Engine build

[Maxim]

So, since this car will likely have right around 200hp, and I'm always after more power....you guys need to school me a bit.

I know plenty about making more power out of turbo or large displacement engines. Teach me how to get power out of an N/A 2.0L.

Since we don't know exact engine specs yet, maybe stick to the general stuff.

I doubt that intake and exhaust will net more than 10hp, though it contributes greatly to the sound. I also know that once the mods are done, a computer reflash is needed to further optimize things.

What other things can be done to get larger gains? What kind of prices am I looking at?

I know that lightening the internals will net gains, but I'm not sure how much. Also, after that is done, a computer reflash to re-position the rev limiter/fuel cut-off is needed. Does anybody have experience with that sort of thing?

What else can I do? Money isn't going to be an issue, at 25k this car is well below my means and I fully plan on dumping money into it. I've only got a few years left until I need to settle down and find a permanent female and probably start a family, so this might be one of the last performance cars I ever buy.

I've got mechanic friends and I'm not going to be paying labor for the mods, just parts cost and a few cases of beer here and there.

What do I need to increase the redline without hurting the engine? What do I need to make it breath easier? How much power is safe to attempt to get through stock injectors? That sort of thing!

[Abflug]

don´t want to be offensive!

maybe get a S65B40!

If you say you got the cash, go for the germans, you have the source!

[Snaps]

Originally Posted by Maxim

I doubt that intake and exhaust will net more than 10hp, though it contributes greatly to the sound. I also know that once the mods are done, a computer reflash is needed to further optimize things.

I disagree, I think if Toyota are only aiming for 200hp with this engine (when they said they could reach ~230), that most of the restrictions/power loss will come from a (slightly) restrictive Exhaust, intake or de-tuned ECU. IMO doing the Intake, Exhaust (Including Headers) may net as high as 20hp...

Originally Posted by Maxim

I know that lightening the internals will net gains, but I'm not sure how much. Also, after that is done, a computer reflash to re-position the rev limiter/fuel cut-off is needed. Does anybody have experience with that sort of thing?

Most Toyota ECU's are very hard to crack, so require a stand-alone or piggyback ECU (I think?) to be able to tune the car. This should set you back the same amount as any other car, depending on how hard it is to install in the '86.

Originally Posted by Maxim

What do I need to increase the redline without hurting the engine? What do I need to make it breath easier? How much power is safe to attempt to get through stock injectors? That sort of thing!

Increasing Redline - A lot of engines redline's are decreased from factory, you can probably get a small increase (maybe 400-500rpm) without doing any damage to the stock engine, but this depends on how far the engine has been pushed from factory. To find that out will require more testing once we actually get the engine! Otherwise, you can more safely increase the redline by lowering the weight of internal components, increasing things like the valve spring strength (once again, it depends), and reducing the stroke (lowering piston speed).

Breathe easier - Port and polish the heads, intake manifold, match the exhaust manifold shape to the exhaust port shape, etc. There is sooo much information on this on the internet! Do a search!

Power through stock injectors - depends what size they are, depends on fuel pump, fuel pressure's, etc. I'm not sure what effect the Direct Injection will have on this sort of thing, though...

[WingsofWar]

What kind of power are you thinking about? Its not so much making more power out of a 2.0 N/A, but making it out of the FB20.

Ill give you a few hints from my experience with the EJ22 and EJ25. But the actual scenario may change because of the altered characteristics of the FB20. Especially since it will be different than the current FB20 on the market and vastly different from EJ engines. For this thread, lets label the FB20 on the FR-S, FB20R.

1. Intake - Unfortunately for us, a simple mod such as a air filter or intake pipe will not net any power. Recent Flat-4s intake designs are vastly optimized already with very little flow restriction. BUT what has seen promising power increases on the dyno is cooling the intake charge. Simplest way is the cold air intake mods. Next would be adding Phenolic Intake Gasket to separate the block from the intake manifold allowing the intake manifold to cool. But from my understanding the FB20R will use a thermo plastic intake manifold and probably wont respond to a Phenolic Intake Gasket like the EJ motors do with metal intakes.

2. Exhaust - The FB20R should come with factory EL headers, which are the best for performance. Similar to how all the N/A EJ models have EL headers, however the diameter and flow could be better over OEM. TWE currently makes the only EL 4-2-1 subaru header that has the highest gains seen on the dyno. Next is strangely OBX, due to their pipe design. Cat Back exhausts are a hit and miss on N/A subarus, Iv seen as high as 10hp and as low as 3hp gains. Mated with high flow cats we can see some increases, but the real magic happens at the header.

