dohc. ONE pully Options

[freakyre33c]

the 5sfe have dohc but one cam is driven by the belt, and that cam drives the other cam, why is it set up like this , why not just two pullys ? what are advantages and disadvantages?

[pure_dx]

toyota's fe heads, notice on the ge heads, its true twin cams

fe=economy
ge-performance

This post has been edited by pure_dx: Aug 15, 2006 - 1:38 PM

[x_itchy_b_x]

its called a slave cam. you can adjust them together but not seperate since its gear driven limiting its tunabilty.
fe head ftl ge ftw

advantages: easier to set timing since u have less independent moving parts.
disadvantages: as for making more power, slave cam setups arent as good for tuning.

This post has been edited by x_itchy_b_x: Aug 15, 2006 - 1:44 PM

[alltracman78]

It is because of the valve angles.
The FE and GE valves have different angles in relation to the "deck" of the head.
Because Toyota didn't use rockers in these engines the cams have to be over the valves.
And because the FE heads have a higher angle, they are close together up top.
Leaving less room between the camshafts.
So 2 cam gears wouldn't fit.

[Kwanza26]

advantage = 16V performance without rocker assemblies, increased fuel economy over true dual cams, quiet.
disadvantage = narrow design hurts n/a performance, no tuneability

[alltracman78]

advantage = 16V performance without rocker assemblies, increased fuel economy over true dual cams, quiet.
disadvantage = narrow design hurts n/a performance, no tuneability

?
It doesn't hurt NA performance.
It hurts high rpm power.
NA or FI.
The higher angle creates better swirl in the combustion chamber, but it also hinders flow at high rpms.

[Kwanza26]

It doesn't hurt NA performance.
It hurts high rpm power.
NA or FI.
The higher angle creates better swirl in the combustion chamber, but it also hinders flow at high rpms.

How do you make more n/a power with limited displacement? Revs...

[alltracman78]

It depends what you are trying to do......................................................
The 5SFE wasn't designed for high rpms.
It was designed for low rpm power. In which that particular setup works quite well..................
The narrow design hurts high rpm performance, weather it's NA or FI.
Look at Mannys 5SFTE. Wonder why he's making more torque? At lower rpms?.

[Kwanza26]

It depends what you are trying to do......................................................
The 5SFE wasn't designed for high rpms.
It was designed for low rpm power. In which that particular setup works quite well..................
The narrow design hurts high rpm performance, weather it's NA or FI.
Look at Mannys 5SFTE. Wonder why he's making more torque? At lower rpms?.

I don't think you understand what I'm saying. There's no way to make additional n/a power (not talking about making stockish power here) in a 4 cylinder without revving the engine... PERIOD... regardless of the head. Case in point... how many 1.6 to 2.0 liter 4 bangers do you see making 200hp n/a with a 6200 rpm redline? None.

In the case of the 5SFE... it can't rev because the head doesn't breathe well at higher rpms (makes it redundant to rev) nor does the stroke ratio like being revved (stress peaks = torque loss)... true enough... but forced induction changes the game. The power potential isn't so much limited by the head with forced induction, as it is limited by how much you boost (the set-up). The only thing the FE head affects strongly, is where that power is located... but the more torque you have, the less you have to worry about "where" power comes it the strongest. To further elaborate this point... think gearing.

FE head = bad n/a platform... great F/I Platform... excellent daily driver
GE head = great n/a platform... great F/I platform... ehh daily driver (TVIS/ACIS for the daily driver)

[Bigmeanbulldog55]

I know it's been argued, but I need to just put in my plug on the NA 5sfe. It is what I have, and it is great for track use. I might not say that if I had more experiance in high rev cars, but I like it. Lots of torque, and quick pick up. I need better suspension though for my solo2 runs.

[alltracman78]

It depends what you are trying to do......................................................
The 5SFE wasn't designed for high rpms.
It was designed for low rpm power. In which that particular setup works quite well..................
The narrow design hurts high rpm performance, weather it's NA or FI.
Look at Mannys 5SFTE. Wonder why he's making more torque? At lower rpms?.

I don't think you understand what I'm saying. There's no way to make additional n/a power (not talking about making stockish power here) in a 4 cylinder without revving the engine... PERIOD... regardless of the head. Case in point... how many 1.6 to 2.0 liter 4 bangers do you see making 200hp n/a with a 6200 rpm redline? None.

