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HPX system for the BA XR8s

9K views 82 replies 17 participants last post by  FANTM1 
#1 ·
This was just recently sent to me by another ford forum member.


HPX have now got a bolt on true twin system for the ba xr8s.
This is their claim "This sports system will out perform any similar product below 5000RPM"

They have also kept the pipes 2 1/4 as they say the XR8s are very back pressure sensitive.

Has anyone tried this?

I don't like the fact how it is still within legal limits....to me that is just too soft. But I guess they have to do it if they are to mass produce it.

Here is the PDF.

http://members.optusnet.com.au/fullthrottle/BAV8.pdf

I had to upload it onto my site as I dunno how to upload files here. Please let us know if you have one of these systems on your beast!
 
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#3 ·
So did I. They are adamant that 2.5 inch is too big for the XR8s.
THeir system keeps the orignal Y piece (which is 2.5inch)...same as the herrod setup.
They run a dual 2 1/4 the rest of the way. Herrod's is dual 2.5 going into a single 3". I have no doubt both these setups have been designed to maintain back pressure.

As you probably know I have tried a dozen setups. Previously they have all been barky. However as of yesterday I found a muffler that is giving me the deep and boomy sound I was after. The current setup is a 2 1/2 inch running to a front twin in twin out muffler. Then 2 1/4 the rest of the way going into a smaller resonator.

Now that I have the deep and boomy sound, I am missing the v8 pulse!! You can only hear the pulse on idle or if you floor it. The rest of the time it runs like a turbo 6. Creates a very similar sound to the herrod setup except louder.
What I want to do is get rid of the merge pipe at the front and have 2 seperate pipes. This SHOULD give more pulse. But I'm not sure how this will affect performance (if at all). Perhaps someone with some knowledge on balance pipes can enlighten us?
 
#5 ·
Nope.
I rang a few places and they all tell me that balance pipes are only necessary for very high powered engine where the pulse needs to be balanced. It can sometimes produce more torque but you're not looking at big differences here. I'm gonna bite the bullet and try the split system. Will let you know if I feel any difference. (it will certainly sound better).

PS. The HPX system seems to be selling like hot cakes...rang two places and they have been sold out! Waiting for more.... hmmmm
 
#7 ·
im getting mixed messages in terms of price.
hpx themselves tell me 1200 retail. I rang a retail (won't say who) and they said 1100 fitted. Not bad for a dual full stainless steel system.
 
#12 ·
Herrod is $1300. Full stainless steel also.
I doubt there would be much difference in power between the two of them. Maybe slightly different torque characteristics..one is dual 2 1/4 all the way, the other is a dual 2 1/2 to a 3" then out to a dual 2 1/2".

Rod. The original mufflers are seperated pipes. They don't merge.
The front muffler is only 2".
 
#15 · (Edited)
philstoj. I asked them (HPX) if they could describe what it sounds like. The answer was "a bit like the AU XR8s". :eek:) I'd have to hear it to believe it as the windsor v8s with an exhaust sound really good! I asked them to gimme a buzz when they do the next xr8 ute. So will have to wait and see.

Con... I would tell you if i knew. It is a single muffler with twin in twin out. It is quite heavy and feels very solid. Inside the chambers are split i.e. it doesn't merge into a single pipe. I believe it came off a skyline gtr (i didnt know skylines came with twin systems!). The pipes inside are 2.5inch The entry and exit are 2 1/4 inch. Thats the best I can describe it. I'll ask the people what type of muffler it is and will let u know... probably over the weekend.

I only pray that splitting the front section into two seperate pipes will gimme the v8 pulse I'm after and won't loose any torque.

