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Discussion Starter #1
According to Lexus the GS400 supposedly makes 310lb/ft of torque. I remember reading an article on the web saying that BMW's V8 engine produces significantly more torque on the Dyno when compared to the GS400's V8 (even though the factory specs are very similar). According to the dyno the BMW V8's produced near their factory spec torque figures however the GS400 was only producing 260lb/ft of torque (50 lb/ft less than what Lexus quotes. Then I went to www.swift-racing.com and according to them the GS400 WITH the supercharger makes 314.4 lb/ft of torque. That's only 4 more ft/lbs of torque than Lexus quotes for the Stock GS400. So apparently my stock GS400 puts out much less torque than Lexus quotes
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Eric...
 

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Yea, but I will have no problem running to sixty in six and quarters in the fourteens out of a stock, luxo cruiser, baby!


Originally posted by EricK:
According to Lexus the GS400 supposedly makes 310lb/ft of torque. I remember reading an article on the web saying that BMW's V8 engine produces significantly more torque on the Dyno when compared to the GS400's V8 (even though the factory specs are very similar). According to the dyno the BMW V8's produced near their factory spec torque figures however the GS400 was only producing 260lb/ft of torque (50 lb/ft less than what Lexus quotes. Then I went to www.swift-racing.com and according to them the GS400 WITH the supercharger makes 314.4 lb/ft of torque. That's only 4 more ft/lbs of torque than Lexus quotes for the Stock GS400. So apparently my stock GS400 puts out much less torque than Lexus quotes
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Eric...
 

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the numbers you saw are probably torque measured at the rear wheels, not considering any loss through the drivetrain. If you want an accurate test, pull out the motor from your GS400 and put it on an engine dyno (versus a chassis dyno).
 

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Discussion Starter #5
I agree Brad and I have personally run under 6 seconds with a stop watch (although hardly accurate)... It's a very fast machine, no question but wondered why the large discrepency in torque.
Eric....
 

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How many extra ponies could we get out of that $1200 intake/chip system webmaster mentioned?

Originally posted by EricK:
I agree Brad and I have personally run under 6 seconds with a stop watch (although hardly accurate)... It's a very fast machine, no question but wondered why the large discrepency in torque.
Eric....
 

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Discussion Starter #7
oh-dawg,
Then why is that BMW's V8 engines lose much less torque at the drive wheels than the Lexus V8? Did Lexus Design for it to be that way? In any case the torque figures are misleading because that amount of torque never reaches the road....
Eric....
 

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Almost always, horsepower and torque specifications from the manufacturer are "at the crank". Most people quote dyno numbers "at the wheels", sometimes abbreviated as RWHP (rear wheel horsepower). RWHP numbers will always be less than crank numbers due to drivetrain losses. Some dynos can estimate the amount of drivetrain loss and spit out crank numbers too.

When you're comparing numbers, make sure you're comparing the same thing.

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Tony
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'94 Turbo Miata
 

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Erick, was the BMW a stick? If it is, then it explains why the number is closer to the shaft output because manual is more efficient.
If it is an automatic, then I don't know. Either they have very very efficient auto tranny or their number on the brochure is for the rear wheel?
 

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Discussion Starter #11
Tony,
I was comparing dyno numbers at the wheel between the BMW 540iA and the Lexus GS400. According to that specific Dyno graph the GS400 was losing a lot more torque before reaching the drive wheels than the BMW did. So I was just wondering why this was so. The supercharger added to the GS400 by swift racing (www.swift-racing.com) increased the torque output at the rear wheel to 314.4 lb/ft of torque, which is around the dyno torque numbers for a Stock 540iA. Then again a Supercharged GS400 would terrorize a BMW M5 I'm sure.
Eric....
 

