break the wheels loose on the line, which generally relieves some of the stress on the drivetrain and provides optimal acceleration times.

The 996TT has enough torque to get the wheels loose, but that car has >400hp. Some say the STi will break the wheels loose from a stop with reaonable rpm launches, but I haven't verified, nor do I really plan to.

bluesubie · July 2003

Will be Prodrive's new auto that they are working on for consumer applications. Don't know when and if it'll end up in Subaru's (one would hope eventually).

From what I remember, it will be clutchless (like the rally car) and it probably won't have the torque converter.

Remember, off-boost the WRX is like a 3,000 lb. 100 h.p. car. :-)

-Dennis

duff8 · July 2003

My dealer had one STi and he actually talked me out of even testing it. He said he felt the mark up was too high for the car (over $40). So, not to beat it to death....but you get what you pay for when it comes to how much torque you have to spread over four tires, and thereby your launching speeds. I didn't know any of this and figured a car touted for it's speed, or racing ability would be fast pulling out. I didn't expect or even want to burn rubber. Just didn't want to get t-boned pulling out of the post office. Still, considering the beautiful handling in higher gears and the added safety and comfort of AWD in bad weather, I think I got as much bang for the buck as you could get. Maybe I'll drive the hell out of this and trade it in someday for a used 911.

kens · July 2003

That's a great explanation, juice.

When I was watching an episode of Motorweek, I recall the narrator mentioning that with AWD vehicles, the best launch times are usually recorded when the track is slightly wet. The wheel spin prevents the engine from bogging down -- along the lines of what robmarch wrote.

Ken

outback_97 · July 2003

In light of the above discussion about some potential drawbacks of the 2.0T / 4EAT pairing, could some auto WRX owners comment on why they chose the WRX over the (IMO often overlooked) RS or TS?

A couple of other things: Good AWD writeup, juice. And re: AC affecting acceleration, doesn't the compressor shut off when the engine's under heavy load?

utahsteve

1hokie · July 2003

I'm through my breakin period, as I have over 5,000 miles on the car. It's a bit tricky to get a good launch (good isn't even the right word...) - it seems you have to give it like 40% throttle, but then hit the gas harder before it shifts into 2nd. If it shifts into second then it's too late, and it won't downshift to accelerate, so your stuck in low rpms again. I've gotten the best launches when stopped at a light making a right hand turn. The thing likes to take off - I'm thinking it may have to do with wheel spin/traction. When making a sharp turn and trying to accelerate quickly from a standstill, there is a tendency to lose traction. I actually got all 4 wheels to spin in the rain doing this (surprised the heck out of me - quite unintentional).

Flooring it from a standstill, the car has little response. Reminds me of my old old old car in that when you did that, you basically flooded the carb and the car just inched along. No carb in the wrx, but the same feeling. No engine response - just a very gradual acceleration until 3k rpm, then it takes off like mad - but that's usually too late.

I also noticed that if you start in "2", then you will actually start in 2nd gear, bypassing first - which is a nice feature in very limited traction situations, but not what I was trying to acheive at the time.

To the person posting the love/hate relationship with the car - I'd say to hang in there. I live around the Baltimore area where the traffic is fast paced, and pulling into it can be a problem. I've adjusted by having the car moving before pulling into traffic. (start to slowly accelerate into the roadway as a car is approaching and then nail it right as he is passing). This seems to work, and isn't as dangerous as it sounds with slight practice.

Again though, I think a few mods with help with this. I was going to get the extended warranty, but now I might use that money towards more power (at low revs).

Oh - and I didn't look at the RS very long b/c I wanted a performance car (and wasn't allowed to get a sportscar). I wanted good brakes, handling, and power.