In the case of the 5SFE... it can't rev because the head doesn't breathe well at higher rpms (makes it redundant to rev) nor does the stroke ratio like being revved (stress peaks = torque loss)... true enough... but forced induction changes the game. The power potential isn't so much limited by the head with forced induction, as it is limited by how much you boost (the set-up). The only thing the FE head affects strongly, is where that power is located... but the more torque you have, the less you have to worry about "where" power comes it the strongest. To further elaborate this point... think gearing.

FE head = bad n/a platform... great F/I Platform... excellent daily driver
GE head = great n/a platform... great F/I platform... ehh daily driver (TVIS/ACIS for the daily driver)

I understand EXACTLY what you are saying.
My point is, it's not just NA. If you throw a turbo on there, you have the EXACT same problem. It won't make the same hp as a G head, all mods being relative. It will make more torque.
You can bump the torque a bit, granted not as much as you can raise the hp with higher rpms.
But the point of the F head is to make power at low rpms. FI or not.

I agree it's not a good NA platform, but the same power blocks are there if you go FI [relative of course].

[Kwanza26]

I understand EXACTLY what you are saying.
My point is, it's not just NA. If you throw a turbo on there, you have the EXACT same problem. It won't make the same hp as a G head, all mods being relative. It will make more torque.
You can bump the torque a bit, granted not as much as you can raise the hp with higher rpms.
But the point of the F head is to make power at low rpms. FI or not.

I agree it's not a good NA platform, but the same power blocks are there if you go FI [relative of course].

Then why are we even discussing? =P

I still do say the FE head is as good as the GE head in boosted form because the amount of horsepower you shoot for is only limited by the amount of boost. The torque is ALWAYS there with boost, so picking between FE and GE is simply a matter of where in the powerband you'd prefer to race in. Take for example paradiseracing.com's AE86... powered by a turbo'ed 2RZFE. It's very possible to tune for horsepower. Another good example that comes to mind is the Scion tC's 2AZFE. In stock trim... makes 160 horses 160 ftlbs of torque. With the TRD supercharger, makes more horsepower than torque (trd estimates around 200hp and 180 ftlbs of torque... scion guys dyno around 180-190whp with 160-70 some odd torque at the wheels)! It's more so a matter of the turbo and tune.

then again... this is the n/a forum and n/a tuning is pretty much out of the question for the FE head.

This post has been edited by Kwanza26: Aug 20, 2006 - 12:04 AM

[alltracman78]

Then why are we even discussing? =P

I still do say the FE head is as good as the GE head in boosted form because the amount of horsepower you shoot for is only limited by the amount of boost. The torque is ALWAYS there with boost, so picking between FE and GE is simply a matter of where in the powerband you'd prefer to race in. Take for example paradiseracing.com's AE86... powered by a turbo'ed 2RZFE. It's very possible to tune for horsepower. Another good example that comes to mind is the Scion tC's 2AZFE. In stock trim... makes 160 horses 160 ftlbs of torque. With the TRD supercharger, makes more horsepower than torque (trd estimates around 200hp and 180 ftlbs of torque... scion guys dyno around 180-190whp with 160-70 some odd torque at the wheels)! It's more so a matter of the turbo and tune.

then again... this is the n/a forum and n/a tuning is pretty much out of the question for the FE head.

We are discussing because you don't seem to understand what you are saying.

And FE head is not as good as a GE head for HIGH RPM power. FI or not. Of course you can make alot of power with FI on a FE head. But it WILL NOT be as much as a GE head at high rpms, all mods being equal. PERIOD.

A FE head takes the power and moves it south.
FI or NA. You can play with it quite a bit more with FI, but it's still there.

You CAN make decent power with a FE head, even in NA.
It is all in where you want the power to be.
If you are looking for max hp, or high rpm power, a FE head wont' do you as well as a GE head.
BUT, if you are looking for a larger area under the curve, or power at low rpms, a FE head CAN BE UTILIZED .

Compare the 22RE [technically not a FE head, but it is designed for low rpm power, just like the FE heads] and the 3TGE.
When they raced Celicas in the early 80s with these 2 engines, the 22RE powered cars were FASTER than the 3TGE ones. Because they had more torque and useable power. They weren't tuned for power in a [relatively] small band up top. They had MUCH more useable power.
A PERFECT example of how a NA FE makes more [useable] power than a NA GE.
AT LOWER RPMS.

[Kwanza26]

We are discussing because you don't seem to understand what you are saying.

