Split from Harvey headers thread...advice pls!
05 November 2008, 08:02 AM
#31
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.
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.
I've always liked value for money mods and will only part with my hard earned when I can personally see that something hasn't worked or can see that the car is struggling through data logging.
I'm currently using my own home brew ported headers but with a totally standard STi up-pipe on an AndyF TD05/20g (std 2.5 STi engine). The up-pipe may be the current ***** in the armour (ran out of time in finishing mods before remap time).
However, the 380/360 results on Zens Dastek rollers and the way that power is a dead straight slope up to the rev limiter suggest that the headers aren't restricting gas flow and the standard up-pipe isn't really that bad.
If anyone can give a qualified reason that I should have used tubular headers then I am all ears.
If the engine was built to take more revs and was to be on the track then tubular headers may be on my list, but I can't quite see why the sheep like bleating of stating that tubular headers are needed on 300+ or 350+ builds helps anyone other than the seller.
Nick
05 November 2008, 03:31 PM
#32
Hi Nick,
I agree that porting a set of headers yourself will be cost effective. But if the cost is more or less the same as decent quality tubular headers then it really is a no brainer (I think someone paid £400 for a set of ported ones on the last thread).
You can improve on poorly made cast OE headers, but purpose made/designed aftermarket ones will be the best bet at that level. If you have them side by side you will see what I mean.
Tubular headers will make more power than ported headers.
Lots done on this in the past.
I took the advise from respected tuners when I specced my car years ago and am glad I did. The car is great.
You can speak to any of the top tuners and I don't think they will disagree (Andy Forrest, Zen, RCM, JGM, Mocom, etc).
Lots done in the past on this subject:
I agree that porting a set of headers yourself will be cost effective. But if the cost is more or less the same as decent quality tubular headers then it really is a no brainer (I think someone paid £400 for a set of ported ones on the last thread).
You can improve on poorly made cast OE headers, but purpose made/designed aftermarket ones will be the best bet at that level. If you have them side by side you will see what I mean.
Tubular headers will make more power than ported headers.
Lots done on this in the past.
I took the advise from respected tuners when I specced my car years ago and am glad I did. The car is great.
You can speak to any of the top tuners and I don't think they will disagree (Andy Forrest, Zen, RCM, JGM, Mocom, etc).
Lots done in the past on this subject:
Ricky, if you are looking for the best torque and BHP from your car then forget about ported headers, you will not make the same bhp although torque may be similar.
Here is a link to a car of exactly the same age and model as yours, running GT spec 2 headers. I've never seen VF35's do anywhere near this on cast headers.
A lot of the ported header promotion on here lately has been of suspicious origin
https://www.scoobynet.com/private-sa...i-type-uk.html
Here is a link to a car of exactly the same age and model as yours, running GT spec 2 headers. I've never seen VF35's do anywhere near this on cast headers.
A lot of the ported header promotion on here lately has been of suspicious origin
https://www.scoobynet.com/private-sa...i-type-uk.html
Agree with AndyF and JGM. I went from ported OEM headers to GT Spec headers on an MY03 STI running an MD321H making just under 400bhp (at that time - more now 
) and the spool was virtually identical - perhaps just a fraction later (100rpm or so). However, (with appropriate mapping) I also gained an absolutely massive amount of mid and top end torque, with no loss of low down torque. A huge improvement - night and day difference - and one of the best mods I've done.
) and the spool was virtually identical - perhaps just a fraction later (100rpm or so). However, (with appropriate mapping) I also gained an absolutely massive amount of mid and top end torque, with no loss of low down torque. A huge improvement - night and day difference - and one of the best mods I've done.all i can say is mapped by the same mapper on ported headers i was seeing around 350bhp 330torque measured on delta dash, Was advised the mapper he felt the headers were holding it back a little.
Headers replaced with lateral ones which are the same as gt spec/roger clark ones etc. Picked lateral ones cos thet were the best price wise and still excellent quality and came with a roll of wrap.
Mapped again same peice of road and now have 369 and 352
The spool point is almost identical. I cant feel a difference it can only be seen on a laptop. There is much more of a chuck in the back whenfull boost is reached. i assume thats down to the extra torque. The noise is a bit more raspy.
Headers replaced with lateral ones which are the same as gt spec/roger clark ones etc. Picked lateral ones cos thet were the best price wise and still excellent quality and came with a roll of wrap.
Mapped again same peice of road and now have 369 and 352
The spool point is almost identical. I cant feel a difference it can only be seen on a laptop. There is much more of a chuck in the back whenfull boost is reached. i assume thats down to the extra torque. The noise is a bit more raspy.
05 November 2008, 06:38 PM
#33
For somebody that has never had a set of my ported headers and matched uppipe you have a lot to say. I have already pointed out that Lunar Tick got his ported headers over three years ago and they have moved on significantly since then.
There is also a magazine article from three years ago before I had my own uppipe when my ported headers without my uppipe were compared against various tubular headers.
Now since that article was done I have invested in further flow bench time and have my own purpose designed uppipe which greatly enhanced the performance of the ported headers and this has happened since the date of the article above.
Like I said before, had you actually used a set of my ported headers and matched uppipe there might be some validity to your opinion. Your statement
is in some cases factually wrong. Ported headers are a best option in many circumstances but tubular headers have tangible advantages in higher power applications and it is for that reason that I sell both ported headers and tubular headers and I match the selection of headers to the turbo and the power aspirations of the particular owner.
As regards cost please get your facts right. The basic cost of porting headers is £115.
You clearly don't have an appreciation of what is involved in getting the best out of porting a set of OE headers.
I have done back to back tests and I know what I am talking about from a position of observation and knowledge not just supposition and I have already offered to do a further back to back test.
