Hi guys,

I've got a version 3 WRX running around 330bhp. When I did the mods to up the power I went with a varity or bolt on mods including a set of equal lenght tubular headers and an up-pipe with a flexi fitment in the middle.

I was very happy with the power out put but the spool was shocking not really coming on song much before 4k rpm.

Now I've done all the checks, and its not a mapping problem or mechanical problem, and every tuner I've spoken to said its the headers. Going on to say tubular headers are good bits of kit but only for cars 500bhp plus, anything lower and they just increase spool time. I thought equal lenght headerswould be a good thing.

Hearing this I was thinking I only needed to get a new set of headers to sort the problem, but the tuners went on and also said that becase of my plans to twist the turbo in the near furture the up pipe I've got fitted will need to be change too, going for a sold pipe instead over the flexy fitting.

Has anyone ever experienced similar problems with incresed spool time when fitting a set of tubular headers. I'm not too sure what to do, change the headers or not, change the up-pipe or not? Advice please???

 

iv recently fitted tubular un equal length headers to my MY99 uk turbo coz the standard headers were burst, i havent noticed any increase in spool up time, just a slight noise increase when booting it!:P

 

Harvey's the boy to speak to I reckon. Granted, he sells his own up pipe and ported headers, but in my experience he'll offer you good, honest advice without trying to push his own products on you (unless that;s what you want, I guess!).
Yeah, I think I remember hearing/readin that about the tubular being good for high BHP cars and less so for the lower spec ones.

 

I think the type of headers makes a difference.I guess if they have the flexi pipe then their the cheap ones.I had a set with the flexi bit and they cracked within 3 months on my last scoob.
I wouldn't change them untill you fit the rotated turbo,see what options you have then.

Mit

 

What spec is you car? Yeah the noise increase is OK, but as mine are equal lengh, I lost the burble sound which is another bad point.

What type of headers did you get who from? Do you have a fexy fit up-pipe?

 

Thats the thing apparently I can't twisted the turbo, with a flexy fit up pipe?

 

im not sure wat type they are coz i bought them from a mate, it does have a flexi fit up pipe.

 

I think it depends alot on what turbo and power your running. I fitted a set on my last car (td04 equipped) and the spool up was awful and the car lost top end power, even after a map tweek so i got rid of them and went back to a standard set up.

I now have an unequal length set on my current car. Different turbo(td05/18),power out put etc. And when i fitted them spool up is exactly the same although top end power is much better. This car was running ported o/e headers.

 

It's all down to the quality, by the sounds of it they were a cheap set (because of the flexi joint). If the internal diameter of the primary tubes is too big etc then the spool up will be affected, same goes for the diameter of the up-pipe.
Unfortunately the cheapo (normally made in the far east) sets are sold on flea-bay by companies that are just producing something that looks the part without all the R&D that goes into producing something that actually performs better than the OE equipment.
You will need a different up-pipe when and if you twist your turbo so wait until then to change it. The other thing that gives away cheap and inferior manifolds is that normally the cheapo brands only have a 2 bolt flange where the up-pipe meets the manifold collector. If you do go the twisted route (and it is only a 2 bolt) then this flange will give you further problems, you really need a 3 bolt flange which can only be done by changing the complete manifold again.

 

Hi Mate. Got your PM which I will answer in detail tonight but what you do not need is a twisted turbo kit for what you are planning. You can post anything in the PM on here after I answer it but I have a bit of shipping to do for deadline.

 

I ran a set of ported (by Harvey) OEM headers on my TD05 16G at 325 BHP with good spool up

I moved over to Roger Clark tubular headers when I swapped over to the TD05 18G and again it's no slouch. It might be the well made headers (for that read expensive) or Bob Rawle's mapping

Shaun

 

Mine have a three bolt flange, and weren't cheap I got them from Scooby Sport so I thought they'd be good quailty.

 

If you have tubular headers with a 3 bolt flange they are probably what you want to run your MD321T but most certainly not what you need to run your TD05.
Did you get my PM?

 

PM recieved and replied to. Thanks for your Help.

 

My TD05-16g with tubular unequal length headers = 1bar by 3400rpm and full boost soon after (in 4th).

Proven to work very well.

Andy Forrest says there are "significant gains" with tubular headers over 340bhp.

 

Here is the information already given by P.M.