And FE head is not as good as a GE head for HIGH RPM power. FI or not. Of course you can make alot of power with FI on a FE head. But it WILL NOT be as much as a GE head at high rpms, all mods being equal. PERIOD.

Who's to say the FE head bad for FI? Or at the very least not as good as the GE? There are many many cases of the FE head able to produce and maintain power comparable to GE heads in the high rpms. Under forced induction, the FE head is no longer limited by high-rpm breathing... because the breathing is done by the turbo/supercharger. Unfortunately, there just aren't too many people who have purpose built FE heads... but it's there. The head does have inherit disadvantages from the get go... but like I keep saying, under boost with the right set-up... horsepower can be pushed deeper into the rpms.

Check out this dyno of a stock scion tc versus a supercharged scion tc...

Stock n/a form (blue) makes more torque than horsepower. Supercharged form (red) makes more horsepower than torque... and when you look at the s/c torque curve, this thing can easily maintain that torque/horsepower towards 6.5-7K rpms before it significanly declines (considering how jumpy the curve is... could use some tuning also), while the n/a torque curve starts to decline by 4.5k rpms.

A FE head takes the power and moves it south.
FI or NA. You can play with it quite a bit more with FI, but it's still there.

True for n/a... not quite true for FI because the reason it pushes power south is because it reaches its peak velocity very quickly. This is not a factor when fully tuned and boosted because the breathing and velocity is not done solely by the head.

You CAN make decent power with a FE head, even in NA.
It is all in where you want the power to be.

On this point... no. n/a horsepower with small displacement = REVS. You can open up the engine a little bit with extreme mods, but performance gains are negliable. Take Jim Snodgrass as the prime example... the best breathing mods you can do to the engine and power still fails by 4500 rpms. He made what... 145-150 whp? Bang for the buck? Not worth it. That's like 20-30hp over stock for his thousands spent in modifications.

If you are looking for max hp, or high rpm power, a FE head wont' do you as well as a GE head.
BUT, if you are looking for a larger area under the curve, or power at low rpms, a FE head CAN BE UTILIZED .

This is only relative to a person's taste about the engine's feel. No true n/a performance 4 banger is all about making low-end torque unfortunately. I have nothing against the FE head... bu it's simply not designed with performance in mind. When we speak of performance... we speak of horsepower. Don't even think about mentioning torque curves unless you got a load of it.

Compare the 22RE [technically not a FE head, but it is designed for low rpm power, just like the FE heads] and the 3TGE.

The 22R head had rather huge valves with rockers, allowing it to SPIN... and was built like a tank. It made more power because the strength of the design allowed the engine to maintain revs... and yes... those suckers revved. The 3T's were simply a smaller motors and thier G heads weren't really any good, likewise the 18RG was not that great either. The first good G head was on the 4AG.

When they raced Celicas in the early 80s with these 2 engines, the 22RE powered cars were FASTER than the 3TGE ones. Because they had more torque and useable power. They weren't tuned for power in a [relatively] small band up top. They had MUCH more useable power.
A PERFECT example of how a NA FE makes more [useable] power than a NA GE.
AT LOWER RPMS.

Here's the rundown on typical track guys from the days I used to race (late 90's early 2000's). High-end horsepower is better for track racing, where you slam through the gears and can keep the rpms high. This is mostly club racing or formula racing or something along those lines. Fatter torque bands with more useable torque is better for short tracks, or where you maintain gears longer. Think autoX or rally.... however even in rally they mate big torque with short gearing most of the time to keeps revs up. High torque handles the different traction situations better than big horsepower. Each to his own. What works for what is a matter of the track and conditions.

In the end... it's purely a matter of prefrence... and NO... I still say building an n/a motor out of an FE 4 cylinder is still a waste of time. The only thing we don't agree on is the FE head's capability to make top-end horsepower... but refer back to that 2AZ dyno and re-think it a bit...

This post has been edited by Kwanza26: Aug 24, 2006 - 11:05 PM

[alltracman78]

Who's to say the FE head bad for FI? Or at the very least not as good as the GE? There are many many cases of the FE head able to produce and maintain power comparable to GE heads in the high rpms. Under forced induction, the FE head is no longer limited by high-rpm breathing... because the breathing is done by the turbo/supercharger. Unfortunately, there just aren't too many people who have purpose built FE heads...
but it's there. The head does have inherit disadvantages from the get go... but like I keep saying, under boost with the right set-up... horsepower can be pushed deeper into the rpms.

