New rumor: 1.6-liter turbocharged engine one year after initial introduction

[Dimman]

Originally Posted by 82mm 4g63

That statement is entirely too general and I partially disagree with the boost handling part.

What do you consider to be short stroke? 100mm bore x 80mm stroke? I prefer a "square" engines powerband characteristics, which is why I never stroked my 4g63, or swapped in a destroked 4g64. I have adequate power in the lowend and more than enough power in the high end. The 2.3 stroker version of my 63 gives up too much high end, the 2.1 destroked 4g64 gives up too much low end.

Yes, a shorter stroke = higher revs. Yes, higher revs = more top end power. On the other hand... longer stroke = more low end torque = smoother transition from pre-boost to boost. Longer stroke/shorter stroke, unless taken to the extreme, doesn't make a car handle more/less boost. [Edit] Look at the 2JZ GTE, perfectly square 86mm x 86mm and it handles gobs of boost before needing to be rebuilt with beefier internals.



Then you agree with my original statement "TLDR: Larger displacement = more robust and forgiving torque curve." :happy0180:

I agree with fundamentally what you are saying.

But in some situations I think a higher revving (short stroke) boosted motor could have an advantage. With the right turbo spooling tech, the extra rev-range of a slightly smaller high rpm motor could end up with a longer powerband (more power under the curve). Since in most turbo cars it is boost that plays the more important role in torque. So a small peak torque and lag penalty, but being able to rev under boost for an extra 1000 rpm could put the advantage in the smaller higher revving motor.

The key would be if the low rpm lag difference is offset by more top end rpm range. Ie: boost comes on 500 rpm or less later, but it revs out 1000 rpm or more higher. And if the peak torque is not too much less.

But that would be a rather specialized example...

I was planning on experimenting with this idea on my 1JZ before I sold it, using the latest IS300 VVT-i 2JZGE head with stock 1JZGTE ceramic parallel twin turbos, on a short-stroke, high revving 1JZGTE bottom. I would be anticipation better spool and more top-end than a lot of Mk4s still on their stock sequential twins. Not exactly apples to apples, but still a fun idea...

[Type[R]+]

Originally Posted by 82mm 4g63

That statement is entirely too general and I partially disagree with the boost handling part.

What do you consider to be short stroke? 100mm bore x 80mm stroke? I prefer a "square" engines powerband characteristics, which is why I never stroked my 4g63, or swapped in a destroked 4g64. I have adequate power in the lowend and more than enough power in the high end. The 2.3 stroker version of my 63 gives up too much high end, the 2.1 destroked 4g64 gives up too much low end.

Yes, a shorter stroke = higher revs. Yes, higher revs = more top end power. On the other hand... longer stroke = more low end torque = smoother transition from pre-boost to boost. Longer stroke/shorter stroke, unless taken to the extreme, doesn't make a car handle more/less boost. [Edit] Look at the 2JZ GTE, perfectly square 86mm x 86mm and it handles gobs of boost before needing to be rebuilt with beefier internals.



Then you agree with my original statement "TLDR: Larger displacement = more robust and forgiving torque curve." :happy0180:

yep, yep, yep, and yep. I won't start about turbos, I'll just leave it at that. :happy0180:

We are essentially debating which is better. 2JZ or RB26. Same bore, different stroke. Destroke a 2JZ and you get an RB26.....
I'm trying to say RB26 doesn't suck because it's smaller/short stroke. It has it's advantages elsewhere. Torque up higher in the rev range is just one of them.

[Type[R]+]

Originally Posted by 82mm 4g63

Right. Longer rods, taller pistons, or shortened deck height. I've never destroked a motor so I'm not sure exactly which is more cost effective.

Don't forget about crank either. Destroking usually comes about by swapping in the smaller crank into the bigger engine - with Subaru its the 205/7 crank in the 257 block.

[82mm 4g63]

Originally Posted by Type[R]+

yep, yep, yep, and yep. I won't start about turbos, I'll just leave it at that. :happy0180:

We are essentially debating which is better. 2JZ or RB26. Same bore, different stroke. Destroke a 2JZ and you get an RB26.....
I'm trying to say RB26 doesn't suck because it's smaller/short stroke. It has it's advantages elsewhere. Torque up higher in the rev range is just one of them.

Right. The only reason I question the 1.6L destroked motor is because if we, for whatever reason, need to destroke a motor why not destroke a larger 2.5L down to 2.1L and apply the same technology to the 2.1L that you would've on the 1.6L? I'm not in the market for any of the 1.6L boosted cars anyway so, whatever.

[Type[R]+]

Originally Posted by Dimman

I agree with fundamentally what you are saying.

But in some situations I think a higher revving (short stroke) boosted motor could have an advantage. With the right turbo spooling tech, the extra rev-range of a slightly smaller high rpm motor could end up with a longer powerband (more power under the curve). Since in most turbo cars it is boost that plays the more important role in torque. So a small peak torque and lag penalty, but being able to rev under boost for an extra 1000 rpm could put the advantage in the smaller higher revving motor.

