Slow revving? Manual car.

[wu_dot_com]

I am in a development program with regards to a flywheel development. Currently the light weight flywheel is installed. All I can say if the light weight flywheel made the engine much more responsive and willing. However the ideling will need to be retune.

[SprayedBigCube]

That's awesome. It'll be great to see parts like that hit the market.

[jedibow]

Originally Posted by SprayedBigCube

I don't know, but to me, my new FR-S seems to rev incredibly slow. Seems like it struggles to get thru 4000 rpm whether unloaded or loaded. Makes me want to do a LS motor swap like...soon...but all fantasy aside, I knew going into this it would be underpowered, but that AND slow to rev is a bit much.

With the electronic throttle in my LS3 Camaro, I can tune several parameters that help throttle response, and that heavy motor revs instantly, almost Honda-like compared to my Scion. Would something like the Cobb access port help the FR-S out?

Okay I was told to help again and forget about my personal problems (thank coyote) What you have to understand is that yes this car makes 200 horse power but it does it by maintaining 150 ft-lbs of torque throughout the rev range. If you are not used to a "Honda" like power band it will feel slow. Yes the flywheel could be lightened, but you would also want to lighten the pulleys at that point in an attempt to balance the crank again. I believe that over time you will appreciate how the engine revs out.

There are three factors to increase the power in an engine, increase the area,(bore or stroke), increase the cylinder pressure (forced induction or compression ratio), or increase the speed at which it runs. In this case the joint venture chose to use RPM and compression. For this reason you will never have a neck snapping low end, or midrange without changing volumetric efficiency in that area, or using forced induction. If you use cams to pick up the low end the top end will suffer, and then you will be back on here complaining about how your car doesn't pull hard to redline.

I will say that by using a solid 3" intake to the throttle body throttle response was improved noticeably.

G

[Symbiont]

I'm absolutely in love with the way my throttle responds to the Injen intake strapped to my engine right now. That being said, there is a bit of a dead area in the pedal when you first start to press it down. Moto reviewed a throttle controller that he liked; may have some effect on what you're feeling:

http://www.ft86club.com/forums/showthread.php?t=6482

[Mitch]

ST legal options, give them to me.

[SprayedBigCube]

Thanks for keeping this on track Don't get me wrong, I may be close to 50 years old and seem like a "domestic" guy, but I did my high school time in Okinawa learning to drive small torqueless Japanese cars of the 70's. I continued that back stateside and until recently always raced 13B RX7's, 4G63 DSM's, and of course, those odd 73 and 74 German Capri's with the 2.0 Pinto engine. In fact because I did so well building powerful 4G63's, a Mustang guy I raced regularly against ended up trading that for a Evo X (and then a year later I ironically got a LS3 Camaro and started modifying that). So I'm no stranger to Japanese imports.

All those engines STILL revved better than this stock FA20...until maybe recently:

Going on the assumption that Toyota employs some timing retard function or low octane table from knock sensor input and assuming the dealer's "free tank of gas" was 87 and not 93, I disconnected the battery early yesterday morning until lunchtime when the wife wanted to take the FRS for a spin. The motor definitely feels a whole lot more responsive, but I'll reserve judgement for a couple hundred miles. Also, it seems like the oil is a 1/2 quart or more high, so until I pull that out, I'm a bit reluctant to rev this much past 6k.

I did order a Perrin crank pulley, but I'm still not so sure how I'm going to sell the wife on the idea of a lightweight flywheel/clutch assembly. I might be able to slip one in when I put a full exhaust on, then just claim preventative maintenance "since the car was in the air"

Originally Posted by jedibow

Okay I was told to help again and forget about my personal problems (thank coyote) What you have to understand is that yes this car makes 200 horse power but it does it by maintaining 150 ft-lbs of torque throughout the rev range. If you are not used to a "Honda" like power band it will feel slow. Yes the flywheel could be lightened, but you would also want to lighten the pulleys at that point in an attempt to balance the crank again. I believe that over time you will appreciate how the engine revs out.

There are three factors to increase the power in an engine, increase the area,(bore or stroke), increase the cylinder pressure (forced induction or compression ratio), or increase the speed at which it runs. In this case the joint venture chose to use RPM and compression. For this reason you will never have a neck snapping low end, or midrange without changing volumetric efficiency in that area, or using forced induction. If you use cams to pick up the low end the top end will suffer, and then you will be back on here complaining about how your car doesn't pull hard to redline.

I will say that by using a solid 3" intake to the throttle body throttle response was improved noticeably.

G

[wu_dot_com]

Originally Posted by SprayedBigCube

That's awesome. It'll be great to see parts like that hit the market.

it will soon. i am timing my review of the prototype parts with their marketing plan.

this gives me more time to feel the product at more operation conditions as well as letting the manufacture to have more time to fine tune their product.