3. Compression - N/A engines powerband is in the upper registries of the RPM range, and higher compression ratios net the best kind of power the engine can produce. Some EJ251 and EJ252 phaseII tuners use a EJ22 PhaseI head, to bump the compression ratio from 9.7:1 to 11:1. Netting anywhere from 15-23hp. The current FB20 has a 10.5:1 C/R, but at this point we don't know the compression ratio of the FB20R, but its something to look out for when considering mods, anywhere from different pistons to heads.

4. Heads - EJ N/A engines have use a SOHC head design for a long time, but this time around the FB20 will be using a DOHC head. Probably the same for the FB20R. What we are looking for are better exhaust flow characteristics. Some EJ22 tuners enlarge the exhaust ports for better flow and has seen better results vs messing with the intake ports. When we do this its better to do better cams. But my only concern is the if we even need to do anything in the heads to begin with because Yamaha may be doing the work for us.

5. Fuel/Timing and ECU tuning - Here is where it gets a bit tricky, Direct injection theory is we wont ever max out the injectors based on the variation of how they operate. We still get pulse width and duty cycle, but many EFI gurus have had troubles in tuning direct injection. Currently Motec, Megasquirt and AEM are the only Stand alone EMS units that touch direct injection. From there we will probably metering using a MAF, as subaru has favored over MAP when it was changed over in the late 2000s. Id like to see AIT metering implemented in factory ECU settings. Reflashing the ECU using an access port will probably not see major fuel map changes, but timing. But there in lies another problem. Subaru and Toyota both have active learning ECUs in which people have been plauged with because even if you reflash the ECU, it will revert back to its original settings over time. Which is why COBB refuses to make more aggressive maps for N/A accessport guys. This is by far the most important mod for some real gains but we have some major hurdles to overcome.

6. Internals - If Yamaha/Toyota/Subaru is planning on making good power with the car. FB20R should have much better internals overall. Forged crank is likely and could be lightened and balanced. Im not to sure about the piston and rods over the current FB20. But im sure its an area they we need to touch if Yamaha/Toyobaru doesnt.

7. ITBs - This mod is likely among hardcore builders and those who see the track more than anything.

8. Ignition - FB20R will probably use coil-on-plug distributer-less ignition and will feed its power from the electrical system of the car. If we want to see better spark and less ignition break up especially in the higher RPM ranges where we get our power, we need to optimize the electrical output. Higher AMP alternators, maybe a CDI box. We will see when the car actually comes out.

9. Pullies and Flywheel lightened but not overdriven. good for freeing up power we already have.

[Maxim]

Originally Posted by Snaps

I disagree, I think if Toyota are only aiming for 200hp with this engine (when they said they could reach ~230), that most of the restrictions/power loss will come from a (slightly) restrictive Exhaust, intake or de-tuned ECU. IMO doing the Intake, Exhaust (Including Headers) may net as high as 20hp...



Most Toyota ECU's are very hard to crack, so require a stand-alone or piggyback ECU (I think?) to be able to tune the car. This should set you back the same amount as any other car, depending on how hard it is to install in the '86.



Increasing Redline - A lot of engines redline's are decreased from factory, you can probably get a small increase (maybe 400-500rpm) without doing any damage to the stock engine, but this depends on how far the engine has been pushed from factory. To find that out will require more testing once we actually get the engine! Otherwise, you can more safely increase the redline by lowering the weight of internal components, increasing things like the valve spring strength (once again, it depends), and reducing the stroke (lowering piston speed).

Breathe easier - Port and polish the heads, intake manifold, match the exhaust manifold shape to the exhaust port shape, etc. There is sooo much information on this on the internet! Do a search!

Power through stock injectors - depends what size they are, depends on fuel pump, fuel pressure's, etc. I'm not sure what effect the Direct Injection will have on this sort of thing, though...

Yeah, I knew it would require a piggyback or replacement ECU. I'm running one on my GTI.

Swapping out internal components for lighter weight ones and stronger valve springs would require a custom tune on the ECU to take advantage of correct? To account for the shift in the powerband from stock, the fuel map and fuel cut off?

It sounds like if I want to do this, it'd be better to do it all at once...port/polish, titanium/forged internals, injectors/fuel pump, probably spark plugs too, then have a custom ECU tune at the end to take advantage of all of it.

I kind of figured that would be the case....that would actually work out perfectly for me, since it will take a couple model-years for tuners to get familiar with the systems and develop some of this stuff. I wouldn't want to do all of that to a brand-new car.

[Maxim]

Originally Posted by WingsofWar

What kind of power are you thinking about? Its not so much making more power out of a 2.0 N/A, but making it out of the FB20.