Oh #2 - the ac kills any acceleration. I have to think ahead and turn it off before hitting the gas b/c otherwise it makes the take-off problem worse. The owners manual says it will cycle off (and it does sometimes, you can feel the warm air instead of cold while cruising up a hill) - but my experience with it is to turn it off yourself to get rid of any power robbing it does, even when "cycled off". The other day I was going 50mph, and wanted to accelerate, I had the a/c on and it was 90+ degrees and very humid - well, you can picture what happened - it went, and faster than one might expect, but you could tell it was missing some ponies.

hypov · July 2003

Steve-
My original plan was to wait out for the then to materialize 2.5T, hopeful for a 2.5T Legacy GT wagon.

Fast Forward >>
Accident cuts short the life of my '98 Outback.

Fast Forward >>
I went with the WRX because I didn't want to look back and say, "I wished I had experienced the WRX"

Rewind back a little. The TS was the front runner of my choices, but somehow after the accident life is a little different - you know what I mean ;-)
I did not consider the RS because I wanted a wagon.

-Dave

duff8 · July 2003

1 hokie.....not exactly the feeling you want when you have 20 miles on your car and just spent over $25 grand to get it. I have never had a new car that died when you floored it. I didn't expect a rocket (well, yeah, I did). But it surprised the hell out of me to feel it just DIE. Bad bad first date. I have driven a lot in the baltimore area. Where I live is even worse. Bunch of 90 yr. old blind people going 90mph at you in their brand new Sequoia, Expedition, etc. I don't like A/C, but if it's on, I definitely have to turn it off if I need some power. And I didn't look at the RS because I wanted a performance car. And that is all I read about the WRX...performance, performance, performance...yada yada yada. Live and learn. I still love driving it on twisty roads. And I live in twisty country. You can't have it all. It's a lot of car for the money. I am also mastering the art of driving down the center lane before pulling out. Pisses me off that I even have to do it. Oh well. It's my own fault. I obviously flunked the test drive.

qbrozen · July 2003

just wanted to chime in on this. My automatic turbo volvo does (or at least used to) the same thing and it has very similar acceleration numbers to the ReX. If I stomp the pedal to the floor, it hesitates for a second or 2. so its not just the subie.

I used to compensate for this by stomping on it a few seconds before I actually needed to move. But, as others have stated, it doesn't seem to have this problem if I give it less than full throttle.

On my volvo, however, there is an adjustment that can be made to the wastegate actuator rod that cuts down on this delay. It has definitely improved response time. I don't know if this adjustment is at all possible on the WRX, however. My guess is someone would have posted it by now if it was.

ateixeira · July 2003

Think of this - I've seen some tests where slalom numbers were quicker in the wet vs. dry. That seems counter-intuitive, but it allows AWD cars to slide out a bit.

-juice

kevin111 · July 2003

Again, I test-drove a '98 prelude with the same problem. This is where the big-displacement, low-end torquey vehicles are better. They just are not as fun once you get them going as vehicles like the Honda VTEC cars and the Turbos.

rsholland · July 2003

My wish for a WRX equipped with a 5EAT w/SportShift won't cure that problem.

Bob

kevin111 · July 2003

Problem cured. :-)

c_hunter · July 2003

Juice wrote: "If the torque converter is not locked up, it'll slip (normal design). That gets the ATF flowing, and then the drivetrain sort of has to catch up. Once it does it'll lock up and you'll have more immediate response."

As far as I know, torque converters only lock up in top gear, usually at higher speeds (probably above 45mph). You can usually feel it as though an extra "shift" is happening (and see a slight drop in engine RPM). That's the way it is in my Outback, at least.

TC should not be locking up in any of the lower gears.

Craig

bluesubie · July 2003

Have you seen Bob's post on nasioc's news & rumors forum about putting the 2.5 in the WRX?

-Dennis

robmarch · July 2003

the following is unconfirmed heresay:

I've heard some people say that there are automatics out there that can lock up in gears other than their top gear. I have no idea if this is the case in the Subaru 4EAT, or not.

of course, this could be totally false, in which case I will gladly withdraw the statement

himiler · July 2003

When the 5-spd auto was first into'd in the Lexus ES300 (back in '94?), the TC did lockup in 2nd gear, creating 5 ratios out four.

kevin111 · July 2003

That would be interesting! The 2.5 would be more ideal for the auto, but not sure about the Manual.