I never said it was bad for FI.
I said it wasn't as good as the GE in HIGH RPMS. You can still get PLENTY of power from a FE head through FI. However, you WILL NOT get the same as from a GE, mods being equal AT HIGH RPMS.

True for n/a... not quite true for FI because the reason it pushes power south is because it reaches its peak velocity very quickly. This is not a factor when fully tuned and boosted because the breathing and velocity is not done solely by the head.

I highlighted the two key words there.
No matter how much boost, how well tuned, ect, a turbo cannot change the inherant design of the head.
It also cannot change 100% the breathing charateristics of the FE head. The head still has to flow the air the turbo pushes. And a FE head CANNOT flow as much as a GE head at high rpms. The design of the head doesn't allow it. FI or not.

n/a horsepower with small displacement = REVS. You can open up the engine a little bit with extreme mods, but performance gains are negliable. Take Jim Snodgrass as the prime example... the best breathing mods you can do to the engine and power still fails by 4500 rpms. He made what... 145-150 whp? Bang for the buck? Not worth it. That's like 20-30hp over stock for his thousands spent in modifications.

It's more like 40 hp increase. I dont' know how much he spent, or what he did. To me, it's not worth building a NA 4 cyl period. FI is the way to go for smaller engines. We'll come back to this in a minute.

This is only relative to a person's taste about the engine's feel. No true n/a performance 4 banger is all about making low-end torque unfortunately. I have nothing against the FE head... bu it's simply not designed with performance in mind. When we speak of performance... we speak of horsepower. Don't even think about mentioning torque curves unless you got a load of it.

If you read what I said, RELATIVELY SPEAKING. I never said OR insinuated you would get monster loads of torque from a NA FE.
You are NOT going to beat a stock 302 Mustang with a FE built for torque, whereas you can with a GE built for hp. However, compared to other 4 cyls, it IS powerful at low rpms.
Compared to a Celica with a built GE, you can accelerate easier AT LOW RPMS, and do not need to rev the heck out of your engine to accelerate fast.

I also never stated it was designed for performance. It is designed for low rpm power, where it is better than a GE.

The 22R head had rather huge valves with rockers, allowing it to SPIN... and was built like a tank. It made more power because the strength of the design allowed the engine to maintain revs... and yes... those suckers revved. The 3T's were simply a smaller motors and thier G heads weren't really any good, likewise the 18RG was not that great either. The first good G head was on the 4AG.

It had large valves because it was only 2V cylinder. The FE is 4V cylinder. 2 small = 1 big....[For the record,I don't know much exactly the 2 flow off the top of my head. I used it as a illustration].
Yes it is a tank. I know. I have a [semi] built one in my truck.

Going back to Jim Snodgrass, did he use the stock manifold for either side?
Was his engine stroked/bored?
The 22Rs that rev ARE NOT the same rod:stroke as stock. They are HEAVILY built engines.
Do you think they just had "breathing mods" done?
Or that they were cheap to build?
It takes more than just a couple thousand to build a 22R/E for that.
A LC Engineering short block ALONE is several thousand.....
A stage 5 long block is over 5k.....
Then there's both manifolds, stand alone/carb, ect, ect, ect.

A 22R/E is the same way as far as mods. If you just do bolt ons and a head job [even with cam/valves] it doesn't add all that much....

Here's the rundown on typical track guys from the days I used to race (late 90's early 2000's). High-end horsepower is better for track racing, where you slam through the gears and can keep the rpms high. This is mostly club racing or formula racing or something along those lines. Fatter torque bands with more useable torque is better for short tracks, or where you maintain gears longer. Think autoX or rally.... however even in rally they mate big torque with short gearing most of the time to keeps revs up. High torque handles the different traction situations better than big horsepower. Each to his own. What works for what is a matter of the track and conditions.

Highlighted again.
For certain races, a fatt[er] torque curve is preferred. For others, high rpm power is preferred.
NA or FI.

In the end... it's purely a matter of prefrence... and NO... I still say building an n/a motor out of an FE 4 cylinder is still a waste of time. The only thing we don't agree on is the FE head's capability to make top-end horsepower... but refer back to that 2AZ dyno and re-think it a bit...

It doesn't hurt NA performance.
It hurts high rpm power.

I never said it couldn't make high rpm power, I said the design HURTS high rpm power. Which it does.