Do you want a turbo engine for the FT-86? Read here

[Dimman]

Looking around on the web for info on the new WRX/STI motor is about as fact-filled as the motor specs for here. Grrr...

(If the FT86 gets a turbo, it will be a version of this motor. And if they don't give it to the FT86, I'm sure it'll be swappable.)

[Maxim]

Originally Posted by Dimman

Looking around on the web for info on the new WRX/STI motor is about as fact-filled as the motor specs for here. Grrr...

(If the FT86 gets a turbo, it will be a version of this motor. And if they don't give it to the FT86, I'm sure it'll be swappable.)

Yeah. But the transmission that's built to actually handle the huge increase in torque without squirting shit out of it's eyes won't be.....

[chulooz]

Originally Posted by Maxim

Yeah. But the transmission that's built to actually handle the huge increase in torque without squirting shit out of it's eyes won't be.....

Oh you have official specs on the trans? Share them with us.

From what has been speculated in the past Aisin might be providing it, and there boxes have been quite sturdy.

[serialk11r]

Hey hey he's got somewhat of a valid point, seeing that the max torque of the STI motor is double that of a naturally aspirated 2.0L. I don't know how much headroom they usually leave but a 100% increase in torque is a lot.

[PAImportTuner]

I don't want to get OT or even waste time with this. But yeah it's a done deal. 16x has been built already.

Originally Posted by Deslock

Can you provide a source for the 16X being already developed? A report in October 2010 at http://www.leftlanenews.com/mazdas-1...ogressing.html says it's been pushed back to at least 2013:



That report also says the 16X will make more power, but I read elsewhere that most of the improvement will be for mid-range power (with only a slight increase in peak power). I'm skeptical about claims that the 16X is promising a 30% increase in efficiency as I remember reading that the 13B-MSP was going to get 30 MPG highway (while it ended up making 24, by the old EPA standard).

That written, if they can hit 21/31 MPG with 235-250 hp N/A and a short wheelbase in a balanced, reasonably priced, 2600-2700 pounds, RWD 4 seater, it'll be a winner.

[PAImportTuner]

Originally Posted by serialk11r

Hey hey he's got somewhat of a valid point, seeing that the max torque of the STI motor is double that of a naturally aspirated 2.0L. I don't know how much headroom they usually leave but a 100% increase in torque is a lot.

Not a big deal with a rwd 2800lb car versus a awd 3400lb car. The transmission should take it.. but it's no honda transmission.

[Dimman]

Originally Posted by Maxim

Yeah. But the transmission that's built to actually handle the huge increase in torque without squirting shit out of it's eyes won't be.....

Which brings us to issue number two with turbo development.

Toyota has traditionally offered a VASTLY superior manual transmission on their turbo models.

The WRX/STI trans will likely be AWD, and if they use the traditional Subaru Symmetric AWD system, this is a completely different transmission. It's not a RWD trans with a separate transfer case/center diff. It's all integrated.

So what does Toyota do?

Do they risk reliability issues with the NA trans on a turbo model?

Do they spend more on an additional heavier-duty trans?

Or... just leave it NA, hmmm?

[WingsofWar]

Originally Posted by Dimman

Which brings us to issue number two with turbo development.

Toyota has traditionally offered a VASTLY superior manual transmission on their turbo models.

The WRX/STI trans will likely be AWD, and if they use the traditional Subaru Symmetric AWD system, this is a completely different transmission. It's not a RWD trans with a separate transfer case/center diff. It's all integrated.

So what does Toyota do?

Do they risk reliability issues with the NA trans on a turbo model?

Do they spend more on an additional heavier-duty trans?

Or... just leave it NA, hmmm?

Well a 6speed short gear transmission proposed in the FT86, regardless if it was built by Aisin might have some limitations because of the size of the gears. The transmission should take some abuse, and with performance transmissions today, we can EXPECT good performance up to 300-400hp.

transmissions for cars with FI are sometimes a hit or miss. The RX7 turbo had a better 5 speed transmission because of the size of the gears, but when the RZ and Spirit-R models came out with the 6speed with closer gears sure the performance was better, but didnt hold as much power as the 5speed. The Nissan S15 silvia had the 6speed placed in Spec-R models but underperformed compared to 5speed s15s when increasing power upwards to +400hp.

