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Absolute value in the Maf mod, the ZeroExhaust header is now cheaper also. PPE exhaust system may also be a good one.
 

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I'm not a racer, but I want some more horsepower without spending too much. Suggestions ?
Cheapest and easiest is put a 3" pipe onto the air box and route it into the wheel arch. Remove the silencer intake tube behind the wheel arch liner. You can buy a 3" bellmouth from Ram Air with a pipe quite cheaply.

On two basically stock cars we picked up 4 and 5 wheel bhp with this mod. 117 to 122 and 118 to 123.

Monkeywrench reckon 3-4 for a K&N element, I personally saw 2 wbhp. Could be temps or margin of error.

Rather than a noticeable speed gain these mods seem to make the car more tractable lower down.

The MAF mod as posted would be your next port of call and the third cheapest after these. (Apart from gutting pre cats which is just hassle and gasket cost which gives a few bhp (probably).

Everything else is quite expensive, relatively.

Losing weight to car is free (sort of).
 

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Cheapest and easiest is put a 3" pipe onto the air box and route it into the wheel arch. Remove the silencer intake tube behind the wheel arch liner. You can buy a 3" bellmouth from Ram Air with a pipe quite cheaply.

On two basically stock cars we picked up 4 and 5 wheel bhp with this mod. 117 to 122 and 118 to 123.

Monkeywrench reckon 3-4 for a K&N element, I personally saw 2 wbhp. Could be temps or margin of error.

Rather than a noticeable speed gain these mods seem to make the car more tractable lower down.

The MAF mod as posted would be your next port of call and the third cheapest after these. (Apart from gutting pre cats which is just hassle and gasket cost which gives a few bhp (probably).

Everything else is quite expensive, relatively.

Losing weight to car is free (sort of).
Yes... weight reduction feels just like power increase. This will be based on the % weight reduction of the entire car.

Dave
 

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Yes... weight reduction feels just like power increase. This will be based on the % weight reduction of the entire car.

Dave
Sorry, I have to disagree. Weight reduction feels more like a torque increase, similar to deeper gears. Having more horsepower is pretty hard to substitute on a production car with a fixed drag coefficient and friction losses.

However, I do agree that dumping weight is pretty easy to a point and will improve overall performance. Getting rid of the spare tire, entire a/c system, and passenger seat would probably be noticeable at the track.

The first thing I did on my 1zz was catalytic converter delete, install a straight intake from the side scoop, and convert to a standalone. It was certainly more fun after that. Is that the same thing as HP?
 

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... Having more horsepower is pretty hard to substitute on a production car with a fixed drag coefficient and friction losses...
That is true if you spend much time over 80mph. However, over the range of speeds where most people are interested in acceleration, then the ratio of power to mass pretty much tells the story. That is because the drag power goes as the cube of the vehicle speed. At moderate speeds, it has little effect on perceived performance. As you get into extreme speeds, drag power moves up quickly and limits top speed.
 

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The other advantage of removing weight is you could do it strategically and make the car less rear biased. Batteries and exhaust pipes would cost money but you get a double effect. The ZZW30 does not have such a rear bias as other small mid engined cars like the Elise and VX220 (Opel Speedster). They made the wheelbase 15cms longer than the Elise S1 and ended up with a more even weight distribution. An S1 Elise is ultimately a much lighter car with a more sophisticated construction but it's relatively short wheelbase is a minor drawback.

This can be capitalised on. But at a price.
 

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Great commentary on the less weight increasing the effective power/ weight calculation.

Ive wondered a few things and this seems to be a group of people who can answer my question (Sorry for the tangent OP)

#1 What is the FR/RR weight bias of the MR2? Im hoping its around 45/55 but havent found anything on it (limited searching, I will admit)

#2 Do people relocate batteries up front to shift the balance, or is it felt that the added weight of the long battery cable negates the shift?
 

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It is more like 43 than 45. Maybe depends on if you have AC. The LHD models are also not as balanced with a driver as RHD, it says this in one of the books about the cars but it probably isn't much.

The battery is a three stage thing. A. Get a lighter battery and leave it where it is. B. Move it lower down (maybe pointless doing with this with a big heavy battery) to the crossmember . C. Move it to the front and add the weight of a cable (which isn't going to be loads but will be something).

If the car is 43/57 and it weighs 970kg in basic Euro trim PFL with no AC and you save 15kg on exhaust and battery mods you may get about 45/55 or approx as obviously weight is on all four wheels and not just the ones near the weight you remove.

Personally I went from a stock Panasonic battery to a lighter Hankook one to a smallish lead acid Yuasa which weighs 16lbs Vs the 28 of stock, plus lighter exhaust.

My exhaust is about 8kg for the tailpipe section Vs about 13kg for stock.
 

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Sorry, I have to disagree. Weight reduction feels more like a torque increase, similar to deeper gears. Having more horsepower is pretty hard to substitute on a production car with a fixed drag coefficient and friction losses.

