Switching to 1 7/8 headers

[SAMCRO]

Hi all, I was just wondering if it's worth switching from 1 5/8 headers and 2 1/2
exhaust to 1 7/8 and 3'' exhaust? How much more power would I gain roughly? Got xforce at the mo, but I'm considering getting kpm..??

[LooneyR8]

Just out of curiosity.....what motor? This is an important question as 1 7/8th are rather large for anything running standard 853 or 241 heads...but should you be running any of the 6 or 6.2 litre variants with a decent flowing cat back you will definately get gains but they will be in a different rev range....

[chev]

You know what to do big man:thumbsup:

[zorro]

I swapped from 1 5/8 try-ys and 2.5" catback to 1 7/8 4>1s & 3" when I put the ported 243's on my old ute. Until then ran consistent times & numbers (all on same dyno but really I couldnt give a toss). After new exhaust and touch up it felt better top end that was about all, plus the sound of the thing gave us a hard on whenever I drove it.

TBH unless you got a decent cam on the cards or heads save your money

[Cmycv8]

I swapped from 1 5/8 try-ys and 2.5" catback to 1 7/8 4>1s & 3" when I put the ported 243's on my old ute. Until then ran consistent times & numbers (all on same dyno but really I couldnt give a toss). After new exhaust and touch up it felt better top end that was about all, plus the sound of the thing gave us a hard on whenever I drove it.

TBH unless you got a decent cam on the cards or heads save your money

I am currently running Tri-Ys and a unknown brand of CAT and this was all done well and truely before I went to a performance shop. Now that I have a cam and tune the headers and cats are definitely holding it back. If your looking at a cam down the track I would get new headers and cats at the very least.

Just my 2c.

[zorro]

I wouldnt hold your breath on getting any massive gains. Ute ran 376rwhp on the try-ys and 2.5" catback (which was a pretty sad affair, badly made), and fwiw it had only ever been on the one dyno having 4 runs at different dates and all making within 5rwhp of each run to check AFRs and power curve

The bigger pipes were noticeable top end where you dont normally see on roads and I threw them on mainly as I was planning on doing track days and trying to get to the strip more often, then I moved to melbourne and sold the ute.

[SAMCRO]

I got mild cam in my VE. Managed 315rwkw 2 weeks ago at Chev's.
I thought bigger headers=better bottom end??
I'd like to get KPM as they are drone free. The xforce that I have is not kids friendly (drones, but not too bad tho)

[SAMCRO]

You know what to do big man:thumbsup:

Hey Gary!
Thought you were closed until 10th? And I had this question doing my head in so I thought I might ask :)
I'll come down to see you (by that I mean annoy you :) )

[dogsballs]

don't 1 7/8 have 3.5" outlets??

i swapped out some sureflo shorty 1 3/4" 4-1's modified cats and crusty twin 2 1/2" , to 1 3/4 4-1's long, 200 cpi cats and twin 3" x-force. made no difference on dyno, but improved mph on strip.

[Souljah]

don't 1 7/8 have 3.5" outlets??

i swapped out some sureflo shorty 1 3/4" 4-1's modified cats and crusty twin 2 1/2" , to 1 3/4 4-1's long, 200 cpi cats and twin 3" x-force. made no difference on dyno, but improved mph on strip.

This is very interesting mate. Sounds like we both had the same exhaust system before and after as i have just brought a twin 3 xforce and was considering swapping my shorties to the long pacemakers.

[Wonky]

don't 1 7/8 have 3.5" outlets?

Pacemaker 1 3/4" and 1 7/8" both have 3" outlets.

[dogsballs]

Pacemaker 1 3/4" and 1 7/8" both have 3" outlets.


http://www.pacemaker.com.au/holden_commodore_v8_gen3_6ltr_ls2_vt-vz.html

PH 5362 - COMPETITION HEADER
COMMODORE | VT-VX-VU-VY-VZ
MONARO
5.7 Litre Gen3 | 6 Litre LS2 | Manual & Automatic
TUNED Design

P/Steering: Yes
Gasket: DSF 138
Air Con: Yes
Primary Pipe: 1 ⅞" (48mm)
Oxy Sen: Yes
Secondary Pipe:
E.G.R: N/A
Outlet (flanged): 3 ½" (90mm)
Y Branch: N/A
Fitting Time: 3 Hrs

[dogsballs]

This is very interesting mate. Sounds like we both had the same exhaust system before and after as i have just brought a twin 3 xforce and was considering swapping my shorties to the long pacemakers.

i am going the bigger again, but with a L76. previous car bolt-on with ls1 ran 11.95@112 mph, so they have merit.

plus sound awesome.