Larger engines with a broader power band can afford to have a beefy/heavier 6speed that can use longer gears. The supra and skyline GTR are evident of that.

Turbo and non-turbo arn't things we should be looking at..i think we should be looking at powerband. And if we expect to make good power at 200hp and the higher RPMS, and take abuse for being a performance oriented vehicle. I'm sure inadvertently the transmission capable to holding 300-350hp. Assuming the manufacturer is not an idiot and expect this car to fall apart under its own power, and Toyota or Subaru I give respect to in these aspects.

[Dimman]

Originally Posted by WingsofWar

Well a 6speed short gear transmission proposed in the FT86, regardless if it was built by Aisin might have some limitations because of the size of the gears. The transmission should take some abuse, and with performance transmissions today, we can EXPECT good performance up to 300-400hp.

transmissions for cars with FI are sometimes a hit or miss. The RX7 turbo had a better 5 speed transmission because of the size of the gears, but when the RZ and Spirit-R models came out with the 6speed with closer gears sure the performance was better, but didnt hold as much power as the 5speed. The Nissan S15 silvia had the 6speed placed in Spec-R models but underperformed compared to 5speed s15s when increasing power upwards to +400hp.

Larger engines with a broader power band can afford to have a beefy/heavier 6speed that can use longer gears. The supra and skyline GTR are evident of that.

Turbo and non-turbo arn't things we should be looking at..i think we should be looking at powerband. And if we expect to make good power at 200hp and the higher RPMS, and take abuse for being a performance oriented vehicle. I'm sure inadvertently the transmission capable to holding 300-350hp. Assuming the manufacturer is not an idiot and expect this car to fall apart under its own power, and Toyota or Subaru I give respect to in these aspects.

This is because they both traditionally put tougher transmissions in their turbo offerings.

[serialk11r]

@Wings of War what do you mean horsepower though? The limiting factor in a transmission is the torque the gears can put up with not power, since the gears won't be flying apart due to centripetal forces anytime soon. Sure if it's at say 8000rpm you make 300hp, that's a 50% torque increase. But if you use a motor that makes power lower, you're looking at a huge increase in torque, such as the 290ft-lbs of the STI compared to maybe 140-150 from a 2.0L N/A.

[Maxim]

Originally Posted by serialk11r

@Wings of War what do you mean horsepower though? The limiting factor in a transmission is the torque the gears can put up with not power, since the gears won't be flying apart due to centripetal forces anytime soon. Sure if it's at say 8000rpm you make 300hp, that's a 50% torque increase. But if you use a motor that makes power lower, you're looking at a huge increase in torque, such as the 290ft-lbs of the STI compared to maybe 140-150 from a 2.0L N/A.

Yes, the limiting factor is definitely the torque. The fact that the car will weigh less than other offerings DOES ease the strain on the gearbox somewhat, but it would still need to be built heavier.

I'm sure Aisin could do it without a problem...a variant of what they offered on the Solstice GXP might be a possibility, for example. The issue is, if there isn't a FACTORY turbo offering, reliability will probably be an issue once people start adding power or swapping engines. With a car that's being optimized for low weight and low torque output, I can only assume that a light-weight transmission would be part of the recipe.

That's why I want a factory turbo offering....many of the engineering issues would already be taken care of by the factory, meaning if I want to start adding even more power (which I always want to do because hell, why not!) I don't have to worry about so much.

One thing I can see as a potential problem: A gearbox built to handle more torque would definitely FEEL different than the lightweight one. It wouldn't be quit as snickt snickt, if you know what I mean. The effort would go up. Tremec makes some really great transmissions for high-power applications, and they feel great, but nobody would ever mistake the Camaro/Mustang transmission (they're the same) for an S2000.

