Hi,

As the title says, I am in the market to do some upgrades to my 05 Sti (has PPP already) and have got my eye on the Zen package in the form of an TD05 18g or 20g turbo, tubular manifolds and probably the up pipe as well.

Has anyone done a similar upgrade?
How did you find the lag with the above setup (less lag, more)?
Scooby burble - did you lose the burble?

I like the distinctive burble the car has at the moment so would love to retain it but I am not sure how much of an effect the tubular manifold has on the sound, also am I right in assuming the power band is moved higher up the rev range with the above setup?

Thanks in advance,

Fz

 

The power band will be moved upwards slightly although Paul will be able to claw most of this back with good use of the AVCS, a smaller bore uppipe will also help.
IMHO the sound is much nicer with tubelar headers, not as deep but you'll retain some burble.

 

As for torque, will this increase as much as the bhp at the top end?

 

Stick with ported O/E headers if you are going to a turbo of the TD05-06 20G level. I speak from direct experience.

 

As said , stick with the standard headers, dont follow the commercially interested advice. I know from first hand experience and £10,000s of pounds not to listen to hype. Listen to people like harvey who dont have a commercial interest and have tried the ideas themselves.
Too much commercial cr*p on here. Plenty of so called specialists waiting to line there pockets selling you things you dont need.

 

I have done exactly what you have in mind, and did this 3 years ago on a stock Sti V3 and a 20g.
Learnt a lot, and it was all DIY except for mapping.

Squeezed about 370 bhp x 350 lbft from the lot in the end.

The 20g is a bit laggy below 3500 rpm but keep it buzzing and the engine is just great.
I hillclimb my car and the class benchmark is 500+ bhp, so I need to 'up-grade' things a touch

My gearbox has survived all manner of grief with this level with no disasters.
A good clutch will be a wise move.

Getting past the commercially driven advice/temptations etc is hard going, but easier than 4 years ago when I knew so little....
There are some very straight and true dealers out there, and I was lucky in my finds in the end.

I did a massive thread in Projects section about the whole conversion.

 

have you got a link to the page about the manifold please 911

 

https://www.scoobynet.com/projects-4...tml?showfull=1

That took some finding!
Read through the first 10 or so pages and you will see it all. Not sure if all the pictures will be there but there is a lot of detail to say the least.
ie
http://tinypic.com/zwhet
Use the search a lot and you can find what you need.
Graham.

 

Thankyou for your comments. It's probably fair to say that if you've spent tens of thousands and are unhappy then you've been visiting the wrong people. I do hope that i am not too commercial for you, although it seems that once you're a "tuner" then you're either public enemy number one or the saviour of the car owning world.

From my first hand experience, I would say you need to consult with a tuner, or someone with genuine knowledge (there are lots of "experts" on here) who will be able to make recommendations based on your specific needs. I have had good results with standard headers, and either 18/20g turbos, but the newage STI cars (with variable cams) respond exceptionally well to the latest garrett based turbos, the cams reducing the lag to sensible levels. And depending on the overall spec of the car tubular headers may be worth doing in conjunction with a turbo swap.

Bottom line is it depends on what you're trying to achieve. Speak with a tuner who can recommend a setup for YOU, if you want absolute minimal lag, then the standard headers are probably the way forward. But the additional of tubular headers often results in a bigger hit of torque, held till higher RPM, once the turbo is on boost. It would be fair to say that not all turbos see a great benefit with tubular headers, but they do have their place.

As for lining pockets, everyone has to make a living, and we never sell people things they don't need, unless they really want it (and some people do just want stuff for the hell of it no matter what you tell them!).

 

My 2p worth - I run an MD321H turbo with supporting mods. Originally I used ported OEM headers, but I then opted for some tubular headers and a remap. I was completely gobsmacked at the improvement - a huge increase in mid and top end torque, with virtually no loss of spool (maybe a couple of hundred rpm at most if that). On the road, the gains were stunning - almost of the same magnitude as swapping from the original VF35 to the 321H

This is not to say that ported OEM headers aren't worth considering. Just that they may not be the best option for maximising performance in higher powered applications. Oh and the comments about specialist tuners are on the whole unwarranted and merely demonstrate the poster's ignorance. I made the mistake of listening to so-called 'expert enthusiasts' on here and wished I hadn't. I've now got it right and the car is a joy to drive. And since the name was mentioned, I should add that I have nothing but praise for Zen Performance - others may spout crap on here, but Paul quietly goes about providing excellent products and upgrades at extremely competitive prices - end of.

