Engine build

[WingsofWar]

Originally Posted by Dimman

It's not so much the under/oversquareness, as the total length of the stroke and rpm. That's was affects piston speed, and therefore acceleration. The more acceleration the piston goes through up and down, the more force on all the components. And the stronger and either heavier or more expensive the parts have to be. There's a reason the Mugen redlines a bit less. (Is the Mugen on factory rods?)

And it's making its power partly from a displacement increase (2.16L so it's not huge, but it is bigger). If they increase flow potential from porting, cam lift, whatever, they still need to get more air in, either through more air per revolution (bigger stroke) or more revolutions.

To me it's that the B X S of the FB20 reminds me a bit too much of the 7M (83mm x 91mm), a motor not known to enjoy revs vs the 1JZ with 71.5mm stroke which LOVES to rev. Yes, they're old tech these day, but physics doesn't change...

Edit: Self facepalm... 'factory rods? It's stroked... fail.

Ahh i get what your saying, yeah a 90mm travel per 2 rpms is pretty worry some, even if it does make power at that travel (which it could) it does make that power strenuous and unstable. But can be easily remedied with engineering even if they retained those same stock FB20 stroke ratio.

But your 7m and 1jz comparison is kind of confusing to me;

7M-GE (83mm x 91mm) 3L I6 engine with a 9.1C/R makes power at 6000rpms

vs

1jz-GE (86mm x 71.5mm) 2.5L I-6 and a 8.5 C/R and makes power at 6000rpms

...where exactly is this high reving?

if we compare the turbo models

7m-GTE has the same stroke but with lower compression to compensate boost making the the power band lower (5600rpms). The 1jz-GTE retains the same compression ratio and later gains compression at 9.0:1 with VVT-i raising the Powerband RPM slightly higher (6300rpms).

Your right about physics but im having a hard time finding the correlation and differences in your reasoning.

Key items that make the difference regardless of stroke in a small total displacement engine is, high compression+low friction.

If the 7m-GE using the same stroke and bore, had 11.0:1- 12.0:1 compression, low friction pistons, stronger rods, a lighter forged crank, and a suitable intake cam lift. It wouldn't surprise me to see the 7m-GE powerband in the 8000-9000rpm range.

[Exage]

Can't remotely speculate on what modifications will benefit the engine or what can be done. At this point there are so many variables and no conclusive data to go off of.

Generally speaking:

Increase Engine Breathing: IM, CAI, header/exhaust manifold, exhaust system, camshaft, port and polish head, valve work and valve-springs (latter for RPM).

Increase Fuel Delivery and Ignition: ECM, injectors, fuel pump, spark plugs, high compression pistons

Reduce Inertia Weight: Lighter and stronger internal components, pistons, connecting rods, crankshaft, blueprint (internal weight and friction distribution)

Reduce Friction: Piston rings/cylinder liners, smaller bearing and component widths (will need added strength to components).

Increase Lubrication: High output oil pump is required for drastic RPM increases.

Increase Cooling Capacity: Water pump, radiator, thermostat.

There are others but this is generally speaking.

Making more power to a naturally aspirated engine means you want torque higher in the RPM band to produce horsepower, consequently you will be looking for RPM gains and those need internal tinkering and work if you really want something.

Raising the Redline of a stock engine doesn't really do a whole hell of a lot. It's out of the power band (for various reasons), and producing unneeded stresses on the internals.

Lets say some dumb a** raised and tuned only the fuel cutoff (redline) +1000 to 9200rpm of a bone stock 2ZZ-GE. What happens??? Maximum torque and horsepower are the same stock values at same RPM. Power significantly nosedives after 8400rpm and valve float begins appearing, at 8800rpm there is a noise and significant loss of power; that noise is the piston colliding with the valves. The previous also happens if the dumb a** misses his 5-6 shift at redline and goes 5-4 .

At continuos 8500rpm for periods of time there is a good possibility of the oil pump disintegrating (2ZZ have notoriously weak oil pumps), stretched connecting rods, and severely increased bearing wear.

I wouldn't touch a redline increase (on any engine) until a decent amount of components have been improved and optimized so that the engine can sustain the increase.

Rant over I guess...