I learned my lesson on power modification effects on the rest of the driveline the hard way. When I was 16, I purchased a 1989 IROC-Z Camaro with the 5 speed manual. The car was not offered with the 350ci engine and a manual...the manual only came with the 305ci. However, 4 months after I bought it, the engine threw a rod. Insurance covered an engine replacement, but due to the fact that Chevy wasn't making the 305 anymore, they just gave me a 350 from the C4 Corvette, as it was less expensive than finding/rebuilding a 305. 2 weeks after that, the transmission ripped off it's own face. They then replaced the transmission with a newer unit from a Camaro. Just 2 days after I got THAT back from the shop, the rear-end got ripped to pieces. That's what happens when you put a 330hp and torque in a car that came with 225. On the upside, after several months of frustration, I legally owned an IROC-Z with a complete, rebuilt/new Corvette drivetrain.

[WingsofWar]

Originally Posted by serialk11r

@Wings of War what do you mean horsepower though? The limiting factor in a transmission is the torque the gears can put up with not power, since the gears won't be flying apart due to centripetal forces anytime soon. Sure if it's at say 8000rpm you make 300hp, that's a 50% torque increase. But if you use a motor that makes power lower, you're looking at a huge increase in torque, such as the 290ft-lbs of the STI compared to maybe 140-150 from a 2.0L N/A.

Yes a transmission's strength does rely on its ability to handle torque, but when designing a transmission, we look at peak horsepower and a narrowband of power. This is how we determine our gear ratio..and the gear ratio will determine the size of the gear, and the size of the gear will or will not withstand more than factory stress.

The STI and Supra have very wide powerbands with a long final gear for higher top speed, which allows them to use longer gears (physically). Which is why they can get away with so called "TURBO TRANMISSIONS", a plus side to having bigger gears is they can withstand more stress once people start modded them for more power.

The FT-86 powerband is narrow (narrowband), but heres the kicker, its peak power is at the higher RPMS. Which also forces them to use bigger gears, because they need to SLOW down the engine to produce the proper amount of TQ needed to move the car from 0-xx speed.

There are multiple methods to build a performance oriented transmission, but it is usually based on appropriate powerband...and not wither a car is turbocharged or not to withstand stress..from TQ multiplication. Because quite frankly transmissions and gears today do not shred like they did in the 80s-90s

Now if we are looking at FT86s 6speed close ratio transmission, we need to expect that the first 3 gears are beefy if they are going to be short. and if they are beefy, they can withstand more beating and stress.

[serialk11r]

Okay thanks for the clarification

hmmm I guess that makes sense, shorter gears = beefier gears needed. But I still am wondering since the comment was specifically on swapping in the engine and keeping the transmission. If you keep the transmission you still have the very short gears, but now a crapton more torque. The transmission is still made for that relatively low max torque, I'm not entirely sure I can see why the manufacturer would choose a transmission with that much overhead. Then again I guess there is headroom needed anyways to prevent poor clutch actuation from destroying the transmission, but is it really that much? How much extra torque can transmissions typically handle in this application?

[WingsofWar]

Originally Posted by serialk11r

Okay thanks for the clarification

hmmm I guess that makes sense, shorter gears = beefier gears needed. But I still am wondering since the comment was specifically on swapping in the engine and keeping the transmission. If you keep the transmission you still have the very short gears, but now a crapton more torque. The transmission is still made for that relatively low max torque, I'm not entirely sure I can see why the manufacturer would choose a transmission with that much overhead. Then again I guess there is headroom needed anyways to prevent poor clutch actuation from destroying the transmission, but is it really that much? How much extra torque can transmissions typically handle in this application?

How do we know the bellhousing will line up with the older EJ motors? Anywho, if it does....lets say we put a modded 380hp EJ257 on the 6spd, and we get ratios similar to the Aisin AZ6, we can extend the total power output if we change the final drive to a lower ratio..giving us less stress on the gears and a broader band, so we can peak the turbo a bit and not blow up our gears.

If we don't have that option, i would suggest either cryo-treating the gears..or if your expecting +400hp i would swap out the gear box for a bigger gear set, like from a supra. That way you can retain your transmission case and bellhousing but get a different set of ratios to fit your powerband and not run out of steam.