However, I do agree that dumping weight is pretty easy to a point and will improve overall performance. Getting rid of the spare tire, entire a/c system, and passenger seat would probably be noticeable at the track.

The first thing I did on my 1zz was catalytic converter delete, install a straight intake from the side scoop, and convert to a standalone. It was certainly more fun after that. Is that the same thing as HP?
And I have to disagree that weight reduction feels more like a toque increase. Now many might feel that we are just getting into semantics here, but there is a clear relationship between Power/weight ratio and vehicle performance, but Torque (at the engine) to weight ratio just does not correlate nearly as well. The reason can be found by understanding the equation of motion of a vehicle: Acceleration is proportional to [power at the wheels] / [(vehicle speed) x (vehicle mass)] from: Power or Torque? – Roth Automotive Science

This is just physics and is derived from F=MA. The reason why engine torque is not as useful is that gearboxes multiply torque but not power, and you can make up for a lack of engine torque with gearing, but you can not make up for a lack of power with gearing. Please read the referenced article before continuing this thread.

Dave
 

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The fact that peak torque can be achieved at 0 rpm demonstrates that it is of little use on determining the performance or potential performance of a vehicle without knowing a host of other variables.

Possibly the most misleading thing bandied about . A VW TDi golf of a few years back produced exactly 100lbs more flywheel torque than the Corolla T-Sport with a 2ZZ. It was established that although the Golf made a lot more torque at the flywheel its MEAN wheel torque output was lower than the Corolla.
 

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The fact that peak torque can be achieved at 0 rpm...

... MEAN wheel torque output was lower than the Corolla.
Not sure what you are talking about here. This is true for an electric motor, but not for internal combustion. At 0 rpm, an ICE is stalled.

Don't know what Mean wheel torque is, either.

Power is the parameter that is derived from conserved quantities. Energy is conserved, and power is the rate of energy delivery. As long as you have gearing that can keep you near the power peak, then torque is irrelevant. Lower gearing will give you a better launch, because an ICE dies at low rpm, and you have this gap to fill in from zero up until your engine gets into its power band. When someone mentions a high torque engine, this really means a high ratio of peak torque to peak power. That indicates a blunt tune with a wide power band, and that also helps to fill in the gap at zero speed. So, a high torque engine or low gearing really does give you a faster launch, but once you are past first gear, it is only peak power and your ability to stay at it that matters.
 

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And I have to disagree that weight reduction feels more like a toque increase. Now many might feel that we are just getting into semantics here, but there is a clear relationship between Power/weight ratio and vehicle performance, but Torque (at the engine) to weight ratio just does not correlate nearly as well. The reason can be found by understanding the equation of motion of a vehicle: Acceleration is proportional to [power at the wheels] / [(vehicle speed) x (vehicle mass)] from: Power or Torque? – Roth Automotive Science
...
This is absolutely true and it's good that I was corrected because that is pretty basic and important stuff. I chose my phrasing not to mislead from science but to describe how I feel on the subject of mild weight reduction vs power increase. I probably shouldn't have said anything but now we are here.

Drag and friction increases exponentially as speed increases therefore the power to weight ratio changes with the speed because the weight remains the same as the power on tap decreases. This doesn't all of a sudden happen at some speed, it happens as soon as the car gets into motion and increases from there.

Lets say a car at 10mph has zero losses, 200hp / 2000lbs. the option is add 10hp or take 100lbs. They are the same percentage, pick one.

Lets say a car at 50mph uses 20hp to overcome losses, now 180hp / 2000lbs but you still have 10hp or 100lbs. They are no longer the same percentage, but pick one.

Lets say a car at 100mph uses 80hp to overcome losses, now 120hp / 2000lbs but you still have 10hp or 100lbs. At this point it seems clear that 10hp is an ~8% increase where 100lbs is still just 5%, pick one.

I'm sure we could debate till the end of time on friction coefficients and loss percentages but the fact of the matter is they are there and they have some impact. If they can be felt or not at certain levels is a matter of opinion I guess. Bottom line for a few HPs, drop the Lbs and do a few bolt-ons. That's pretty much all there is at an entry level. I wouldn't be able to notice that but you might. I noticed a turbo though.
 

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If you have no smog check to worry about, I imagine an Ebay short intake and headers would give "a few horsepower". Better headers will get you a little more, for more money. Crude and cheap ways of tampering with the ECU like a piggyback can get you a bit more. After that you gotta pull things apart and spend.

The nice thing about weight reduction is that since the car is so light to begin with, each pound counts for more. Cheapest is the battery, if you downsize to a 10 or 14Ah it'll cost next to nothing for -15lbs. Next cheapest is catback (find a Magnaflow Turbo, have it welded in at a shop, should be around 200-300ish for -15lbs), and then fixed bucket seats bolted to the floor (non-FIA seats for ~400 for a pair, around -20lbs total). Then I guess you have wheels, which are like 1.5x effective reduction, you can lose around 15lbs on all 4 corners (like dropping 23 from the body) for like 600 with cheap flow formed wheels. After that it gets expensive.
 