 

Before I did the 20g thing I ported my cast headers (I have the right deep reach high speed cutters) and the stock Sti engine was better, but not that much in my mind (I did not re-map after the work).
It was then i decided to change the turbo and a few other bits looking for 380 x 350 ish, but keeping drivability.

I feel that was achieved with the Gruppe S headers helix up/pipe.

There was a noticeable hike in everything with a Harvey supplied Hybrid FMIC over the V8 TMIC which was remapped after.
Another point: The difference btween the same 20g engine and a 3'' decat verses a 3'' sport cat (one with the biggest cat I could find) was depressing.
The sport cat killed the top end noticably.

 

I have a set of hks headers sitting in the shed that I've been meaning to put on the car but never got round to. Would they make any difference on an sti v2 running just filter and exhaust (299bhp) or would I be wasting my time?

 

Define 'commercial interest'....

 

Geoff:
imho waste of time. Set of ported headers off Harvey could work better though.

 

Mine is V2 sti ra, I fitted tube headers to car and lost HP. It was with a custom modded tdo5. On cast headers and yellow injectors I am doing 300BHP at the wheel hud on dyno pack. I believe add 70 to 80 HP for transmission loss and that puts me at a respectable number for a standard engine. The tube headers gave lag and power drop....i was surprised and dont understand why.

 

???? 1 + 1 = ??

 

I think that is called a Common Denominator!

About the fastest Impreza I know, Rob Harriman's hill climber has huge output and ported stock headers (about 440 bhp on a steel 2 litre I think).
There is a good reason for that.

We should all remember the benefits of a 3'' decat in all this, stock engines or not.

 

Rob's car is the exception. If you want a genuine 400hp, or want more power without a bigger turbo then headers should be on your list for consideration.

 

Go with Pauls (Zen) suggestions, headers and a modern Garrett turbo (MD321H or equivalent) , I'm pretty sure you wont be dissapointed

 

agree 100%

 

I put a set of tubular headers, Gruppe "S" ver 2, on my 95 WRX Wagon with my own TD05-06 20G. They were on for exactly a week and removed. What a disappointment and work for nothing, including having to lag the turbo again. The original O/E cast headers (ported) and matched up-pipe were refitted.
The lag on the tubular headers was very noticable and 1 bar boost in 4th gear was 3,600 rpm. At present that is back down to 3,300-3,400 rpm and a very respectable 422bhp on a DynoDynamics R.R.
I do run a set of Gruppe "S" tubular on my STi 6 wagon but that has a much bigger turbo and is around 600 bhp.

 

Agree, non-commercial person here, I have garrett hybrid with tube headers and she's mint...goes like ****.

 

Exactly my point, I have had dissapointing results with both standard and tubular headers, on cars where I felt that a given setup that was poor, should have worked nicely.

 

Dare i twist this good conversation please.

2.5 engine all steel and with a 321 of the right size, would not the Gruppe S headers then be better than the ported stock?
My thoughts being there is far more gas volume flowing down the same dia tubes and the smoother flow of the tube headers would start to come into their own?

Has anyone done this comparison?

I am obviously thinking of my own situation with what I have and will be going to (chasing 500 x 500 hillclimb engine, ie low down guts), Sti V3 2 litre to 2.5/StiV3 heads/cams.

 

about too..

 

I done exactly that some time ago on my 2.5 with a 321T. I picked up approx 25bhp at the same boost and lost nothing at the bottom end, if anything the engine was breathing better off boost and felt more lively.
I have found that the uppipe is critical, I have retained the std Sti uppipe at just under 500bhp, my headers are the smaller bore Gruppe S so the uppipe can be opened out to make a smooth transition from the headers, optionally the magnex uppipe at 44mm bore would be the next best thing.

Andy