The key would be if the low rpm lag difference is offset by more top end rpm range. Ie: boost comes on 500 rpm or less later, but it revs out 1000 rpm or more higher. And if the peak torque is not too much less.

But that would be a rather specialized example...

twin turbo's/twin charging is how they do it. Quick spool, doesn't fall on it's face. Heaps of examples out there like 82mm 4g63' RX7 is a prime example.

[82mm 4g63]

Originally Posted by Type[R]+

Don't forget about crank either. Destroking usually comes about by swapping in the smaller crank into the bigger engine - with Subaru its the 205/7 crank in the 257 block.

Yeah, I thought someone already mentioned the crank, guess not. Longer rods, taller pistons, or shortened deck height would make for a pretty snazzy engine failure if the crank wasn't swapped out.

[Dimman]

Originally Posted by 82mm 4g63

Right. The only reason I question the 1.6L destroked motor is because if we, for whatever reason, need to destroke a motor why not destroke a larger 2.5L down to 2.1L and apply the same technology to the 2.1L that you would've on the 1.6L? I'm not in the market for any of the 1.6L boosted cars anyway so, whatever.

The whole point of the 1.6T is to create a connection between the WRX to whatever is racing in the WRC, which require 1.6T motors these days.

We're not really talking about de-stroking just for the sake of it, but of them creating a dedicated performance 1.6T, possibly for homologation purposes. When Toyota ran in the WRC with the Celica, the formula was 2.0L, so the GT4/Altrac was 2.0L. Now it's 1.6L, so if Subaru wants to go back, they need a 1.6L. I still think that if they do a 1.6T for the WRX they may still do a 2.0L for the STI. At least in North America.

[Type[R]+]

Originally Posted by 82mm 4g63

Right. The only reason I question the 1.6L destroked motor is because if we, for whatever reason, need to destroke a motor why not destroke a larger 2.5L down to 2.1L and apply the same technology to the 2.1L that you would've on the 1.6L? I'm not in the market for any of the 1.6L boosted cars anyway so, whatever.

Don't get me wrong, I don't want a 1.6L, I want the 2.5L.

It's just that it's looking very well like 1.6L will be the future of the WRX/STI.

From the info i've read, Toyota reduced the FB's bore and increased the stroke for the 2L, so a destroke to 1.6L essentially brings the stroke ratio back to near where it was.

Boost the shit out of it and let it scream, then take advantage of gearing.....

[Dimman]

Originally Posted by Type[R]+

twin turbo's/twin charging is how they do it. Quick spool, doesn't fall on it's face. Heaps of examples out there like 82mm 4g63' RX7 is a prime example.

The 1JZGTE I keep mentioning is twin turbo. Parallel setup. With the IS300 VVT-i head it would've spooled like crazy (it already spools really fast), and probably made an extra 30ish hp from 6k-7k rpm. It's also a 2.5L, so more appropriate to compare with the 3.0L 2JZGTE than the RB26DETT.

I miss my Supra.

[Type[R]+]

Originally Posted by Dimman

The 1JZGTE I keep mentioning is twin turbo. Parallel setup. With the IS300 VVT-i head it would've spooled like crazy (it already spools really fast), and probably made an extra 30ish hp from 6k-7k rpm. It's also a 2.5L, so more appropriate to compare with the 3.0L 2JZGTE than the RB26DETT.

I miss my Supra.

Yamaha head FTW!

[Matador]

Originally Posted by Type[R]+

Don't get me wrong, I don't want a 1.6L, I want the 2.5L.

It's just that it's looking very well like 1.6L will be the future of the WRX/STI.

From the info i've read, Toyota reduced the FB's bore and increased the stroke for the 2L, so a destroke to 1.6L essentially brings the stroke ratio back to near where it was.

Boost the shit out of it and let it scream, then take advantage of gearing.....

What? Where did you read that? That makes no sense....

Originally Posted by Dimman

The 1JZGTE I keep mentioning is twin turbo. Parallel setup. With the IS300 VVT-i head it would've spooled like crazy (it already spools really fast), and probably made an extra 30ish hp from 6k-7k rpm. It's also a 2.5L, so more appropriate to compare with the 3.0L 2JZGTE than the RB26DETT.

I miss my Supra.

[Dimman]

I know that a few of us were speculating here http://www.ft86club.com/forums/showp...7&postcount=30 on what strokes the FB20 and FB25 need (72mm) to reduce them to over-square 1.6L and 2.0L motors while keeping the same bores.

Could be a circular rumour (started here, picked up somewhere else, posted here).

But given the detailed post on the 1ZZFE to 2ZZGE I think Yamaha will have even greater ability to choose their own bore and stroke.

[Type[R]+]

Originally Posted by MatadorRacing_F1

What? Where did you read that? That makes no sense....

What makes no sense? You do know it's basically a new engine?

http://blog.edoperformance.com/2011/...irated-engine/

[Type[R]+]

Originally Posted by Dimman

It's also a 2.5L, so more appropriate to compare with the 3.0L 2JZGTE than the RB26DETT.

I agree, but you have missed the point of the exercise. 2J and RB26 have the same bore size, different stroke.