Twisting the turbo does absolutely nothing to improve spool. The reason for twisting the turbo is to allow you to fit a bigger turbo to the Subaru engine than can be accomodated in the normal position.
What model and year is your car?
The 2 litre Subaru and 2.5 can take the MD321T turbo in the standard position although it might be necessary to cut away some of the webbing that joins to the bell housing. This is no big deal. So for turbos up to the size of the MD321T there is absolutely no point twisting the turbo as that is an expensive exercise on its own.
Your existing turbo will be spooling late for a number of possible reasons but tubular headers generally add 350-500 rpm to the spool point. In 4th gear on a 5 speed box I expect a TD05 16G OE turbo to hit 1 bar around 3100 rpm on a level road. Any later and there are issues. These issues are usually tubular headers, too big an uppipe, restrictions or pipework issues too or from the intercooler or poor mapping.
Without seeing your car I cannot identify the issues for sure but I do know that ported headers and matched uppipe will show a big improvement on what you already have.
What ECU do you have and who mapped it?
If you want further input please give me your full spec including model year and all relevant mods and what you propose. With all supporting mods the TD05 16G can get to around 350 bhp and with all supporting mods the MD321T will do something around 450 bhp and perhaps a bit more. I have had good results from this turbo on 2.5 litres but have not been impressed with it on 2 litres and there are far cheaper alternatives with similar power.
Whereas ported OE headers are the best option for the TD05 16G, 18G and 20G and any other turbo up to and over 400 bhp, by the time you get to 450 bhp , tubular headers become a good option but you have to ensure you have the right tubular headers to get the performance to match your turbo.
I have quality tubular headers with 3 bolt flange and special uppipe for this purpose and these can be supplied DEI heat wrapped. Headers £335 and wrapping £85 but I would suggest your first priority has to be getting the best out of what you already have and ported headers and matched uppipe exchange is £369 but let's look at your spec and see if there is anything obvious to start with.
Regards,
Harvey

 

I'm not hitting 1 bar in 4th gear until 4k rpm. Although it is a real agressive pick up, and full boost comes in 4100-4200rpm

 

OK mate. There may be other underlying issues.
Where are you based ? Clacton where all the Essex girls are ? A bit far to travel either way although another night out in Colchester could be fun
Let me have your full spec and see the last PM that may have crossed with this.

 

Full spec is on My Scooby Page, thanks for al your Help Harvey really appreciated.

Yeah, Darlington is a bit of a trek, but if you are ever down this way I'll make self availble.

 

Real nice spec and obviously your pride and joy. I have a very similar 95 WRX Wagon in silver but it has had a bit harder life.
Will send PM.

 

Are these the type of headers you need me to get?

Subaru Impreza Standard Headers/Exhaust Manifold on eBay, also, Subaru, Car Parts, Cars, Parts Vehicles (end time 24-Sep-08 17:58:58 BST)

When I removed my old ones, I had this type fitted.

Subaru Impreza WRX / STi / EJ20 STANDARD HEADERS on eBay, also, Subaru, Car Parts, Cars, Parts Vehicles (end time 23-Sep-08 16:43:07 BST)

Does that matter?

 

Get what is cheapest. As long as they do not have holes and you do not need the uppipe.

 

All paid for, touch wood these sort of the problems I've been having.

 

I juts got this PM from Mo;

Jiffy,

from your pictures it looks like you run a TD05-16G, this has a lower boost threshold than a TD05-20G which I run on my car. My car is a MY94 UK2000, it still runs a 2.0ltr although it has STi3 heads - check out my spec for full details.

The reason for the PM is that no-one has suggested the mapping or boost control system being at fault with your car - I suggest this as my car runs the very same equal length headers as yours (slip jointed with twin pipe uppipe), sold by Scoobysport and manufactured by Heywood and Scott. I also run an RA low ratio gearbox so my 4th gear should produce a lower load than your 4th gear yet my 20G still sees full boost (1.6bar) when your 16G only just manages to produce 1bar.

If my large(r) turbo has a lower boost threshold than yours how can your headers be at fault? My car has been built and prepared by Mocom Racing over in North Weald, my next port of call would be to seee them before laying out any cash on further modifications.

Hope this helps and all the best with your motor

Its a good point, I did have my Apexi power fc and AVCR mapped by Engine advantage with the headers on. That was my next port of call, although I have already discussed the matter with Paul HILLS and from a little test he told me to perform we worked out it was a mecanhical problem over a mapping problem.

 

Post 16. I guess Mo missed this bit.

 

I would be looking at solving the problem first and see what the car is like.

If the headers are not faulty, I wouldn't be replacing them just yet.

 

I've got the headers on order now, if i bolt them on and the problem goes touch. If not I'll go and get the map looked into.

This way I can be sure, plus when I go for the 2.5 I'll still have the headers for that coversion.

I don't think it is the map, and from all the reading I've done I do think it is the manifold. If its not, not sure what else it could be as I've tried all the simply stuff, and obvisous answers.

Heres hoping.