Pictures of the 2014-2016's Header Design

[CandyRedRC46]

Stumbled across some nice high res pictures of the 8th gen's header. Very interesting design. It is a stark contrast to the 5th and 6th gens, as the front 2 pipes merge and the rear 2 pipes merge, before hitting the cat. Also worth mentioning is the single o2 sensor right before the cat, as opposed to the 5th/6th gens two o2 sensors.

 

You can zoom way in on them here on their ebay listing:
 

http://www.ebay.com/itm/2014-Honda-VFR800F-Interceptor-Exhaust-Header-Pipe-Manifold-18150-MJM-D00-/232031761742?hash=item36062bb54e:g:oqAAAOSwdzVXm5tR&vxp=mtr

[CandyRedRC46]

[CandyRedRC46]

[CandyRedRC46]

[CandyRedRC46]

[CandyRedRC46]

[CandyRedRC46]

[CandyRedRC46]

[CandyRedRC46]

[CandyRedRC46]

Looking at the CAD drawing, compared to the real life pictures, its funny, Honda knows what a proper 2-1 merge is supposed to look like, they drew it correctly, but by the time it makes it past the bean counters, it always seems to turn into some kind of 90 degree T-pipe travesty...

[SEBSPEED]

Looks like a wonderfully shitty cost cutting measure to me, making use of stampings vs tubing.

[CandyRedRC46]

 

Man it is a pain in the ass to insert pictures on this forum. I had to delete a bunch of pictures from 5 years ago, one at a time, before adding anymore. Apparently I was at 107% of my allotted storage lol.

 

Anyways, the two front cylinders are definitely merging at around 90*, the two rear, I can't get a decent view, it appears to be better than the front, but still pretty crummy, especially where the rear two come together and immediately make a 300* bend. Honda may have done a better job with creating an equal length header, than the 5th and 6th gens, though.

 

I would like to get my hands on one of these headers and take some piping diameter and length measurements. It would be interesting to see if Honda continued the trend of smaller and smaller primary diameters (98/99>6th>8th) or if they went back to the 98/99 diameter (8th = 98/99 > 6th) or even bigger (8th> 98/99 >6th). It would be pretty cool if these headers were like the 7th gen's, where all you have to do is cut out the cat and merges and install quality 2-1 merges, to make some big power.

[RDMcD]

I've spent many, many hours trying to come up with a design for underbelly exhaust for my fifth gen and I think there are a couple of ways it could be done. The uncertainty of the performance of the final product has stopped me from spending the time and money on it.

Looking at these pictures has me thinking maybe a simple alternative would be to convert or chop off the large cat on this exhaust and replace it with a muffler???

Does anyone know if this system will fit a fifth or sixth gen?

[SEBSPEED]

15 hours ago, RDMcD said:

I've spent many, many hours trying to come up with a design for underbelly exhaust for my fifth gen and I think there are a couple of ways it could be done. The uncertainty of the performance of the final product has stopped me from spending the time and money on it.

Looking at these pictures has me thinking maybe a simple alternative would be to convert or chop off the large cat on this exhaust and replace it with a muffler???

Does anyone know if this system will fit a fifth or sixth gen?

 

Same engine & frame as 6th, why wouldn't it?

 

Shoot me a PM if you want to discuss underbelly exhaust, I have an upcoming project that is getting one.

[CandyRedRC46]

16 hours ago, RDMcD said:

I've spent many, many hours trying to come up with a design for underbelly exhaust for my fifth gen and I think there are a couple of ways it could be done. The uncertainty of the performance of the final product has stopped me from spending the time and money on it.

Looking at these pictures has me thinking maybe a simple alternative would be to convert or chop off the large cat on this exhaust and replace it with a muffler???

Does anyone know if this system will fit a fifth or sixth gen?

 

So you basically want to run open header? I wouldn't be surprised if that lost some power or compromised the powerband, due to drastically shortening the tuning length of the entire exhaust system. If going for an underbelly exhaust, you should probably try to put a loop in it to keep the overall length of the exhaust in check.

[RDMcD]

Seb, I guess I'm thinking more fifth gen. it should fit but I wondered if there were any subtle differences that would be a problem...pm sent.

 Candyred, something along these lines, but it looks like the gen 8 system has a longer cat so more room for a muffler.

[CandyRedRC46]

Thats pretty cool. If you are thinking to do something similar, I would take the time to improve the 2-1 merge angles (aim for closer to 15*) and step up the diameter a couple mm's, before and after the merges.

[RDMcD]

One day I will build an entire system from scratch. This would only an experiment so not too worried about performance.

Why does the eighth gen merge the front cylinders together and the backs together when all other vfrs join diagonal cylinders? I thought this only worked on 360 degree engines.

The eighth is still a 180 correct ?

[CandyRedRC46]

Yes the eighth gen is still a 180* like the 5th/6th gen's. I really don't think the cylinder pairing is a big deal with these bike's uneven firing order, as all the different 5th/ 6th/ 8th gen header offerings seem to pair different cylinders and work fine. My Two Brothers Race header actually pairs the front/back left together and the front/back right together.

 

I think primary diameter/length and merge quality is much more important than actual cylinder pairing. Ideally you should be shooting for 35mm internal piping diameter on the primaries (slowly stepping up to 38mm towards the end, before the merge, then 42mm secondaries and I think a 50mm collector?), 15* merge angles, as close to equal length as possible (around 30 inches each, I forgot the exact length, but I took the measurements in one of my threads).

 

Where the ebay headers fail, is their internal diameter is only about 31mm (about the same as the 98/99 factory headers), their primary lengths are all over the f@#$ing place (like a 10 inch variance) and they have huge merge angles of like 180 degrees, with bubble gum welding and chicken wire wrapped on the inside of the collector.... But nobody cares, because they're catless and not rusty lol.

[Epyon007]

On ‎9‎/‎28‎/‎2016 at 8:47 AM, CandyRedRC46 said:

Looking at the CAD drawing, compared to the real life pictures, its funny, Honda knows what a proper 2-1 merge is supposed to look like, they drew it correctly, but by the time it makes it past the bean counters, it always seems to turn into some kind of 90 degree T-pipe travesty...

Give that ish to Black Widow.  They will do it up right!!!!

[HighSideNZ]

The RC45 pipes I modded to fit my 825cc Gen 5/Gen 6 have the front pipes merged together and the rears merged together.

They are around the sizes that CandyRedRC46 outlined but with mine the front primaries are longer than the rear and the rear secondary is longer than the front.

Overall, the primary/secondary pairs are the same length front to back and I believe the idea was to balance the mid range and top end.  More top end on the rear and more mid on the front.

 

From what I can see from the mappings I've built, with a wide band in both sets of pipes, shows quite different mixture curved front to back with the front fatter in the middle.

 

My 2 cents worth.

 

Cheers

Phil 

[Mohawk]

Hey Phil,  How goes the modified VFR 5/6th gen ?  Did you ever get a DJ dyno run done ?

[RVFR]

Wow,  How'd I miss this thread,   good stuff to go by..

[auggius]

Remember this thread?

 

Tok Tokkie 5th gen exhaust

[RVFR]

Ehhhoooo. interesting approach. but other than a diffent look and sound wonder if there was any gains?   But all for not in a sad way,  Ouch!   that had to hurt.