wrighty338

iTrader: (33)

As suggested by the man himself. id like opinions from people who have run BOTH harveys headers and a set of tubular headers. on their subaru's

Also people running either Harverys headers OR Tubular headers (gruppe s/gt/other)

Reason i ask is because, when i asked for advice on tuning my uk turbo to 350bhp, people said buy a vf34/35 turbo and supporting mods - iv now got a vf34, hybrid fmic, walbro 255. 3' turbo back decatted exhaust and an apexi PFC Im also getting nismo 550cc injectors, an apexi avcr boost controller and possibly a fuel reg and deffinatly some headers! (cars a project, iv not just slapped stuff on and run it )

Now im told matching tubular headers with a vf turbo is like shooting yourself in the foot as you wave bye bye to quick spool (yet this is a quick spool turbo) im also told a TD05 turbo would be better..yet when i asked people suggested a vf and not a td05 as it would be do more damage then good?

So opinions please from people in the know to help me make a decision on whats right for my motor (not from people not. as i get the feeling certain members dont actually have a clue! ) Id really a nice manifold wrapped up thats going to give me a decent performance gain to reach my goal.

Any info on what youve got / had and ups/downs from these is appreciated!

Jon

RA Dunk

it depends who you talk to and what day of the week you talk to them on peoples opinions vary!, many people have many "different opinions" as to whats hot and whats not, people on here will tell you many different things

so by your above post your going to get many different people telling you many many different things all over again (shooting your self in the foot springs to mind here)

if you want the best advice as to how you want your car, ask a reputable tuner

GC8

My opinions are pretty constant. Most fabricated manifolds are sh*te and I believe that most people will see a better return (and far greater longevity) by having their standard cast manifolds improved by Harvey Smith.

'tubular headers' (sic) belong with VTA air bypass valves and cone filters.

wrighty338

iTrader: (33)

hey whats wrong with my apexi power intake and hks sqv?

stevebt

iTrader: (8)

I think the aftermarket headers are better for the car in the long run. I have always used the groupe s headers. From what I know you "can possibly" loose say 400rpm of spool from using aftermarket headers but when you use aftermarket headers you can run more boost so the car will be quicker. You will make more power with the car on aftermarket ones than ported standard ones. Its pointless someone saying I got the same power as X and I have Y as each car is different even with the same mods. I'm basing what I say on john banks mapping experience of his old car when he did back to back tests with his 20g turbo!

Here is a thread about aftermarket headers and harvey agrees with me

https://www.scoobynet.com/general-te...d-headers.html

lunar tick

iTrader: (2)

I ran Harvey's headers on my STI Newage (VF35 turbo) together with all the usual supporting mods and they were excellent - the car was running just over 340bhp. When I later upgraded the turbo to a 321H, I retained the headers and also achieved good results. However, at a later date I switiched to tubular headers (Gruppe S) and with a remap, gained significant extra mid and top end grunt. I lost about 200rpm of spool if that, so on balance I was very pleased.

My overall impression therefore is that for most applications (ie up to the mid 300s in bhp), Harvey's headers are an excellent choice. However, for even higher power applications (400bhp and beyond), tubulars can give you very real gains, albeit with a small loss of low down spool

Aztec Performance Ltd

iTrader: (234)

I had some ported headers when I was speccing mine a few years ago.

They never made it onto the car as I didn't want to cut corners, so chose tubular ones instead. Car is great, sentiment to that is not needing to change the spec of it since it was first done years ago.

For anyone going for mid 300s I would suggest decent quality tubular headers. This is in line with what one of the UKs' best tuners views on it also.

Andy Forrest:
"Mild porting of the internal passages can give some limited improvement to power and turbo spool up. For cars running over 340 bhp there are considerable gains to be had from fitting tubular headers and matching up pipe.
Most designs are unequal length and still retain some of the traditional “rumble” but blend into a super bike type wail at higher rpm."

vindaloo

It's difficult to figure out what's a good choice. IMO most, if not all, USA headers (reputable), are designed with the USA STI in mind, a 2.5 litre engine. A USA enthusiast may live with the 200-400 RPM spool increase on a 2.5. Particularly if they then claw some of it back by derestricting the exhaust and fitting a sportscat or cats.

I think the rule of thumb regarding power is a good one. Unfortunately, that leaves us running a TD05 16 or VF28/34 etc in the middle ground, where anticipated usage of the car influences the decision.

