Missing a few BHP on my RCF

[CJP1]

2 minutes ago, BillNick said:

That’s a remarkable result. Anything else changed since the baseline run in December? Same fuel?

All exactly the same and changed nothing (apart from tinting the windows and putting a new set of wipers on🤣).

To be very honest I thought there may of been an increase and thought possibly 20 bhp more but certainly didn’t expect that. 

[BillNick]

I’m going to do the same when my invidia arrives, eventually….

will also report back.

[Rob RCF]

12 hours ago, CJP1 said:

 

Wow, a simple exhaust swap is giving you such a big torque bump all the way through the rev range and nearly 50bhp gain? Isn't this too good to be true? I've seen many reports of exhausts giving little to no benefit on RCFs. People often say only headers free up power, and I was even sceptical of that tbh. Either way, great result!

No tune, literally stock except for the exhaust swap? How long did you drive the car with the new exhaust before getting that dyno run?

*Edit* - Looking at the graphs again, the run still ends around 6900rpm. I'm puzzled that they wouldn't take it to the full 7300.

[C.B]

I think this is a prime example of why it sometimes gets called the dyno lottery.

I find it very hard to believe just a cat back exhaust has gained 50bhp on a NA car. 10 would be a good result and 20 a shock, the cats are still in place so there has been very little restriction removed.

[CJP1]

8 hours ago, Rob RCF said:

Wow, a simple exhaust swap is giving you such a big torque bump all the way through the rev range and nearly 50bhp gain? Isn't this too good to be true? I've seen many reports of exhausts giving little to no benefit on RCFs. People often say only headers free up power, and I was even sceptical of that tbh. Either way, great result!

No tune, literally stock except for the exhaust swap? How long did you drive the car with the new exhaust before getting that dyno run?

*Edit* - Looking at the graphs again, the run still ends around 6900rpm. I'm puzzled that they wouldn't take it to the full 7300.

I didn’t have a map on it and just had the exhaust fitted. It was fitted just over 2 weeks ago and I’ve covered around 850 miles.

The dyno was set to 7000rpm as it was the last time I put it on. When my car was on the dyno before he was setting quite a few things up but this time he didn’t need too as he was using all the same info from before. He was very surprised too about the result but looking at the old exhaust system the pipe that is on both back box’s for some reason seem to go into an oval shape and massively restricts the air flow which may have something to do with it along with the resonators / second cats whatever they are 🤷🏻‍♂️.

He will take it to 7300rpm next time we throw it on as before the exhaust was installed the power was dropping off around 6800rpm so no point taking it any further. 

[BillNick]

I’ve also noticed the OEM pipe on the rear sections are flattened in places. Panicked first of all thinking someone had damaged them whilst stored in my garage. I guess it’s to clear some suspension or for consistent ground clearance.

But you’re right, must be restrictive even if negligible.