[Dimman]

Edit: to WoW:

7MGTE runs to about 6500 rpm stock, 1JZGTE to 7000 rpm. Not a huge difference. But how they rev up is astoundingly different. 1JZ just wants to GO! Looking at other things, the 1JZ is choked by what are probably the worst factory turbo manifolds ever made. It looks very much like it was choked deliberately to limit it to the 280 PS limit.

Now when comparing built motors, with a better manifold/turbos and cams, a 1JZ motor with stock rods, stock head will spin easily to over 8000 rpm. Drag racing 2JZ's with an 86mm stroke have been hitting the 9k range (built bottom too, though, and due to more development here).

In the case of my buddy's ridiculous 7MGTE (1015 whp) with Cunningham titanium rods, and a heavily ported head, knife-edged crank, plus custom cams (280 degree range), its hard rev limit is set to 7600 rpm for reliability.

I imagine a properly built 1JZGTE could actually make equally reliable power up to 9.5-10K rpm. Of course being smaller displacement, it would need the extra revs to match the power, or more boost.

[WingsofWar]

Originally Posted by Exage

I wouldn't touch a redline increase (on any engine) until a decent amount of components have been improved and optimized so that the engine can sustain the increase.

I like your post, I completely agree.

reminds me of the time where i was just getting into rotaries and a few FC guys removed their rev-limiters and installed FCDs. Because they heard that we can make power at the higher RPM ranges also, which is partially true. But without supporting mods, goodbye apex-seals.

[Dimman]

Exage, what would the g-load be on the rods of the 90mm stroke FB20 be, spinning at about 8500 rpm? (What would they effectively 'weigh' when changing direction?)

Edit: Hmmm, I guess you would need the starting weights first, though... NVM the weight part, g would be fine...

[WingsofWar]

Originally Posted by Dimman

Edit: to WoW:

7MGTE runs to about 6500 rpm stock, 1JZGTE to 7000 rpm. Not a huge difference. But how they rev up is astoundingly different. 1JZ just wants to GO! Looking at other things, the 1JZ is choked by what are probably the worst factory turbo manifolds ever made. It looks very much like it was choked deliberately to limit it to the 280 PS limit.

Now when comparing built motors, with a better manifold/turbos and cams, a 1JZ motor with stock rods, stock head will spin easily to over 8000 rpm. Drag racing 2JZ's with an 86mm stroke have been hitting the 9k range (built bottom too, though, and due to more development here).

In the case of my buddy's ridiculous 7MGTE (1015 whp) with Cunningham titanium rods, and a heavily ported head, knife-edged crank, plus custom cams (280 degree range), its hard rev limit is set to 7600 rpm for reliability.

I imagine a properly built 1JZGTE could actually make equally reliable power up to 9.5-10K rpm. Of course being smaller displacement, it would need the extra revs to match the power, or more boost.

Ohh ya, i see what you mean, yeah that whole free-reving characteristics on a high mid-high RPM range is EXILERATING vs a car that just has a decent powerband on mid-high RPM range.

Now i see what your getting at.. a 90mm stroke may make desired power, but wont give us that free-reving characteristic that we are ultimately looking for in a performance high reving engine. In that sense, ya 90mm is way to long to achieve that level of performance.

the 7m and 1jz make similar total output but perform vastly differently.

trying to picture a scenario..
So a FB20 making 200hp at 7500rpm vs a FB20R making 200hp 7500rpm with a shorter stroke will perform vastly different in the power band range.

[Maxim]

Hell, I'd be happy with 250hp in a car like this...

[WingsofWar]

Originally Posted by Maxim

Hell, I'd be happy with 250hp in a car like this...

If its the number your looking at, then 250hp in this car would be attainable. I believe Toyota said in an interview that they can push 230hp easily, and I'm assuming without a turbo. I'm keen on believing what they say. I wouldn't believe it 10-15 years ago, but with today's precision engineering and seeing what Japanese automaker can do now they couldn't do before, anything is possible.

[Maxim]

Originally Posted by WingsofWar

If its the number your looking at, then 250hp in this car would be attainable. I believe Toyota said in an interview that they can push 230hp easily, and I'm assuming without a turbo. I'm keen on believing what they say. I wouldn't believe it 10-15 years ago, but with today's precision engineering and seeing what Japanese automaker can do now they couldn't do before, anything is possible.