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okay...yuoou guys were flamign me before but this is perfect "idiot" material....car manufacturers ALWAYS state numbers at the crank(thye're always bigger, and therefore, bigger is better they figure)...some drivetrains are more efficient than others but dyno numbers are always at the wheel(unless its an engine dyno)...the reason bmw seems to be more efficient is because bmw cheats, they' underrate their crank hp on all their cars, so that the WORST production model will have at LEAST taht much power. for instance on OBDII m3s, they're claimed 240hp but they're really closer to 250...so since the hp at the crank is lower than it really is, when you get a dyno on it, the numbers appear closer together and therefore more "efficient." lower hp also means lower insurance, which is why they also underrate their 0-60s
 

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MRCLAM writes: "...the reason bmw seems to be more efficient is because bmw cheats, they' underrate their crank hp on all their cars, so that the WORST production model will have at LEAST taht much power."

I'm just curious why you think it is "cheating" for a manufacturer to use a minimum number for a published spec. To me, this is the most fair thing to do. I would feel cheated if the car I bought won't do at least the factory spec. I feel mis-lead if the published number is the best they have ever seen or even the average. You have to allow for manufacturing tolerances. IMHO to do any less is false advertising.
 

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i'm just being mean to bmw =) anyhow another example of this is the motortrend(i think motortrend) comparo of the miata and the mr2 spyder. both have similiar hp ratings but when it came to whp the miata ate it. the mr2 spyder's engine was hand assembled or something and probably a top of the line engine compared to an average miata engine(somethingl ike that)....so yeah...whp is really what's going to make the difference. from a 6 cyl engine i wouldn't want any more than 20% loss through the drivetrain, and since the gs400 is an 8 cylinder, bigger, and suffers less tan 20%, i think tis fine =)
 

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Clam, it is becuz the MR2's drivetrain is more efficient. The Miata is driving the rear wheels from the front engine, whereas the MR2 is driving the rear wheels from the back of the car, essentially like a front engine front wheel drive car. The MR2 engine is not hand assembled, it is mass produced. It is the same engine that is in the GT Celica.
 

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yes i knwo but i think i rmeember reading that the engine in that particular mr2 was hand assembled for the test...i'm nto sure
 

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Originally posted by jerryd:
I'm just curious why you think it is "cheating" for a manufacturer to use a minimum number for a published spec. To me, this is the most fair thing to do. I would feel cheated if the car I bought won't do at least the factory spec. I feel mis-lead if the published number is the best they have ever seen or even the average. You have to allow for manufacturing tolerances. IMHO to do any less is false advertising.
I'm kinda with Clam on it not really being fair. I think the standard should be HP at the wheels... and it should be independently tested.

Its cheating or unfair because all cars should have the same standard, we shouldn't have to learn on our own that E36 M3's and LS6's are underrated, then learn that other cars like perhaps the GS400 are overrated. How many average buyers know this kind of information? And this is one of the most important figures when buying a car!!

Either that or we should judge cars by their straight line acceleration.

And as far as the GS400 goes... Most tests (MT, R&T, C&D) the GS400 accelerates faster to 60 than the 540i... what does that prove?

And as a side note just FYI (A R34 Skyline GTR engine was chipped and measured hp at the crank... 480 hp when the car is rated from the factory at 320 hp...
ohhhhkay... you know someone's lying when.)

But its pretty common in Japan to underrate the engine, because of the restrictions they have over there... WRX's, and Lancer's as well too, I wouldn't be surprised if the whole slew of top end race cars over there were underrated...

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Kenny
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About that MR2....any chance we'd see the Celica GT-S engine in it? 180 hp in that thing would scream!

[From TEG: Yeah - that would be cool.
I have heard from a few sources that the MR2 team wants to stick with the 140hp engine.
It sounds like they WILL have a Ferrari style hydraulic sequential transmission option soon. No clutch pedal - but you are controlling a manual transmission.
TRD may come out with a supercharger for the 140hp MR2-Spyder that gives it as much power as the Celica GT-S engine. My guess is that TRD will release a MR2-Spyder supercharger _before_ anything for the IS300.]


[This message has been edited by TEG (edited September 07, 2000).]
 
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