G40R Exhaust

Author
Discussion

D7PNY

Original Poster:

382 posts

170 months

Friday 18th May 2018
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Anyone messed about with their exhaust?

I need to sort out the knocking behind my right ear but was also considering possibility of a decat section or a 100 cell sports cat.

Has anyone modified or changed their exhaust before?

Don't want to have to wear ear plugs but I find it a little quiet on occasion. Was thinking a decat or small 100cell sports cat would give a little more noise and release a very small amount of much needed power?

Cheers,

Dave

jamesG20V6

873 posts

264 months

Friday 18th May 2018
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I can’t quite believe yours is too quiet?!

Mine is close to ear plugs needed in general driving, although a GRDC car.

I have had my exhaust on and off twice in last few months - fixed the fundamental problem of the manifold joint but the side / rear pipe still hits the chassis in use. The problem is there just is not enough room between the chassis and sill to run the exhaust really - mine has millimetres of clearance either side of the pipe and it is just not enough.

I had considered a flexi section post cat and then reducing the amount the rear / side pipe section can move around on the mounts but I think that will likely lead to broken mounts and more vibration through the chassis.

If you come up with anything please let me know. I’m probably going to get a full system made from scratch at some point also bough with the restricted space, I worry it will be a lot of money only to find the same problem remains.

kwak82

24 posts

195 months

Sunday 20th May 2018
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I have a decat pipe fitted to my duratec car. Slightly louder but didn’t make a huge difference. I didn’t have any knocking noises before when running the cat nor do I have any now with the decat. Where does it hit the chassis, I could take a pic of mine? There is the side pipe which has 90deg bend at mounting point then a short section in wheel well with 90deg bend then the silencer. I have powerflex mounts holding silencer, mikalor clamps on exhaust and recently replaced bush for side pipe as old one was perished.

D7PNY

Original Poster:

382 posts

170 months

Sunday 20th May 2018
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Where did you get decat pipe? Custom made?

Gonna get mine up on the ramp soon and have a look at exhaust.

Hopefully my lights will finally arrive soon and I can sort them at the same time!

A little extra rasp from a decat would be nice as I find it sounds a bit wheezy compared to my caterham. Really missing the induction noise!

Dave

kwak82

24 posts

195 months

Sunday 20th May 2018
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Yeah was a custom pipe, only a short section to replace decat. Would love to get a full system made at some point with longer headers etc. It does sound a bit sharper with the decat. I think the standard airbox does a lot to suppress the induction side noise, it looks a lot like a Pipercross px600 which seems a popular choice for people trying to get through IVA or track noise regs. The volume doesn’t look big so I’m sceptical how it performs. I see the race cars have bigger airboxes now and some are running an open filter. Would be interesting to know the differences. I think I will be changing mine for an open filter, just need to sort out an oil breather catch tank

jamesG20V6

873 posts

264 months

Sunday 20th May 2018
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I only just scraped through a noise test at Llandow on Saturday.

Inside the car , induction noise is more noticeable on mine than the exhaust, but the exhaust is bloody loud outside of the car.

My pipe is rattling along the length of the sill, making contact with the aluminium inner sill between the body and chassis. It is also making contact at the 90degree bend I front of the rear wheel. I have taken it apart and reset it a few times but it seems to find where it wants to move back to over time.

jamesG20V6

873 posts

264 months

Sunday 20th May 2018
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jamesG20V6 said:
I only just scraped through a noise test at Llandow on Saturday. I was 97db at 4000rpm at 1metre away. Had it been tested at the correct rpm I reckon it would have been well over 100db.

Inside the car , induction noise is more noticeable on mine than the exhaust, but the exhaust is bloody loud outside of the car.

My pipe is rattling along the length of the sill, making contact with the aluminium inner sill between the body and chassis. It is also making contact at the 90degree bend I front of the rear wheel. I have taken it apart and reset it a few times but it seems to find where it wants to move back to over time.

D7PNY

Original Poster:

382 posts

170 months

Sunday 20th May 2018
quotequote all
kwak82 said:
Yeah was a custom pipe, only a short section to replace decat. Would love to get a full system made at some point with longer headers etc. It does sound a bit sharper with the decat. I think the standard airbox does a lot to suppress the induction side noise, it looks a lot like a Pipercross px600 which seems a popular choice for people trying to get through IVA or track noise regs. The volume doesn’t look big so I’m sceptical how it performs. I see the race cars have bigger airboxes now and some are running an open filter. Would be interesting to know the differences. I think I will be changing mine for an open filter, just need to sort out an oil breather catch tank
I did think about an open filter to ditch the standard setup. Wasn't sure how much road crap would get up there but actually seems ok after some runs in the rain etc (unlike up behind the headlights!) Annoyingly I had a catch tank in my loft and gave it away to someone as it was surplus to requirements at the time!
Wonder if open filter would work ok on current backing plate...I'll need to have a proper nosey at it!