I'm sure they CAN get 250hp from it, but they're going to balance it for emissions and economy. If 250 is as easy as headers-back exhaust, an intake, and replacing the pulleys with something lighter, then I'd be absolutely thrilled, so long as the weight target is hit as well.

I don't care so much about actual peak numbers....really what I care about is the swept area of the powerband (IE, area under the curve). That's a true indication of an engine's power, not the peak number. The feel of the engine as it revs is also very important. I hate engines that have a power fall-off before redline....it's just a complete buzz kill. I also HATE how modern cars are tuned to hang on to revs, for emmissions sake. Totally ruins the responsiveness of an engine.

[EvO^GsR]

This might be a bit off topic but with engine tuning especially with the headers and exhaust parts wouldn't using titanium and other various light parts also help with the overall feel and performance of the car?

One example of this is the AMUSE S2000 which basically used titanium parts to reduce weight but keeping the engine stock. BTW sorry if this was OT.

[Dimman]

Originally Posted by EvO^GsR

This might be a bit off topic but with engine tuning especially with the headers and exhaust parts wouldn't using titanium and other various light parts also help with the overall feel and performance of the car?

One example of this is the AMUSE S2000 which basically used titanium parts to reduce weight but keeping the engine stock. BTW sorry if this was OT.

There is a weight thread. But yes it would help performance.

And it would also help performance by keeping my wallet lighter.

I don't like that mod.

[Levi]

At the moment we can't really say what can be improved on the NA Flat4 because we have no data. If it is the EJ20, then I am going to get the 2,2l stroker kit.
However it can be possible to come closer to 300 PS staying NA. The BMW 320si WTCC has a 275 PS 2.0l I4 with redline at 8.500 RPM. Here other two Crosworth engines.

[Dimman]

Originally Posted by Levi

At the moment we can't really say what can be improved on the NA Flat4 because we have no data. If it is the EJ20, then I am going to get the 2,2l stroker kit.
However it can be possible to come closer to 300 PS staying NA. The BMW 320si WTCC has a 275 PS 2.0l I4 with redline at 8.500 RPM. Here other two Crosworth engines.

Um, Levi. What exactly is your budget for this car? From this, and your other posts, it sounds like:

A.) You've got a lot of money to throw at your FT86 when you get it. If this is the case, awesome. Be sure to share your build pics, because it will probably be epic.

or

B.) You don't have a solid grasp on this car and what it will take to make it give you the 300 PS you want, with no boost.

Those Cosworth motors are not exactly production motors. They're high-performance motors for race/kit cars (Caterham, I believe). The second one is a 2.3L, has a carbon fiber intake with individual roller barrel throttles and dry sump oiling system, and it's still 20 PS short of your 300 PS goal. And it probably costs 1/2 to 3/4 the price of what the entire FT86 is expected to cost.

[Exage]

Originally Posted by Levi

At the moment we can't really say what can be improved on the NA Flat4 because we have no data. If it is the EJ20, then I am going to get the 2,2l stroker kit.
However it can be possible to come closer to 300 PS staying NA. The BMW 320si WTCC has a 275 PS 2.0l I4 with redline at 8.500 RPM. Here other two Crosworth engines.

In reference to your and supporting Dimmans post.

1. The engine will not be a EJ20 (Period)

2. If your trying to get 150bhp/L Naturally Aspirated then you're effectively trying to create a race engine regardless of engine size. (Porsche GT3 RS 4.0 is 125hp/L at 500hp)

3. Trying to street a 300bhp 2.0L Naturally Aspirated engine on pump gas is nearly insane. I mean look at the F20C: it's USDM spec was 237hp @ 8300rpm and 153lb-ft at 7500rpm (and that engine breaths very well). Theoretically along the same lines you would like 160lb-ft at 8700rpm as peak torque for what you're proposing.

4. It's simpler and way cheaper to go the forced induction route via aftermarket or engine swap for 300bhp (even with the fabrication, wiring harness and ECM niggles). Something along the lines of EJ turbo from a WRX STI, or whatever Subaru is cooking up as the replacement.