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Discussion Starter #1
Hybrid WRX STi

I asked my Boss today about something to fix the turbo lag in the WRX. He is a big GearHead and built a drag car from scratch so he knows everything to get extra power. But anyways he said the best way to make up for the slow speeds at lower RPMs is to change out the drive gears. I know this will work because i have a toyota P/U with 35" tires and when i got my gears changed it made a hell of difference. I do not currently own a WRX but i was wondering if anyone that has one could tell me how hard it is to get to the drive axels. I am assuming that it is setup like my truck, but is always in AWD; but i am not positive.
He also suggested the nitrous kit thing that i saw someone post on here but he said the gears would be the best bet.
 

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Did he tell you that you'd lose off of your top end? 0-60 in 3.2seconds! Top end of 90MPH! ;) Not really that extreme, but just wanted to illustrate my point.

If you really want to get rid of turbo lag, then you have only one option... get a different turbo. The benefits, if there are any, of using nitrous with a turbo are dubious at best. NO2 pushes out the air being stuffed into the engine by the turbo/supercharger. Therefore your benefits are negated. If you were to get around that, then you are more than likely going to detonate. Do you really want to F--- around with the drivetrain?

-WRCFocus
 

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Actually, there are many ways to get rid of turbo lag. We'll assume this is for just a single turbo.

- reduce the weight of the roating parts in the turbocharger therefore reducing inertia.

-More efficient blow-off valves and wastegatates help reduce turbo lag while also increasing the lifespan of the turbo. I've heard that an efficient blow-off valve can increase the lifespan of a turbo by 1/3!!!

-A smaller turbo charger would decrease the lag but one will sacrifice power at the top end. Larger turbo charges do deliver more power but they take longer to spool up.
 

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You also can try reducing other rotating masses in the car; e.g. a lighter flywheel and pulleys can help your car get up to the higher RPMs faster so your existing turbo kicks in sooner; you keep the same lag but surpass it a bit faster.
 

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WRCFocus said:
Did he tell you that you'd lose off of your top end?
Not if you don't mess with 5th (or 6th)! I think the point would be to change only the bread-&-butter acceleration gears. But you'd still have to sacrifice at least one fast shift because you'd be separating the ratios out too much. Like maybe 1, 2, & 3 would be quick, but then you'd have a bigger jump to 4th assuming you left it alone.
 

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What's typical lifetime of a turbo charger? Given that typical has a ton of assumtions? What parts have relatively similiar wear characteristics.
 

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lifetime of the turbo charger?

ABCDriver said:
What's typical lifetime of a turbo charger? Given that typical has a ton of assumtions? What parts have relatively similiar wear characteristics.
There is no one answer to that. I've spoken to a lot of 300ZX owners that had to replace both of their turbos at 50k miles. On the other hand, I have a KKK model 27 on my Alpina that has over 100k very abusive miles on it with no problems. The Garette on my F-350 SD went 300k miles with no problems, and I've talked to guys with close to a million miles on their trucks with no problems.

Lubrication and bearings seem to be the determining factor. Most turbos are lubricated via lines from the engine sump. If the oil isn't changed religiously, you can contaminate the bearings in the turbo. Since it spins at several times the speed of the engine, it wears out that much quicker. If the bearings themselves are low-grade, they will wear faster regardless. Finally, if debris gets into the turbo, you can bend, crack, or shatter the veins on the impeller, possibly toasting the whole turbo in a nice bang.

J.B.
 

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Discussion Starter #8
face lift?

Thanks for all the INFO! :eek:

I know you would loose some of the top end but you would just reach that point alot faster. If anything it would improve your 0-60 cause you are faster at the begining and you should only loose about 10MPH at the most in your top end. I would rather do that cause how many times do you drive 140MPH.
And Yes the shifting will change, making you shift earlyer in every gear. i know this from experiance. My first gear is what i call a granny gear cause i can just let out the clutch and i go. i am in 3rd gear at 45MPH.
but anyways i am not talking about a major change in gear ratio's just the next one down. This will also help when you start increaseing HP cause the teeth will be larger and handle more torgue.

I just want to be able to just fly out of corners and not really worried about top speed.(I WANNA FEEL SOOM G'S!!!!!!!!!!!!!!!!) :lol:
 

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Discussion Starter #9
Thanks for all the INFO! :eek:

I know you would loose some of the top end but you would just reach that point alot faster. If anything it would improve your 0-60 cause you are faster at the begining and you should only loose about 10MPH at the most in your top end. I would rather do that cause how many times do you drive 140MPH.
And Yes the shifting will change, making you shift earlyer in every gear. i know this from experiance. My first gear is what i call a granny gear cause i can just let out the clutch and i go. i am in 3rd gear at 45MPH.
but anyways i am not talking about a major change in gear ratio's just the next one down. This will also help when you start increaseing HP cause the teeth will be larger and handle more torgue.

I just want to be able to just fly out of corners and not really worried about top speed.(I WANNA FEEL SOOM G'S!!!!!!!!!!!!!!!!) :lol:
 

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Well, that is another good thing about the STi's 6spd... it is geared for acceleration. I read 4th in the STi is like 3rd in the WRX. I know when driving my buddy's WRX and power shifting it there is like this bog or something when I slam it into 2nd. I didn't really get a chance to notice the rpms or anthying cause I only drove it twice now and the first time it was new and not broken in so I had to take it easy, but it's like even when I redline 1st and slam it into second, the rpms are too low or something when it shifts to second. I don't know, but it's just not a smooth shift. Of course the only thing I can really compare it to performance wise is the 6spd in my Supra and that slams gears nicely with no lag or bog from gear to gear. I am real interested to see how the STi's 6spd shifts.
 

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I don't think so, but that is what it seemed like. I will have to drive it again and see what they were at after the shift. It was like the turbo took a second to spool or something.
 

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That sounds unusual. Maybe his BOV or wastegate actuator are letting too much pressure off between shifts. On my WRX, if I redline in first and grab second, I can keep the revs above 5000 RPM. If I'm on my snow tires I can chirp the tires going into second on dry pavement and there is no hesitation.

J.B.
 

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Ya know what, now that I think about it he did put a different BOV on. Hmmm, I wonder if that has something to do with it.
 

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The stock fifth gear in a WRX is much higher than the top speed. The only time gearing lowers top speed is in redline limited cars such as the Civic Si. The WRX is electronically limited. If you get the speedometer recalibrated after having the gearing change, the only disadvantage will be decreased gas mileage.
 

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The stock fifth gear in a WRX is much higher than the top speed. The only time gearing lowers top speed is in redline limited cars such as the Civic Si. The WRX is electronically limited. If you get the speedometer recalibrated after having the gearing change, the only disadvantage will be decreased gas mileage.
 

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Discussion Starter #17
Sorry if i confused you all but i was talking about the gears in the Axels.
Like in the Pumpkin in the back of a truck. (Ring & Pinion)

The Transmission gears would be way to expensive to change, but so would the drive gears with the limited slip.
 

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Best Motoring DVD with the STi and EVO

As you noted, the gears in the tranny would be expensive to change. But also note that on an AWD vehicle, just like a 4WD vehicle, you have 2 sets of diff gears to change out. With labor and parts, it'll probably cost you $1000-$1500. I'd rather keep my gearing the same for highway travel and economy and spend that money on a Vishnu stage 0 or most of a stage 1 kit.

J.B.
 
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