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Not sure what you are talking about here. This is true for an electric motor, but not for internal combustion. At 0 rpm, an ICE is stalled.

Don't know what Mean wheel torque is, either.
Sit in say a diesel engine and rev the engine to the peak torque figure supplied by manufacturer. How fast do the wheels turn ? 0 rpm.


Mean is simply a method of describing the average of the sample. In basic terms in the example I gave if both cars accelerated as fast as they could from say standstill to 120mph the Corolla would be outputting more total torque to the ground over the distance than the Golf would be, despite the 'peak torque figure' at the crank being much higher. Power band and gearing are responsible.
 

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This is absolutely true and it's good that I was corrected because that is pretty basic and important stuff. I chose my phrasing not to mislead from science but to describe how I feel on the subject of mild weight reduction vs power increase. I probably shouldn't have said anything but now we are here.

Drag and friction increases exponentially as speed increases therefore the power to weight ratio changes with the speed because the weight remains the same as the power on tap decreases. This doesn't all of a sudden happen at some speed, it happens as soon as the car gets into motion and increases from there.

Lets say a car at 10mph has zero losses, 200hp / 2000lbs. the option is add 10hp or take 100lbs. They are the same percentage, pick one.

Lets say a car at 50mph uses 20hp to overcome losses, now 180hp / 2000lbs but you still have 10hp or 100lbs. They are no longer the same percentage, but pick one.

Lets say a car at 100mph uses 80hp to overcome losses, now 120hp / 2000lbs but you still have 10hp or 100lbs. At this point it seems clear that 10hp is an ~8% increase where 100lbs is still just 5%, pick one.

I'm sure we could debate till the end of time on friction coefficients and loss percentages but the fact of the matter is they are there and they have some impact. If they can be felt or not at certain levels is a matter of opinion I guess. Bottom line for a few HPs, drop the Lbs and do a few bolt-ons. That's pretty much all there is at an entry level. I wouldn't be able to notice that but you might. I noticed a turbo though.
When I was an engineer at one of the "big 3", the vehicle guys would quote the "rule" that almost no one can feel a power (or power/weight) difference of less than 10%.

Dave
 

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This is absolutely true and it's good that I was corrected because that is pretty basic and important stuff. I chose my phrasing not to mislead from science but to describe how I feel on the subject of mild weight reduction vs power increase. I probably shouldn't have said anything but now we are here.

Drag and friction increases exponentially as speed increases therefore the power to weight ratio changes with the speed because the weight remains the same as the power on tap decreases. This doesn't all of a sudden happen at some speed, it happens as soon as the car gets into motion and increases from there.

Lets say a car at 10mph has zero losses, 200hp / 2000lbs. the option is add 10hp or take 100lbs. They are the same percentage, pick one.

Lets say a car at 50mph uses 20hp to overcome losses, now 180hp / 2000lbs but you still have 10hp or 100lbs. They are no longer the same percentage, but pick one.

Lets say a car at 100mph uses 80hp to overcome losses, now 120hp / 2000lbs but you still have 10hp or 100lbs. At this point it seems clear that 10hp is an ~8% increase where 100lbs is still just 5%, pick one.

I'm sure we could debate till the end of time on friction coefficients and loss percentages but the fact of the matter is they are there and they have some impact. If they can be felt or not at certain levels is a matter of opinion I guess. Bottom line for a few HPs, drop the Lbs and do a few bolt-ons. That's pretty much all there is at an entry level. I wouldn't be able to notice that but you might. I noticed a turbo though.
Good examples of how to factor drag into the performance equation. A point of reference: A typical large car only needs about 10-12 HP delivered to the driving axle to maintain highway speeds on a level road with no wind.
 

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It is more like 43 than 45. Maybe depends on if you have AC. The LHD models are also not as balanced with a driver as RHD, it says this in one of the books about the cars but it probably isn't much.

The battery is a three stage thing. A. Get a lighter battery and leave it where it is. B. Move it lower down (maybe pointless doing with this with a big heavy battery) to the crossmember . C. Move it to the front and add the weight of a cable (which isn't going to be loads but will be something).

If the car is 43/57 and it weighs 970kg in basic Euro trim PFL with no AC and you save 15kg on exhaust and battery mods you may get about 45/55 or approx as obviously weight is on all four wheels and not just the ones near the weight you remove.

Personally I went from a stock Panasonic battery to a lighter Hankook one to a smallish lead acid Yuasa which weighs 16lbs Vs the 28 of stock, plus lighter exhaust.

My exhaust is about 8kg for the tailpipe section Vs about 13kg for stock.
When you finally go to a 3-lb Lithium-ion battery, you can put it anywhere convenient. Mine is in the space in front of the pass-side-rear-light.
 
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