Complicated exhaust issue (raspy mid-high rpm)

[soag17redline]

Hey guys complicated question here but I'll just list the mod then the problem..

I have hurricane mild steel 1 3/4 headers, 100 cell cats joined up to my existing stock bimodal system on my vf2 redline with otr and tune.. sounds good for the most part but quite raspy/echoey at mid to high rpm (4-7k).. im guessing its from the smaller diameter of the bimodal exhaust/the baily tip causing the raspiness.. i need to fix that im guessing i need to just replace the stock catback as well?

Now seeing as my extractors are mild steel should i stick with it or go stainless and should i stick with brand or go with a different catback brand?

Any advice would be massive as i want a deeper note across the rev range not just low-mid rpm.. cheers

 

[Not_An_Abba_Fan]

What you use will depend on how the cats were fitted. Do you have a photo of the join where the cat pipes meet the cat back?

Is it only raspy with the bimodals open?

 

[soag17redline]

Nah i dont have a picture..

Yeah with it open, when open the exhaust is very loud which is great until it starts getting raspy.. with it closed the car is pretty quiet which is handy too..

What you use will depend on how the cats were fitted. Do you have a photo of the join where the cat pipes meet the cat back?

Is it only raspy with the bimodals open?

 

[daves8]

Are the hurricane headers ceramic coated?

For depth of note I would look at either manta or difllipo/ Walkinshaw.

I went a Manta mild steel cat back as it tends to carbon up a little bit more, giving a slightly deeper dirtier note (my preference)

 

[Not_An_Abba_Fan]

If you want to keep the bimodals and stop the raspiness I would recommend a front section with a muffler. Will make it deeper and quiet with the bimodals closed, but with them open it should give a smoother more defined note.

The problem with mixing components is that none of them are frequency matched. It will be a bit of a lottery to find parts that go well together. I would fit a whole cat back, but it will probably need modifying depending on how the cats were fitted.

 

[soag17redline]

Hmmm yeah its a toss up atm whether i get a dpe stainless 2.5 catback to match up and hopefully fix the note or gamble on the cheaper alternative and get a mild steep 2.5 inch hurricane catback and have it all the same and hopefully fix it..

 

[daves8]

I have been told hurricane catbacks drone a little on the VF.

I would go DPE

 

[blackve76]

Hey guys complicated question here but I'll just list the mod then the problem..

I have hurricane mild steel 1 3/4 headers, 100 cell cats joined up to my existing stock bimodal system on my vf2 redline with otr and tune.. sounds good for the most part but quite raspy/echoey at mid to high rpm (4-7k).. im guessing its from the smaller diameter of the bimodal exhaust/the baily tip causing the raspiness.. i need to fix that im guessing i need to just replace the stock catback as well?

Now seeing as my extractors are mild steel should i stick with it or go stainless and should i stick with brand or go with a different catback brand?

Any advice would be massive as i want a deeper note across the rev range not just low-mid rpm.. cheers

I had the same with GM motorsport headers and cats with standard system just raspy crap sound as you say up over 4000 revs, added a 3" KPM system and nice deep note.

I'd just change system, note the 6.3 factory tune has extra fuel in it to get those crap sound crackles and pops, asked my tuner to get rid of them in tune and heaps nicer again

 

[Witto]

I've just fitted HSV Headers and 100 cell cats to my VF1 Calais Sportwagon. But with a R8 mid section and Bimodals, also have the same issue, particularly when going from 1st to 2nd gear under light throttle( valve is constantly open ). I'm thinking its possibly the tips are the issue as well. Sounded fine with standard headers and Cats.

 

[duaned]

What do you mean by raspy / echoey? Wouldnt it sound similar to the standard exhaust only a little louder?