- The problem with putting the 2.5 in the manual is that you will loose the "high-revving" reward that comes with a car with a high-band power curve. After driving my manual WRX for over a year, the lack of low-end punch is no longer an issue.

- On the other hand, the 2.5, if it is the same forged engine (detuned of course) from the STi, it will be even easier to tune-up.

kevin111 · July 2003

Maybe you are reffering to the LS400? I know someone with a '98 ES300, and I can reassure you, he only has 4 speeds.

himiler · July 2003

Yeah, my bad -- I was confused. It must be on the newer ES.

kevin111 · July 2003

The opportunities are few and far between with you. ;-) BTW, I enjoy reading your posts, they are generally very informative.

bluesubie · July 2003

Check it out. Some people are hoping/predicting that the 2.5 ends up in the WRX. Bob really had people going on the debate. :-) The post has 176 replies.

IMO, the 2.0 with AVCS and 247 hp would be great for the N. American WRX.

-Dennis

hypov · July 2003

I'll wait a year or two for the 2.5l and 5EAT to settle in on their teething problem(s) if any,...
then shoehorn them into my wagon; it'll totally rule

-Dave

dill6 · July 2003

anyone else find that while driving with the a/c on, turbo lag is much more prominent?

If I have the a/c on high, and am stopped on a hill, then try to get started, going uphill, its kind of like getting the proverbial mule to budge. I'm wondering if something might be out of adjustment of my car.

I have a 2002, 5 spd. wagon, 28K mi., BTW. Car is perfect otherwise, and I've had no other problems with it at all.

dill6 · July 2003

I wrote the post above, THEN looked at some of the previous ones - to find a bunch of similar comments. Not surprising, its the nature of the beast I guess.

There must be an engineering reason you lose that low, low end pull with a turbo, but I can't imagine what it is.

I recently bought a second, summer fun car to play around with - a '91 Miata - cheap kicks, a blast to drive handling-wise. Couldn't be more opposite in its power delivery from the WRX.

Very strong and torquey from a standstill, though its only a 1.6 liter. Of course, the car's weighs barely over 2,000 lbs., and the gearing is much lower than the WRX. It runs out of poop just about the time the WRX is reaching lift-off.

Both fun in their own ways, though I have to say the Miata is more forgiving in around-town situations. I've had my WRX for nearly 2 years now, and I DO know how to drive 'around' the lag. Pretty easy to do once you get the feel, but much tougher with the a/c on, as I said.

I DO count it a pretty significant drawback. The biggest negative about the WRX, IMHO. Not sure I'd buy another, to be honest.

c_hunter · July 2003

I see it too. However, I would classify it as a general issue with small displacement 4-cyl engines and AC. More noticeable with manual transmission in my opinion.

Craig

carscout · July 2003

Hi guys, just shopping for a new car and Im considering the Rex as a canidate. If I could get some info from owners about the total wattage of the upgraded audio package, and if theres been any mechanical problems or of that nature for you 2-3 years owners. Thanks.

bluesubie · July 2003

According to subaru.com, the sub/amp adds 120W of power. I'm an owner for < 1 year.

-Dennis

1hokie · July 2003

I got the upgraded sound system package. I think 120watts for the subwoofer (6" speaker?) sounds right. It's located under the front passenger seat. The stereo gets pretty loud, and stays clear-ish at higher volumes. It's not totally muddy at say volume level 26, but there's a lot of extra noise going on. I've seen much much worse out of "upgraded" systems from alpine, sony, kenwood, etc. If you're an audiophile, the upgraded subaru stereo won't cut it for you. If you just want a louder stereo, with some decent bass response, then the upgrade seems to be worth it. The indash 6 disc changer is nice and the sub will shake the rearview mirror pretty nicely too. :oP

kenoka · July 2003

"There must be an engineering reason you lose that low, low end pull with a turbo, but I can't imagine what it is."

