every explanation you have given about this exhaust had been spot on! I agree, perfect balance.

 

Thanks man. Glad I could help.

 

I don't recommend this. The service manual says Expect the engine will not start on the first attempt. Pretty common with these ECMs.

Also, looking at the dyno charts, shift at redline no matter what. Torque is inconsequential to shift points, the only thing that counts is horsepower. Since horsepower stays flat all the way to redline, redline is your shift point no matter what. Area under the curve is what you want, and shifting at redline will maximize area under the curve. Don't get confused, this is simple mathematics, Flat horsepower means shift right at the point horsepower dips. If horsepower doesn't dip, shift at redline.

 

Actually, both methods work but the fuse pulling is preferred for reasons stated in Step 1.


https://www.clublexus.com/how-tos/a/...our-ecu-363500

 

Here are the gains. Laid over from previous gains. Highest run was the first, the next 2 runs peaked at the same lower power of 411. After i do the 60k maintenance i’ll continue on with the dyno tune and will make a separate thread for that.

 

416 whp with Invidia exhaust only is pretty good. I realize you have the LEMS intake, but that does not add any power so great numbers for exhaust only.

 

Looks like a decent 15 hp and tq gain around 3500 rpm, but minimal peak gains.

Thank you for documenting your progress.

 

It added 8 whp at the peak, but the final peak number of 416 whp are on-par with how much RCF dynos with exhaust only.

 

Thanks for providing. I too have the invidia, and always wanted to know the actual gains. The community has too many abstract numbers without actual confirming figures. The gains are kind of disappointing tbh, but gains nonetheless!

Curious the dynos after the tune.

 

How do you like the LEMS intake? Does it sound like stock or the LEMS intake changes or makes the intake noise louder?

 

I feel you. For me, the noise it makes was worth the money. The gains were icing on the came for me. I still have another 6k miles until the spark plugs, but i’ll post those tune results as soon as i can.

Its the Mod in Japan intake but i didn't install it yet. Even though it adds no power i just wanted to play it safe and do the dyno run without any other mods. I wonder if it would have made a difference, because when i touched the stock tube, it was still pretty hot after 2 hour drive in 100 degree temps. I Wonder if it was warming the air being sucked into the engine, or does the air travel too fast to be effected by the tubes temperature?

 

Yeah, that 100 F temperature will have a big effect on your performance due to heat soak. I was going to say that the temperature can make the dynos fluctuate a lot. Proper before/after is dyno'ing on the same day. Your starting out numbers were a lot higher than normal at 408 whp bone stock. RCFs stock dyno at max 400 whp. In the end, your number even out with the hub dyno, is right where they should be with a full exhaust. At 416 whp, that is what they typically dyno at the most. Also, the area under the curve really matters where it has gained 15+ whp through the rev range. Peak is just when you hit close to the redline.

Here is a Meiesterschaft dyno where it dyno'ed at 414 whp with dynojet. Even if one factors in lower drivetrain loss with the hub dyno, your 416 whp with the 100 F heat soak would be very comparable to that considering the dynopack dyno'ed higher than usual.

 

I know everyone knows this, but remember: Dyno numbers should be taken with a grain of salt because of all of the varying conditions between dynos, atmospheric conditions and cars. It is very hard to draw any real conclusions by saying "this car got these numbers on that dyno on that day and therefore it is more/less powerful than that car that got those numbers on that dyno and that day." The best way to compare cars is at a dyno day, where cars are running back to back on the same dyno.

The OP showed some mid-low range torque gains and a little bit of HP up top by adding his exhaust. Some people have reported much higher gains from adding an exhaust only, but again, I wonder how many have done what the OP did, which is go to the same dyno a week later with a new mod and get another measurement. It would have been great if he could have done the before and after on the same day, but for most people that is totally impractical.

Of course the bottom line is that adding an exhaust to a car like our RCF is (or should be) about the sound moreso than the actual power gains, because most of us are not trying to squeeze that extra tenth out of our quartermile times or shave that extra second from our lap times. I definitely think sound, looks and cost should be the main drivers in choosing an exhaust, because if you're in it for the power gains you'll probably be disappointed.

Thanks for the data javrabbit.

 

Thanks for taking the time to post this information.

As mentioned above, the sound of the car is so important. When I first got the RCF I was so bummed by how quiet it sounded. I think a better tuned exhaust from the factory would have helped this car sell better in the beginning. I went with a much simpler Tanabe Medallion axle back and it gave me the sound I was looking for and the car certainly sounds faster...LOL.

 

Again, his final number is 416 whp when his RCF had heat soak loss due to hot 100 F day. If you factor in drivetrain loss, that is around 490 crank HP with minimum 15% loss with the hub dyno factored in. That is what should really matter.