R34 too loud

Hi all

my r34 is too loud for track days due to screamer pipe and straight pipe all the way 3.5inch

it is forge engine …

if I plumb the wastegate back to exhaust, I think the waste gate duty cyle map needs to be adjusted, right?

also if you put a silincer in, would that impact the map, create loads back pressure?

With an open exhaust, I wouldn't expect it to, but if it does it should be relatively minor.

Depends on how well it's designed and built. There will be a small-ish increase in back pressure, and you're just going to have to test to see how significant it is.

Thanks mate

i was thinking one one band to screamer pipe and put motorbike baffle there and one for the back box

Ah, I'd forgotten many of the UK tracks are subject to rather strict noise limits - you're going to have to check exactly what the tracks you want to visit are working with, as some are difficult for even stock vehicles to meet.

I'd suggest simply plumbing the waste gate into the front/down pipe, with a suitable expansion/bellows for differential heat expansion, to simplify things and reduce (stupid) noise of a "screamer" over that of a separate muffler.

3" systems can be hard to muffle, and not something I've had to worry about - others may be better able to advise - but you may also run into issues with the induction/turbo' noise as well. Depending how much underfloor area, and ground clearance you have, the rule of thumb is bigger is better. Different muffler/silencer designs can be most effective at different frequencies - if you know what they test at, you may get an edge selecting to suit.

Consider series or parallel setups, depending on your available options, to balance noise and restriction.

So spoke to few people one suggested he can plumb it back using electric switch

size of my screamer is 1.7inch or 45mmish and my exhaust is 3inch all the way

my questions is when you have increased back pressure what maps do you need to adjust usually, wastegate cycle? What else on back pressure would be impacted?

Turning a 3.5" exhaust into a 1" or similar exhaust by placing a silencer in it can cause serious engine damage. I really don't suggest doing that. The heat and pressure buildup on track can become catastrophic very quickly. If you need to quiet the vehicle, a muffler is much better suited.

The tune may need adjusted for either adding a muffler, or recirculating the EWG. I would plan on a tuning adjustments being required, and perhaps you'll get lucky and not much has changed after log review.

In context, you may want to edit that, Mike?

As most of the tracks in the UK are claiming down on noise levels, my customers have to re-think their straight pipes.

Depending on how loud it is and which track you're visiting you'll need to make plans to suit. Usually, a large, long mid-resonator alone side a large diameter rear silencer and as an extreme measure, a downturned tailpipe is enough for most tracks, plumbing the gate back into the front pipe will depend on the design and flow as to how it will affect the duty cycle/ boost levels.

If your exhaust fabricator is good they'll use 3-inch internal resonators and depending on space they'll have up to 5-inch external diameter or even larger for the rear.

Abbey Motorsport have a track R32 GTR and they have a massive silencer they mount on the rear bumper essentially, I am not sure of the exact dimensions but it makes them sound compliant for most tracks, Picture attached

On that last, might be worth checking out the truck mufflers, too, if one of the aftermarket car types isn't acceptable?

Hi. I have been using 3.5 inch muffler with adjustable throttle body inside of it. You can adjust the noise level as you need by simply turning electrical knob. I bought it from New Zealand long time ago and it's been very handy on the streets.

https://xforceusa.com/varex-mufflers/

Well my wastegate is 1.5inch and going to 3inch pipe. I think that shouldn’t cause back pressure unless you add silincers etc?

Why would you want to put a restriction in the exhaust rather than using the same size everywhere? One important thing to remember is that flowing gas doesn't like any type of non-linear movement as it gets turbulent causing unnecessary loss of power...