[wu_dot_com]

Originally Posted by SprayedBigCube

Thanks for keeping this on track Don't get me wrong, I may be close to 50 years old and seem like a "domestic" guy, but I did my high school time in Okinawa learning to drive small torqueless Japanese cars of the 70's. I continued that back stateside and until recently always raced 13B RX7's, 4G63 DSM's, and of course, those odd 73 and 74 German Capri's with the 2.0 Pinto engine. In fact because I did so well building powerful 4G63's, a Mustang guy I raced regularly against ended up trading that for a Evo X (and then a year later I ironically got a LS3 Camaro and started modifying that). So I'm no stranger to Japanese imports.

All those engines STILL revved better than this stock FA20...until maybe recently:

Going on the assumption that Toyota employs some timing retard function or low octane table from knock sensor input and assuming the dealer's "free tank of gas" was 87 and not 93, I disconnected the battery early yesterday morning until lunchtime when the wife wanted to take the FRS for a spin. The motor definitely feels a whole lot more responsive, but I'll reserve judgement for a couple hundred miles. Also, it seems like the oil is a 1/2 quart or more high, so until I pull that out, I'm a bit reluctant to rev this much past 6k.

I did order a Perrin crank pulley, but I'm still not so sure how I'm going to sell the wife on the idea of a lightweight flywheel/clutch assembly. I might be able to slip one in when I put a full exhaust on, then just claim preventative maintenance "since the car was in the air"

keep in mind that the ECU will also need to be retune if the flywheel is changed.

if you want a dramatic engine repsonse improvement, you will need a really light flywheel. however, the ECU will need to be retune becuase ideling will be effected.

[jedibow]

Originally Posted by SprayedBigCube

Thanks for keeping this on track Don't get me wrong, I may be close to 50 years old and seem like a "domestic" guy, but I did my high school time in Okinawa learning to drive small torqueless Japanese cars of the 70's. I continued that back stateside and until recently always raced 13B RX7's, 4G63 DSM's, and of course, those odd 73 and 74 German Capri's with the 2.0 Pinto engine. In fact because I did so well building powerful 4G63's, a Mustang guy I raced regularly against ended up trading that for a Evo X (and then a year later I ironically got a LS3 Camaro and started modifying that). So I'm no stranger to Japanese imports.

All those engines STILL revved better than this stock FA20...until maybe recently:

Going on the assumption that Toyota employs some timing retard function or low octane table from knock sensor input and assuming the dealer's "free tank of gas" was 87 and not 93, I disconnected the battery early yesterday morning until lunchtime when the wife wanted to take the FRS for a spin. The motor definitely feels a whole lot more responsive, but I'll reserve judgement for a couple hundred miles. Also, it seems like the oil is a 1/2 quart or more high, so until I pull that out, I'm a bit reluctant to rev this much past 6k.

I did order a Perrin crank pulley, but I'm still not so sure how I'm going to sell the wife on the idea of a lightweight flywheel/clutch assembly. I might be able to slip one in when I put a full exhaust on, then just claim preventative maintenance "since the car was in the air"

Okay, so it is okay to run crank pulleys by themselves, so that wasn't clear in my original post, however there will inevitably be additional vibration transmitted to the crank, how much you would have to ask Perrin. It is ALWAYS in your best interest to balance the crank from vibrations as it could lead to main bearing wear, I suggested the flywheel, however that may or may not correct the issue, as the weight may still be off (does that make sense?). Anyways, wait until you have atleast 1k on the engine as my engine feels completely different know, than it did when I bought it.

[jedibow]

Originally Posted by wu_dot_com

keep in mind that the ECU will also need to be retune if the flywheel is changed.

if you want a dramatic engine repsonse improvement, you will need a really light flywheel. however, the ECU will need to be retune becuase ideling will be effected.

Please explain this to me???? As most of the look up tables reference load and RPM, how is the engine going to determine that the RPM is changing now at x delta, instead of y delta? If RPM is constant than the ECU will trace faster along the X axis (RPM) it cannot change the lookup of the X axis...

G

Sorry if this came across wrong another one of those days....

[SprayedBigCube]

AFAIK, the FA20 is internally balanced. While dynamic balance can be affected, I've never had a problem with bearing wear on any of my internally balanced rotating assemblies in other cars. If it were an externally balanced engine, sure, I'd hold up the BS flag. Also, Perrin did inform me that the pulley is good to go as is, no other modifications like lightened flywheel/clutch are required.

Originally Posted by jedibow

Okay, so it is okay to run crank pulleys by themselves, so that wasn't clear in my original post, however there will inevitably be additional vibration transmitted to the crank, how much you would have to ask Perrin. It is ALWAYS in your best interest to balance the crank from vibrations as it could lead to main bearing wear, I suggested the flywheel, however that may or may not correct the issue, as the weight may still be off (does that make sense?). Anyways, wait until you have atleast 1k on the engine as my engine feels completely different know, than it did when I bought it.

