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I know something litle about engine tuning. But I (we) are happy if we can get 100HP/liter out of an N/A. But what do they to the engines to get out 150HP/liter or more. When we take a look at the old BTCC Primera GT it had ~290HP @ 8300 rpm if I remeber it right or the ETCC VECTRA B 2.0i 16V had over 320HP @ 9000rpm. And they were limited with pump fuel.

Is it all about better(light) materials and higher rpm?
 

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i would assume its based on the heads and other parts.. with more flow, and sufficent fuel you can produce large amounts of power.. same thing with the current VVL motors.. a disadvantage is that you will loose tq with this process. Other cars such as the rsx-S, and nissans vvl cars will be able to produce these kinds of numbers any day.
 

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rpms are essential. Look at motorcycle and F1 motors. Current 600cc bikes make around 105-110 whp, so they're around 200hp/liter which rev to 15k+ rpms. F1 motors make about 300hp/liter revving to 19k+.

Torque is basically limited to how much air you can get into the cylinders so the easiest way to make power it to rev higher.
 

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this is true.. you do need high RPM's to be able to hit those numbers on N/A applications, but you will loose tq as a result.. by lookin to the Vtec and VVL motors, they will rev high and not redline till after 8k+. Another disadvantage is that a lot of cars that can rev that high will only get the power after a certain RPM, thus why hondas dont really have any tq... and another important part is to see how the power band flows.. in many cars that have high revs, the power band is very choppy and not smooth, while such motors as the sr20 and other nissan motors we have a more useable power band.



Mainly its all bout air flow.. the better the heads and more flow the more power and less tq you will get..
 

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psuLemon said:
Another disadvantage is that a lot of cars that can rev that high will only get the power after a certain RPM, thus why hondas dont really have any tq...

the better the heads and more flow the more power and less tq you will get..
Hondas have no torque because they're small motors :) If you compare honda motors of similar displacement to other motors (such as the K20 and F20, rsx-type s and s2000 motors), they have more torque than the sr20de i believe and probably more than the VVL.

Torque depends on how much air you can cram in the cylinders and stroke length. The more air, the more fuel, the more torque. And generally, the longer the stroke, the more torque.

How much air you can get into the cylinders depends on volumetric efficiency which depends on valve lift, etc. That's why you generally want less lift at low rpms; it keeps the air velocity high going into the cylinder. At high rpms though, you need more lift to get more flow, etc.

And you see the torque drop at high rpms because you get a decrease in volumetric efficiency. It's harder to get air to fill the cylinders at the high rpms. well, that's the short version.
 

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SR20VE - 187hp @ 7000rpm / 145lb torque @ 6000rpm
RSX-S- 210hp and 143 tq...

hondas and acuras dont have the tq the nissan produces... i do understand how tq works and it hp is derived from tq mathematically.
 

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What makes power on NA engines is a good equal length hedder or hedders, a bad ass cam, high compression has a whole lot to do with it, a head or set of heads that flow, and a damn good tune.

A long stroke will net you increased torque but it will not rev high (piston speed is too high) like on bigass V8's, with a stroke of 4+ inches

a short stroke will reduce torque, but you can spin the crap out of the engine and make a bunch of HP (like on F1 and motorcycles). Most crotchrockets that spin to 15000rpm have a stroke of <2 inches

to spin high, you also need a really stout set of valvesprings, as valve float (valves not closing fast enough) will occor at high RPM.

Heavy vehicles need a lot of torque to move, light vehicles need a lot of HP to accelerate.
 

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is real small always a bad thing... the rb26dett isn't a huge motor, its just twin turboed... you dont need a V8 to have tons of power... shoot, just look at the RSX-S motor, its has been recorded to produce an extra 18whp with just a CAI... i believe thats what i remember chimmike or wes saying once.. the vvl motors are quiet insane little motors also.. it just means you have less weight and less parts to deal with.
 

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^thats why i also mentioned the rsx-s... there are plenty of 2.0L putting out close to 200hp.. regardless, the small motors shouldn't be underestimated
 

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Yeah the 3.2 in the NSX is real small. :rolleyes:
that was in response to the quote/blanket statement that honda motors don't have much torque/less than Nissan motors, which is ususally applied the to 1.6L and 1.8L motors. which is smaller than the SR20 which is the motor that is used in the car of the same class as the civics and integras. therefore, they have no torque because they ARE smaller than the SR20. and then I went on to prove that given equal displacements, Honda has motors that produce more torque than Nissan motors.
 

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spdracerUT said:
that was in response to the quote/blanket statement that honda motors don't have much torque/less than Nissan motors, which is ususally applied the to 1.6L and 1.8L motors. which is smaller than the SR20 which is the motor that is used in the car of the same class as the civics and integras. therefore, they have no torque because they ARE smaller than the SR20. and then I went on to prove that given equal displacements, Honda has motors that produce more torque than Nissan motors.
well the majority of the time, given the same displacement and same drivetraing (rwd, fwd) hondas aren't known for their torque. The VVL example that i gave was from a 97 vvl motor as compared to Hondas 05 version of the RSX-S motor which is goin to have more technology. Hondas are known for their high flowing heads and N/A technology, while nissans are more known for their Turbo motors or the vq35de motors know. Nissans generally produce equal amounts of hp to tq and have a smoother powerband(from the dyno charts i have seen, i could be wrong in newer cars) while hondas have more a choppy powerband because a large portion of the power comes at extremely high RPM's. Grannit most of my experience is with the four cylinder motors.
 

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psuLemon said:
well the majority of the time, given the same displacement and same drivetraing (rwd, fwd) hondas aren't known for their torque. The VVL example that i gave was from a 97 vvl motor as compared to Hondas 05 version of the RSX-S motor which is goin to have more technology. Hondas are known for their high flowing heads and N/A technology, while nissans are more known for their Turbo motors or the vq35de motors know. Nissans generally produce equal amounts of hp to tq and have a smoother powerband(from the dyno charts i have seen, i could be wrong in newer cars) while hondas have more a choppy powerband because a large portion of the power comes at extremely high RPM's. Grannit most of my experience is with the four cylinder motors.
This is true. Take a look at the powerband on the GA16DE. It doesn't shoot up at any specific point. It has a broad power band where as I've seen with most 4 cylinder Honda motors(mainly civics and integras) their power is at high rpms. Nissan is know for having this broad powerband while hondas and acuras are known screaming rpms. Which is better? That mainly depends upon ones preferences and how they plan to use the car. But I'd say Nissans better known for there 6 cylinders. For instance there is the RB26DETT in the skylines and we all know the VQ35DE. I saw in a mag a few months ago a list of a bunch of cars that were tested in the 1/4 mile and the 350Z was 2 tenths faster than the V8 Mustangs. 2 less cylinder and still faster.

Mitch

Mitch
 
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