RCF vs C43 AMG Race
Posting this here because the racing section hasn’t been touched since 2014. This is just a friendly roll race, I’m not claiming one car is better than the other.
The RCF has a full Apexi exhaust. The C43 has a JB4 beta piggyback tune and E30 fuel. Temperature was 50F.
The RCF has a full Apexi exhaust. The C43 has a JB4 beta piggyback tune and E30 fuel. Temperature was 50F.
the RC F has like over 100 hp more than the C450, just a tune and different fuel made the C faster?
and if it hasn't been touched since 2014 it's probably because this is "frowned upon" behavior
and if it hasn't been touched since 2014 it's probably because this is "frowned upon" behavior
The JB4 beta can make 100+ hp and 130+ tq. I believe that C43 made 18-19 psi on that run (stock is 12). JB4 only has also ran an 11.5 @ 121 at the track with a 3.35 0-60 record.
I know a stock RCF is pretty quick, so the video is surprising.
The JB4 tunes always did big things on BMW’s so the power boost isn’t surprising? Those numbers are impressive.
I do miss seeing more posts in the street racing sections of forums. There was always some good stuff. My cars are all so slow that nobody would be impressed by racing stories.
I do miss seeing more posts in the street racing sections of forums. There was always some good stuff. My cars are all so slow that nobody would be impressed by racing stories.
Last edited by Kira X; Oct 24, 2018 at 08:42 AM.
The JB4 tunes always did big things on BMW’s so the power boost isn’t surprising? Those numbers are impressive.
I do miss seeing more posts in the street racing sections of forums. There was always some good stuff. My cars are all so slow that nobody would be impressed by racing stories.
I do miss seeing more posts in the street racing sections of forums. There was always some good stuff. My cars are all so slow that nobody would be impressed by racing stories.
I have seen a max of 21.6 psi, and other users have hit 25 psi in higher gears. For some reason, the JB4 tuned C43 doesn’t dyno well, but runs great times at the track. Most of the beta testers are cutting a full second off of their quarter mile times, which is amazing for $550.
I’d assume the next IS350 will run a similar turbo 6 motor so Lexus may benefit from piggyback tunes soon as well. I know BMS made one for the IS200 but sales have been slow.
Luckily this was all recorded on Forza. Most forums have racing threads.
The JB4 beta can make 100+ hp and 130+ tq. I believe that C43 made 18-19 psi on that run (stock is 12). JB4 only has also ran an 11.5 @ 121 at the track with a 3.35 0-60 record.
I know a stock RCF is pretty quick, so the video is surprising.
but damn i'd love to go up against one of these tuned C450s. i know it'll get an early lead with AWD and those short little gears, i mean it's already about to shift into 4th by the time it hits 60. by then, i've only just shifted out of 1st! the ol kompressor needs a nice long stretch to get the most out of it lol. although, assuming there's infinite traction, you can just pull off a sub 4 sec 0-60 but in the real world that almost never happens.
lol yea forza... forza, mexico? if you say so mr. TXgearhead, or should i say... mr. HTXgearhead, arch nemesis of AMR tuning?
but damn i'd love to go up against one of these tuned C450s. i know it'll get an early lead with AWD and those short little gears, i mean it's already about to shift into 4th by the time it hits 60. by then, i've only just shifted out of 1st! the ol kompressor needs a nice long stretch to get the most out of it lol. although, assuming there's infinite traction, you can just pull off a sub 4 sec 0-60 but in the real world that almost never happens.
but damn i'd love to go up against one of these tuned C450s. i know it'll get an early lead with AWD and those short little gears, i mean it's already about to shift into 4th by the time it hits 60. by then, i've only just shifted out of 1st! the ol kompressor needs a nice long stretch to get the most out of it lol. although, assuming there's infinite traction, you can just pull off a sub 4 sec 0-60 but in the real world that almost never happens.
The problem with the C450/C43 is the gearing is too long after 3rd. Luckily the JB4 allows higher boost in 4th and 5th gear to help with that.
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Hahaha I’m guessing you are on the other forum. Yeah, I don’t get along with AMR. I have a big problem with tuning companies not being upfront with their customers.
The problem with the C450/C43 is the gearing is too long after 3rd. Luckily the JB4 allows higher boost in 4th and 5th gear to help with that.

2nd gear in the E55 goes up to about 85, and 3rd goes all the way to about 135 (mph) so it would definitely benefit from another gear or two. there's just SO much torque that you don't really notice though. you can go from 20 to 135 with just 1 gear, which i think is awesome. the amount of fuel you use doing so is not quite as awesome though haha.
the whole piggyback thing seems awesome though, i love the flexibility of it. i wish something like that was available for the E55. i'd like to be able to find an ECU on ebay or something, put a tune on that, and keep the existing ECU stock so there's always a backup. during the colder months it's especially easy to accidentally activate "burnout mode" if ya know what i mean 
2nd gear in the E55 goes up to about 85, and 3rd goes all the way to about 135 (mph) so it would definitely benefit from another gear or two. there's just SO much torque that you don't really notice though. you can go from 20 to 135 with just 1 gear, which i think is awesome. the amount of fuel you use doing so is not quite as awesome though haha.

2nd gear in the E55 goes up to about 85, and 3rd goes all the way to about 135 (mph) so it would definitely benefit from another gear or two. there's just SO much torque that you don't really notice though. you can go from 20 to 135 with just 1 gear, which i think is awesome. the amount of fuel you use doing so is not quite as awesome though haha.
i love the E55... it's such a damn hot rod! a bit overkill to be one's only car i think but if you have other, more fuel efficient vehicles to use then i say absolutely have one in the fleet
Yeah roots blowers aren’t very good with gas mileage. My V averaged single digits. C43 is averaging 15 mpg on E30 fuel. It can get 30 mpg on the highway with 93 octane and a light foot though.
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Yeah roots blowers aren’t very good with gas mileage. My V averaged single digits. C43 is averaging 15 mpg on E30 fuel. It can get 30 mpg on the highway with 93 octane and a light foot though.
one thing that does help in these is that the supercharger is actually on a magnetic clutch, so most of the time it's not engaged. when it does it's like someone flicking a switch that gives you a 2nd engine lol. they make fixed pulleys but i like the clutched pulley. the slight chirp when it engages just becomes a doug demuro quirk of the car.
lol right after making that i'm like hmm he probably is on mobile or something. i average 15-17 mpg usually since i only use it when traffic is light and never really to make short trips around town. >20 mpg on the highway is easily obtainable as long as you stay below like 75 or so. 24 mpg is about as good as it can possibly get, and to get that you'd have to go full eco warrior mode.
one thing that does help in these is that the supercharger is actually on a magnetic clutch, so most of the time it's not engaged. when it does it's like someone flicking a switch that gives you a 2nd engine lol. they make fixed pulleys but i like the clutched pulley. the slight chirp when it engages just becomes a doug demuro quirk of the car.
one thing that does help in these is that the supercharger is actually on a magnetic clutch, so most of the time it's not engaged. when it does it's like someone flicking a switch that gives you a 2nd engine lol. they make fixed pulleys but i like the clutched pulley. the slight chirp when it engages just becomes a doug demuro quirk of the car.