[Wonky]

http://www.pacemaker.com.au/holden_commodore_v8_gen3_6ltr_ls2_vt-vz.html

They're special (expensive?) headers and I think you'll find their standard headers are 3" outlet. Plus HoTBoZ has a VE and on VE the 1 7/8" headers (like I and a few others I know have) have 3" outlet.

[AMADR8]

They're special (expensive?) headers and I think you'll find their standard headers are 3" outlet. Plus HoTBoZ has a VE and on VE the 1 7/8" headers (like I and a few others I know have) have 3" outlet.

i think they are about the same price as the ve ones wonks

[VYSHSV8]

i think they are about the same price as the ve ones wonks

Definitely have 3 1/2 outlets seen them the other day in Perth and from what inunderstand when speaking to one of the owners of pacemaker no price difference

[Wonky]

:doh: Looks like I'm both right and wrong. :confused: First time in my life I've ever been wrong too!! :lmao:

I suspect only people after every single kw would go for 3 1/2" outlet as would be messier marrying them up to the exhaust i.e. reducers????

[VYSHSV8]

It's cool Gaz btw can't wait for the new tips pacey are making to suit various models:))

[Tre-Cool]

my new 4-1 pacies for my vy come with 3 1/2 collectors and along with the flange to adapt it down to 2 1/2". go figure.

[VYSHSV8]

my new 4-1 pacies for my vy come with 3 1/2 collectors and along with the flange to adapt it down to 2 1/2". go figure.

How many sets of extractors sitting on the shelf now mate:)

[BLACKVE]

Don't know F all about flow etc but noticed the standard ve heads exhaust port is only about 1 5/8 so you'd think 1 3/4 would be fine, fitted 1 7/8 to be sure though lol

[dogsballs]

don't the new pacies have that weird collector, which rumour has it robs power compared to the old style?!?

[BLACKVE]

don't the new pacies have that weird collector, which rumour has it robs power compared to the old style?!?

My VE had the early style 1 7/8" header, changed to a ceramic coated set with the funny merge and no real difference.

[SAMCRO]

Hey Wonky, you know my car and you have KPM. Do you think it's worth me doing it? How much would I gain you reckon? Or am I better of getting the head work done?

[zorro]

Don't know F all about flow etc but noticed the standard ve heads exhaust port is only about 1 5/8 so you'd think 1 3/4 would be fine, fitted 1 7/8 to be sure though lol

Hence why when I put the 243 heads on my old ute one of the things I did was match port the exhaust on the heads.

Look at the Hurricanes, I had the 1 7/8 (non VE) and next to a set of Paceys they came up better in quality (very tidy welds) and the price was for me $200 better than Paceys

[DCV1NU]

Hey Wonky, you know my car and you have KPM. Do you think it's worth me doing it? How much would I gain you reckon? Or am I better of getting the head work done?

The person you want to be speaking to is blackdiamond aka John from protek tyres, he orginally had a full xforce system with the stepped headers,cats & 3inch catback. I cant remember if he swapped over to the full kpm before or after he head & cammed his ve ss ute(i think it was after), but either way he would be able to answer your question.

Put it into perspective a Higgins cnc ported head change over will cost roughly $1800 not inc install for a gain of roughly 15rwkw, a full 3inch kpm system with the bigger 1 7/8 hpc paccies is roughly around $4400 installed with a gain of roughly 20-30rwkw over a stock system.

[Tre-Cool]

i cant get over the cost of ve exhaust systems when it is essentially some bent pipe and mufflers...

[fishla]

a full 3inch kpm system with the bigger 1 7/8 hpc paccies is roughly around $4400 installed with a gain of roughly 20-30rwkw over a stock system.

With a tune :)

I'll just finish this off for ya Boony :cheers:

[HYMEY]

Yeah there sure is a massive mark up. The diffilipo 1 7/8 is a nice header but has a crap collector on it I would get ones through Dus speed. There is a little more power in them from what I have seen but very little. I still like the x force stepper headers the most, they work good. Russo's already proven while they made less peak the avg power was better and car accelerated harder in Mick's old VE. 1 3/4 is plenty enough though just look at some of the engine masters stuff a lot running 1 3/4" still on 700hp 400ci small blocks. Bigger is not always better.