D7PNY

Original Poster:

382 posts

170 months

Monday 21st May 2018
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Had a nosey at the filter tonight.

Airbox actually has pipercross stamped inside it and after some measurements it would appear it is the px600 you thought.

Open filter ordered. Picking up an old catch tank I lent a friend tomorrow so will see if I can make that work before buying one! Not sure where/how I will mount it right enough!

Hopefully that will sort out the noise that I'm craving! Even my 8 year old says my caterham (k series on roller barrel throttle bodies) sounded much better!

Dave

D7PNY

Original Poster:

382 posts

170 months

Tuesday 22nd May 2018
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Anyone got any pics of catch tanks fitted in g40? Trying to figure it out

Cheers,

Dave

kwak82

24 posts

195 months

Tuesday 22nd May 2018
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Fitted pipercross open filter, definitely a pipercross backplate as fits ok. Have just used an old water bottle as temporary catch tank while I test it. Had to modify PCV non return valve as well as no longer a vacuum to open it. I did it the hard way by removing the whole black plastic assembly, then realised the small orange 90deg bend comes out with just an external clip.


Also took a pic of rear exhaust section in wheel well to show my clearance, not an easy spot to photograph

kwak82

24 posts

195 months

Tuesday 22nd May 2018
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Saw this pic of a catch tank fitted online as I was trying to figure out what size/shape to buy, it’s a zetec car so has the extra chassis brace at the front which appears to be where it’s mounted. Was wondering how low it could be mounted seeing as duratec cars don’t have the brace?

D7PNY

Original Poster:

382 posts

170 months

Tuesday 22nd May 2018
quotequote all
kwak82 said:
Fitted pipercross open filter, definitely a pipercross backplate as fits ok. Have just used an old water bottle as temporary catch tank while I test it. Had to modify PCV non return valve as well as no longer a vacuum to open it. I did it the hard way by removing the whole black plastic assembly, then realised the small orange 90deg bend comes out with just an external clip.


Also took a pic of rear exhaust section in wheel well to show my clearance, not an easy spot to photograph
Hadn't thought of just using a plastic bottle (albeit as a temporary measure).

Hadn't thought about the pc valve needing modified? Do you have any more details on that?

kwak82

24 posts

195 months

Wednesday 23rd May 2018
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PCV is just a valve on the crank case breather assembly, it means that at idle or low speed it stays closed but at higher rpm the manifold vacuum (as the breather is tied into airbox) causes the valve to open to allow airflow. If you connect to tank then valve will always be closed. I didn’t take any pics of mine but this shows the part I’m talking about, it is blue in this pic but mine was orange on the G40R,
There are a few guides online like this one, http://www.focusfanatics.com/forum/duratec-perform...

D7PNY

Original Poster:

382 posts

170 months

Wednesday 23rd May 2018
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Thanks for that. Very useful. Looks a bit of a pig to get to!

Couldn't see in the article but do you need to modify anything where the system comes out of the rocker cover as well?

Still to figure out how to mount the catch tank but thinking best place is beside the washer bottle and expansion tank (Not much other space to mount it or if there's space, nothing to attach it to!)
Cheers,

Dave

D7PNY

Original Poster:

382 posts

170 months

Friday 1st June 2018
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Filter and catch tank all fitted.

Not much room for catch tank and my original idea of fitting it beside washer bottle didn't work as hoses wouldn't clear bonnet.

Plan be was attaching to chassis leg just down from there. A bit lower than I'd like so may look at getting a different style tank that will fit up by the washer bottle.

Absolutely transformed the sound of the car and this was what I was missing before! Think I can now fall in love with the car!

Just sounded strained at higher revs before but now it sings all the way up the rev range so I'm delighted.

Dave

jamesG20V6

873 posts

264 months

Saturday 2nd June 2018
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It looks like my air box is coming off then. Maybe the increased induction noise will help drown out the exhaust rattle biggrin

D7PNY

Original Poster:

382 posts

170 months

Sunday 3rd June 2018
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jamesG20V6 said:
It looks like my air box is coming off then. Maybe the increased induction noise will help drown out the exhaust rattle biggrin
You won’t regret it!