It has been a very long journey for me. Altogether tried about 14 different setups. The zorst joint I went to has been extremely patient with me lol. They were willing to let me try as many system as I like until I got the sound I was after for my intial investment. (I think they regret it lol)
 
#16 ·
well .... had the front section demerged ( made into two seperate pipes). Surprising result. Pulse still not as evident! Sounds good when idling or free reving but no pulse on light to medium throttle. I suspect the "deep and boomy" front muffler has killed the pulse. Good thing is that it doesn't seem to have effected the torque characteristics on the bummometre. I've decided im gonna keep this current one...still not exactly how I like it...but it is one of the better setups out of the 15 odd that I've tried :eek:/

Still keen to hear the HPX one.
 
#18 ·
Herrod is $1300. Full stainless steel thats fitted.. is the hpx for Roughly $1400 fitted ???
 
#20 ·
To "rod c" I have stripped the orig rear muffler. The internals are, 1st section is made up of two perforated 2" pipes sharing a common perforated oval chamber,then a wrap of sound deadener, the pipes then go into a second chamber stepping back up to 2&1/4" inch pipes which seem to have some tuning ports hanging off of them. I have modified my rear by packing the first section with f/glass and welding the two ports closed. I then cut off the rear pipes and removed the perforated inserts and deadenig material and welded them back on. This gives a much better idle note from the rear(deeper and slightly louder) and under heavy acceleration sounds like it really means business. But it still doesn't have that meaty sound at lesser throttle.

The HPX system may be the answer but I'd like to hear one.

One of the guys in our club has a 3" single system using a Redback chambered muffler. that sounded pretty meaty. It was on an auto XR8. made plenty of beefy noise, maybe a rear res. would work to reduce the level, if required.
 
#21 ·
Fantm1. Great to hear someone else experimenting with the systems. I have been doing so for the last 3 months...the exhaust shop has been my second home.

Getting these things to sound a) meaty b) loud [much louder than 90db] c) with distinct v8 burble is very difficult. If someone can come up with the magic formula I'll be the first customer.

From my experiments you can get a meaty sound by a) having a single system running at some stage in your setup b) using a mixed dual in dual out muffler. But this takes away the v8 burble.

Keep me in the loop with your experiments.

ta
 
#25 ·
Ive changed the system on my au2 xr8 ute, it looks identical to the hpx system, i think that manufacturer made them fo ford...
that system was very quiet from the outside, tho it had a nice sound from the cabin, i decided to go to a full 3' single system, with 4-1 extractors and hi flow cats, it sounds very meaty now, deep and loud, i was told that this system is not legal, but it is only quite loud once you start accelorating from low revs(it booms) i got a good hp gain from it too...
A while ago, i heard one of these systems on a ba gt at herrods, same type of sound, very nice burble and you could hear it idle quite destinctly..
Have you tryed one of those systems? it really does sound nice and strong. Ive always been a twin system fan, but ive heard a few cars with this type of system and i prefer the sound to twins.
 
#26 · (Edited)
Don't be mistaken between the GTs and the XR8s. The GTs run slightly different cams and yes they do sound better. I had the herrod/difillop 3" catback system put on my ute... drove it around the block... took it off. Nice deep note but made the thing sound like a turbo 6. **no offence to anyone..just personal preference**

Maybe extractors and high flow cats will help a little with the v8 burble. But I've been told by herrod it doesn't make a lot of difference. Which is why i haven't gone extractors yet. Philstoj did you get the herrod setup? If you did then it will be within legal limit.

It's hard to say what sounds good with an exhaust system...we all have different tastes. however I think I was previously spoilt by my toyota soarer v8 (1UZ-FE). That thing sounded nuts.

phantom. That twin 3 inch sounds nice. I noticed that it does merge into a single 3 1/2" inch. Looks like a bigger replica of the herrod dual 2.5 inch setup where it merges into a single 3". I think the merge section controls the bark. Sounds good...would love to heard it in real though...bet it sounds even better! .... did you test the DB levels? And also... with a system that huge...did you experience any loss in torque at lower revs? HPX say anything bigger than a dual 2 1/4 inch will adversely impact drivability i.e. low to midrange.
 
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