[jedibow]

Originally Posted by SprayedBigCube

AFAIK, the FA20 is internally balanced. While dynamic balance can be affected, I've never had a problem with bearing wear on any of my internally balanced rotating assemblies in other cars. If it were an externally balanced engine, sure, I'd hold up the BS flag. Also, Perrin did inform me that the pulley is good to go as is, no other modifications like lightened flywheel/clutch are required.

Good to know, useful info thanks.

[wu_dot_com]

Originally Posted by jedibow

Please explain this to me???? As most of the look up tables reference load and RPM, how is the engine going to determine that the RPM is changing now at x delta, instead of y delta? If RPM is constant than the ECU will trace faster along the X axis (RPM) it cannot change the lookup of the X axis...

G

Sorry if this came across wrong another one of those days....

here is what i think its happening.

the ECU control the engine performance by adjusting the fuel input and monitor the output shaft RPM. for reach RPM range change, the time duration from one state to another is also tracked. from my understanding, the ECU does not track the actual load output. the data for the fuel map are generated empirically from the running the engine at different throttle condition with OEM components.

now a lighter flywheel will give a higher angular acceleration. which means for the same input, the output shaft RPM will be higher with a lighter flywheel.

now i will try to describe what ive experience with the light weight flywheel. i will use some fabricated numbers to help the understanding since i cant graph it for you.

so lets just say for this car, the idle RPM is at 800 with throttle setting of 8. if we want to increase the RPM to 1K, the throttle setting will be 10, if we want to reduce the RPM to 500, the throttle setting will be 5. in a car, the data in this fuel map are all empirically gather based on OEM hardware. if you want a graph, the X axis will be your RPM, and your Y axis will be your throttle. you can drawing a expediential line and call it your OEM baseline. now with a light flywheel, when your throttle setting is at 8, your actual flywheel RPM will be at 1k because you lessen the rotational mass and inertia. on the same graph, you now will draw a second expediential line from 0, 0 but the line will be to the left of the original OEM baseline. this new line will be your delta, however, this line is unknown to the ECU.

now to achieve idle, your ECU is going to give a throttle command of 8, while expecting to get a feedback of 800 RPM. however, the output shaft output shows an RPM of 1K. so the ECU feedback loop now think your actual throttle response is actually at 10, and it compensated by reduce it down to 5 to quickly bring the RPM back down to 800. since the lightweight flywheel dissipate the store energy much faster, at throttle input of 5, the actual RPM is 400 RPM. at that moment, the ECU will recognizes the engine is now too slow, and increase the throttle back to 10 in an attempt to bring up the rpm quickly.

this is what i've experience so far with my prototype flywheel. i hope my attempted at discribing what happened makes sense.

[uspspro]

Originally Posted by wu_dot_com

here is what i think its happening.

the ECU control the engine performance by adjusting the fuel input and monitor the output shaft RPM. for reach RPM range change, the time duration from one state to another is also tracked. from my understanding, the ECU does not track the actual load output. the data for the fuel map are generated empirically from the running the engine at different throttle condition with OEM components.

now a lighter flywheel will give a higher angular acceleration. which means for the same input, the output shaft RPM will be higher with a lighter flywheel.

now i will try to describe what ive experience with the light weight flywheel. i will use some fabricated numbers to help the understanding since i cant graph it for you.

so lets just say for this car, the idle RPM is at 800 with throttle setting of 8. if we want to increase the RPM to 1K, the throttle setting will be 10, if we want to reduce the RPM to 500, the throttle setting will be 5. in a car, the data in this fuel map are all empirically gather based on OEM hardware. if you want a graph, the X axis will be your RPM, and your Y axis will be your throttle. you can drawing a expediential line and call it your OEM baseline. now with a light flywheel, when your throttle setting is at 8, your actual flywheel RPM will be at 1k because you lessen the rotational mass and inertia. on the same graph, you now will draw a second expediential line from 0, 0 but the line will be to the left of the original OEM baseline. this new line will be your delta, however, this line is unknown to the ECU.

now to achieve idle, your ECU is going to give a throttle command of 8, while expecting to get a feedback of 800 RPM. however, the output shaft output shows an RPM of 1K. so the ECU feedback loop now think your actual throttle response is actually at 10, and it compensated by reduce it down to 5 to quickly bring the RPM back down to 800. since the lightweight flywheel dissipate the store energy much faster, at throttle input of 5, the actual RPM is 400 RPM. at that moment, the ECU will recognizes the engine is now too slow, and increase the throttle back to 10 in an attempt to bring up the rpm quickly.

this is what i've experience so far with my prototype flywheel. i hope my attempted at discribing what happened makes sense.

So are you getting a surging, or lightly oscillating idle?