RCF vs M4 Roll Racing
Lexus Champion
Joined: Oct 2005
Posts: 10,364
Likes: 2,762
From: Calgary, AB
I don't disagree with anything you said there. You are absolutely correct in everything you wrote there.
Like I stated before, this specific statement you wrote, is what is misleading. That is all I am saying. HP is not reserved for top speed, like the statement below might suggest.
A 135 HP and 200 ft-lbs car will not be quick at all. It will barely do 8-9 seconds 0-60 mph simply because it has no horsepower (or high end torque relative to rpm). It will scoot off the line quickly, but die off rather soon. A 135 ft-lbs with 200 HP car with similar weight and gearing to match will however be a lot quicker comparatively speaking.
hp for top speed, torque for acceleration.
Like I stated before, this specific statement you wrote, is what is misleading. That is all I am saying. HP is not reserved for top speed, like the statement below might suggest.
A 135 HP and 200 ft-lbs car will not be quick at all. It will barely do 8-9 seconds 0-60 mph simply because it has no horsepower (or high end torque relative to rpm). It will scoot off the line quickly, but die off rather soon. A 135 ft-lbs with 200 HP car with similar weight and gearing to match will however be a lot quicker comparatively speaking.
hp for top speed, torque for acceleration.
Not a misconception and a massive effort at over intellectualizing of and twisting of my words regarding a very simple concept. Of course they are not completely separate or independent and hp is a by product of torque and rpms. I never said that. I spent the better part of 30 years tuning race cars and hot rodded Porsches for the street, some with stand alone fuel management systems. Torque at the wheels gives you acceleration or gets a car moving. Once moving, it is more important to have more hp and less torque to sustain high speed. As I stated above, total area under the curve and a curve that is as flat as possible (much like the M4 torque curve versus the RCF torque curve) is highly preferable for acceleration, but perhaps not for high speed.
On the race track, I have used different cams and tuning that actually decrease area under the torque curve and both torque and hp below 5252, but increase hp curve above 5252 and peak hp to provide me a little better speed on momentum type tracks where massive speed is rarely or never scrubbed. The focus here is maintaining or increasing speed once moving through more hp as the sacrifice of torque.
There is some truth about building for torque and hp will follow, but there is always a trade off. While you cannot have hp without torque, you can have torque without hp . . . i.e., dump truck.
On the race track, I have used different cams and tuning that actually decrease area under the torque curve and both torque and hp below 5252, but increase hp curve above 5252 and peak hp to provide me a little better speed on momentum type tracks where massive speed is rarely or never scrubbed. The focus here is maintaining or increasing speed once moving through more hp as the sacrifice of torque.
There is some truth about building for torque and hp will follow, but there is always a trade off. While you cannot have hp without torque, you can have torque without hp . . . i.e., dump truck.
Last edited by 05RollaXRS; Sep 9, 2016 at 11:45 PM.
Lexus Test Driver
Joined: Mar 2015
Posts: 818
Likes: 30
From: Nashville
I don't disagree with anything you said there. You are absolutely correct in everything you wrote there.
Like I stated before, this specific statement you wrote, is what is misleading. That is all I am saying. HP is not reserved for top speed, like the statement below might suggest.
A 135 HP and 200 ft-lbs car will not be quick at all. It will barely do 8-9 seconds 0-60 mph simply because it has no horsepower (or high end torque relative to rpm). It will scoot off the line quickly, but die off rather soon. A 135 ft-lbs with 200 HP car with similar weight and gearing to match will however be a lot quicker comparatively speaking.
Like I stated before, this specific statement you wrote, is what is misleading. That is all I am saying. HP is not reserved for top speed, like the statement below might suggest.
A 135 HP and 200 ft-lbs car will not be quick at all. It will barely do 8-9 seconds 0-60 mph simply because it has no horsepower (or high end torque relative to rpm). It will scoot off the line quickly, but die off rather soon. A 135 ft-lbs with 200 HP car with similar weight and gearing to match will however be a lot quicker comparatively speaking.
1st is an F1, then a dragster and then a Porsche GT3 Cup.
Lexus Test Driver
Joined: Mar 2015
Posts: 818
Likes: 30
From: Nashville
I don't disagree with anything you said there. You are absolutely correct in everything you wrote there.
Like I stated before, this specific statement you wrote, is what is misleading. That is all I am saying. HP is not reserved for top speed, like the statement below might suggest.