J.

Peanuts

iTrader: (15)

imo the talk about losing spool on tubular headers is mostly down the the stupid bloody sizes of the up pipes.
Too big and it creates a step and makes the air flow turbulant.

I ran with Harvey's ported headers at approx 300 and they were fine.
I changed to tubular and lost no spool of note and with remap was able to stretch its legs more in the mid and top ends.

wrighty338

iTrader: (33)

nice on guys keep them coming

harvey

iTrader: (48)

I have no problem with people commenting about my ported headers and matched up-pipe IF THEY HAVE ACTUALLY HAD A SET OF THEM ON THEIR CAR ie my headers and up-pipe, otherwise comments from the likes of Bob5 are not valid.
Plenty people are running these successfully well over 400 bhp. Also remember these headers have evolved over a period of time with several flow bench sessions so the latest guise have been in existence for about 18 months.

Wrighty, I stake my reputation on what I say and I will put my money where my mouth is. You fit a set of tubular headers to your car, I can supply these for £335 if you wish. Come here via Northallerton and put your car across their rolling road at my expense. I will then remove your tubular headers and fit a set of my ported OE headers and matched uppipe and you can go back to Northallerton for a further rolling road run at my expense. If at that point you want the tubular put back on I will do that FOC but if you want to keep the ported you buy them off me at the published prices.
This will demonstrate to everyone the performance differences between tubular headers (which I also happen to sell) and my ported OE with matched uppipe. I happen to know that up to and over 400 bhp there are clear advantages from the ported headers.
So let's keep to those who have had my headers fitted and here is a genuine open offer.

172sport

iTrader: (6)

Also dont for get the cracking issues with tubular manifolds, most are made from very cheap 304 grade stainless steel. You really want them made from inconel but it will cost you......

stevebt

iTrader: (8)

EHHHH????? I have never had a set of my groupe s headers crack and I have never heard of a quality set of headers crackinng ???

ade_sti

iTrader: (2)

just removed a gt spec set of headers from my car - 6 weeks old - the car actually lost a few torque, but gained 9 bhp. However the car was pants below 3,500K and that is with TD04. Changed it for ported headers and custom up pipe. Now full boost (1.25bar) in 2950 rpm in 3rd gear, and full boost at 2500 in 5th. Have to say unless going for TD05 18 G upwards I would not bother with tubular headers. up pipes are over 50mm in most, yes your car will hold power better at high rpm if mapped properly but you will loose lower to mid power.

I would get Harveys headers if I was you - don't make my mistake unless you want well over 350 bhp then the tubular would be good choice as bigger turbos make power higher up.

You need to pick what is best depending on the turbo - small turbo - standard or ported headers. You need to get the best out of the turbo. No point loosing bottom end if a road car, but if you want out and out power then you will ultimately get better reults with the tubular headers as the ported ones will not to able to flow enogh exhaust for big bhp figures - over 400bhp.

harvey

iTrader: (48)

Bear in mind that I have done back to back trials. 420 bhp ported O/E with matched up-pipe and 422 bhp on GT Spec tubular. The car was far faster and spooled 300 rpm earlier on the ported and these are staying on the car as it is by far the best option.

Turbotits

iTrader: (2)

I had Harveys ported header on my sti running with the standard vf35 and mapped for them. They were good and increased spool nicely. I then switchd turbos to a td05/18 and had the car mapped for it. The mapper felt the headers were maybe holding the top end and mid range back a little, Spool was still excellent.
I switched headers to a set of lateral performance ones which were also wrapped and then of to the mapper again.

Ive lost about 2-300rpm in spool which isnt noticable on a road car and gained 20ft/lb torque through the mid range and about 20bhp at the top end.