Ill give you a few hints from my experience with the EJ22 and EJ25. But the actual scenario may change because of the altered characteristics of the FB20. Especially since it will be different than the current FB20 on the market and vastly different from EJ engines. For this thread, lets label the FB20 on the FR-S, FB20R.

1. Intake - Unfortunately for us, a simple mod such as a air filter or intake pipe will not net any power. Recent Flat-4s intake designs are vastly optimized already with very little flow restriction. BUT what has seen promising power increases on the dyno is cooling the intake charge. Simplest way is the cold air intake mods. Next would be adding Phenolic Intake Gasket to separate the block from the intake manifold allowing the intake manifold to cool. But from my understanding the FB20R will use a thermo plastic intake manifold and probably wont respond to a Phenolic Intake Gasket like the EJ motors do with metal intakes.

2. Exhaust - The FB20R should come with factory EL headers, which are the best for performance. Similar to how all the N/A EJ models have EL headers, however the diameter and flow could be better over OEM. TWE currently makes the only EL 4-2-1 subaru header that has the highest gains seen on the dyno. Next is strangely OBX, due to their pipe design. Cat Back exhausts are a hit and miss on N/A subarus, Iv seen as high as 10hp and as low as 3hp gains. Mated with high flow cats we can see some increases, but the real magic happens at the header.

3. Compression - N/A engines powerband is in the upper registries of the RPM range, and higher compression ratios net the best kind of power the engine can produce. Some EJ251 and EJ252 phaseII tuners use a EJ22 PhaseI head, to bump the compression ratio from 9.7:1 to 11:1. Netting anywhere from 15-23hp. The current FB20 has a 10.5:1 C/R, but at this point we don't know the compression ratio of the FB20R, but its something to look out for when considering mods, anywhere from different pistons to heads.

4. Heads - EJ N/A engines have use a SOHC head design for a long time, but this time around the FB20 will be using a DOHC head. Probably the same for the FB20R. What we are looking for are better exhaust flow characteristics. Some EJ22 tuners enlarge the exhaust ports for better flow and has seen better results vs messing with the intake ports. When we do this its better to do better cams. But my only concern is the if we even need to do anything in the heads to begin with because Yamaha may be doing the work for us.

5. Fuel/Timing and ECU tuning - Here is where it gets a bit tricky, Direct injection theory is we wont ever max out the injectors based on the variation of how they operate. We still get pulse width and duty cycle, but many EFI gurus have had troubles in tuning direct injection. Currently Motec, Megasquirt and AEM are the only Stand alone EMS units that touch direct injection. From there we will probably metering using a MAF, as subaru has favored over MAP when it was changed over in the late 2000s. Id like to see AIT metering implemented in factory ECU settings. Reflashing the ECU using an access port will probably not see major fuel map changes, but timing. But there in lies another problem. Subaru and Toyota both have active learning ECUs in which people have been plauged with because even if you reflash the ECU, it will revert back to its original settings over time. Which is why COBB refuses to make more aggressive maps for N/A accessport guys. This is by far the most important mod for some real gains but we have some major hurdles to overcome.

6. Internals - If Yamaha/Toyota/Subaru is planning on making good power with the car. FB20R should have much better internals overall. Forged crank is likely and could be lightened and balanced. Im not to sure about the piston and rods over the current FB20. But im sure its an area they we need to touch if Yamaha/Toyobaru doesnt.

7. ITBs - This mod is likely among hardcore builders and those who see the track more than anything.

8. Ignition - FB20R will probably use coil-on-plug distributer-less ignition and will feed its power from the electrical system of the car. If we want to see better spark and less ignition break up especially in the higher RPM ranges where we get our power, we need to optimize the electrical output. Higher AMP alternators, maybe a CDI box. We will see when the car actually comes out.

9. Pullies and Flywheel lightened but not overdriven. good for freeing up power we already have.

Thanks. This gives me some great things to look into. I definitely want to be fully educated on all of this before I go trying to choose what to do with my car.

Mustang fans ran into the same ECU "learning" issues with the Mustang when they released the 2005's. It took a good 3 years before anybody was offering a good replacement ECU that didn't cause more problems than it solved. I'm ok with that, since that gives me some time to enjoy the car in close-to-stock form. Make me appreciate the gains that much more when I finally go through with it.

[Abflug]

mhhh... ITB´s on a 4AG(E)! I like!

[WingsofWar]

Originally Posted by Maxim

Thanks. This gives me some great things to look into. I definitely want to be fully educated on all of this before I go trying to choose what to do with my car.