A 135 HP and 200 ft-lbs car will not be quick at all. It will barely do 8-9 seconds 0-60 mph simply because it has no horsepower (or high end torque relative to rpm). It will scoot off the line quickly, but die off rather soon. A 135 ft-lbs with 200 HP car with similar weight and gearing to match will however be a lot quicker comparatively speaking.
Like I stated before, this specific statement you wrote, is what is misleading. That is all I am saying. HP is not reserved for top speed, like the statement below might suggest.
A 135 HP and 200 ft-lbs car will not be quick at all. It will barely do 8-9 seconds 0-60 mph simply because it has no horsepower (or high end torque relative to rpm). It will scoot off the line quickly, but die off rather soon. A 135 ft-lbs with 200 HP car with similar weight and gearing to match will however be a lot quicker comparatively speaking.
The 135 hp, 200 torque car will be quicker off the line and could be faster down the track if you had the correct, albeit ridiculous, transmission. I have heard the professional hot rod guys kidding around about those dump truck type motors producing over a 1000 torque and around 250 hp saying all you need is the correct transmission or gearing (setting size and weight aside) to get you down the track with one.
Last edited by DougHII; Sep 10, 2016 at 06:28 AM.
Lexus Champion
Joined: Oct 2005
Posts: 10,364
Likes: 2,762
From: Calgary, AB
The dragster dyno has rpms on the Y-axis so I am not sure what to make of it. It is moot point anyway. What is the purpose of HP? Why is it engineered? That is the question. I only stated HP is not reserved for top speed since HP is nothing more than torque relative to rpm. The higher the torque at high rpms, the more the HP would be. HP is needed for car to accelerate hard once it gets into the high rpm band through gears regardless of which speed it is at.
A Viper ACR for example makes 640 HP, but has a top speed of only 177 mph because it is limited by the aero and the gearing does not give it sufficient torque multiplication at 6000 rpm to overcome the drag at those speeds to continue acceleration.
It would die off at higher speeds even if it is using 2 - 3 transmission. A short geared high-revving 200 HP and 130 ft-lbs car should beat it since it will have a much broader torque across the rev range albeit a low one. It will get much of the torque multiplication from its short gearing.
Such car will have a high early peak, but an extremely narrow torque spread focused on the low rpms so it needs to remain in low rpms. Therefore, the only transmission that can keep it from going into high rpm is like those old muscle cars from the 60s that used to rev to only 4000 rpm with 3 speed transmissions, but used to die off near the end of the track and it showed in their low trap speeds.
My point is, the purpose of high rpm torque (or horsepower) is to give sustained/consistent acceleration through the speed ranges with gears acting as torque multipliers.
A Viper ACR for example makes 640 HP, but has a top speed of only 177 mph because it is limited by the aero and the gearing does not give it sufficient torque multiplication at 6000 rpm to overcome the drag at those speeds to continue acceleration.
The 135 hp, 200 torque car will be quicker off the line and could be faster down the track if you had the correct, albeit ridiculous, transmission.
Such car will have a high early peak, but an extremely narrow torque spread focused on the low rpms so it needs to remain in low rpms. Therefore, the only transmission that can keep it from going into high rpm is like those old muscle cars from the 60s that used to rev to only 4000 rpm with 3 speed transmissions, but used to die off near the end of the track and it showed in their low trap speeds.
My point is, the purpose of high rpm torque (or horsepower) is to give sustained/consistent acceleration through the speed ranges with gears acting as torque multipliers.
Last edited by 05RollaXRS; Sep 10, 2016 at 11:41 AM.
Lexus Test Driver
Joined: Mar 2015
Posts: 818
Likes: 30
From: Nashville
The dragster dyno has rpms on the Y-axis so I am not sure what to make of it. It is moot point anyway. What is the purpose of HP? Why is it engineered? That is the question. I only stated HP is not reserved for top speed since HP is nothing more than torque relative to rpm. The higher the torque at high rpms, the more the HP would be. HP is needed for car to accelerate hard once it gets into the high rpm band through gears regardless of which speed it is at.
A Viper ACR for example makes 640 HP, but has a top speed of only 177 mph because it is limited by the aero and the gearing does not give it sufficient torque multiplication at 6000 rpm to overcome the drag at those speeds to continue acceleration.