I believe this is mostly due to the reduced compression in most turbocharged engines.

kevin111 · July 2003

Have the upgraded stereo. Has plenty of bass and volume. Actually seems louder than previous 200 watt stereos I have had. In terms of clarity, it is decent for a car stereo, but not outstanding. My old Pioneer 200 watt system was clearer, but this one produces better bass response and volume.

ateixeira · July 2003

Wow, you find the Miata torquey? I have a '93 5 speed. Did you know it only makes 100 lb-ft, and at 5500rpm?

So it's two things - gearing, and weight. The WRX is about 800 lbs heavier, and probably geared taller.

-juice

duff8 · July 2003

I feel guilty about ever complaining about my new WRX auto. It runs better everyday. I can't believe the difference after the first l000 miles. I took it on several (9) long drives (about l00 miles each, half on open freeway and half on twisty backroads with no stops) and put the other l00 miles on it in town. Lots of short drives. Made a real effort not to take it up to 4000 rpm's, but did slip up a few times, maybe l0 at the most. Then I changed the oil. Maybe I'm just imaginging it, but it seemed to make a difference, seemed to help the performance. I have absolutely no problems pulling out. I only press the pedal a third to half down and there is zero lag. None. Real smooth and even , no jerky movement. Just easy. Then if I have to, I floor it and it just flies. Big smile. I don't run the A/C. Sucks the life right out of it, but so what? That's true with many cars. I'm definitely putting in a new stereo. But that's a minor deal, too. I expected to. Thanks to everyone for all of the feedback. It was immensely helpful.

kevin111 · July 2003

I had heard that the Autos were an issue with the car, but was hearing otherwise with posts on this board and people I had talked to who have the Auto.

Hope all goes well, and happy motoring!

andmoon · July 2003

I think even the 911 turbo needs 4~5000 rpm clutch dump to get a good launch. The Porsche's drivetrain may take the abuse better but it's abuse just the same....Maybe a 90/10 or 80/20 rear torque bias with a not too quick torque distribution system may be nice...The Honda Element and Crv have the ratio in reverse and the front wheels spin a bit before torque is sent to the rears...the driver controlled whatever in the sti...biased max towards the rear to get some wheel spin off the line...would that help? Just dreaming/yaking folks.

sonya4 · July 2003

After over 16K miles, I've learned not to stomp on the gas in 1st gear. Nice and smooth is the way to go. I'm really still learning about the Rex as I have few opportunities where I live to put it through its paces as much as I'd like to. Time for a vacation!

The A/C does sap a little power but I figure that's OK; if it's hot enough to run the A/C, I'm not inclined to fly around. If I do want a boost of power for any reason, I turn the A/C off, as someone mentioned earlier.

Just my 2 cents.

--sonya

wrc555sti · July 2003

A K&N air filter gives better throttle response in my experience. I did an experiment in the past few weeks. After using the K&N filter in my WRX for 12,000 miles, I immediately started experiencing the turbo lag effect everyone is talking about after putting the stock air filter back in. The engine literally hesitates or stutters for a split second whenever I upshift in the lower 1st, 2nd, and 3rd gears or starting in 1st. I am talking about normal driving below 3,500 rpm. The turbo now simply feels lethargic and very slow to spool up with the almost-new stock air filter.

axp696 · July 2003

I hate to disappoint you, but I'm afraid you're experiencing the placebo effect. K&N filters have been dyno-proven to do absolutely nothing except save you money. This is especially the case on forced induction cars, you might gain a HP or two on an NA car. Two cheap upgrades that actually do improve upon turbo lag are removing the intake silencer (free) and Samco intercooler hoses ($75-100, only the Y-pipe is needed).

duff8 · July 2003

Why is it (intake silencer) put there in the first place, if it isn't needed and increases the lag? And how would removing the hoses help? Doesn't the turbo engine tend to overheat? Would removing these increase that problem? Have you actually done this with an auto WRX and experienced a noticable improvement?

rexaroo · July 2003

With temps here in Denver hitting 100 degrees, this is a real annoyance, without a doubt.

