Granted there is some passing similarity but they are really nothing alike, especially when seen in real life. Sure is fun ribbing Gen III and IV vert owners though.
Ya'll are way too sensitive and lacking in the sense of humor department. I guess it's just the jealousy that all the people are loving my big red clown shoe, especially the ladies, because they know what a big shoe means.
PeerBlock
You are very good at diversion, however, I will concede that you are the almighty if you can name me TWO conventional transmissions where direct drive is 3rd gear and two conventional transmissions that do not have a direct couple path from input to output?
If by diversion you mean sticking to the facts...
Ratios for Evo 8 & 9
http://www.jackstransmissions.com/pages/evo-8-9-transmission-gear-ratios
Ratios for SRT-4 (second post down):
http://www.turbo-mopar.com/forums/showthread.php?16051-T-850-(SRT-4-trans)-gear-ratios
Ratios for Toyota Supra (use ctrl+f and search for "Transmission Types"):
http://mkiv.supras.org.nz/specs.htm
The supra does have a 1:1 drive, but it's in 5th gear on the Getrag trans (the 6-speed manual). Throwing that in there to counter the derpness of claiming that it's always 4th gear.
All of those tranmissions are what you get from the factory, stock and all but the supra are LACKING in a 1:1 drive gear.
When you started in on this thread, it was about 3rd gear being the correct gear for a dyno pull, where did you pull that from, that is the reason for this discourse - by the way I am not your bro, far from it!
Which is often the case if you're dynoing an automatic transmission...although I did not specify which car I dynoed so to claim I was wrong for saying it is 3rd once again highlights that you're going to be assumptive rather than simply acknowledging that you know what I meant - that dyno pulls are typically done in the gear that yields 1:1 or closest to it. The reason for this discourse is that you and anyone else who disagreed with me is trying to save face rather than simply learning something new and moving on with life.
i think all that myself and a host of others were trying to do was point out an obvious error, it seems like you are always right even when you are wrong. Lastly, your comment on veterans of a war, is way out of place. that tells us a lot about you. I am bowing out, there is no further reason for a one way discourse. I have to leave, going racing, I am sure you will be busy also, on your keyboard doing research.
Except that the only ones in error were you and "the host of others" blindly agreeing with you.
I had an s2000 for five years and the acr now for a couple. They overall shape and feel of the cars are similar. But, it's not like they look like twins or anything, but their shape and some design cues look similar.
Yes. The body lines look very similar, especially the headlights, the windshield and the overall stance.
Like others, I'm done beating my head into a wall trying to just provide some insight as to where the power goes when run through a transmission. Flipping through some physics books and reading about conservation of energy and how to calculate friction should shed some light on some of what is going on.
Never disagreed with you that excess energy was being dissipated as heat - that is essentially correct; I disagreed with you that the heat itself was causing a driveline loss on the dyno readings.
Is that what we are talking about here? This seems to have gotten lost in your rambling.
Let's do a quick recap...looking at the post below, you'll note that the Gen IV and Gen V were on the same dyno on the same day.
Was it truly apples to apples? No, because the Gen IV wasn't 100% stock, and the Gen V was. Minus the high flow cats on the Gen IV, the only other differences are the lighter clutch/flywheel combo on the Gen V (advantage Gen V, but doesn't always show up on a dyno), and as noted below, the ring and pinion as noted by Nine Ball:
I was never concerned with the comparison of the Gen 5 and Gen 4 dyno numbers - my point was and still is that dyno numbers are not something that should be taken too seriously. They are useful for tuning a car and getting a rough idea of what to expect when you take the car out to the race track or drag strip, and the numbers you get should be within 10-20% of the factory ratings assuming nothing has been done to the car...but let's reiterate that 10-20% is a pretty wide margin of error.
This is the heart of the discussion here...so the Gen IV had 3.07 gears, high flow cats, presumably dynoed in 4th gear (1:1) and put down 535 RWHP on its best run. The Gen V has stock 3.55 rear gear and was also presumably dynoed in 4th gear (1:1), and put down 529 RWHP on its best run.
I've already established the context for which I was posting. You can say that is the heart of your perspective on this discussion, and to that I'd say the difference between 529 and 535 less than 2%. If you think a dyno has such a narrow margin of error I'd like to offer you some beachfront property right outside of Las Vegas.
...and that's where everything fell apart, and where everyone (including me) disagreed with your logic. To your credit, comparing a Gen III/IV Viper to an S2000 was nice and classy...why admit you were incorrect when you can just make fun of how something looks?
Funny how easy it is to jump on a bandwagon believing that "groupthink" is on your side, only to discover that you and the others were wrong.