It would die off at higher speeds even if it is using 2 - 3 transmission. A short geared high-revving 200 HP and 130 ft-lbs car should beat it since it will have a much broader torque across the rev range albeit a low one. It will get much of the torque multiplication from its short gearing.
Such car will have a high early peak, but an extremely narrow torque spread focused on the low rpms so it needs to remain in low rpms. Therefore, the only transmission that can keep it from going into high rpm is like those old muscle cars from the 60s that used to rev to only 4000 rpm with 3 speed transmissions, but used to die off near the end of the track and it showed in their low trap speeds.
My point is, the purpose of high rpm torque (or horsepower) is to give sustained/consistent acceleration through the speed ranges with gears acting as torque multipliers.
A Viper ACR for example makes 640 HP, but has a top speed of only 177 mph because it is limited by the aero and the gearing does not give it sufficient torque multiplication at 6000 rpm to overcome the drag at those speeds to continue acceleration.
It would die off at higher speeds even if it is using 2 - 3 transmission. A short geared high-revving 200 HP and 130 ft-lbs car should beat it since it will have a much broader torque across the rev range albeit a low one. It will get much of the torque multiplication from its short gearing.
Such car will have a high early peak, but an extremely narrow torque spread focused on the low rpms so it needs to remain in low rpms. Therefore, the only transmission that can keep it from going into high rpm is like those old muscle cars from the 60s that used to rev to only 4000 rpm with 3 speed transmissions, but used to die off near the end of the track and it showed in their low trap speeds.
My point is, the purpose of high rpm torque (or horsepower) is to give sustained/consistent acceleration through the speed ranges with gears acting as torque multipliers.
Yep, I would love to see that.
I grenaded an M96.7x approaching 800 hp (K24 hybrids and GT2 Intercoolers based bolt on kit) in a 2001 996tt and the M96.7x is virtually indestructible. Replacement M96.7x build Carillo rods, Carr bolts, protomotive cp pistons, signed sleeves, 12 mm head studs, etc., etc., etc. and ran 30,000 + miles on it without a hiccup.
I cannot see a standard BMW 335 engine which isn't all that special to begin with staying together at 1,000 whp or being worth a shyte at half that for any decent, extended use. I used to race with the BMW CCA and PBOC guys. The Porsche cases are much better and have never been overly impressed with anything BMW engine wise when compared to Porsche.
. . . Actually, when really thinking about . . . I don't put much faith in a bone stock 335 engine driven hard for an any extended period of time . . . They are pure crap once you about 60,000 miles or the warranty wears out year wise. Almost like it is programmed into the ECU to turn into an expensive, frustrating POS the moment the warranty is gone.
Last edited by DougHII; Sep 10, 2016 at 01:20 PM.
Lexus Champion
Joined: Oct 2005
Posts: 10,364
Likes: 2,762
From: Calgary, AB
Also, PDK will not make a difference because a 5252 rpm range is too short for speed range per gear coverage. You would either need a 3 - 4 speed tall geared DCT transmission to keep a broad enough speed range/gear PDK or you will have an extremely short speed range/gear since a 6 speed DCT across only 5252 rpm would mean each gear is covering too short of a speed range unless you gear it ridiculously long in each of the 1 - 4th gear, but that would mean far less torque multiplication through the gear set/final drive.
A good example of that is, the DSG Golf Turbo Diesel that makes 256 ft-lbs of torque at low rpms and 150 HP. It has the shift speed with the DSG and mountains of midrange torque to 5000 rpm or so, but runs a 7.8 seconds 0-60 mph and 16.1 seconds 1/4 mile because it does not have the high rpm torque for acceleration. By comparison, my car with a 6 speed manual (8 lbs modified flywheel) 8350 rpm, ~ 135 ft-lbs and 190 HP does a 1/4 mile in 14.6 seconds@97 mph.
Last edited by 05RollaXRS; Sep 10, 2016 at 01:32 PM.
Lead Lap
Joined: Jun 2016
Posts: 750
Likes: 59
From: Naples, FL
I cannot see a standard BMW 335 engine which isn't all that special to begin with staying together at 1,000 whp or being worth a shyte at half that for any decent, extended use. I used to race with the BMW CCA and PBOC guys. The Porsche cases are much better and have never been overly impressed with anything BMW engine wise when compared to Porsche.