Mustang fans ran into the same ECU "learning" issues with the Mustang when they released the 2005's. It took a good 3 years before anybody was offering a good replacement ECU that didn't cause more problems than it solved. I'm ok with that, since that gives me some time to enjoy the car in close-to-stock form. Make me appreciate the gains that much more when I finally go through with it.

no problem, you can ball park the future mod list by researching how EJ engines respond to mods, which will give you a better outlook of the FB engines too, but over all its the same shit everywhere else. i don't think you need much additional learning.

Where we average tuners will start to have issues with this particular car is ECU-fuel-timing. Because there just isnt any real solutions as of yet. We can't just add larger injectors and a piggy back..because there are no such thing as larger Direct injectors. or a piggy back that is programed for direct injection. Or an ECU that we can just tell to stop active learning and fucking up our timing maps

[Abflug]

Originally Posted by WingsofWar

no problem, you can ball park the future mod list by researching how EJ engines respond to mods, which will give you a better outlook of the FB engines too, but over all its the same shit everywhere else. i don't think you need much additional learning.

Where we average tuners will start to have issues with this particular car is ECU-fuel-timing. Because there just isnt any real solutions as of yet. We can't just add larger injectors and a piggy back..because there are no such thing as larger Direct injectors. or a piggy back that is programed for direct injection. Or an ECU that we can just tell to stop active learning and fucking up out timing maps

your´re right but there is almost no oppertunity to do that in D!

[WingsofWar]

Originally Posted by TomGT

mhhh... ITB´s on a 4AG(E)! I like!

me too

[u2b]oRjvqtdo-FI[/u2b]

ITBs on a flat 4...pretty good too

[u2b]42rN2BYDXSc[/u2b]

[4agze]

stick this just like this ricer you'll get 20 to 30bhp

[Dimman]

Maxim, it's going to be pretty hard to give decent advice, until we get solid info on what motor will be used.

If this is a 'tuned' FB20 with the stock 84mm bore and 90mm stroke, I don't have a lot of faith that we will be able to get much more than 200 hp out of it. At least without a lot of $$$. Reason being, it will need to rev to make more power. But the forces on the rods go WAY up with long stroke motors when the revs climb.

So I'm STILL waiting for complete official engine specs...

[WingsofWar]

Originally Posted by Dimman

Maxim, it's going to be pretty hard to give decent advice, until we get solid info on what motor will be used.

If this is a 'tuned' FB20 with the stock 84mm bore and 90mm stroke, I don't have a lot of faith that we will be able to get much more than 200 hp out of it. At least without a lot of $$$. Reason being, it will need to rev to make more power. But the forces on the rods go WAY up with long stroke motors when the revs climb.

So I'm STILL waiting for complete official engine specs...

..why wouldnt it? FB20 is slighty undersquared engine yes ....but so is the B18c5 Type-R engine with an 81 bore and 87.2 stroke which has a redline at 8400rpms. and makes 200hp from the factory. Which also responds to mods very well.

What we are worried about is friction and stress in a performance oriented undersquared engine, but can be remedied by high compression and low friction pistons and appropriate crank throw.

Even Mugen has favored an undersquared high reving engine with a modified K20 at 87 stroke x 90.7 bore redlining at 8500rpms with fuel cut at 10,000 rpms making 260hp and 180ftlbs. Versus the factory K20 with 86 stroke x 86 bore. redlining at 8600rpms

The FB20 has no worries making more than 200hp at any RPM range up to 10,000rpms at a .93 stroke ratio. Meaning we might get a torque band faster, than squared or oversquared variant of the same engine. If Yamaha/Toyota does stroke the engine, its going to be by a few very small points closer to a 1.0 stroke ratio but doubtful for a oversquared engine.

[Dimman]

Originally Posted by WingsofWar

..why wouldnt it? FB20 is slighty undersquared engine yes ....but so is the B18c5 Type-R engine with an 81 bore and 87.2 stroke which has a redline at 8400rpms. and makes 200hp from the factory. Which also responds to mods very well.

What we are worried about is friction and stress in a performance oriented undersquared engine, but can be remedied by high compression and low friction pistons and appropriate crank throw.

Even Mugen has favored an undersquared high reving engine with a modified K20 at 87 stroke x 90.7 bore redlining at 8500rpms with fuel cut at 10,000 rpms making 260hp and 180ftlbs. Versus the factory K20 with 86 stroke x 86 bore. redlining at 8600rpms

The FB20 has no worries making more than 200hp at any RPM range up to 10,000rpms at a .93 stroke ratio. Meaning we might get a torque band faster, than squared or oversquared variant of the same engine. If Yamaha/Toyota does stroke the engine, its going to be by a few very small points closer to a 1.0 stroke ratio but doubtful for a oversquared engine.

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.