Bob - why are ported headers "cutting corners"?

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

 

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:

 

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.

 

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

 

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

 

Keith : Get in touch with the BBC. They are looking for a real comedian to take over from that poor sad person Johnafon Woss.
Andrew : What power are you at just now ?

 

No need for the BBC when you have SN Harvey

 

Hi Harvey - a tad over around the 400bhp mark estimated from delta-dash. I can be more specific week after next when I have a power done on the RR

 

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.

 

That's a great offer for someone and I'd be surprised if you don't get lots of people forming a queue

 

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.

 

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

 

The largest critic seems to have quietened down of late Harvey...

 

nice read,

 

Ditto that m8.

Be interesting to hear the opinions of tuners such as Andy F, Bob R and JGM on this subject

 

Post 33 show a article by Andy F for Scooby Mag

 

hi harvey
after coming up with granby to have his headers and up pipe i would be interested in trying your tubular headers are they ceramic
steve

 

iirc harvey does gt specs, wrapped & unwrapped eureka

 

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.