[Souljah]

I've heard from a few on here and seen one in person that the Xforce extractors for vt/z sit very close to the p/steer rack and have in the instance i've seen burnt a hole in the boot. Have they changed there design at all?

[Wonky]

Hey Wonky, you know my car and you have KPM. Do you think it's worth me doing it? How much would I gain you reckon? Or am I better of getting the head work done?

Knowing what was Curtis' old car and now is yours is a bit of a freak I would have said no, even as a KPM poster boy. :D However, that was until I read about the drone you have, something I wasn't aware of. From a power perspective you may not gain a lot as that car seems to work very well as it is.

[dogsballs]

Yeah there sure is a massive mark up. The diffilipo 1 7/8 is a nice header but has a crap collector on it I would get ones through Dus speed. There is a little more power in them from what I have seen but very little. I still like the x force stepper headers the most, they work good. Russo's already proven while they made less peak the avg power was better and car accelerated harder in Mick's old VE. 1 3/4 is plenty enough though just look at some of the engine masters stuff a lot running 1 3/4" still on 700hp 400ci small blocks. Bigger is not always better.
bang for buck i think x-force are the go.

[SAMCRO]

:confused::confused::confused: Yeah, I don't mind the drone as it's not bad, but with kids and wife in the car..I'm waiting for a backhander all the time :):)
Might do the head instead.. It's a huge difference between vy,vz and ve exhaust upgrade, the cost wise that is..:vpo::vpo: and I have to agree that xforce is a good value for money.. I actually almost left my exhaust at Apollo Bay last week as I ht the bottom pretty darn hard that you could see the sparks from Melbourne I reckon :vpo::vpo::vpo:

[Tre-Cool]

anyone here got a auto ve with the difillipo 1 7/8's and finding the pipe that does the bend near the gearbox is sitting right on the bell housing?

thinking i might need to heat up the pipe with an oxy torch and bend the pipe off the gearbox.

[AMADR8]

i went from the stepped headers and xforce cats to the, pacey 1 7/8 headers not long after my cam install, there was no power difference on the dyno and i cant tell any difference at all on the road

[SAMCRO]

So...unless planing to slap on a blower or a turbo the difference is insignificant? Does KPM cat back fit onto xforce header? I might just have to do that if it fits to get rid of the drone and get that tough sound..

[robbo_ve]

Hi bud

I think the xforce headers will bolt straight up to the kpm system.

Cheers

[SAMCRO]

Good news hey!!:goodjob::goodjob:
Cheers

[DCV1NU]

So...unless planing to slap on a blower or a turbo the difference is insignificant? Does KPM cat back fit onto xforce header? I might just have to do that if it fits to get rid of the drone and get that tough sound..

Bolting up a bigger set of headers will reduce your droning, so bolt up a set of 1 7/8 4-1's with some better higher flowing cats would be the go.

[MTC]

So...unless planing to slap on a blower or a turbo the difference is insignificant?

Well No My Senator Sig is blown & going from full HM system with 1 3/4 headers & 2.5inch exhaust. to 1 7/8 pacie's, ballistic's & KPM 3inch. got zero gain.

So all I gained was a shiny exhaust with nice tips & a better sound.

[HRT 8]

Bolting up a bigger set of headers will reduce your droning, so bolt up a set of 1 7/8 4-1's with some better higher flowing cats would be the go.
The exact opposite occurred when I installed 17/8 headers and cats to my WM.
It not only got louder, but droned worse.

[AMADR8]

in my opinion the only benefit out of the 1 7/8 headers over the xforce stepped header is that u no longer use the shitty xforce cats. They could possibly be the reason u are getting drone. i started getting drone in my car with the full xforce system, but after i changed headers and cats it dissapeared, i am assuming it was because of the cats because they shat themselves about a week after i sold them, but i could be wrong, thankfully he got them replaced under warranty tho.
Personally i wouldnt change anything done to your car hotboz, i know the car pretty well and pretty much everything about it is perfect. i dont think u will see too much of a noticeable gain out of the higgins head

[SSV8TE]

I know the car pretty well too and have driven it quite a few times and i dont think you would see much of a change going to 1 7/8 pacies.
The note is awsome at idle and full noise and goes hard as.
Personally i wouldnt change it outside of a blower.
Cheers,
Andy.

[chev]

As the boys have said big fella, the biggest draw back with the xforce was the small cats which we had a lot of problems with. We still remove these cats in service and inspect for damage. We believe the 366ci prefers the 1 7/8" long tube with a freeflow cat design with either 2 1/2 or 3" catback depending on what sound needs to be achieved, but still might not give the extra torque you are searching for.

