I Have A Question Thats Been Hunting Me.....

[Jesus954]

Hi well we all know that the is300 isnt a speed demon car out of the factory. What is hunting me is how come the is300 doesnt give more power? i mean 215hp seems very low for a 3.0liter V6 car, it gives an average power of a 4 cylinder. doesnt the 2jz engine count for anything lol? Could it be its weight as well? just to compare it with a Honda civic Si that car i hear about its vtec that n this, but that car really aint much of a sports car neither. Only thing it has, as an advantage is its weight, so that pops my question that if the IS300 were 2980lbs it would probably be way faster correct?

[bartkat]

First the IS is an inline six that's not real highly tuned, and will virtually run forever if well maintained.

The SI is a relatively highly tuned four.

[djspawn00]

I wasn't aware that the average 4 cylinder punched out 215hp.... and yeah reducing the weight would increase the effective hp... so strip out all of the interior, seats, sound deadening materials, AC components, spare tires, throw on some light weight wheels and boom... you've got yourself a rice eater... and intake, exhaust, and maybe some fancy stickers wouldn't hurt either... well actually they would.

[smooth1]

there is actually alot more to the numbers than they appear. Lets say you have a 4 cyl and a 6 cyl that both produce 200 hp. and very close in torque. Just knowing those numbers isn't really enouph. You have to look at the power curves. The 4 cyl. may make 200 hp at 5800 rpm, and redline at 6500 rpm. while the 6 cyl may make 200 hp at 4200 rpm and redline at 6000 rpm. Hence the 6 cyl. may be faster in a car of the same weight and gearing. It makes more power earlier in the rev range, and has a higher AVERAGE HORSEPOWER. That's what is called usable hp. I can give you a really good example of this. I have a freind that has a 98 Honda Civic that is putting down 700 rwhp. It's a 2.0 liter 4 cyl. and a huge turbo. My IS 300 with 430 rwhp walks away from him and keeps pulling all the way down the street. It drives him insane!!!! But he's front wheel drive, and only really makes 700 hp for like a second or two before he has to shift. While the IS 300 hits it power curve at 4200 Rpm and just stays in it all thru the gears.

Next you have mass. The more mass you have, the more hp you need. ( and bigger brakes, LOL!) I rarely see street cars go for mass reduction. You really have to remove alot to see some significant weight reduction. IMHO, you need to drop 250 lbs. to even begin to feel the difference. But, if you couple this with the next speed factor, it can really start to add up.

Which brings us to parasitic drag on the motor. Remember, all mfgr. horsepower specs are off the crank, and not at the rear wheels. So things like clutch fans, power steering, a/c components water pumps and alternators add alot of additional load to motors. and that amount is not equal among all manufactures.

And also remember, that some car mfgrs have to keep costs in line. So sometimes depending on the market they are trying to appeal to, they can take a motor that is already in the line up and alter it to fit thier needs. So they may detune a preexsisting motor or tune one up more to fit the bill. Beleive it or not, some people actually complain that a car has to much acceleration and is hard to control off the line. I know, silly, but true. And it seems everyone wants smooth shifting trannys. So that really limits the amount of hp they can send thru it, which then means they don't have to make more hp, which then leads to better fuel mileage, and so they look good for it. You have to remember that when they first built the IS 300, they were at the top of the power curve for import cars then. Nissan, Toyota, Honda, and their associate companies had a sort of Gentlemans agreement to keep the hp around that figure. That's why the old Supra's said they produced around 245 hp, but that figure on the dyno showed it was really like 320 hp. Then Nissan came out with the 350Z, and the gloves are starting to come off now, as the European mfgrs such as Merc, BMW and Audi have stepped up the hp also.

[Jesus954]

there is actually alot more to the numbers than they appear. Lets say you have a 4 cyl and a 6 cyl that both produce 200 hp. and very close in torque. Just knowing those numbers isn't really enouph. You have to look at the power curves. The 4 cyl. may make 200 hp at 5800 rpm, and redline at 6500 rpm. while the 6 cyl may make 200 hp at 4200 rpm and redline at 6000 rpm. Hence the 6 cyl. may be faster in a car of the same weight and gearing. It makes more power earlier in the rev range, and has a higher AVERAGE HORSEPOWER. That's what is called usable hp. I can give you a really good example of this. I have a freind that has a 98 Honda Civic that is putting down 700 rwhp. It's a 2.0 liter 4 cyl. and a huge turbo. My IS 300 with 430 rwhp walks away from him and keeps pulling all the way down the street. It drives him insane!!!! But he's front wheel drive, and only really makes 700 hp for like a second or two before he has to shift. While the IS 300 hits it power curve at 4200 Rpm and just stays in it all thru the gears.

Next you have mass. The more mass you have, the more hp you need. ( and bigger brakes, LOL!) I rarely see street cars go for mass reduction. You really have to remove alot to see some significant weight reduction. IMHO, you need to drop 250 lbs. to even begin to feel the difference. But, if you couple this with the next speed factor, it can really start to add up.

Which brings us to parasitic drag on the motor. Remember, all mfgr. horsepower specs are off the crank, and not at the rear wheels. So things like clutch fans, power steering, a/c components water pumps and alternators add alot of additional load to motors. and that amount is not equal among all manufactures.

And also remember, that some car mfgrs have to keep costs in line. So sometimes depending on the market they are trying to appeal to, they can take a motor that is already in the line up and alter it to fit thier needs. So they may detune a preexsisting motor or tune one up more to fit the bill. Beleive it or not, some people actually complain that a car has to much acceleration and is hard to control off the line. I know, silly, but true. And it seems everyone wants smooth shifting trannys. So that really limits the amount of hp they can send thru it, which then means they don't have to make more hp, which then leads to better fuel mileage, and so they look good for it. You have to remember that when they first built the IS 300, they were at the top of the power curve for import cars then. Nissan, Toyota, Honda, and their associate companies had a sort of Gentlemans agreement to keep the hp around that figure. That's why the old Supra's said they produced around 245 hp, but that figure on the dyno showed it was really like 320 hp. Then Nissan came out with the 350Z, and the gloves are starting to come off now, as the European mfgrs such as Merc, BMW and Audi have stepped up the hp also.

I can always count on you for a great answer with good information lol. I was just curious because like the supra and like the BMW m3 are both 6 cyl yet they give out alot more power so thats why i was wondering wtf happen to the IS but ya you clear that up for me lol =)

[IndyKen]

Smooth1,

Disregard this post. I found the answer to my question.