So to be clear, third gear in a Viper has never been 1:1, so your statement that it usually is is not true, especially not in this context...
Except that the context is cars in general, not "viper only", and since the point was that the transmission should be at or near 1:1 for a dyno pull I was never wrong about that.
after all, we are on a Viper forum, and we are talking about Vipers here. As for the last part of that statement, that is not only false, it is so wrong that I'm not even sure what you were thinking. Since when do a ring and pinion change have an impact on transmission gear ratios? If your answer is "sometimes", please stop before you hurt yourself.
We're on a car forum focused on vipers where we can and do talk about vipers as well as how it compares to other cars. Is this a weak attempt at moving the goalposts since you never had a reason to disagree with me in the first place?
Are you talking about 1:1, as in one tire rotation per one engine revolution?
So...what exactly were you thinking? I'm trying hard to figure it out.
Woops, you got me there. I did make an error regarding the relationship of the engine speed to final drive. Go give yourself a high five!
PeerBlock, I have owned a couple of performance cars at my younger age (not really that long ago
) and with the same car, same dyno, a change from 3.42 to 4.10 resulted in a loss of 17 HP. The next rear gear I went to was a 3.73 and I gained about 9 horsepower back. That was a starting point of 415 rwhp. Significant percentage change. Let's put this in perspective. The gear change I had from 3.42 to 4.10 is close to a change from 3.07 to 3.55. Given that I saw a 4% decrease in the dyno reading due to increased parasitic loss, a average Gen IV Viper that dyno's 545 rwhp will dyno at 523. Now we add the claimed 40 horsepower increase (net 38 since we are losing 4% in this hypothetical scenario) we end up at 561 rwhp. That is pretty damn close to what the dyno readings are coming back at.
I don't have a problem with anything you said here, except that you're putting a lot of faith in the readings you get from a dynojet, readings which should include a disclaimer that they are calculated using a healthy dose of fairy dust. If you went from a theoretical 3.00 rear axle gear to 4.00 and had the driveshaft spinning 1:1 with engine crank, every 3 turns of the engine with 3.00 gears would cause one complete revolution of the rear axle. With the 4.00 gears it would be 4 driveshaft revolutions to turn the rear axle one complete revolution.
You're not losing engine power; the dyno shows a lower reading because for any given RPM, the taller gears require more revs to spin the drum, which means that the time it takes the engine to accelerate the drum increases. In other words, since power is the rate at which torque can be applied by the engine, more power is used to turn the taller gears due to the difference in ratio.
The most relevant factor with gearing is keeping the engine revs in its powerband, and depending on how the transmission is geared, the rear axle should also be geared accordingly. For instance, if you tune the engine for mid to high RPM power, there is a benefit to using taller rear axle gearing >4. But if you're running a broader power band with more low and mid range, you can go with shorter gears to gain better overall utility while driving "normally". I think 3.55s are just right for the Viper.
I work in engineering with industrial engines and our packages have two factors of parasitic loss. In both of those factors, the faster we spin the object, the more horsepower it takes. You are correct in saying it takes 'x' horsepower to spin the drive-train. However, you are forgetting that the rate at which you reach that speed factors into the horsepower used to rotate the object. Let's put it in the simplest terms. How can you argue that a car accelerating from 0-100 MPH in 10 seconds takes the same horsepower it takes to accelerate the same car 0-100 in 7 seconds? It is simple, it doesn't. In other words, a 3.55 will have greater resistance to spin than a 3.07, but that is a performance advantage given the fact that the engine will enter its power-band at an earlier time frame thus resulting in quicker acceleration at lower speeds. Conversely, it results in slower acceleration at higher speeds once you get to a certain point.
Well, the using those theoretical ratios again, 3.00 and 4.00, going from 3 to 4 is a 33% increase in revs required to spin the rear tires once.
With 3.00 gears and 3,000 RPM engine/driveshaft speed, the rear axle should be spinning at 1,000 RPM.
Same thing, but with 4.00 gears and the rear axle spins at 750 RPM, a loss of 250 revs at the wheels or a 25% loss in rotational speed.
Using 4.00 gears in the rear axle, the engine would have to be at 4,000 RPM to match the the speed of the 3.00 gears, and wheel revs are what is used to calculate horsepower with a dynojet.
Scale that up to 6,000 RPM and with 3.00 gears the wheels spin at 2,000 RPM while 4.00 gears only get 1,500 RPM - the 25% loss in revs remains constant since the gear ratios are fixed, but that's 500 fewer revs reaching the wheels which are correctly calculated as a power loss as far as what's getting to the wheels - and that's without factoring in inertial or frictional losses (which I would say play less of a role than they are often credited for in this case).