There are many satisfied customers of ported headers and they will continue to be a good option for many people in the same way that tubular headers will remain the choice for big power application.
There is also a magazine article from three years ago before I had my own uppipe when my ported headers without my uppipe were compared against various tubular headers.
Now since that article was done I have invested in further flow bench time and have my own purpose designed uppipe which greatly enhanced the performance of the ported headers and this has happened since the date of the article above.
Like I said before, had you actually used a set of my ported headers and matched uppipe there might be some validity to your opinion. Your statement
Tubular headers will make more power than ported headers.
As regards cost please get your facts right. The basic cost of porting headers is £115.
I agree that porting a set of headers yourself will be cost effective.
I have done back to back tests and I know what I am talking about from a position of observation and knowledge not just supposition and I have already offered to do a further back to back test.
There are many satisfied customers of ported headers and they will continue to be a good option for many people in the same way that tubular headers will remain the choice for big power application.
05 November 2008, 07:29 PM
#34
Just to clarify (as I have now been quoted twice), Harvey is correct - I had his ported headers fitted 2 and a half years ago and it's great to hear that he has developed them further. I know from personal experience that Harvey is passionate about Subaru tuning and I have no reason to doubt that the improvements since then will be every bit as significant as he says. Unfortunately I sold my earlier version ported headers - if I hadn't, I'd be very tempted to send them back to Harvey for further fettling and then try them to see how they compare them to the tubulars I now use 
05 November 2008, 09:52 PM
#35
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On a dull evening when it's wet and dark outside and there is not much of interest on the TV - these threads read with a beer or two make the whole day worthwhile
06 November 2008, 08:47 AM
#39
Let me know Andrew. I was going to offer to fit ported headers and special up-pipe but at that level you are approaching the performance gains are unlikely to show up. I need to find someone on tubular headers that is unhappy and get before and after figures just like I offered Wrighty and then put them on a set of my headers. That will shut the pundits up and be a worthwhile marketing exercise.
11 November 2008, 08:01 AM
#41
Knowing that Granby had a set of Mark 2 headers from about three years ago and did not have one of my up-pipes he was invited to make the trip up from London.
His original ported collector was replaced with the revised porting design Mark 3 and a competitors aftermarket performance up-pipe was replaced with one of my purpose designed items.
Here is what he posted elsewhere when he got home :
Remember this is an improvement over Mark 2 ported headers and a competitors performance aftermarket up-pipe, previously fitted, that already showed an improvement over the original set up.
His original ported collector was replaced with the revised porting design Mark 3 and a competitors aftermarket performance up-pipe was replaced with one of my purpose designed items.
Here is what he posted elsewhere when he got home :
Good to see you again today Harvey and thanks for fitting the uprated headers & up-pipe, initial impressions on the way home is that the turbo spools from 2600 and i'm hitting full boost by 3100 (all in fifth if that makes any difference) which are about 200-300 sooner than the last set and it does feel very strong midrange
Just for anyone that doesn't know this is my spec
2004 WRX wagon
STi intercooler
STi injectors
full decat
Harveys ported headers & up-pipe
VF34 turbo
Remap by Bob Rawle
Just for anyone that doesn't know this is my spec
2004 WRX wagon
STi intercooler
STi injectors
full decat
Harveys ported headers & up-pipe
VF34 turbo
Remap by Bob Rawle
22 November 2008, 01:44 PM
#42
Good to know that the people who actually have these headers are well satisfied. So much for the pundits who have not tried them.
Reano/Ray and Granby/Ian : Both in the same week.
https://www.scoobynet.com:80/dealer-...t-warning.html
Reano/Ray and Granby/Ian : Both in the same week.
https://www.scoobynet.com:80/dealer-...t-warning.html
04 January 2009, 11:33 AM
#49
Hi Mate, how is your car ? I think you got a Simtek not a Solaris ?
Yes GT Spec DEI wrapped or you can wrap yourself. The charge for wrapping is £95 and while that sounds a lot I assure you it is a lot of work to do it properly ie. each runner separately and it takes more than a full 50 foot roll.
In the past I have had headers ceramic coated but it was expensive but I can put you in touch with the ceramic coaters if you want.
The article referred to above related to a set of ported headers only with no uppipe and since the date of that article we have produced our own purpose designed uppipe, again with the assistance of flow bench testing. The difference in ultimate power output between a set of GT Spec headers and ported OE headers with uppipe was 422 bhp for the GT Spec and 420 bhp for the ported with uppipe. The tubular were removed in favour of the ported because the ported were spooled over 300 rpm earlier than the tubular and the car was far nicer to drive especially in the bottom half of the rev range where it spends most of its time.
The purpose designed uppipe on its own, slip jointed and DEI heat wrapped with five new Subaru studs is £139.
Yes GT Spec DEI wrapped or you can wrap yourself. The charge for wrapping is £95 and while that sounds a lot I assure you it is a lot of work to do it properly ie. each runner separately and it takes more than a full 50 foot roll.
In the past I have had headers ceramic coated but it was expensive but I can put you in touch with the ceramic coaters if you want.
The article referred to above related to a set of ported headers only with no uppipe and since the date of that article we have produced our own purpose designed uppipe, again with the assistance of flow bench testing. The difference in ultimate power output between a set of GT Spec headers and ported OE headers with uppipe was 422 bhp for the GT Spec and 420 bhp for the ported with uppipe. The tubular were removed in favour of the ported because the ported were spooled over 300 rpm earlier than the tubular and the car was far nicer to drive especially in the bottom half of the rev range where it spends most of its time.
The purpose designed uppipe on its own, slip jointed and DEI heat wrapped with five new Subaru studs is £139.
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