Certainly a noticable increase and feel with the lateral headers but i dont think they would have had that effect had i still had the vf35 fitted.
I think matching the turbo your running to the right headers is important and its just not a case of one set of headers will work well on every turbo.
vvt also plays a part and cars without vvt may suffer more from loss of spool with aftermarket stuff.

wrighty338

iTrader: (33)

Thats an excellent offer harvey, but my cars not gonna be seeing the road / mapper / rolling road til about may

wrighty338

iTrader: (33)

Thanks for that i arnt sure how long my UK box and engine will last, im sorta planning ahead, my mods are going to have potential for MORE then what im aiming for, as if my bottom end lets go or box for instance...il be having an STI lump in there

lunar tick

iTrader: (2)

Couldn't have put it better myself

Turbotits

iTrader: (2)

Wrighty, I stake my reputation on what I say and I will put my money where my mouth is. You fit a set of tubular headers to your car, I can supply these for £335 if you wish. Come here via Northallerton and put your car across their rolling road at my expense. I will then remove your tubular headers and fit a set of my ported OE headers and matched uppipe and you can go back to Northallerton for a further rolling road run at my expense. If at that point you want the tubular put back on I will do that FOC but if you want to keep the ported you buy them off me at the published prices.
This will demonstrate to everyone the performance differences between tubular headers (which I also happen to sell) and my ported OE with matched uppipe. I happen to know that up to and over 400 bhp there are clear advantages from the ported headers.
So let's keep to those who have had my headers fitted and here is a genuine open offer





great offer but i dont think you can just bolt them on and see the max or minimuim benifits from them with out mapping

harvey

iTrader: (48)

I agree with you but it will give a very clear indication of the potential and if the car already has tubular headers on it and is presumably mapped for these when the ported items go on they will be at a slight disadvantage in that the car is not mapped for them but it will show clearly their potential. Having done this exercise on a number of occasions there is absolutely no doubt in my mind as to the outcome which can only be good advertising for me.

Ginge !

iTrader: (1)

are ported headers also recomended for classic STI's ?

i plan to get more power from mine soon as i got a list of parts i need to sort out first, currently holding 1.1bar and is "ok" power wise but want more from it, they exhaust is currently blowing and i need rid of the cats soon anyway

is these any benifit on a classic sti when looking for 400ish bhp

sorryto hijack thread but im very close to buying a manifold

harvey

iTrader: (48)

These are fitted to STis and WRXs all the time and as far as I am concerned ported headers and matched uppipe are your best option up to whatever you can get out of a TD05-06 20G for instance. My own TD05-06 20G is doing 422 bhp and another one that I built recently was rolling roaded two weeks ago at 434 bhp !!!

Aztec Performance Ltd

iTrader: (234)

You might need to read the OPs 1st post.

I don't think you'll get many top tuners agreeing with you that porting is the best way to go for the 400+ bhp figures you quote.

Each to their own. Porting headers has limited benefits, afterall it is simply improving on what are poorly made headers in the first place. Worthwhile doing at sub/low 300s if costs are low.

Purpose made tubulars headers are better by design, with a choice of bore sizes and up-pipes to suit different applications.

GC8

In your opinion, but what qualifies it?

wrighty338

iTrader: (33)

Well, surly this qualifies it, from someone else??

trails

iTrader: (41)

I've run Harvey's headers on a sub 300bhp TD04 set up and a 350bhp plus AFP 18g set up, both drove really well and made for a fast spooling (particularly the TD04), drive. I'm now running SYMS 4-2-1 equal length on the 18g and although it spools up a little slower its not really noticeable. Seat of the pants dyno tells me the car is quicker, but its never been dynoed so I have no figures.

harvey

iTrader: (48)

Fortunately I am not a sheep so I do not have to follow the herd. When I was first involved with Scoobies 360 bhp was getting towards a top figure and I remember several of the top tuners telling me 400 bhp would be impossible from 2 litres and even if it was possible the car would be undriveable and unreliable. Some of these people are still "experts" on our forums today.
X923 AGM produced more than 400 bhp very quickly and went on to exceed 550 bhp in short order.
I have noticed that a number of tuners promote the products they sell as opposed to the best product for the job.

It is your opinion that ported headers have limited benefits. If you had tried a set of my ported headers your comment might have more relevance but I have been doing this for seven years and the headers have evolved over that period with a number of significant steps forward with flow bench testing. It is probably three years since Lunar Tick had his ported headers and they have moved on significantly since that time. You don't have the experience or knowledge to back up the statement that it might be worth doing for the sub/low 300s.

I realise you have a personal agenda, that's pretty obvious to many people but it's water off a ducks back to me.

Ginge !

iTrader: (1)

so what is the actual price of these headers then out of interest ?

harvey

iTrader: (48)

Send me your e-mail address and I will send you the standard letter with all the information you could possibly need.
harveysmith1@btopenworld.com