I was hoping the Cobb Stage 1 reflash would help, but no luck--the car still wants to bog a little coming off the line.

It's gotten to the point where I just turn off the A/C button at a stop light (while keeping the fan on recirc), and turn it back on once the car is rolling again.

ateixeira · July 2003

I removed the silencer snorkus from my 2.5l Phase I boxer.

You do get more intake noise. With the Phase I engine, you even hear a characteristic low-pitched hum at idle. I'm used to it, but it's not for everyone.

At WOT (wide open throttle) you definitely get more noise, but I do feel it's breathing a little easier.

-juice

kevin111 · July 2003

the STI. Surprising how close the modified WRXs get. The only question is reliability, but it seems that many of the upgrades have minimal effect. That magazine is also working on a project WRX in which they have logged over 60K miles. So far the wear and tear items from the last issue have been the wheel bearings (needed to replace these) and steering brace (bearings or bracket, I forget). They upgraded the WRX with Vishnu stage 0, 1, and 2.

duff8 - intake silencer - reason for it is for decible control (I believe). The quieter the better.

bluesubie · July 2003

duff8 - axp is referring to replacing the stock intercooler hoses with silicon hoses. You can also buy STi brand silicon hoses from a Subaru dealer.

Kevin - If Stephen B. still posted here, you could ask him about reliability. He had a Vishnu on his wagon, but ended up selling the car because of the headaches. He admitted though, that some of the problems were due to installation.

-Dennis

prayerfor · July 2003

IIRC Stephen's problems stemmed from an EGT probe that wouldn't stay seated in its uppipe bung. Most of the newer uppipes (incl. Vishnu I believe) don't even include a bung for this very reason.

In general, I think it's safe to say that the growing pains suffered by the early adopters like Stephen have mostly been addressed and are no longer an issue. Certainly the quirkiness of the unichip piggyback setup is completely eliminated by the Ecutek reflash.

axp696 · July 2003

Just to rehash what's already been said...

Why is it (intake silencer) put there in the first place, if it isn't needed and increases the lag?

It's there to decrease noise, but at the same time further obstructs the passage of air. Removing it from the fender well and replacing the quasi-ram air scoop will allow fresh air in through the fender well, and you'll be able to hear your turbo and bypass valve working.

And how would removing the hoses help?

Sorry, I meant replacing them with the less restrictive Samco/Vishnu/etc hoses. Getting rid of the stock, ribbed-for-her-pleasure hoses gets air to the intercooler faster, and you'll pick up 5 hp, give or take.

1hokie · July 2003

On the silencer issue - I haven't looked for it under the hood or anything - but is it easy to get to, and easy to remove, and easy to reinstall if I don't like how it sounds removed? And just where is this device located?

I like the sound of the turbo kicking in - though the engine spends a great deal of it's time below 3k rpm (with the occasional "I'm gonna blow past this slow car at 7k rpm...").

c_hunter · July 2003

This is often overlooked, but the "silencer" (aka resonator) is primarily there to tune the intake system. Working in conjunction with the engine's pulses, the resonator creates a standing wave pattern in the intake that boosts pressure going into the engine.

I can't say whether or not removing the resonator impacts turbo lag, but I'm fairly certain you will get better performance out of the engine wiht the resonator in place.

For some good info on resonators, see:

http://www.grapeaperacing.com/GrapeApeRacing/tech/intakehelmholtz- - .cfm

http://www.users.bigpond.com/pgscott/resonator/resonator.html

If Subaru just wanted to reduce noise, they could have done it a number of different ways in a fashion that would not involve all that plumbing. The resonator is there for a purpose! Don't take it off!

Craig

Subaru Impreza WRX

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