. . . Actually, when really thinking about . . . I don't put much faith in a bone stock 335 engine driven hard for an any extended period of time . . . They are pure crap once you about 60,000 miles or the warranty wears out year wise. Almost like it is programmed into the ECU to turn into an expensive, frustrating POS the moment the warranty is gone.
. . . Actually, when really thinking about . . . I don't put much faith in a bone stock 335 engine driven hard for an any extended period of time . . . They are pure crap once you about 60,000 miles or the warranty wears out year wise. Almost like it is programmed into the ECU to turn into an expensive, frustrating POS the moment the warranty is gone.
Here's an article I linked to in another thread for some reason. It's the top 10 turbocharged cars of all time according to Popular Mechanics. Notice who made the cut and who didn't? Porsche is in there, so is the Supra. I don't see any BMW.
http://www.popularmechanics.com/cars/a3786/4296068/
Lexus Test Driver
Joined: Mar 2015
Posts: 818
Likes: 30
From: Nashville
All of my assumptions are correct since they are rooted in science. The 2 - 3 transmission means 3 speed transmission (such as, a powerglide transmission) that the old muscle cars used to use in order to utilize tall gearing to keep the revs low through full-throttle accelerations.
Also, PDK will not make a difference because a 5252 rpm range is too short for speed range per gear. You would either need a 3 - 4 speed tall geared DCT transmission to keep a broad enough speed range/gear PDK or you will have an extremely short speed range/gear since a 6 speed DCT across only 5252 rpm would mean each gear is covering too short of a speed range unless you gear it ridiculously long in each of the 1 - 4th gear, but that would mean far less torque multiplication through the gear set/final drive.
A good example of that is, the DSG Golf Turbo Diesel that makes 256 ft-lbs of torque at low rpms and 150 HP. It has the shift speed with the DSG and mountains of midrange torque, but runs a 7.8 seconds 0-60 mph and 16.1 seconds 1/4 mile because it does not have the high rpm torque for acceleration. By comparison, my car with a 6 speed manual (8 lbs modified flywheel) 8350 rpm, ~ 135 ft-lbs and 190 HP does a 1/4 mile in 14.6 seconds@97 mph.
Also, PDK will not make a difference because a 5252 rpm range is too short for speed range per gear. You would either need a 3 - 4 speed tall geared DCT transmission to keep a broad enough speed range/gear PDK or you will have an extremely short speed range/gear since a 6 speed DCT across only 5252 rpm would mean each gear is covering too short of a speed range unless you gear it ridiculously long in each of the 1 - 4th gear, but that would mean far less torque multiplication through the gear set/final drive.
A good example of that is, the DSG Golf Turbo Diesel that makes 256 ft-lbs of torque at low rpms and 150 HP. It has the shift speed with the DSG and mountains of midrange torque, but runs a 7.8 seconds 0-60 mph and 16.1 seconds 1/4 mile because it does not have the high rpm torque for acceleration. By comparison, my car with a 6 speed manual (8 lbs modified flywheel) 8350 rpm, ~ 135 ft-lbs and 190 HP does a 1/4 mile in 14.6 seconds@97 mph.
I only mention pdk due to quickness of shift when having to make multiple shifts to keep in power band (I.e., so as not to lose additional time with a slow manual shift) . . . Not because of how pdk is geared which is different depending on vehicle anyway. 3-4?????? I was think 3 times that many gears . . . Funny you weren't.
BTW, I was kind of poking fun at you that you would even think a 2 to 3 speed, not really asking what it was except for disbelief and seeking confirmation that you went that route.
Last edited by DougHII; Sep 10, 2016 at 01:39 PM.
Rookie
Joined: Dec 2015
Posts: 57
Likes: 8
From: New York
I'll agree that the m3/4 is quicker on paper, but in reality the cars are pretty close and comes down to driving conditions and driver. I've raced some M3 friends and i've beaten them from a dig and rolling (roll was at my peak power range) and theres times where they've beaten me. The only thing i wish that the RCF was more similar is that M3/4 is a lot easier to tune/mod as they have a huge aftermarket and tuning community. I know some guys putting down 800hp to the wheel in these things it's nuts.
I agree overall it's a great and fast car and they have a huge following that fuels the aftermarket business, I even had one on order before i picked up the RCF. But honestly, i'm not a big fan of a lot of the M community, they can never acknowledge a car for it's beauty and engineering, mostly hating and dismissing competition and i wasn't about that bmwbro life. In the end, i got the RCF becaause it stands out and i can guarantee you more ppl come up to me for compliments and questions and break necks when i drive by everyday than any of the 100 M's i see on a daily basis.