I have had a set of custom made 2" primary headers made for the clubby with race cats but wanted to retain some noise credibilty for the family, thats why I decided on 2 1/2" full custom catback.

Hope this helps.
Cheers Chev

[Black Diamond]

As Boon said before, when we first did the cam/head package on my car, i ran the Xforce stepped headers, cats and 3" pipes.
Then after a couple of Xforce cat failures i went the full 3" KPM system with the 1 7/8 pacies.

Apart from the absolute improvement in sound quality, i actually found that i lost a little bottom end but gained a lot more mid/top end power which couldve been the cats, and a hell of a lot smoother which i put down to the headers.
Dyno showed it did not jump in power, but torque did as you would expect.

The KPM is simply the best sounding system out there. I continously get people commenting at lights on how deep it is, including ford heads.
But as Wonky and Andy said, yours is probably the best sounding Xforce system ive heard and i know everyones interpretation on drone is different, but i have driven and been in your car many times and i cant remember it droning, but like cam said maybe the cats have flogged out and caused it to.
cheers John

[klink]

I may be way off base here but doesnt the collector length adjust the power band marginally?

longer collector without going rediculous wouldnt that help bring the power on 500-1000rpm earlier without effecting the top end power?

ie: leave the collector pipe at say 3inch diam then use 3inch pipe back to the cat etc then tapper it back to 2.5 to assist back pres.

just my interpritation of what i read somewhere

[SAMCRO]

I don't believe my cats have sh@# them selfs as Chev did a service and tune touchup on it just before Xmas and as he said they inspect them when the car is serviced. The only time I get the drone is when car is traveling at 1800 - 2000 rpm especially if you accelerate without changing the gear. It is very noticeable, especially in 4, 5 & 6 gear. Seems like every car reacts differently, doesn't it? Maybe I should just leave it as is and do something about it when the cats S@#t them selfs... I do love the sound of it, but every time I hear KPM I have a meltdown.. :):) so, so good!!:goodjob:

[SAMCRO]

As the boys have said big fella, the biggest draw back with the xforce was the small cats which we had a lot of problems with. We still remove these cats in service and inspect for damage. We believe the 366ci prefers the 1 7/8" long tube with a freeflow cat design with either 2 1/2 or 3" catback depending on what sound needs to be achieved, but still might not give the extra torque you are searching for.

I have had a set of custom made 2" primary headers made for the clubby with race cats but wanted to retain some noise credibilty for the family, thats why I decided on 2 1/2" full custom catback.

Hope this helps.
Cheers Chev

I'll come down sometime next week Gary to speak to you :) and I might have a Tex "Z" grip under my arm too ;)

[etrocket]

Did any notice going to bigger pipes they lost down low zip

[Wonky]

Did any notice going to bigger pipes they lost down low zip

Very interesting comparison video done professionally by HPF on a VE LS3 Senator showing no loss, in fact even a small gain down low plus the expected gains up higher when going larger and larger. http://www.ls1.com.au/forum/showthread.php?t=141705

[SAMCRO]

Very good vid Wonky. I like both VCM and Difillipo. vcm is quieter and its also 100 % legal hence the short headers to retain the sensors in the same position. But then DIfillipo.. I wouldn't mind it at all :):) Your KPM Wonky :drool::drool::drool::drool::drool:

[Wonky]

DF on your car would most likely be a problem though as their VE extractors hang quite low. That, plus a bit of drone when he went from 2.92 to 3.27 diff, is why Boon (DCV1NU) sold his full 3" DF and got a full KPM 3" which he's rapt in. On the dyno and at idle his DF system sounded great, but on the road something sounded not quite right. One day at Chev's there were a few of us out the front when he left and we all just sort of looked at each other with puzzled looks.

[Podge]

hey hotboz, as you know, i have the KPM system... i have a feeling it wont match up but if it does, we can rip mine off one Sunday and put it on yours for an hour or so to see how it sounds if you like

[Wonky]

I doubt it will either - PM sent.

[SAMCRO]

hey hotboz, as you know, i have the KPM system... i have a feeling it wont match up but if it does, we can rip mine off one Sunday and put it on yours for an hour or so to see how it sounds if you like

Hey mate how you been? Thanks for that. That would be really good, but I'll find out first if KPM will bolt onto Xforce headers and cats. If they match we could do it after that.? Where would we get it done?