HM Headers, How good r they ?

[ozwild]

Looking at up grading the exhaust system on the VY SS
my neighbour works for HM headers in Hallam and has
offered a discount, just not sure the best way to go,
im looking for a better sound and of course better performance.

any ideas would be greatly appreciated, thanx.

[NOS540HQ2DOOR]

I'm using them on my vy ss with 2 1/2" manta exhaust.Made 248 rwkw (mafless tune).If you do use them make sure you use the hm-101 part number not hm-100 part number.

[Sonnymad]

They are great headers as recently on a head and cam pakage i fitted and tuned the hm tri y's made more torque than the pacie's 4 into ones.

goodluck

regards sonny

[MTC]

I've just had a set of HM headers & a Redback dual 2.5inch exhaust fitted to the wife's VY LS1 wgn last Friday. & they have given the car heaps more get up & go. & a awesome note (have not had it on a dyno as yet) but yeah feels pretty good next a VCM suite tune hmmm :driving: :D

[Falchoon]

They were OEM on Phase 3 Falcons and some Brock Commodores (not sure what models).

[ratter]

HM's used to have a good reputation as good extractors a few years ago, have not heard much lately though

[COOKIE!]

Im using there try y's and i think they are a great upgrade. Better Note better economy, More power, WIN WIN WIN in my books.
As said above go the HM101 S/S in the 2.5inch.

[Panelman]

I've got HM 4 into 1's (porcelain coated) to REMUS Racing system on my VZ SS. Had her dyno'd and putting out 222 rwkw - NO Edit yet. (soon)

We were stoked at the figure for such basic mods. Hopefully after tune she'll be up around 270 rwkw.

Happy happy happy with the HM's.

[downbylaw]

I can remember back in the 'ol days re.1998 when i was looking for extractors for my vsII v6 they were the ducks guts according to alot of the shops i went to. And i must say i wasnt dissapointed with them when i did purchase.
Although now on this site and in general it seems paccies are the preferd choice of most for the ls1.

[One tonner]

Got em too, best thing with the HMSS101 headers is you don’t have to move the O2 sensors just the cats to the series one under car position when fitting to a VYII.
These headers are a good option if you don’t want to edit the car straight away and save some $$.
But you will have to get cats as well. Ask your mate for a discount on these too. Standard price is around $550 "per" HM high flow cat.
They are also stainless steel, one of the best things I have put on my car.

[sillyoldone]

Not 100% sure but don't HM make the headers for HSV?

[Wayne@GM Motorsport]

Ive got HM S/S Tri Y's on mine

[MNR-0]

Ive got HM S/S Tri Y's on mine
Says something about headers, doesn't it. Id rather sacrifice peak power for mid-range torque anyday, and you have the timeslip to prove it.

[COOKIE!]

Not 100% sure but don't HM make the headers for HSV?


Yeah they do make them for H.S.V

[MNR-0]

HM Headers were originally Perry exhausts. They do make them for the HSV and Holdens too.

IMO these LS1s aren't that exhaust sensitive, so most headers will do their job - even the shorties.

Iv'e heard both good and bad from HM headers. The same from all the header manufacturers. The biggest gripe seems to be from the O2 sensors.

On todays modern Gen3/4s, the safest and most effective trade-off is still the short 4-1s. Noticed how there are many more headers like these becoming available now? And how exhaust manufacturers are beginning to recommend them for bolt-on streeters?

HSV
Sureflow
HM
CSV
Genie

CSV pioneered the short 4-1 design in OZ while everyone thought they would perform crap. Well they don't perform crap. Header manufacturers will be forced to comply with newer Euro specifications in the coming years, so you will see even more become available.

IMO, its the HM tri-ys or short 4-1s as they keep the O2 sensors hot due to their placement in the exhaust pipe. That, or a custom header.

[Mongy]

The one thing not stated, is it a VY series 1 or series 2 because there is a LOT of difference between the 2 exhaust systems and how it needs to be done correctly.

[SV8VY]

I've just had a set of HM headers & a Redback dual 2.5inch exhaust fitted to the wife's VY LS1 wgn last Friday. & they have given the car heaps more get up & go. & a awesome note (have not had it on a dyno as yet) but yeah feels pretty good next a VCM suite tune hmmm :driving: :DI have the same set up with the headers ceramic coated and a stainless rear muffler (to tone it down a little) Works a treat

[One tonner]

The one thing not stated, is it a VY series 1 or series 2 because there is a LOT of difference between the 2 exhaust systems and how it needs to be done correctly.

Good one Mongy but I think I covered it.


Got em too, best thing with the HMSS101 headers is you don’t have to move the O2 sensors just the cats to the series one under car position when fitting to a VYII.
These headers are a good option if you don’t want to edit the car straight away and save some $$.
But you will have to get cats as well. Ask your mate for a discount on these too. Standard price is around $550 "per" HM high flow cat.
They are also stainless steel, one of the best things I have put on my car.

Just to clarify, you can fit HMSS101 header straight up to any Gen III powered Commodore up to VYI. They have two positions for the O2 sensor one up high the other down low. You may want to get some advise in regard to standard cats mated up to headers in regard to burning out the CAT and the flange size.
With a VYII the headers can be bolted straight up and the sensors will be located in the up high position. The cats will or should be replaced and moved to the VYI one under car position.

I should also add it is always wise to have your Air Fuel Ratios checked after any modification involving intake or exhaust. A good tuner or exhaust place should Know this anyway.
HM Headers, cats and Zorsts I think are very good. Allegedly they are one of only a few that complies with emission laws. But don’t quote me ask HM themselves for any professional advise.

[ozwild]

VY series 1 ? 2002

thanx for all the info guys.
Few more $ and i am going to go for it.

[abi]

The only problem with HMSS101's on a post VY2 is the dodgy gas sampling. When the O2's are mounted high, only 2 cylinders per side are sampled(Not good).