I agree overall it's a great and fast car and they have a huge following that fuels the aftermarket business, I even had one on order before i picked up the RCF. But honestly, i'm not a big fan of a lot of the M community, they can never acknowledge a car for it's beauty and engineering, mostly hating and dismissing competition and i wasn't about that bmwbro life. In the end, i got the RCF becaause it stands out and i can guarantee you more ppl come up to me for compliments and questions and break necks when i drive by everyday than any of the 100 M's i see on a daily basis.
Lead Lap
Joined: Jun 2016
Posts: 750
Likes: 59
From: Naples, FL
Links to these cars please. If they are putting down that much hp then they are going to be visible on the net. The best M4's I've been able to find are snapping rods in the 700 whp range with the stock internals. The best turbo kit that I can find is for 650 whp. If they rebuilt their engine then it's possible. But for what that costs they could have bought a better car/engine to start with.
Rookie
Joined: Dec 2015
Posts: 57
Likes: 8
From: New York
Links to these cars please. If they are putting down that much hp then they are going to be visible on the net. The best M4's I've been able to find are snapping rods in the 700 whp range with the stock internals. The best turbo kit that I can find is for 650 whp. If they rebuilt their engine then it's possible. But for what that costs they could have bought a better car/engine to start with.
Point being, i'm in the RCF for sheer uniqueness and everyday use. Although I do often wish we had a larger community to spice up the aftermarket business as i'd love to get some tunes and bolt ons or some internals and extract more power out of the car.
Lead Lap
Joined: Jun 2016
Posts: 750
Likes: 59
From: Naples, FL
Read it how you want, but as much as i love our RCF i don't see anyone but that 1 guy who's putting down almost 600 with NOS. Even then, not a single RCF is coming near any M with a few grand into it. They don't necessarily need to be visible on the net as they stay away from prying eyes. Either way the 800hp example i'm referring too is for track use and has fully built internals with tunes and meth yadi yadi yada. Everyday driving is probably closer to 650 as you mentioned until you hit the injection and change the tune map.. Have i seen his dyno? no. But i trust him and didn't care much as he is 1 of a million M owners and anyone of them can spend a few grand be quick.
Point being, i'm in the RCF for sheer uniqueness and everyday use. Although I do often wish we had a larger community to spice up the aftermarket business as i'd love to get some tunes and bolt ons or some internals and extract more power out of the car.
Point being, i'm in the RCF for sheer uniqueness and everyday use. Although I do often wish we had a larger community to spice up the aftermarket business as i'd love to get some tunes and bolt ons or some internals and extract more power out of the car.
As for the RC F. We'll see what happens when we start tuning. Until then, you can talk all the crap you want. I know the RC F engine is going to kill the M4 engine with the stock internals.
Rookie
Joined: Dec 2015
Posts: 57
Likes: 8
From: New York
You said it, not me. Now you're trying to dance around what you said. You said, "I know some guys putting down 800hp to the wheel in these things it's nuts." "guys" (plural) means more than 1. The debate isn't what it costs to be quick. It's what the car is actually capable of...
As for the RC F. We'll see what happens when we start tuning. Until then, you can talk all the crap you want. I know the RC F engine is going to kill the M4 engine with the stock internals.
As for the RC F. We'll see what happens when we start tuning. Until then, you can talk all the crap you want. I know the RC F engine is going to kill the M4 engine with the stock internals.
Lead Lap
Joined: Jun 2016
Posts: 750
Likes: 59
From: Naples, FL
Alright "bro", "dancing around and talking crap". I'm not perfect, even if i'm wrong about the F8X.. what about all the e46's e9x's out there. Don't be a tough guy and admit defeat when you see it and have sportsmanship. There's a reason why the fanboy's and following exists for BMW M's. Don't take it personally. If you really want, you can volunteer to fund all the R&D our cars need to unlock all the capability of the RCF. I'm sure we'll all appreciate it.
I'm not talking about all BMWs and at no point did I even imply that I was. I'm talking about the M4 (the topic of this thread?). I also have not lied, like you did when you said you knew "guys" with the M4 putting down 800 whp.
As for the R&D... It's already being done.
https://www.clublexus.com/forums/cl-...rr-racing.html